{"paper_id":"0a84a201-9dbb-437f-b7cd-c5a5c3afafcd","body_text":"Dynamic transformations in fruit color and textural characteristics of purple-fleshed dragon fruit (Hylocereus costaricensis) across fruit developmental stages under humid tropical climate | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Dynamic transformations in fruit color and textural characteristics of purple-fleshed dragon fruit (Hylocereus costaricensis) across fruit developmental stages under humid tropical climate Shameena Sajitha, Geetha Lekshmi Prabhakaran Radhamma, Pratheesh Pradeep Gopinath, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4839398/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract The purple-fleshed dragon fruit ( Hylocereus costaricensis ) is rapidly emerging as a ‘superfruit’ due to its striking color, exotic appearance, refreshing taste, exceptional nutritional and medicinal benefits, vast adaptability, and ease of cultivation. The fruit undergoes dynamic color transformations and changes in the physical attributes throughout its maturation stages, which are influenced by species and growth conditions. The study comprehensively examined color parameters and their correlation with peel characteristics and fruit and pulp firmness in the purple-fleshed dragon fruit grown under humid tropical conditions. The detailed analysis of color parameters, such as L*, a*, b*, and C* values, and hue angle, provides a clear depiction of the fruit's progression from green to purplish-red hues during maturation, with a distinct shift in color intensity and purity. The asynchronous color transition in the fruit and pulp highlights the complex nature of fruit maturation, with the pulp exhibiting an earlier color change at 25 days after flowering, followed by fruit peel at 27 days after flowering. Additionally, the investigation documented a reduction in peel thickness, peel percentage, and firmness during fruit development that emphasized the importance of these parameters in determining optimal harvest maturity. By elucidating these changes and their interrelationships, the research offers valuable insights for optimizing the harvest with better quality and marketability of purple-fleshed dragon fruit. Biological sciences/Plant sciences Biological sciences/Plant sciences/Plant development Biological sciences/Plant sciences/Plant physiology Figures Figure 1 Figure 2 Figure 3 Figure 4 Introduction Dragon fruit, popularly known as Pitaya, is a climbing cactus belonging to the Hylocereus genus of the Cactaceae family. This genus comprises 16 species, primarily classified based on their peel and pulp color. The four most cultivated species 1 are (i) Hylocereus undatus (white-flesh with pink skin), (ii) Hylocereus polyrhizus (red-flesh with pink skin), (iii) Hylocereus costaricensis (purple-flesh and pink skin) and (iv) Hylocereus (Selenicerus) megalanthus (white-flesh with yellow skin) 2 , 3 . Dragon fruit is notable for its anti-inflammatory, anti-spasmodic, and radioprotective effects 4 and antioxidant, anti-microbial, anti-cancer, and anti-diabetic activities 5 . This has led to growing global interest and expanding its cultivation into non-traditional areas with suitable climatic conditions. Although native to Central Mexico and South America 6 , it is now successfully cultivated in South Asian tropical countries, including the Indian continent, which offers diverse agroclimatic conditions conducive to its growth 2 . The fruit’s ability to adapt to various growing conditions and its high economic return further contribute to its increasing popularity and economic value 7 . The fruit is consumed as fresh or processed into jams, jelly, beverages, juice powders, and wine 8 . Even though different colored pitaya fruits are cultivated, the dark pink/ purple-fleshed species ( Hylocereus costaricensis) is gaining momentum due to its attractive, vibrant color, unique exotic appearance, refreshing taste, and promising nutritional and functional properties. The distinctive pulp and fruit color of H. costaricensis is mainly due to the presence of betalain pigments, which are rich in antioxidants 9 . As the dragon fruit is non-climacteric, it must be harvested at optimum maturity to ensure fruit quality. A spectrum of color changes occurs in the fruit and pulp during the growth and maturation of dragon fruit 10 . These color transformations serve as a critical indicator of fruit growth and maturity, which determines consumer acceptance 11 . In red-fleshed dragon fruit, significant color changes occurred under the distinct climatic conditions of Malaysia, highlighting the relationship between color development and fruit growth 12 . Similarly, Magalhaes et al. 13 observed substantial changes in textural and peel characteristics of dragon fruit in the isoclimatic conditions of Brazil. Several authors have reported that the edaphoclimatic conditions of the cultivation site caused variation in color development and fruit growth 14 , 16 . The fruit color, pulp color, and texture are the key factors in determining the optimum harvest maturity, which affects the fruit quality, consumer acceptance, and shelf life of dragon fruits. Since the climatic conditions in the growing region greatly influence these factors, studying the changes when an exotic crop acclimates to a new geographical location is essential. The purple-fleshed dragon fruit ( Hylocereus costaricensis ) is a relatively new introduction to Indian humid tropical climates, which differs significantly from the climate of previously studied regions. Hence, the present study comprehensively investigated the dynamic transformations in the fruit (peel), pulp coloration, and textural characteristics across developmental stages of purple-fleshed dragon fruit grown under a humid tropical climate. The insightful knowledge obtained from the study will be paramount for addressing issues related to fruit management, quality, and harvesting of purple-fleshed dragon fruit grown in humid tropical locations worldwide. Results and discussion The fruit's L* values refer to its ability to reflect or transmit incident light, with high L* values indicating a lighter color and lower L* values indicating a darker color. In the present study of color parameters in H. costaricensis (purple-fleshed dragon fruit), the L* value initially increased from 42.46 at 10 days after flowering (DF) to a peak of 48.00 at 26 DF, then decreased to the lowest value of 36.20 at 32 DF (Table 1 .). The reduction in L* value during growth and developmental stages indicated increased pigmentation. A significant change in the fruit L* values observed at 27 DF (Fig. 1 a) indicated the onset of fruit pigmentation and transition of color from green to red. The lower L* values during the later developmental stages were due to the progression of pigmentation and the development of a reddish color in the fruit. These findings were consistent with previous studies on different species of pitaya, where in red pitaya, the L* values decreased from 51.63 at 20 DF to 38.23 at 45 DF 16 . White pitaya values ranged from 51.18 at 7 DF to 37.93 at 41 DF 20 , highlighting the typical L* value reduction pattern associated with increasing pigmentation during fruit maturation. Table 1 Changes in fruit and pulp color in H. costaricensis during fruit maturation. DF Fruit color Pulp color L* a* b* C Value L* a* b* C Value 10 42.46 d -8.14 g 15.76 ab 17.74 ef 92.85 b 1.20 g 13.19 b 13.24 f 15 42.92 cd − 7.50 fg 15.89 ab 17.57 ef 96.04 a 2.09 f 19.46 a 19.57 e 20 43.75 c -7.87 fg 15.22 a 17.13 fg 57.83 c 3.46 e 2.39 c 4.21 d 25 45.86 b − 8.11 f 16.03 b 17.96 e 40.78 d 15.89 d -6.60 g 17.21 c 26 48.00 a -8.56 f 14.46 c 16.80 g 27.00 e 26.63 c -7.72 h 27.73 b 27 39.19 e 10.41 e 11.57 d 15.56 h 22.53 f 27.01 c -5.47 f 27.56 b 28 37.73 f 20.05 d 7.79 e 21.51 d 22.44 f 29.43 b -5.44 f 29.93 a 29 37.59 f 25.08 c 7.65 e 26.22 c 21.75 g 29.64 a -4.43 e 29.97 a 30 37.43 f 29.16 b 6.93 f 29.97 b 21.30 g 30.19 ab -4.37 e 30.50 a 31 37.14 f 32.83 a 4.65 g 33.16 a 20.19 h 30.10 ab -4.47 e 30.43 a 32 36.20 g 32.96 a 4.42 g 33.26 a 20.25 h 30.08 ab -2.80 d 30.21 a Different letters in the column for each parameter denote significant differences among treatments at p < 0.05, as per Least Significant Difference (LSD) test. The a* values represent the color shift from green to red, negative a* values indicate green color and positive values indicate reddish color. In this study, a* values of the fruit significantly increased throughout fruit growth and maturation stages, and the values increased from − 8.14 at 10 DF to 32.96 at 32 DF (Table 1 .). A notable shift from negative to positive values was observed between 26 DF (-8.56) and 27 DF (10.41) (Fig. 1 b), indicating a color transition from green to red and a pronounced increase in red coloration after that until the end of the evaluation. Similar increasing trends of a* value based on the degree of maturity were observed in red and white-fleshed dragon fruit. The a* values of white-fleshed dragon fruit increased over time from 16.4 at 21 DF to 44.4 at 32 DF 21 , whereas in red-fleshed dragon fruits, it ranged from − 9.53 at 20 DF to 37.54 at 45 DF 16 . On the other hand, the coordinate b* of H. costaricensis fruit, which indicates the transition from yellow (+) to blue (-), exhibited a decreasing trend (Fig. 1 c). Fruit b* values declined from 15.76 at 10 DF to 4.42 at 32 DF (Table 1 .), exhibiting a reduction in yellow pigmentation. A similar decreasing trend of fruit b* values from 30.6 (21 DF) to 7.6 (32 DF) during fruit maturation in white pitaya was reported by Ortiz and Takahashi 21 , while Magalhaes et al. 14 , reported that b* values decreased from 27.31 (28 DF) to 11.18 (42 DF) with difference in the days of maturity. Similarly, a decrease in the coordinate b* of fruit was noticed in red-fleshed dragon fruit grown under iso climatic conditions 20 , with the values ranging from 31.18 to 9.10 during 28 to 42 days of evaluation. The decline in b* values with fruit growth and maturation is linked to the degradation of chlorophyll and carotenoid pigments 15 and the formation of betalains 14 , 22 . The current study revealed a distinct increase in fruit color intensity, as indicated by chroma values (C*), throughout the maturation stages. The chroma values increased from 17.74 at 10 DF to 33.26 at 32 DF (Table 1 .), reflecting greater intensity and purity of the color as the fruit matured. The observed increase in chroma values aligns with the findings of Ortiz and Takahashi 21 and Magalhaes et al. 14 , who observed a linear increase in chroma values in H. undatus . These results underscore the steady pattern of increasing color intensity during the maturation stages of dragon fruit. The analysis of fruit pulp color parameters in purple-fleshed dragon fruit also revealed a progressive change in the pulp color during maturation. The L* value of the pulp, which indicates its ability to reflect or transmit incident light, decreased significantly throughout the development stages, with values ranging from 92.85 at 10 days after flowering (DF) to 20.25 at 32 DF (Table 1 .). A marked reduction in pulp L* values was observed between 15 to 25 DF (Fig. 1 a). In contrast, in red pitaya, this reduction happened between 25 to 30 DF (Phebe et al. 13 ). The decrease in L* values reflects increased pulp pigmentation due to interconversion of pigments 13 , 16 . In the current study on H. costaricensis , seed maturation also played a crucial role in pulp color development (Fig. 2 ), and the development of seeds contributed to reduced pulp L* values 23 . As the seed color became darker in the purple-fleshed dragon fruit, the pulp L* values decreased, revealing a significant relationship between the onset of pigmentation and seed maturation. The fruit pulp pigmentation initially began around the seeds at 25 DF, following the complete blackening of the seeds. This sequence of pulp color development in relation to seed maturation aligns with the findings by Jamaludin et al. 24 in H. polyrhizus . These results suggest that the development of pulp color in dragon fruit is closely linked to seed maturation and pigment interconversion, with notable variations across different species and stages of fruit development. The a* values of the pulp exhibited a substantial increase from 1.2 at 10 DF to 30.08 at 32 DF (Table 1 .) reflecting a pronounced intensification of coloration in the purple-fleshed dragon fruit as it matured. The highest relative change in a* values and the sharp reduction in L* value in the pulp were observed from the 20 DF to the 25 DF (Fig. 1 b). This decrease in the L* values, coupled with an increase in the a* value reflected the loss of whiteness and the progression of redness in the fruit pulp. Comparable trends in red-fleshed dragon fruits, with substantial variations in a* values based on the degree of maturation, reported by Jamaludin et al. 24 . Likewise, Ortiz and Takahashi 21 documented a steady increase in a* values for white-fleshed dragon fruit, ranging from 16.4 at 21 DF to 44.4 at 32 DF. Collectively, these findings reinforce that the pattern of color development varies with different dragon fruit species and growing conditions. Conversely, the b* values of the pulp demonstrated a decreasing trend throughout the maturation stages (Fig. 1 c). The values were initially positive up to 20 DF (2.39) and became negative at 25 DF (-6.60) (Table 1 .), reflecting a transition from yellow to darker tones. This sharp decline in b* values, with a shift occurring after 25 DF, aligns with the findings of Singh et al. 16 in red-fleshed dragon fruit grown under Indian semi-arid conditions. The pulp color intensity values (C*) exhibited significant fluctuations with quadratic behavior (Fig. 1 d). The pulp C* values increased from 17.74 at 10 DF to 19.57 at 20 DF, then decreased to 4.21 at 25 DF and subsequently increased to 30.21 at 32 DF (Table 1 .). This pattern of an initial decrease followed by an increase in pulp C* values of purple-fleshed dragon fruit grown under humid tropical conditions was in agreement with the findings of Singh et al. 16 in red-fleshed dragon fruit grown semi-arid conditions, where C* values decreased from 24.8 at 20 DF to 12.9 at 25 DF and then increased from 24.7 at 30 DF to 58.9 at 45 DF. Similar trends were reported by Jamaludin et al. 24 in red-fleshed dragon fruits in Malaysia across seven growth and development stages. In the present study, the highest perceptible change in color intensity and purity was noticed at 25 DF, indicating the onset of pulp pigmentation. The fruit pulp attained full purplish red color 28 days after flowering (Fig. 2 ). This observation was consistent with the findings of Phebe et al. 13 in red dragon fruit. The present study also confirms the variation in days of expression of color intensity with species and growing conditions. The hue angle (hue 0 ), indicating where the color falls on a 360° color wheel, revealed remarkable changes during the maturation of purplish-red dragon fruit. The fruit and pulp hue 0 decreased throughout the growth and maturation stages. The fruit hue 0 values dropped below 30° at 28 DF and reached 8 ° at 32 DF (Fig. 1 e). The reduction in the fruit hue 0 in white-fleshed dragon fruit from 118° (21 DF) to 10° (32 DF) was reported by Ortiz and Takahashi 21 under Brazil. The decrease in the hue 0 of purplish red dragon fruit in the current study indicated a color change from green to red during fruit development, which concurs with observations by Jamaludin et al. 24 in red dragon fruit and by Magalhaes et al. 14 in white-fleshed dragon fruit. The reductions in hue 0 , as the fruit color changes from green to red, signal physiological maturity and the mature fruits had hue 0 below 30 ° 28 , 21 . The hue angle of purplish red dragon fruit reached below 30 ° at 28 DF, indicating the readiness for harvest maturity. The intensity of red fruit color and days after flowering is a key indicator of maturity and fruit quality in dragon fruit 11 . A study conducted in Vietnam by Van To et al. 26 confirmed that fruits with a hue 0 equal to or less than 30° were suitable for marketing, further emphasizing the importance of hue 0 as a maturity and quality indicator for dragon fruit. Overall analysis of fruit and pulp color parameters (L*, a*, b*, chroma, and hue 0 ) of purplish red dragon fruit ( H. costaricensis ) revealed a noticeable decrease in L* (luminosity), b* (yellowness), and hue 0 values, along with an increase in a* (redness) and C* (color intensity) values. These changes demonstrated a clear transition from green to a purplish-red hue throughout the fruit growth and development stages. This transformation of the fruit color and pulp color from lighter and less intense colors to darker and more intense colors during fruit maturation is in agreement with the findings of Ortiz and Takahashi 21 in white-fleshed dragon fruit and by Singh et al. 16 in red-fleshed dragon fruit. The change in fruit color of H. undatus occurred between 28 and 30 DF under Vietnam conditions 26 , while under Mexican climatic conditions, it occurred at 25 DF 25 . In Brazilian conditions, this change happened at 28 to 29 DF 21 , while in fruits grown in the tropical humid climate of India, it occurred at 26 DF 20 . For red-fleshed dragon fruit ( H. polyrhizus ) grown in Malaysia, the color change appeared at 25 DF 24 and between 26 to 27, as reported by Phebe et al. 13 . In contrast, Singh et al. 16 observed this change at 30 DF in red-fleshed dragon fruits grown under semi-arid conditions in India. However, in the present study, the onset of pigmentation in purple-fleshed dragon fruit occurred at 27 DF, with color intensity and purity increasing steadily until the conclusion of the evaluation period. These findings are in accordance with the results of Phebe et al. 13 and Singh et al. 16 in red-fleshed dragon fruits. The present study revealed that the color changes in the fruit and pulp of purple-fleshed dragon fruits were not synchronized, and pigmentation appeared earlier in the pulp (at 25 DF) than in the fruit (at 27 DF) (Fig. 2 ). Similar reports of asynchronous color development in the fruit and pulp have been observed in red-fleshed dragon fruit 16 . This pattern of color change highlights the significant impact of climatic conditions on the maturation timeline of dragon fruit across various regions. Betalains are responsible for the red color of dragon fruit 27 , and color development of the fruit is correlated with the sharp increase of betalains and the fading of green color due to a marked decrease of chlorophyll 22 . The color changes in the fruit and pulp vary with dragon fruit species and growing climatic conditions. The change in the peel characteristics, firmness of fruit and pulp in relation to color changes were analyzed for purple-fleshed dragon fruit ( H. costaricensis ). Peel characteristics, thickness, and percentage are crucial for determining harvest maturity and post-harvest shelf life. Maintaining optimal peel characteristics is vital for preserving the marketability, shelf life, and overall quality of dragon fruits 28 . In the present study on H. costaricensis , as the fruit developed its color during maturation, there was a corresponding reduction in peel thickness and percentage. Peel thickness significantly reduced from 0.73 cm at 10 DF to 0.22 cm at 32 DF, while peel percentage dropped from 68.42% (10 DF) to 18.18% (32 DF). The most substantial decrease in both peel content and peel thickness occurred between 28 DF and 29 DF, coinciding with the stage of full-color development. These findings align with previous studies on both white-fleshed and red-fleshed dragon fruit 14 , 16 , 21 , 22 . Magalhaes et al. 14 reported that skin thickness decreased linearly with maturation, with a maximum thickness of 9.15 mm obtained at 28 days after flowering, followed by a reduction to 2.96 mm at 48 days in white-fleshed dragon fruit. Similarly, Ortiz and Takahashi 21 observed a decrease in skin thickness from 10.6 mm at 21 days to 1.17 mm at 32 days after flowering. Junior et al. 22 reported a reduction in peel thickness from 11.14 (7 DF) to 3.44 mm (42 days) with advancing ripeness in H. undatus , whereas, in red-fleshed dragon fruit, Singh et al. 16 noted a decreasing trend in peel thickness from 20 DF until 45 DF. The fruit firmness is a crucial determinant of palatability, acceptability and commercial acceptance of most fruits and vegetables 29 . The decline in the firmness of fruit and pulp and peel thickness affects eating quality and post-harvest shelf life. The fruit firmness of H. costaricensis increased initially up to 20 days after flowering (DF). Then, it decreased consistently until the full-color development stage (29 DF) (Table 2 ), with no further significant difference in firmness. The initial increase in the fruit firmness may be due to the increased number of fruit cells during active growth 30 . In the studies conducted on purple-fleshed dragon fruit, pulp firmness decreased consistently throughout the development stages, unlike fruit firmness. It decreased from 1.159 N at 10 DF to 0.169 N at 32 DF (Fig. 3 ), with the fruit becoming much softer by 32 DF. A considerable change in pulp firmness was noticed after 26 DF, coinciding with the fruit color development stages. The decrease in fruit firmness was stabilized at 29 DF (Table 2 ), indicating the optimal maturity. In white-fleshed dragon fruits grown in Thailand, the firmness stabilization was at 33 days 31 , while it was 28 days under Malaysian conditions 14 and 40 days in red-fleshed dragon fruit under Indian conditions 16 . This decrease in firmness is attributed to the increased presence of water-soluble pectin resulting from the breakdown of pectin components and cell wall degradation caused by hydrolytic enzymes 32 . Table 2 Changes in fruit and pulp firmness, peel thickness, and peel percentage in H. costaricensis during fruit maturation. DF Fruit firmness (N) Pulp firmness (N) Fruit peel thickness (cm) Peel percentage (%) 10 2.088 d 1.159 a 0.73 a 68.42 a 15 3.882 b 0.982 b 0.64 b 67.01 a 20 3.981 a 0.966 c 0.63 bc 63.01 b 25 3.369 c 0.694 d 0.62 bc 60.01 c 26 1.812 e 0.542 e 0.60 c 52.21 d 27 0.967 f 0.293 f 0.52 d 46.73 e 28 0.604 g 0.260 g 0.40 e 36.20 f 29 0.540 h 0.252 h 0.35 f 28.20 g 30 0.540 h 0.241 i 0.30 g 26.20 h 31 0.540 h 0.195 j 0.25 h 23.22 i 32 0.495 h 0.169 k 0.22 i 18.18 j SE(± m) 0.017 0.002 0.010 0.636 CD (0.05) 0.049 0.006 0.028 1.778 Different letters in the column for each parameter denote significant differences among treatments at p < 0.05, as per Least Significant Difference (LSD) test. Correlation analysis Fruit color parameters, fruit and pulp firmness, and peel characteristics are interrelated indicators of fruit maturity and quality. Analyzing the correlation between these variables is crucial for interpreting their relationship and ensuring optimal harvest based on external visual cues. By comprehending these correlations, growers can better predict harvest maturity and ensure postharvest quality. The correlogram using the Pearson correlation coefficient (Fig. 4 ) illustrates the potential of using fruit and pulp color in association with firmness and peel characteristics to determine dragon fruit quality and maturity. Among the 120 simple correlations analyzed, 100 parameters were significant at the p ≤ 0.05 significance level. Based on the degree of intensity of the correlations, 60% of the analyzed correlations were strong to very strong, 38.4% were of average intensity, and 1.6% were low intensity. These results emphasize the reliability of the present findings. Significant correlations were observed between days after flowering and all measured variables. Specifically, L*, b*, and hue 0 values of fruit and pulp and fruit and pulp firmness, peel thickness, and peel percentage exhibited strong negative correlations with days after flowering. Conversely, a* and C* values of both fruit and pulp showed strong positive correlations with different development stages. Strong correlations were also noted between the color coordinates (L*, a*, b*, C*, and hue°) of the fruit and pulp and the physical variables (peel thickness, peel percentage, fruit firmness, and pulp firmness). The analysis of color parameters and physical attributes indicated a high-intensity positive correlation between L*, b*, and hue 0 values and a high-intensity negative correlation with a* and C* values. Ersan et al. 33 found that the correlation between fruit growth and pigment content in cactus pear ( Opuntia sp .) could be a reliable indicator of fruit maturity. The correlation results of the current study on purple-fleshed dragon fruit revealed that a deeper red hue in the fruit and pulp was strongly correlated with reduced firmness, thinner peel, and lower peel percentage. Specifically, as ripeness increased with the advancement of development, the color of the dragon fruit transitioned from green to a more intense red, while firmness, peel thickness, and peel percentage decreased, indicating the readiness for harvest. These observations were consistent with previous research on other species of dragon fruit, where the physical attributes were correlated to increased redness 16 . Conclusions The study provides a comprehensive analysis of the dynamic color transformations in fruit and pulp, as well as the relevance of peel characteristics, fruit firmness, and pulp firmness throughout the maturation stages of purple-fleshed dragon fruit ( H. costaricensis ) grown under humid tropical conditions. The results highlight the importance of color parameters such as L*, a*, b*, C* values, and hue 0 in assessing fruit maturity and quality. During maturation, the fruit undergoes significant color changes from green to a purplish-red hue, with asynchronous color changes between the fruit and pulp. Correlation analysis revealed that firmness, peel thickness, and fruit color are interrelated indicators of fruit maturity and quality. Increased ripeness typically resulted in decreased firmness and peel thickness and a shift in fruit color from green to more vibrant hues, signifying maturity and readiness for harvest. Understanding these changes and their correlations is crucial for optimizing harvest maturity and ensuring maximum quality and marketability. The research contributes valuable knowledge to fruit development and harvest maturity, supporting the effective cultivation and commercialization of purple-fleshed dragon fruit. Materials and Methods Experimental site Fruits from three-year-old, purple-fleshed dragon fruit ( Hylocereus costaricensis ), planted on a single-pole system (four plants per pole) at 10 x 9 feet spacing and which started flowering 15 months after planting, were used for the study. The commercial orchard was located in the Thiruvananthapuram district of the Kerala state, India, situated at 8°39'18.5\"N latitude, 76°57'43.2\"E longitude, and an altitude of 177 meters above mean sea level. The climate of the site is humid tropical, with an average annual rainfall of 1665 mm with 74–90% relative humidity. The yearly temperature ranged from 24°C to 31°C, with 7–8 hours of sunshine during the summer. The fruits were collected and analyzed at various growth and development stages, specifically at 10, 15, 20, 25, 26, 27, 28, 29, 30, 31 and 32 days after flowering (DF). The fruits were labeled individually with metallic tags on the day of flowering to track their developmental stages. The study was conducted from May 2023 to June 2024. At each growth stage, the fruits were hand-harvested in the morning at their respective growth stages, and fifteen replicates (15 fruits) were used to analyze fruit characteristics. Experimental design The employed experimental design was completely randomized, with each growth stage as an experimental treatment. Pearson correlation coefficients (r) were computed to assess the linear relationships between various parameters analyzed during the study at a p < 0.05 significance level. All statistical analyses were performed using the Grapes Agri 1 package in R 7 . Color measurement The color of dragon fruit and pulp during the various maturation stages was quantified using a Hunter-Lab Colorimeter (Lovibond). Color was assessed based on the L*, a*, and b* parameters 18 and the color values were expressed as CIE Lab* coordinates where L * denotes Lightness (scaled from 0 for black to 100 for white), a* represents redness (positive values indicate redness, while negative values indicate greenness), and b* indicates yellowness (positive values indicate yellowness, while negative values indicate blueness). Fruit color measurements were recorded in triplicate for each treatment from the fruit's middle section, excluding bracts, and averaged for accuracy. Pulp color values were recorded from the middle of each fruit half after vertically cutting the fruit into halves. The determination of color intensity, chroma (C*), and hue angle (hue 0 ) were further computed from CIE a*b* values. Chroma (C*) was calculated using formula C* = (a 2 + b 2 ) ½ , and hue angle (hue 0 ) that provides insights into color perception by consumers was calculated using formula hue 0 = tan 1 (b/a) 19 . Fruit firmness and pulp firmness The fruit and pulp firmness of individual fruits at different developmental stages were evaluated using a texture analyzer (TA. HD plus, Stable Microsystems, England). A 2.5 mm stainless steel needle (P/2N) probe was used to puncture the fruits, and the pressure required was measured and expressed in Newtons (N). To determine fruit firmness, the whole fruit and pulp firmness and the fruit without peel were analyzed at three equidistant points on the radial axis to ensure standardized and precise firmness measurement across different stages of development. Fruit peel characteristics Peel thickness and peel percentage were analyzed to determine the fruit peel characteristics. Peel thickness was measured using a Vernier Caliper (Mitutoyo 150 mm, resolution 0.02 mm) to record thickness in centimeters. Measurements were taken at different growth and developmental stages to capture changes in peel thickness over time. Peel percentage, representing the proportion of peel weight relative to total fruit weight, was calculated as Peel (%) = (Peel weight/ Fruit weight) x 100 to provide insights into the relative contribution of peel in the overall fruit structure. Declarations Conflict of interest: The authors declare no conflicts of interest. Author Contribution Conceptualisation and methodology, G.P.R, S.S and S.K.; software, validation, formal analysis, investigation, data curation, visualization, S.S., G.P.R., P.P.G., P.G. and S.K.; writing and original draft preparation, S.S., G.P.R., P.P.G., and P.G; review and editing, G.P.R., P.P.G., S.S., and S.K.; manuscript finalization, G.P.R., S.S. and S.K.; and project administration, G.P.R. and S.S. All authors have reviewed and approved the final version of the manuscript for publication. Acknowledgement The authors gratefully acknowledge the support of commercial dragon fruit farmers for facilitating the research Data Availability The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request. References Ortiz-Hernandez, Y. D. & Carilli, J. A. S. Pitahaya ( Hylocereus spp): short review. Commun. Sci. 3(4), 220–237 (2012). Wakchaure, G. C., Kumar, S., Meena, K. K., Rane, J., & Pathak, H. Dragon Fruit Cultivation in India: Scope, Constraints and Policy Issues. Technical Bulletin. (27) 47, DOI: http://niam.res.in/sites/default/files/pdfs/DragonFruitBulletin-27.pdf (2021). Abirami, K., Swain, S., Baskaran, V., Venkatesan, K., Sakthivel, K., & Bommayasamy, N. Distinguishing three Dragon fruit ( Hylocereus spp.) species grown in Andaman and Nicobar Islands of India using morphological, biochemical and molecular traits. Sci. Rep. 11(1), 2894,DOI: https://www.nature.com/articles/s41598-021-81682-x (2021). 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Food Rev. Int. 30, 1–27, DOI: https://doi.org/10.1080/87559129.2020.1742152 (2020). Perween, T., Mandal, K. K., & Hasan, M. A. Dragon fruit: An exotic super future fruit of India. J. Pharmacognosy Phytochem. 7(2), 1022–1026, DOI: https://www.phytojournal.com/archives/2018/vol7issue2/PartO/7-1-435-453.pdf (2018). Lichtenzveig, J., Noy, S., & Zilberstaine, M. The inheritance of white versus red fruit flesh color in pitaya ( Hylocereus undatus ). Hort Sci., 35(7) 1317–1318, DOI: (2000). Wakchaure, G. C., Choudhari, J. D., Kukde, R. B., & Reddy, K. S. Postharvest technology of dragon fruit. Technical Bulletin No. (41) 45 (2023). Phebe, D., Chew, M. K., Suraini, A. A., Lai, O. M., & Janna, O. A. Red-fleshed pitaya ( Hylocereus polyrhizus ) fruit colour and betacyanin content depend on maturity. Int. Food Res. J., 16 (2), 233–242 (2009). Magalhaes, D.S., Ramos, J.D., Pio, L.A.S., Boas, E.V.D.B.V., Pasqual, M., Rodrigues, F.A., Rufini, J.C.M. & dos Santos, V.A. Physical and physicochemical modifications of white-fleshed pitaya throughout its development. Sci. Hortic, 243 , 537–543, DOI: 10.1016/j.scienta.2018.08.029 (2019). Ortiz, T. A. & Takahashi, L. S. A. Pitaya fruit quality ( Hylocereus undatus [Haworth] Britton & Rose) according to physiological maturity. A review. Revista Colombiana de Ciencias Hortícolas, 14 (1), 63–75 (2020). Zitha, E. Z. M., Magalhaes, D. S., Lago, R. C., Carvalho, E. E. N., Pasqual, M., & Eduardo Val’ erio de B. V. B. Changes in the bioactive compounds and antioxidant activity in red-fleshed dragon fruit during its development. Sci. Hortic. 291, 110611, DOI: https://doi.org/10.1016/j.scienta.2021.110611 (2022). Singh, A., Swami, S., Panwar, N. R., Kumar, M., Shukla, A. K., Rouphael, Y. & Sabatino, L. K. P. Development changes in the physicochemical composition and mineral profile of red-fleshed dragon fruit grown under semi-arid conditions. Agronomy. 12, 355, DOI: https://doi.org/10.3390/agronomy12020355 (2022). Gopinath, P. P., Parsad, R., Joseph, B. & Adarsh, V. S., GrapesAgri1: Collection of shiny apps for data analysis in agriculture. J. Open Source Softw., 6(63), 3437, DOI: https://doi.org/10.21105/joss.03437 (2021). Archana R., Rani, C. I., Geetha, P., Amuthaselvi, G., Muthuvel, I., & Neelavathi, R. Value addition in dragon fruit and evaluation of the products ( Hylocereus costaricensis ). Biol. Forum Int. J. 15(8a): 180–186 (2023). Siddiq, M., Iezzoni, A., Khan, A., Breen, P., Sebolt, A.M., Dolan, K.D., & Ravi, R. Characterisation of new tart cherry ( Prunus cerasus L.) selections based on fruit quality, total anthocyanins, and antioxidant capacity. Int. J. Food Prop . 14, 471–480, DOI: https://doi.org/10.1080/10942910903277697 (2011). Lata, D., Narayana, C., Karunakaran, G., Rao, S. D.V.1., & Sane, A. Maturity determination of red and white pulp dragon fruit. J. Hort. Sci. (Online), 17 (1), 157–165, DOI: https://doi.org/10.24154/jhs.v17i1.1309 (2022). Ortiz, C. E. O., & Takahashi, L. S. A. Pitaya ( Hylocereus spp.): Postharvest biology and technology of fruit. Fruit and Veg. Phytochem., 2, 1123–1138 (2015). Junior, I. M. R., Magalhaes, D. S., Rodrigues, F. A., Pasqual, M., & Pio, L. A. S. Fruit quality and harvest point determination in white-fleshed dragon fruit. Res., Soc. Dev., 10(7), e11810716287-e11810716287, DOI: https://doi.org/10.33448/rsd-v10i7.16287 (2021). Weiss, J., Nerd, A., & Mizrahi, Y. Flowering behaviour and pollination requirements in climbing cacti with fruit crop potential. Hort. Sci., 29, 1487–1492 (1994). Jamaludin, N. A., Ding, P. & Hamid, A. A. Physico-chemical and structural changes of red‐fleshed dragon fruit ( Hylocereus polyrhizus ) during fruit development. J. Sc. Food Agric, 91(2), 278–285, DOI: https://doi.org/10.1002/jsfa.4182 (2011). Centurion Yah, A. R., Solis Pereira, S., Saucedo Veloz, C., Baez Sanudo, R., & Sauri Duch, E. Sensorial, physical and chemical changes of pitahaya fruits ( Hylocereus undatus ) during development 31 (1) (2008). Van To, L., Ngu, N., Duc, N.D., & Huong, H.T.T. Dragon fruit quality and storage life: Effect of harvesting time, use of plant growth regulators and modified atmosphere packaging. Acta Hortic. 575(72), 611–621, DOI: 10.17660/ActaHortic.2002.575.72 (2002). Le Bellec, F., Vaillant, F., & Imbert, E. Pitahaya ( Hylocereus spp.): A New fruit crop, a market with a future. Fruits 61 (4), 237–250, DOI: 10.1051/fruits:2006021 (2006). Huang, M. & Zhao, J. Recent advances in postharvest storage and preservation technology of pitaya (dragon fruit). J. Hortic. Sci. Biot, 99 (2), 115–129, DOI: https://doi.org/10.1080/14620316.2023.2263757 (2023). Sugiyama, J., Al-Haq, M.I., & Tsuta, M. Application of portable acoustic firmness tester for fruits. In: Information and Technology for Sustainable Fruit and Vegetable Production. FRUTIC 05, Montpellier France, DOI: https://doi.org/10.1080/14620316.2023.2263757 (2005). Wongmetha, C., Ke, L. S., Liang, R. G., & Chang, C. C. Fruit firmness, cell wall composition and fruit quality of papaya during postharvest ripening. Int. J. Agric. Biol., 17(2). 351–356, DOI: (2015). Wanichang, J. & Jarimopas, B. Firmness and light reflectance properties of dragon fruits. In Proceeding of the Ninth National Conference of Thai Society of Agricultural Engineering on Technology for Sustainable Agriculture and Agroindustry, Chiangmai, Thailand., 31 January – 1 February 2008. 203, DOI: https://doi.org/10.1080/14620316.2023.2263757 (2008). Su, Q., Li, X., Wang, L., Wang, B., Feng, Y., Yang, H., & Zhao, Z. Variation in cell wall metabolism and flesh firmness of four apple cultivars during fruit development. Foods, 11(21), 3518, DOI: https://doi.org/10.3390/foods11213518 (2022). Ersan, K., Yalcin, C., & Salih, A. Some physical fruit properties of cactus pear ( Opuntia spp.) that grow wild in the eastern Mediterranean region of Turkey. J Prof. Assoc. Cactus Dev. 1–8 (2004). Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {\"props\":{\"pageProps\":{\"initialData\":{\"identity\":\"rs-4839398\",\"acceptedTermsAndConditions\":true,\"allowDirectSubmit\":true,\"archivedVersions\":[],\"articleType\":\"Article\",\"associatedPublications\":[],\"authors\":[{\"id\":349287896,\"identity\":\"9542941e-2a9e-4f12-94eb-db8a5fe06c12\",\"order_by\":0,\"name\":\"Shameena Sajitha\",\"email\":\"\",\"orcid\":\"\",\"institution\":\"Kerala Agricultural University\",\"correspondingAuthor\":false,\"prefix\":\"\",\"firstName\":\"Shameena\",\"middleName\":\"\",\"lastName\":\"Sajitha\",\"suffix\":\"\"},{\"id\":349287897,\"identity\":\"8da90cd6-d99e-4f80-8521-ed838729818c\",\"order_by\":1,\"name\":\"Geetha Lekshmi Prabhakaran 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1\",\"display\":\"\",\"copyAsset\":false,\"role\":\"figure\",\"size\":411103,\"visible\":true,\"origin\":\"\",\"legend\":\"\\u003cp\\u003eChanges in color parameters (\\u003cstrong\\u003ea\\u003c/strong\\u003e) Lightness (L\\u003csup\\u003e∗\\u003c/sup\\u003e), (\\u003cstrong\\u003eb\\u003c/strong\\u003e) Redness (a\\u003csup\\u003e∗\\u003c/sup\\u003e), (\\u003cstrong\\u003ec\\u003c/strong\\u003e) Yellowness (b\\u003csup\\u003e*\\u003c/sup\\u003e),\\u0026nbsp;(\\u003cstrong\\u003ed\\u003c/strong\\u003e) Chroma (C\\u003csup\\u003e∗\\u003c/sup\\u003e), (\\u003cstrong\\u003ee\\u003c/strong\\u003e) Hue values (hue\\u003csup\\u003e0\\u003c/sup\\u003e) of fruit (peel) and pulp in \\u003cem\\u003eH. costaricensis\\u003c/em\\u003e during fruit maturation.\\u003c/p\\u003e\",\"description\":\"\",\"filename\":\"1.jpeg\",\"url\":\"https://assets-eu.researchsquare.com/files/rs-4839398/v1/442fbd4acd68544d8eb48ff6.jpeg\"},{\"id\":64031572,\"identity\":\"bbc5f1a3-ac87-4698-830b-03f4e1a706b0\",\"added_by\":\"auto\",\"created_at\":\"2024-09-05 09:19:20\",\"extension\":\"jpg\",\"order_by\":2,\"title\":\"Figure 2\",\"display\":\"\",\"copyAsset\":false,\"role\":\"figure\",\"size\":78509,\"visible\":true,\"origin\":\"\",\"legend\":\"\\u003cp\\u003eChanges in fruit peel and flesh color in \\u003cem\\u003eH. costaricensis\\u003c/em\\u003e during fruit maturation.\\u003c/p\\u003e\",\"description\":\"\",\"filename\":\"2.jpg\",\"url\":\"https://assets-eu.researchsquare.com/files/rs-4839398/v1/fb7d48c3616074dd5ac691a1.jpg\"},{\"id\":64031574,\"identity\":\"3a6700f8-b641-4023-9c8d-0e2948c57ebf\",\"added_by\":\"auto\",\"created_at\":\"2024-09-05 09:19:20\",\"extension\":\"jpg\",\"order_by\":3,\"title\":\"Figure 3\",\"display\":\"\",\"copyAsset\":false,\"role\":\"figure\",\"size\":29649,\"visible\":true,\"origin\":\"\",\"legend\":\"\\u003cp\\u003eChanges in fruit and pulp firmness of \\u003cem\\u003eH. costaricensis\\u003c/em\\u003e during fruit maturation.\\u003c/p\\u003e\",\"description\":\"\",\"filename\":\"3.jpg\",\"url\":\"https://assets-eu.researchsquare.com/files/rs-4839398/v1/d00531ad3f16364382eb246c.jpg\"},{\"id\":64031575,\"identity\":\"9c7642a3-48ad-4723-a7be-af1a0d92f12d\",\"added_by\":\"auto\",\"created_at\":\"2024-09-05 09:19:20\",\"extension\":\"jpg\",\"order_by\":4,\"title\":\"Figure 4\",\"display\":\"\",\"copyAsset\":false,\"role\":\"figure\",\"size\":73552,\"visible\":true,\"origin\":\"\",\"legend\":\"\\u003cp\\u003eCorrelation coefficients (r) and the probability levels of fruit and pulp color parameters (L*, a*, C* and hue\\u003csup\\u003e0\\u003c/sup\\u003e), fruit and pulp firmness, peel thickness and peel percentage of \\u003cem\\u003eH. costaricensis\\u003c/em\\u003e during fruit maturation at p ≤ 0.05 significance level.\\u003c/p\\u003e\",\"description\":\"\",\"filename\":\"4.jpg\",\"url\":\"https://assets-eu.researchsquare.com/files/rs-4839398/v1/bdd35f2732dc7359e6fac8c2.jpg\"},{\"id\":65583194,\"identity\":\"de683f17-ecf7-4de9-9dd6-57a4a03b0dad\",\"added_by\":\"auto\",\"created_at\":\"2024-09-30 08:39:27\",\"extension\":\"pdf\",\"order_by\":0,\"title\":\"\",\"display\":\"\",\"copyAsset\":false,\"role\":\"manuscript-pdf\",\"size\":1221483,\"visible\":true,\"origin\":\"\",\"legend\":\"\",\"description\":\"\",\"filename\":\"manuscript.pdf\",\"url\":\"https://assets-eu.researchsquare.com/files/rs-4839398/v1/791838bb-8207-475d-aa8e-a56aef015fe2.pdf\"}],\"financialInterests\":\"No competing interests reported.\",\"formattedTitle\":\"Dynamic transformations in fruit color and textural characteristics of purple-fleshed dragon fruit (Hylocereus costaricensis) across fruit developmental stages under humid tropical climate\",\"fulltext\":[{\"header\":\"Introduction\",\"content\":\"\\u003cp\\u003eDragon fruit, popularly known as Pitaya, is a climbing cactus belonging to the \\u003cem\\u003eHylocereus\\u003c/em\\u003e genus of the Cactaceae family. This genus comprises 16 species, primarily classified based on their peel and pulp color. The four most cultivated species\\u003csup\\u003e\\u003cspan citationid=\\\"CR1\\\" class=\\\"CitationRef\\\"\\u003e1\\u003c/span\\u003e\\u003c/sup\\u003e are (i) \\u003cem\\u003eHylocereus undatus\\u003c/em\\u003e (white-flesh with pink skin), (ii) \\u003cem\\u003eHylocereus polyrhizus\\u003c/em\\u003e (red-flesh with pink skin), (iii) \\u003cem\\u003eHylocereus costaricensis\\u003c/em\\u003e (purple-flesh and pink skin) and (iv) \\u003cem\\u003eHylocereus (Selenicerus) megalanthus\\u003c/em\\u003e (white-flesh with yellow skin)\\u003csup\\u003e\\u003cspan citationid=\\\"CR2\\\" class=\\\"CitationRef\\\"\\u003e2\\u003c/span\\u003e,\\u003cspan citationid=\\\"CR3\\\" class=\\\"CitationRef\\\"\\u003e3\\u003c/span\\u003e\\u003c/sup\\u003e. Dragon fruit is notable for its anti-inflammatory, anti-spasmodic, and radioprotective effects\\u003csup\\u003e\\u003cspan citationid=\\\"CR4\\\" class=\\\"CitationRef\\\"\\u003e4\\u003c/span\\u003e\\u003c/sup\\u003e and antioxidant, anti-microbial, anti-cancer, and anti-diabetic activities\\u003csup\\u003e\\u003cspan citationid=\\\"CR5\\\" class=\\\"CitationRef\\\"\\u003e5\\u003c/span\\u003e\\u003c/sup\\u003e. This has led to growing global interest and expanding its cultivation into non-traditional areas with suitable climatic conditions. Although native to Central Mexico and South America\\u003csup\\u003e\\u003cspan citationid=\\\"CR6\\\" class=\\\"CitationRef\\\"\\u003e6\\u003c/span\\u003e\\u003c/sup\\u003e, it is now successfully cultivated in South Asian tropical countries, including the Indian continent, which offers diverse agroclimatic conditions conducive to its growth\\u003csup\\u003e\\u003cspan citationid=\\\"CR2\\\" class=\\\"CitationRef\\\"\\u003e2\\u003c/span\\u003e\\u003c/sup\\u003e. The fruit\\u0026rsquo;s ability to adapt to various growing conditions and its high economic return further contribute to its increasing popularity and economic value\\u003csup\\u003e\\u003cspan citationid=\\\"CR7\\\" class=\\\"CitationRef\\\"\\u003e7\\u003c/span\\u003e\\u003c/sup\\u003e. The fruit is consumed as fresh or processed into jams, jelly, beverages, juice powders, and wine\\u003csup\\u003e\\u003cspan citationid=\\\"CR8\\\" class=\\\"CitationRef\\\"\\u003e8\\u003c/span\\u003e\\u003c/sup\\u003e. Even though different colored pitaya fruits are cultivated, the dark pink/ purple-fleshed species (\\u003cem\\u003eHylocereus costaricensis)\\u003c/em\\u003e is gaining momentum due to its attractive, vibrant color, unique exotic appearance, refreshing taste, and promising nutritional and functional properties. The distinctive pulp and fruit color of \\u003cem\\u003eH. costaricensis\\u003c/em\\u003e is mainly due to the presence of betalain pigments, which are rich in antioxidants\\u003csup\\u003e\\u003cspan citationid=\\\"CR9\\\" class=\\\"CitationRef\\\"\\u003e9\\u003c/span\\u003e\\u003c/sup\\u003e.\\u003c/p\\u003e \\u003cp\\u003eAs the dragon fruit is non-climacteric, it must be harvested at optimum maturity to ensure fruit quality. A spectrum of color changes occurs in the fruit and pulp during the growth and maturation of dragon fruit\\u003csup\\u003e\\u003cspan citationid=\\\"CR10\\\" class=\\\"CitationRef\\\"\\u003e10\\u003c/span\\u003e\\u003c/sup\\u003e. These color transformations serve as a critical indicator of fruit growth and maturity, which determines consumer acceptance\\u003csup\\u003e\\u003cspan citationid=\\\"CR11\\\" class=\\\"CitationRef\\\"\\u003e11\\u003c/span\\u003e\\u003c/sup\\u003e. In red-fleshed dragon fruit, significant color changes occurred under the distinct climatic conditions of Malaysia, highlighting the relationship between color development and fruit growth\\u003csup\\u003e\\u003cspan citationid=\\\"CR12\\\" class=\\\"CitationRef\\\"\\u003e12\\u003c/span\\u003e\\u003c/sup\\u003e. Similarly, Magalhaes et al.\\u003csup\\u003e\\u003cspan citationid=\\\"CR13\\\" class=\\\"CitationRef\\\"\\u003e13\\u003c/span\\u003e\\u003c/sup\\u003e observed substantial changes in textural and peel characteristics of dragon fruit in the isoclimatic conditions of Brazil. Several authors have reported that the edaphoclimatic conditions of the cultivation site caused variation in color development and fruit growth\\u003csup\\u003e\\u003cspan citationid=\\\"CR14\\\" class=\\\"CitationRef\\\"\\u003e14\\u003c/span\\u003e,\\u003cspan citationid=\\\"CR16\\\" class=\\\"CitationRef\\\"\\u003e16\\u003c/span\\u003e\\u003c/sup\\u003e. The fruit color, pulp color, and texture are the key factors in determining the optimum harvest maturity, which affects the fruit quality, consumer acceptance, and shelf life of dragon fruits. Since the climatic conditions in the growing region greatly influence these factors, studying the changes when an exotic crop acclimates to a new geographical location is essential. The purple-fleshed dragon fruit (\\u003cem\\u003eHylocereus costaricensis\\u003c/em\\u003e) is a relatively new introduction to Indian humid tropical climates, which differs significantly from the climate of previously studied regions. Hence, the present study comprehensively investigated the dynamic transformations in the fruit (peel), pulp coloration, and textural characteristics across developmental stages of purple-fleshed dragon fruit grown under a humid tropical climate. The insightful knowledge obtained from the study will be paramount for addressing issues related to fruit management, quality, and harvesting of purple-fleshed dragon fruit grown in humid tropical locations worldwide.\\u003c/p\\u003e\"},{\"header\":\"Results and discussion\",\"content\":\"\\u003cp\\u003eThe fruit's L* values refer to its ability to reflect or transmit incident light, with high L* values indicating a lighter color and lower L* values indicating a darker color. In the present study of color parameters in \\u003cem\\u003eH. costaricensis\\u003c/em\\u003e (purple-fleshed dragon fruit), the L* value initially increased from 42.46 at 10 days after flowering (DF) to a peak of 48.00 at 26 DF, then decreased to the lowest value of 36.20 at 32 DF (Table\\u0026nbsp;\\u003cspan refid=\\\"Tab1\\\" class=\\\"InternalRef\\\"\\u003e1\\u003c/span\\u003e.). The reduction in L* value during growth and developmental stages indicated increased pigmentation. A significant change in the fruit L* values observed at 27 DF (Fig.\\u0026nbsp;\\u003cspan refid=\\\"Fig1\\\" class=\\\"InternalRef\\\"\\u003e1\\u003c/span\\u003ea) indicated the onset of fruit pigmentation and transition of color from green to red. The lower L* values during the later developmental stages were due to the progression of pigmentation and the development of a reddish color in the fruit. These findings were consistent with previous studies on different species of pitaya, where in red pitaya, the L* values decreased from 51.63 at 20 DF to 38.23 at 45 DF\\u003csup\\u003e\\u003cspan citationid=\\\"CR16\\\" class=\\\"CitationRef\\\"\\u003e16\\u003c/span\\u003e\\u003c/sup\\u003e. White pitaya values ranged from 51.18 at 7 DF to 37.93 at 41 DF\\u003csup\\u003e\\u003cspan citationid=\\\"CR20\\\" class=\\\"CitationRef\\\"\\u003e20\\u003c/span\\u003e\\u003c/sup\\u003e, highlighting the typical L* value reduction pattern associated with increasing pigmentation during fruit maturation.\\u003c/p\\u003e \\u003cp\\u003e \\u003cdiv class=\\\"gridtable\\\"\\u003e\\u003ctable float=\\\"Yes\\\" id=\\\"Tab1\\\" border=\\\"1\\\"\\u003e \\u003ccaption language=\\\"En\\\"\\u003e \\u003cdiv class=\\\"CaptionNumber\\\"\\u003eTable 1\\u003c/div\\u003e \\u003cdiv class=\\\"CaptionContent\\\"\\u003e \\u003cp\\u003eChanges in fruit and pulp color in \\u003cem\\u003eH. costaricensis\\u003c/em\\u003e during fruit maturation.\\u003c/p\\u003e \\u003c/div\\u003e \\u003c/caption\\u003e \\u003ccolgroup cols=\\\"9\\\"\\u003e \\u003cdiv align=\\\"left\\\" class=\\\"colspec\\\" colname=\\\"c1\\\" colnum=\\\"1\\\"\\u003e\\u003c/div\\u003e \\u003cdiv align=\\\"left\\\" class=\\\"colspec\\\" colname=\\\"c2\\\" colnum=\\\"2\\\"\\u003e\\u003c/div\\u003e \\u003cdiv align=\\\"left\\\" class=\\\"colspec\\\" colname=\\\"c3\\\" colnum=\\\"3\\\"\\u003e\\u003c/div\\u003e \\u003cdiv align=\\\"left\\\" class=\\\"colspec\\\" colname=\\\"c4\\\" colnum=\\\"4\\\"\\u003e\\u003c/div\\u003e \\u003cdiv align=\\\"left\\\" class=\\\"colspec\\\" colname=\\\"c5\\\" colnum=\\\"5\\\"\\u003e\\u003c/div\\u003e \\u003cdiv align=\\\"left\\\" class=\\\"colspec\\\" colname=\\\"c6\\\" colnum=\\\"6\\\"\\u003e\\u003c/div\\u003e \\u003cdiv align=\\\"left\\\" class=\\\"colspec\\\" colname=\\\"c7\\\" colnum=\\\"7\\\"\\u003e\\u003c/div\\u003e \\u003cdiv align=\\\"left\\\" class=\\\"colspec\\\" colname=\\\"c8\\\" colnum=\\\"8\\\"\\u003e\\u003c/div\\u003e \\u003cdiv align=\\\"left\\\" class=\\\"colspec\\\" colname=\\\"c9\\\" colnum=\\\"9\\\"\\u003e\\u003c/div\\u003e \\u003cthead\\u003e \\u003ctr\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c1\\\" morerows=\\\"1\\\" rowspan=\\\"2\\\"\\u003e \\u003cp\\u003eDF\\u003c/p\\u003e \\u003c/th\\u003e \\u003cth align=\\\"left\\\" colspan=\\\"4\\\" nameend=\\\"c5\\\" namest=\\\"c2\\\"\\u003e \\u003cp\\u003eFruit color\\u003c/p\\u003e \\u003c/th\\u003e \\u003cth align=\\\"left\\\" colspan=\\\"4\\\" nameend=\\\"c9\\\" namest=\\\"c6\\\"\\u003e \\u003cp\\u003ePulp color\\u003c/p\\u003e \\u003c/th\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003eL*\\u003c/p\\u003e \\u003c/th\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003ea*\\u003c/p\\u003e \\u003c/th\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003eb*\\u003c/p\\u003e \\u003c/th\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003eC Value\\u003c/p\\u003e \\u003c/th\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003eL*\\u003c/p\\u003e \\u003c/th\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c7\\\"\\u003e 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colname=\\\"c3\\\"\\u003e \\u003cp\\u003e\\u0026minus;\\u0026thinsp;7.50\\u003csup\\u003efg\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e15.89\\u003csup\\u003eab\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003e17.57\\u003csup\\u003eef\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003e96.04\\u003csup\\u003ea\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c7\\\"\\u003e \\u003cp\\u003e2.09\\u003csup\\u003ef\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c8\\\"\\u003e \\u003cp\\u003e19.46\\u003csup\\u003ea\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c9\\\"\\u003e 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colname=\\\"c9\\\"\\u003e \\u003cp\\u003e27.73\\u003csup\\u003eb\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003e27\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e39.19\\u003csup\\u003ee\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e10.41\\u003csup\\u003ee\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e11.57\\u003csup\\u003ed\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003e15.56\\u003csup\\u003eh\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003e22.53\\u003csup\\u003ef\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd 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\\u003cp\\u003e37.59\\u003csup\\u003ef\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e25.08\\u003csup\\u003ec\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e7.65\\u003csup\\u003ee\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003e26.22\\u003csup\\u003ec\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003e21.75\\u003csup\\u003eg\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c7\\\"\\u003e \\u003cp\\u003e29.64\\u003csup\\u003ea\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c8\\\"\\u003e \\u003cp\\u003e-4.43\\u003csup\\u003ee\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c9\\\"\\u003e \\u003cp\\u003e29.97\\u003csup\\u003ea\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003e30\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e37.43\\u003csup\\u003ef\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e29.16\\u003csup\\u003eb\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e6.93\\u003csup\\u003ef\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003e29.97\\u003csup\\u003eb\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003e21.30\\u003csup\\u003eg\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c7\\\"\\u003e \\u003cp\\u003e30.19\\u003csup\\u003eab\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c8\\\"\\u003e \\u003cp\\u003e-4.37\\u003csup\\u003ee\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c9\\\"\\u003e \\u003cp\\u003e30.50\\u003csup\\u003ea\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003e31\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e37.14\\u003csup\\u003ef\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e32.83\\u003csup\\u003ea\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e4.65\\u003csup\\u003eg\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003e33.16\\u003csup\\u003ea\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003e20.19\\u003csup\\u003eh\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c7\\\"\\u003e \\u003cp\\u003e30.10\\u003csup\\u003eab\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c8\\\"\\u003e \\u003cp\\u003e-4.47\\u003csup\\u003ee\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c9\\\"\\u003e \\u003cp\\u003e30.43\\u003csup\\u003ea\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003e32\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e36.20\\u003csup\\u003eg\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e32.96\\u003csup\\u003ea\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e4.42\\u003csup\\u003eg\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003e33.26\\u003csup\\u003ea\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003e20.25\\u003csup\\u003eh\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c7\\\"\\u003e \\u003cp\\u003e30.08\\u003csup\\u003eab\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c8\\\"\\u003e \\u003cp\\u003e-2.80\\u003csup\\u003ed\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c9\\\"\\u003e \\u003cp\\u003e30.21\\u003csup\\u003ea\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003c/tbody\\u003e \\u003c/colgroup\\u003e \\u003ctfoot\\u003e \\u003ctr\\u003e\\u003ctd colspan=\\\"9\\\"\\u003eDifferent letters in the column for each parameter denote significant differences among treatments at p\\u0026thinsp;\\u0026lt;\\u0026thinsp;0.05, as per Least Significant Difference (LSD) test.\\u003c/td\\u003e\\u003c/tr\\u003e \\u003c/tfoot\\u003e \\u003c/table\\u003e\\u003c/div\\u003e \\u003c/p\\u003e \\u003cp\\u003e \\u003c/p\\u003e \\u003cp\\u003eThe a* values represent the color shift from green to red, negative a* values indicate green color and positive values indicate reddish color. In this study, a* values of the fruit significantly increased throughout fruit growth and maturation stages, and the values increased from \\u0026minus;\\u0026thinsp;8.14 at 10 DF to 32.96 at 32 DF (Table\\u0026nbsp;\\u003cspan refid=\\\"Tab1\\\" class=\\\"InternalRef\\\"\\u003e1\\u003c/span\\u003e.). A notable shift from negative to positive values was observed between 26 DF (-8.56) and 27 DF (10.41) (Fig.\\u0026nbsp;\\u003cspan refid=\\\"Fig1\\\" class=\\\"InternalRef\\\"\\u003e1\\u003c/span\\u003eb), indicating a color transition from green to red and a pronounced increase in red coloration after that until the end of the evaluation. Similar increasing trends of a* value based on the degree of maturity were observed in red and white-fleshed dragon fruit. The a* values of white-fleshed dragon fruit increased over time from 16.4 at 21 DF to 44.4 at 32 DF\\u003csup\\u003e\\u003cspan citationid=\\\"CR21\\\" class=\\\"CitationRef\\\"\\u003e21\\u003c/span\\u003e\\u003c/sup\\u003e, whereas in red-fleshed dragon fruits, it ranged from \\u0026minus;\\u0026thinsp;9.53 at 20 DF to 37.54 at 45 DF\\u003csup\\u003e\\u003cspan citationid=\\\"CR16\\\" class=\\\"CitationRef\\\"\\u003e16\\u003c/span\\u003e\\u003c/sup\\u003e.\\u003c/p\\u003e \\u003cp\\u003eOn the other hand, the coordinate b* of \\u003cem\\u003eH. costaricensis\\u003c/em\\u003e fruit, which indicates the transition from yellow (+) to blue (-), exhibited a decreasing trend (Fig.\\u0026nbsp;\\u003cspan refid=\\\"Fig1\\\" class=\\\"InternalRef\\\"\\u003e1\\u003c/span\\u003ec). Fruit b* values declined from 15.76 at 10 DF to 4.42 at 32 DF (Table\\u0026nbsp;\\u003cspan refid=\\\"Tab1\\\" class=\\\"InternalRef\\\"\\u003e1\\u003c/span\\u003e.), exhibiting a reduction in yellow pigmentation. A similar decreasing trend of fruit b* values from 30.6 (21 DF) to 7.6 (32 DF) during fruit maturation in white pitaya was reported by Ortiz and Takahashi\\u003csup\\u003e\\u003cspan citationid=\\\"CR21\\\" class=\\\"CitationRef\\\"\\u003e21\\u003c/span\\u003e\\u003c/sup\\u003e, while Magalhaes et al.\\u003csup\\u003e\\u003cspan citationid=\\\"CR14\\\" class=\\\"CitationRef\\\"\\u003e14\\u003c/span\\u003e\\u003c/sup\\u003e, reported that b* values decreased from 27.31 (28 DF) to 11.18 (42 DF) with difference in the days of maturity. Similarly, a decrease in the coordinate b* of fruit was noticed in red-fleshed dragon fruit grown under iso climatic conditions\\u003csup\\u003e\\u003cspan citationid=\\\"CR20\\\" class=\\\"CitationRef\\\"\\u003e20\\u003c/span\\u003e\\u003c/sup\\u003e, with the values ranging from 31.18 to 9.10 during 28 to 42 days of evaluation. The decline in b* values with fruit growth and maturation is linked to the degradation of chlorophyll and carotenoid pigments\\u003csup\\u003e\\u003cspan citationid=\\\"CR15\\\" class=\\\"CitationRef\\\"\\u003e15\\u003c/span\\u003e\\u003c/sup\\u003e and the formation of betalains\\u003csup\\u003e\\u003cspan citationid=\\\"CR14\\\" class=\\\"CitationRef\\\"\\u003e14\\u003c/span\\u003e,\\u003cspan citationid=\\\"CR22\\\" class=\\\"CitationRef\\\"\\u003e22\\u003c/span\\u003e\\u003c/sup\\u003e.\\u003c/p\\u003e \\u003cp\\u003eThe current study revealed a distinct increase in fruit color intensity, as indicated by chroma values (C*), throughout the maturation stages. The chroma values increased from 17.74 at 10 DF to 33.26 at 32 DF (Table\\u0026nbsp;\\u003cspan refid=\\\"Tab1\\\" class=\\\"InternalRef\\\"\\u003e1\\u003c/span\\u003e.), reflecting greater intensity and purity of the color as the fruit matured. The observed increase in chroma values aligns with the findings of Ortiz and Takahashi\\u003csup\\u003e\\u003cspan citationid=\\\"CR21\\\" class=\\\"CitationRef\\\"\\u003e21\\u003c/span\\u003e\\u003c/sup\\u003e and Magalhaes et al.\\u003csup\\u003e\\u003cspan citationid=\\\"CR14\\\" class=\\\"CitationRef\\\"\\u003e14\\u003c/span\\u003e\\u003c/sup\\u003e, who observed a linear increase in chroma values in \\u003cem\\u003eH. undatus\\u003c/em\\u003e. These results underscore the steady pattern of increasing color intensity during the maturation stages of dragon fruit.\\u003c/p\\u003e \\u003cp\\u003eThe analysis of fruit pulp color parameters in purple-fleshed dragon fruit also revealed a progressive change in the pulp color during maturation. The L* value of the pulp, which indicates its ability to reflect or transmit incident light, decreased significantly throughout the development stages, with values ranging from 92.85 at 10 days after flowering (DF) to 20.25 at 32 DF (Table\\u0026nbsp;\\u003cspan refid=\\\"Tab1\\\" class=\\\"InternalRef\\\"\\u003e1\\u003c/span\\u003e.). A marked reduction in pulp L* values was observed between 15 to 25 DF (Fig.\\u0026nbsp;\\u003cspan refid=\\\"Fig1\\\" class=\\\"InternalRef\\\"\\u003e1\\u003c/span\\u003ea). In contrast, in red pitaya, this reduction happened between 25 to 30 DF (Phebe et al.\\u003csup\\u003e\\u003cspan citationid=\\\"CR13\\\" class=\\\"CitationRef\\\"\\u003e13\\u003c/span\\u003e\\u003c/sup\\u003e). The decrease in L* values reflects increased pulp pigmentation due to interconversion of pigments\\u003csup\\u003e\\u003cspan citationid=\\\"CR13\\\" class=\\\"CitationRef\\\"\\u003e13\\u003c/span\\u003e,\\u003cspan citationid=\\\"CR16\\\" class=\\\"CitationRef\\\"\\u003e16\\u003c/span\\u003e\\u003c/sup\\u003e. In the current study on \\u003cem\\u003eH. costaricensis\\u003c/em\\u003e, seed maturation also played a crucial role in pulp color development (Fig.\\u0026nbsp;\\u003cspan refid=\\\"Fig2\\\" class=\\\"InternalRef\\\"\\u003e2\\u003c/span\\u003e), and the development of seeds contributed to reduced pulp L* values\\u003csup\\u003e23\\u003c/sup\\u003e. As the seed color became darker in the purple-fleshed dragon fruit, the pulp L* values decreased, revealing a significant relationship between the onset of pigmentation and seed maturation. The fruit pulp pigmentation initially began around the seeds at 25 DF, following the complete blackening of the seeds. This sequence of pulp color development in relation to seed maturation aligns with the findings by Jamaludin et al.\\u003csup\\u003e\\u003cspan citationid=\\\"CR24\\\" class=\\\"CitationRef\\\"\\u003e24\\u003c/span\\u003e\\u003c/sup\\u003e in \\u003cem\\u003eH. polyrhizus\\u003c/em\\u003e. These results suggest that the development of pulp color in dragon fruit is closely linked to seed maturation and pigment interconversion, with notable variations across different species and stages of fruit development.\\u003c/p\\u003e \\u003cp\\u003e \\u003c/p\\u003e \\u003cp\\u003eThe a* values of the pulp exhibited a substantial increase from 1.2 at 10 DF to 30.08 at 32 DF (Table\\u0026nbsp;\\u003cspan refid=\\\"Tab1\\\" class=\\\"InternalRef\\\"\\u003e1\\u003c/span\\u003e.) reflecting a pronounced intensification of coloration in the purple-fleshed dragon fruit as it matured. The highest relative change in a* values and the sharp reduction in L* value in the pulp were observed from the 20 DF to the 25 DF (Fig.\\u0026nbsp;\\u003cspan refid=\\\"Fig1\\\" class=\\\"InternalRef\\\"\\u003e1\\u003c/span\\u003eb). This decrease in the L* values, coupled with an increase in the a* value reflected the loss of whiteness and the progression of redness in the fruit pulp. Comparable trends in red-fleshed dragon fruits, with substantial variations in a* values based on the degree of maturation, reported by Jamaludin et al.\\u003csup\\u003e\\u003cspan citationid=\\\"CR24\\\" class=\\\"CitationRef\\\"\\u003e24\\u003c/span\\u003e\\u003c/sup\\u003e. Likewise, Ortiz and Takahashi\\u003csup\\u003e\\u003cspan citationid=\\\"CR21\\\" class=\\\"CitationRef\\\"\\u003e21\\u003c/span\\u003e\\u003c/sup\\u003e documented a steady increase in a* values for white-fleshed dragon fruit, ranging from 16.4 at 21 DF to 44.4 at 32 DF. Collectively, these findings reinforce that the pattern of color development varies with different dragon fruit species and growing conditions.\\u003c/p\\u003e \\u003cp\\u003eConversely, the b* values of the pulp demonstrated a decreasing trend throughout the maturation stages (Fig.\\u0026nbsp;\\u003cspan refid=\\\"Fig1\\\" class=\\\"InternalRef\\\"\\u003e1\\u003c/span\\u003ec). The values were initially positive up to 20 DF (2.39) and became negative at 25 DF (-6.60) (Table\\u0026nbsp;\\u003cspan refid=\\\"Tab1\\\" class=\\\"InternalRef\\\"\\u003e1\\u003c/span\\u003e.), reflecting a transition from yellow to darker tones. This sharp decline in b* values, with a shift occurring after 25 DF, aligns with the findings of Singh et al.\\u003csup\\u003e\\u003cspan citationid=\\\"CR16\\\" class=\\\"CitationRef\\\"\\u003e16\\u003c/span\\u003e\\u003c/sup\\u003e in red-fleshed dragon fruit grown under Indian semi-arid conditions.\\u003c/p\\u003e \\u003cp\\u003eThe pulp color intensity values (C*) exhibited significant fluctuations with quadratic behavior (Fig.\\u0026nbsp;\\u003cspan refid=\\\"Fig1\\\" class=\\\"InternalRef\\\"\\u003e1\\u003c/span\\u003ed). The pulp C* values increased from 17.74 at 10 DF to 19.57 at 20 DF, then decreased to 4.21 at 25 DF and subsequently increased to 30.21 at 32 DF (Table\\u0026nbsp;\\u003cspan refid=\\\"Tab1\\\" class=\\\"InternalRef\\\"\\u003e1\\u003c/span\\u003e.). This pattern of an initial decrease followed by an increase in pulp C* values of purple-fleshed dragon fruit grown under humid tropical conditions was in agreement with the findings of Singh et al.\\u003csup\\u003e\\u003cspan citationid=\\\"CR16\\\" class=\\\"CitationRef\\\"\\u003e16\\u003c/span\\u003e\\u003c/sup\\u003e in red-fleshed dragon fruit grown semi-arid conditions, where C* values decreased from 24.8 at 20 DF to 12.9 at 25 DF and then increased from 24.7 at 30 DF to 58.9 at 45 DF. Similar trends were reported by Jamaludin et al.\\u003csup\\u003e\\u003cspan citationid=\\\"CR24\\\" class=\\\"CitationRef\\\"\\u003e24\\u003c/span\\u003e\\u003c/sup\\u003e in red-fleshed dragon fruits in Malaysia across seven growth and development stages. In the present study, the highest perceptible change in color intensity and purity was noticed at 25 DF, indicating the onset of pulp pigmentation. The fruit pulp attained full purplish red color 28 days after flowering (Fig.\\u0026nbsp;\\u003cspan refid=\\\"Fig2\\\" class=\\\"InternalRef\\\"\\u003e2\\u003c/span\\u003e). This observation was consistent with the findings of Phebe et al.\\u003csup\\u003e\\u003cspan citationid=\\\"CR13\\\" class=\\\"CitationRef\\\"\\u003e13\\u003c/span\\u003e\\u003c/sup\\u003e in red dragon fruit. The present study also confirms the variation in days of expression of color intensity with species and growing conditions.\\u003c/p\\u003e \\u003cp\\u003eThe hue angle (hue\\u003csup\\u003e0\\u003c/sup\\u003e), indicating where the color falls on a 360\\u0026deg; color wheel, revealed remarkable changes during the maturation of purplish-red dragon fruit. The fruit and pulp hue\\u003csup\\u003e0\\u003c/sup\\u003e decreased throughout the growth and maturation stages. The fruit hue\\u003csup\\u003e0\\u003c/sup\\u003e values dropped below 30\\u0026deg; at 28 DF and reached 8\\u003csup\\u003e\\u0026deg;\\u003c/sup\\u003e at 32 DF (Fig.\\u0026nbsp;\\u003cspan refid=\\\"Fig1\\\" class=\\\"InternalRef\\\"\\u003e1\\u003c/span\\u003ee). The reduction in the fruit hue\\u003csup\\u003e0\\u003c/sup\\u003e in white-fleshed dragon fruit from 118\\u0026deg; (21 DF) to 10\\u0026deg; (32 DF) was reported by Ortiz and Takahashi\\u003csup\\u003e\\u003cspan citationid=\\\"CR21\\\" class=\\\"CitationRef\\\"\\u003e21\\u003c/span\\u003e\\u003c/sup\\u003e under Brazil. The decrease in the hue\\u003csup\\u003e0\\u003c/sup\\u003e of purplish red dragon fruit in the current study indicated a color change from green to red during fruit development, which concurs with observations by Jamaludin et al.\\u003csup\\u003e\\u003cspan citationid=\\\"CR24\\\" class=\\\"CitationRef\\\"\\u003e24\\u003c/span\\u003e\\u003c/sup\\u003e in red dragon fruit and by Magalhaes et al.\\u003csup\\u003e\\u003cspan citationid=\\\"CR14\\\" class=\\\"CitationRef\\\"\\u003e14\\u003c/span\\u003e\\u003c/sup\\u003e in white-fleshed dragon fruit. The reductions in hue\\u003csup\\u003e0\\u003c/sup\\u003e, as the fruit color changes from green to red, signal physiological maturity and the mature fruits had hue\\u003csup\\u003e0\\u003c/sup\\u003e below 30\\u003csup\\u003e\\u0026deg;\\u003cspan citationid=\\\"CR28\\\" class=\\\"CitationRef\\\"\\u003e28\\u003c/span\\u003e,\\u003cspan citationid=\\\"CR21\\\" class=\\\"CitationRef\\\"\\u003e21\\u003c/span\\u003e\\u003c/sup\\u003e. The hue angle of purplish red dragon fruit reached below 30\\u003csup\\u003e\\u0026deg;\\u003c/sup\\u003e at 28 DF, indicating the readiness for harvest maturity. The intensity of red fruit color and days after flowering is a key indicator of maturity and fruit quality in dragon fruit\\u003csup\\u003e\\u003cspan citationid=\\\"CR11\\\" class=\\\"CitationRef\\\"\\u003e11\\u003c/span\\u003e\\u003c/sup\\u003e. A study conducted in Vietnam by Van To et al.\\u003csup\\u003e\\u003cspan citationid=\\\"CR26\\\" class=\\\"CitationRef\\\"\\u003e26\\u003c/span\\u003e\\u003c/sup\\u003e confirmed that fruits with a hue\\u003csup\\u003e0\\u003c/sup\\u003e equal to or less than 30\\u0026deg; were suitable for marketing, further emphasizing the importance of hue\\u003csup\\u003e0\\u003c/sup\\u003e as a maturity and quality indicator for dragon fruit.\\u003c/p\\u003e \\u003cp\\u003eOverall analysis of fruit and pulp color parameters (L*, a*, b*, chroma, and hue\\u003csup\\u003e0\\u003c/sup\\u003e) of purplish red dragon fruit (\\u003cem\\u003eH. costaricensis\\u003c/em\\u003e) revealed a noticeable decrease in L* (luminosity), b* (yellowness), and hue\\u003csup\\u003e0\\u003c/sup\\u003e values, along with an increase in a* (redness) and C* (color intensity) values. These changes demonstrated a clear transition from green to a purplish-red hue throughout the fruit growth and development stages. This transformation of the fruit color and pulp color from lighter and less intense colors to darker and more intense colors during fruit maturation is in agreement with the findings of Ortiz and Takahashi\\u003csup\\u003e\\u003cspan citationid=\\\"CR21\\\" class=\\\"CitationRef\\\"\\u003e21\\u003c/span\\u003e\\u003c/sup\\u003e in white-fleshed dragon fruit and by Singh et al.\\u003csup\\u003e\\u003cspan citationid=\\\"CR16\\\" class=\\\"CitationRef\\\"\\u003e16\\u003c/span\\u003e\\u003c/sup\\u003e in red-fleshed dragon fruit.\\u003c/p\\u003e \\u003cp\\u003eThe change in fruit color of \\u003cem\\u003eH. undatus\\u003c/em\\u003e occurred between 28 and 30 DF under Vietnam conditions\\u003csup\\u003e\\u003cspan citationid=\\\"CR26\\\" class=\\\"CitationRef\\\"\\u003e26\\u003c/span\\u003e\\u003c/sup\\u003e, while under Mexican climatic conditions, it occurred at 25 DF\\u003csup\\u003e\\u003cspan citationid=\\\"CR25\\\" class=\\\"CitationRef\\\"\\u003e25\\u003c/span\\u003e\\u003c/sup\\u003e. In Brazilian conditions, this change happened at 28 to 29 DF\\u003csup\\u003e\\u003cspan citationid=\\\"CR21\\\" class=\\\"CitationRef\\\"\\u003e21\\u003c/span\\u003e\\u003c/sup\\u003e, while in fruits grown in the tropical humid climate of India, it occurred at 26 DF\\u003csup\\u003e\\u003cspan citationid=\\\"CR20\\\" class=\\\"CitationRef\\\"\\u003e20\\u003c/span\\u003e\\u003c/sup\\u003e. For red-fleshed dragon fruit (\\u003cem\\u003eH. polyrhizus\\u003c/em\\u003e) grown in Malaysia, the color change appeared at 25 DF\\u003csup\\u003e\\u003cspan citationid=\\\"CR24\\\" class=\\\"CitationRef\\\"\\u003e24\\u003c/span\\u003e\\u003c/sup\\u003e and between 26 to 27, as reported by Phebe et al.\\u003csup\\u003e\\u003cspan citationid=\\\"CR13\\\" class=\\\"CitationRef\\\"\\u003e13\\u003c/span\\u003e\\u003c/sup\\u003e. In contrast, Singh et al.\\u003csup\\u003e\\u003cspan citationid=\\\"CR16\\\" class=\\\"CitationRef\\\"\\u003e16\\u003c/span\\u003e\\u003c/sup\\u003e observed this change at 30 DF in red-fleshed dragon fruits grown under semi-arid conditions in India. However, in the present study, the onset of pigmentation in purple-fleshed dragon fruit occurred at 27 DF, with color intensity and purity increasing steadily until the conclusion of the evaluation period. These findings are in accordance with the results of Phebe et al.\\u003csup\\u003e\\u003cspan citationid=\\\"CR13\\\" class=\\\"CitationRef\\\"\\u003e13\\u003c/span\\u003e\\u003c/sup\\u003e and Singh et al.\\u003csup\\u003e\\u003cspan citationid=\\\"CR16\\\" class=\\\"CitationRef\\\"\\u003e16\\u003c/span\\u003e\\u003c/sup\\u003e in red-fleshed dragon fruits.\\u003c/p\\u003e \\u003cp\\u003eThe present study revealed that the color changes in the fruit and pulp of purple-fleshed dragon fruits were not synchronized, and pigmentation appeared earlier in the pulp (at 25 DF) than in the fruit (at 27 DF) (Fig.\\u0026nbsp;\\u003cspan refid=\\\"Fig2\\\" class=\\\"InternalRef\\\"\\u003e2\\u003c/span\\u003e). Similar reports of asynchronous color development in the fruit and pulp have been observed in red-fleshed dragon fruit\\u003csup\\u003e\\u003cspan citationid=\\\"CR16\\\" class=\\\"CitationRef\\\"\\u003e16\\u003c/span\\u003e\\u003c/sup\\u003e. This pattern of color change highlights the significant impact of climatic conditions on the maturation timeline of dragon fruit across various regions. Betalains are responsible for the red color of dragon fruit\\u003csup\\u003e\\u003cspan citationid=\\\"CR27\\\" class=\\\"CitationRef\\\"\\u003e27\\u003c/span\\u003e\\u003c/sup\\u003e, and color development of the fruit is correlated with the sharp increase of betalains and the fading of green color due to a marked decrease of chlorophyll\\u003csup\\u003e\\u003cspan citationid=\\\"CR22\\\" class=\\\"CitationRef\\\"\\u003e22\\u003c/span\\u003e\\u003c/sup\\u003e. The color changes in the fruit and pulp vary with dragon fruit species and growing climatic conditions.\\u003c/p\\u003e \\u003cp\\u003eThe change in the peel characteristics, firmness of fruit and pulp in relation to color changes were analyzed for purple-fleshed dragon fruit (\\u003cem\\u003eH. costaricensis\\u003c/em\\u003e). Peel characteristics, thickness, and percentage are crucial for determining harvest maturity and post-harvest shelf life. Maintaining optimal peel characteristics is vital for preserving the marketability, shelf life, and overall quality of dragon fruits\\u003csup\\u003e\\u003cspan citationid=\\\"CR28\\\" class=\\\"CitationRef\\\"\\u003e28\\u003c/span\\u003e\\u003c/sup\\u003e. In the present study on \\u003cem\\u003eH. costaricensis\\u003c/em\\u003e, as the fruit developed its color during maturation, there was a corresponding reduction in peel thickness and percentage. Peel thickness significantly reduced from 0.73 cm at 10 DF to 0.22 cm at 32 DF, while peel percentage dropped from 68.42% (10 DF) to 18.18% (32 DF). The most substantial decrease in both peel content and peel thickness occurred between 28 DF and 29 DF, coinciding with the stage of full-color development. These findings align with previous studies on both white-fleshed and red-fleshed dragon fruit\\u003csup\\u003e\\u003cspan citationid=\\\"CR14\\\" class=\\\"CitationRef\\\"\\u003e14\\u003c/span\\u003e,\\u003cspan citationid=\\\"CR16\\\" class=\\\"CitationRef\\\"\\u003e16\\u003c/span\\u003e,\\u003cspan citationid=\\\"CR21\\\" class=\\\"CitationRef\\\"\\u003e21\\u003c/span\\u003e,\\u003cspan citationid=\\\"CR22\\\" class=\\\"CitationRef\\\"\\u003e22\\u003c/span\\u003e\\u003c/sup\\u003e. Magalhaes et al.\\u003csup\\u003e\\u003cspan citationid=\\\"CR14\\\" class=\\\"CitationRef\\\"\\u003e14\\u003c/span\\u003e\\u003c/sup\\u003e reported that skin thickness decreased linearly with maturation, with a maximum thickness of 9.15 mm obtained at 28 days after flowering, followed by a reduction to 2.96 mm at 48 days in white-fleshed dragon fruit. Similarly, Ortiz and Takahashi\\u003csup\\u003e\\u003cspan citationid=\\\"CR21\\\" class=\\\"CitationRef\\\"\\u003e21\\u003c/span\\u003e\\u003c/sup\\u003e observed a decrease in skin thickness from 10.6 mm at 21 days to 1.17 mm at 32 days after flowering. Junior et al.\\u003csup\\u003e\\u003cspan citationid=\\\"CR22\\\" class=\\\"CitationRef\\\"\\u003e22\\u003c/span\\u003e\\u003c/sup\\u003e reported a reduction in peel thickness from 11.14 (7 DF) to 3.44 mm (42 days) with advancing ripeness in \\u003cem\\u003eH. undatus\\u003c/em\\u003e, whereas, in red-fleshed dragon fruit, Singh et al.\\u003csup\\u003e\\u003cspan citationid=\\\"CR16\\\" class=\\\"CitationRef\\\"\\u003e16\\u003c/span\\u003e\\u003c/sup\\u003e noted a decreasing trend in peel thickness from 20 DF until 45 DF.\\u003c/p\\u003e \\u003cp\\u003eThe fruit firmness is a crucial determinant of palatability, acceptability and commercial acceptance of most fruits and vegetables\\u003csup\\u003e\\u003cspan citationid=\\\"CR29\\\" class=\\\"CitationRef\\\"\\u003e29\\u003c/span\\u003e\\u003c/sup\\u003e. The decline in the firmness of fruit and pulp and peel thickness affects eating quality and post-harvest shelf life. The fruit firmness of \\u003cem\\u003eH. costaricensis\\u003c/em\\u003e increased initially up to 20 days after flowering (DF). Then, it decreased consistently until the full-color development stage (29 DF) (Table\\u0026nbsp;\\u003cspan refid=\\\"Tab2\\\" class=\\\"InternalRef\\\"\\u003e2\\u003c/span\\u003e), with no further significant difference in firmness. The initial increase in the fruit firmness may be due to the increased number of fruit cells during active growth\\u003csup\\u003e\\u003cspan citationid=\\\"CR30\\\" class=\\\"CitationRef\\\"\\u003e30\\u003c/span\\u003e\\u003c/sup\\u003e. In the studies conducted on purple-fleshed dragon fruit, pulp firmness decreased consistently throughout the development stages, unlike fruit firmness. It decreased from 1.159 N at 10 DF to 0.169 N at 32 DF (Fig.\\u0026nbsp;\\u003cspan refid=\\\"Fig3\\\" class=\\\"InternalRef\\\"\\u003e3\\u003c/span\\u003e), with the fruit becoming much softer by 32 DF. A considerable change in pulp firmness was noticed after 26 DF, coinciding with the fruit color development stages. The decrease in fruit firmness was stabilized at 29 DF (Table\\u0026nbsp;\\u003cspan refid=\\\"Tab2\\\" class=\\\"InternalRef\\\"\\u003e2\\u003c/span\\u003e), indicating the optimal maturity. In white-fleshed dragon fruits grown in Thailand, the firmness stabilization was at 33 days\\u003csup\\u003e\\u003cspan citationid=\\\"CR31\\\" class=\\\"CitationRef\\\"\\u003e31\\u003c/span\\u003e\\u003c/sup\\u003e, while it was 28 days under Malaysian conditions\\u003csup\\u003e\\u003cspan citationid=\\\"CR14\\\" class=\\\"CitationRef\\\"\\u003e14\\u003c/span\\u003e\\u003c/sup\\u003e and 40 days in red-fleshed dragon fruit under Indian conditions\\u003csup\\u003e\\u003cspan citationid=\\\"CR16\\\" class=\\\"CitationRef\\\"\\u003e16\\u003c/span\\u003e\\u003c/sup\\u003e. This decrease in firmness is attributed to the increased presence of water-soluble pectin resulting from the breakdown of pectin components and cell wall degradation caused by hydrolytic enzymes\\u003csup\\u003e\\u003cspan citationid=\\\"CR32\\\" class=\\\"CitationRef\\\"\\u003e32\\u003c/span\\u003e\\u003c/sup\\u003e.\\u003c/p\\u003e \\u003cp\\u003e \\u003cdiv class=\\\"gridtable\\\"\\u003e\\u003ctable float=\\\"Yes\\\" id=\\\"Tab2\\\" border=\\\"1\\\"\\u003e \\u003ccaption language=\\\"En\\\"\\u003e \\u003cdiv class=\\\"CaptionNumber\\\"\\u003eTable 2\\u003c/div\\u003e \\u003cdiv class=\\\"CaptionContent\\\"\\u003e \\u003cp\\u003eChanges in fruit and pulp firmness, peel thickness, and peel percentage in \\u003cem\\u003eH. costaricensis\\u003c/em\\u003e during fruit maturation.\\u003c/p\\u003e \\u003c/div\\u003e \\u003c/caption\\u003e \\u003ccolgroup cols=\\\"5\\\"\\u003e \\u003cdiv align=\\\"left\\\" class=\\\"colspec\\\" colname=\\\"c1\\\" colnum=\\\"1\\\"\\u003e\\u003c/div\\u003e \\u003cdiv align=\\\"left\\\" class=\\\"colspec\\\" colname=\\\"c2\\\" colnum=\\\"2\\\"\\u003e\\u003c/div\\u003e \\u003cdiv align=\\\"left\\\" class=\\\"colspec\\\" colname=\\\"c3\\\" colnum=\\\"3\\\"\\u003e\\u003c/div\\u003e \\u003cdiv align=\\\"left\\\" class=\\\"colspec\\\" colname=\\\"c4\\\" colnum=\\\"4\\\"\\u003e\\u003c/div\\u003e \\u003cdiv align=\\\"left\\\" class=\\\"colspec\\\" colname=\\\"c5\\\" colnum=\\\"5\\\"\\u003e\\u003c/div\\u003e \\u003cthead\\u003e \\u003ctr\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003eDF\\u003c/p\\u003e \\u003c/th\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003eFruit firmness (N)\\u003c/p\\u003e \\u003c/th\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003ePulp firmness (N)\\u003c/p\\u003e \\u003c/th\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003eFruit peel thickness (cm)\\u003c/p\\u003e \\u003c/th\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003ePeel percentage (%)\\u003c/p\\u003e \\u003c/th\\u003e \\u003c/tr\\u003e \\u003c/thead\\u003e \\u003ctbody\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003e10\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e2.088\\u003csup\\u003ed\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e1.159\\u003csup\\u003ea\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e0.73\\u003csup\\u003ea\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003e68.42\\u003csup\\u003ea\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003e15\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e3.882\\u003csup\\u003eb\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e0.982\\u003csup\\u003eb\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e0.64\\u003csup\\u003eb\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003e67.01\\u003csup\\u003ea\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003e20\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e3.981\\u003csup\\u003ea\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e0.966\\u003csup\\u003ec\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e0.63\\u003csup\\u003ebc\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003e63.01\\u003csup\\u003eb\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003e25\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e3.369\\u003csup\\u003ec\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e0.694\\u003csup\\u003ed\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e0.62\\u003csup\\u003ebc\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003e60.01\\u003csup\\u003ec\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003e26\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e1.812\\u003csup\\u003ee\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e0.542\\u003csup\\u003ee\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e0.60\\u003csup\\u003ec\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003e52.21\\u003csup\\u003ed\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003e27\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e0.967\\u003csup\\u003ef\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e0.293\\u003csup\\u003ef\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e0.52\\u003csup\\u003ed\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003e46.73\\u003csup\\u003ee\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003e28\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e0.604\\u003csup\\u003eg\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e0.260\\u003csup\\u003eg\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e0.40\\u003csup\\u003ee\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003e36.20\\u003csup\\u003ef\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003e29\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e0.540\\u003csup\\u003eh\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e0.252\\u003csup\\u003eh\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e0.35\\u003csup\\u003ef\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003e28.20\\u003csup\\u003eg\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003e30\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e0.540\\u003csup\\u003eh\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e0.241\\u003csup\\u003ei\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e0.30\\u003csup\\u003eg\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003e26.20\\u003csup\\u003eh\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003e31\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e0.540\\u003csup\\u003eh\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e0.195\\u003csup\\u003ej\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e0.25\\u003csup\\u003eh\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003e23.22\\u003csup\\u003ei\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003e32\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e0.495\\u003csup\\u003eh\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e0.169\\u003csup\\u003ek\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e0.22\\u003csup\\u003ei\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003e18.18\\u003csup\\u003ej\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003eSE(\\u0026plusmn;\\u0026thinsp;m)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e0.017\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e0.002\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e0.010\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003e0.636\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003eCD (0.05)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e0.049\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e0.006\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e0.028\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003e1.778\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003c/tbody\\u003e \\u003c/colgroup\\u003e \\u003ctfoot\\u003e \\u003ctr\\u003e\\u003ctd colspan=\\\"5\\\"\\u003eDifferent letters in the column for each parameter denote significant differences among treatments at p\\u0026thinsp;\\u0026lt;\\u0026thinsp;0.05, as per Least Significant Difference (LSD) test.\\u003c/td\\u003e\\u003c/tr\\u003e \\u003c/tfoot\\u003e \\u003c/table\\u003e\\u003c/div\\u003e \\u003c/p\\u003e \\u003cp\\u003e \\u003c/p\\u003e \\u003cdiv id=\\\"Sec3\\\" class=\\\"Section2\\\"\\u003e \\u003ch2\\u003eCorrelation analysis\\u003c/h2\\u003e \\u003cp\\u003eFruit color parameters, fruit and pulp firmness, and peel characteristics are interrelated indicators of fruit maturity and quality. Analyzing the correlation between these variables is crucial for interpreting their relationship and ensuring optimal harvest based on external visual cues. By comprehending these correlations, growers can better predict harvest maturity and ensure postharvest quality.\\u003c/p\\u003e \\u003cp\\u003eThe correlogram using the Pearson correlation coefficient (Fig.\\u0026nbsp;\\u003cspan refid=\\\"Fig4\\\" class=\\\"InternalRef\\\"\\u003e4\\u003c/span\\u003e) illustrates the potential of using fruit and pulp color in association with firmness and peel characteristics to determine dragon fruit quality and maturity. Among the 120 simple correlations analyzed, 100 parameters were significant at the p\\u0026thinsp;\\u003cb\\u003e\\u0026le;\\u003c/b\\u003e\\u0026thinsp;0.05 significance level. Based on the degree of intensity of the correlations, 60% of the analyzed correlations were strong to very strong, 38.4% were of average intensity, and 1.6% were low intensity. These results emphasize the reliability of the present findings.\\u003c/p\\u003e \\u003cp\\u003e \\u003c/p\\u003e \\u003cp\\u003eSignificant correlations were observed between days after flowering and all measured variables. Specifically, L*, b*, and hue\\u003csup\\u003e0\\u003c/sup\\u003e values of fruit and pulp and fruit and pulp firmness, peel thickness, and peel percentage exhibited strong negative correlations with days after flowering. Conversely, a* and C* values of both fruit and pulp showed strong positive correlations with different development stages.\\u003c/p\\u003e \\u003cp\\u003eStrong correlations were also noted between the color coordinates (L*, a*, b*, C*, and hue\\u0026deg;) of the fruit and pulp and the physical variables (peel thickness, peel percentage, fruit firmness, and pulp firmness). The analysis of color parameters and physical attributes indicated a high-intensity positive correlation between L*, b*, and hue\\u003csup\\u003e0\\u003c/sup\\u003e values and a high-intensity negative correlation with a* and C* values. Ersan et al.\\u003csup\\u003e\\u003cspan citationid=\\\"CR33\\\" class=\\\"CitationRef\\\"\\u003e33\\u003c/span\\u003e\\u003c/sup\\u003e found that the correlation between fruit growth and pigment content in cactus pear (\\u003cem\\u003eOpuntia sp\\u003c/em\\u003e.) could be a reliable indicator of fruit maturity.\\u003c/p\\u003e \\u003cp\\u003eThe correlation results of the current study on purple-fleshed dragon fruit revealed that a deeper red hue in the fruit and pulp was strongly correlated with reduced firmness, thinner peel, and lower peel percentage. Specifically, as ripeness increased with the advancement of development, the color of the dragon fruit transitioned from green to a more intense red, while firmness, peel thickness, and peel percentage decreased, indicating the readiness for harvest. These observations were consistent with previous research on other species of dragon fruit, where the physical attributes were correlated to increased redness\\u003csup\\u003e\\u003cspan citationid=\\\"CR16\\\" class=\\\"CitationRef\\\"\\u003e16\\u003c/span\\u003e\\u003c/sup\\u003e.\\u003c/p\\u003e \\u003c/div\\u003e\"},{\"header\":\"Conclusions\",\"content\":\"\\u003cp\\u003eThe study provides a comprehensive analysis of the dynamic color transformations in fruit and pulp, as well as the relevance of peel characteristics, fruit firmness, and pulp firmness throughout the maturation stages of purple-fleshed dragon fruit (\\u003cem\\u003eH. costaricensis\\u003c/em\\u003e) grown under humid tropical conditions. The results highlight the importance of color parameters such as L*, a*, b*, C* values, and hue\\u003csup\\u003e0\\u003c/sup\\u003e in assessing fruit maturity and quality. During maturation, the fruit undergoes significant color changes from green to a purplish-red hue, with asynchronous color changes between the fruit and pulp. Correlation analysis revealed that firmness, peel thickness, and fruit color are interrelated indicators of fruit maturity and quality. Increased ripeness typically resulted in decreased firmness and peel thickness and a shift in fruit color from green to more vibrant hues, signifying maturity and readiness for harvest. Understanding these changes and their correlations is crucial for optimizing harvest maturity and ensuring maximum quality and marketability. The research contributes valuable knowledge to fruit development and harvest maturity, supporting the effective cultivation and commercialization of purple-fleshed dragon fruit.\\u003c/p\\u003e\"},{\"header\":\"Materials and Methods\",\"content\":\"\\u003cdiv id=\\\"Sec6\\\" class=\\\"Section2\\\"\\u003e \\u003ch2\\u003eExperimental site\\u003c/h2\\u003e \\u003cp\\u003eFruits from three-year-old, purple-fleshed dragon fruit (\\u003cem\\u003eHylocereus costaricensis\\u003c/em\\u003e), planted on a single-pole system (four plants per pole) at 10 x 9 feet spacing and which started flowering 15 months after planting, were used for the study. The commercial orchard was located in the Thiruvananthapuram district of the Kerala state, India, situated at 8\\u0026deg;39'18.5\\\"N latitude, 76\\u0026deg;57'43.2\\\"E longitude, and an altitude of 177 meters above mean sea level. The climate of the site is humid tropical, with an average annual rainfall of 1665 mm with 74\\u0026ndash;90% relative humidity. The yearly temperature ranged from 24\\u0026deg;C to 31\\u0026deg;C, with 7\\u0026ndash;8 hours of sunshine during the summer. The fruits were collected and analyzed at various growth and development stages, specifically at 10, 15, 20, 25, 26, 27, 28, 29, 30, 31 and 32 days after flowering (DF). The fruits were labeled individually with metallic tags on the day of flowering to track their developmental stages. The study was conducted from May 2023 to June 2024. At each growth stage, the fruits were hand-harvested in the morning at their respective growth stages, and fifteen replicates (15 fruits) were used to analyze fruit characteristics.\\u003c/p\\u003e \\u003c/div\\u003e\\n\\u003ch3\\u003eExperimental design\\u003c/h3\\u003e\\n\\u003cp\\u003eThe employed experimental design was completely randomized, with each growth stage as an experimental treatment. Pearson correlation coefficients (r) were computed to assess the linear relationships between various parameters analyzed during the study at a p\\u0026thinsp;\\u0026lt;\\u0026thinsp;0.05 significance level. All statistical analyses were performed using the Grapes Agri 1 package in R\\u003csup\\u003e\\u003cb\\u003e\\u003cspan citationid=\\\"CR7\\\" class=\\\"CitationRef\\\"\\u003e7\\u003c/span\\u003e\\u003c/b\\u003e\\u003c/sup\\u003e.\\u003c/p\\u003e \\u003cdiv id=\\\"Sec8\\\" class=\\\"Section2\\\"\\u003e \\u003ch2\\u003eColor measurement\\u003c/h2\\u003e \\u003cp\\u003eThe color of dragon fruit and pulp during the various maturation stages was quantified using a Hunter-Lab Colorimeter (Lovibond). Color was assessed based on the L*, a*, and b* parameters\\u003csup\\u003e18\\u003c/sup\\u003e and the color values were expressed as CIE Lab* coordinates where L * denotes Lightness (scaled from 0 for black to 100 for white), a* represents redness (positive values indicate redness, while negative values indicate greenness), and b* indicates yellowness (positive values indicate yellowness, while negative values indicate blueness). Fruit color measurements were recorded in triplicate for each treatment from the fruit's middle section, excluding bracts, and averaged for accuracy. Pulp color values were recorded from the middle of each fruit half after vertically cutting the fruit into halves. The determination of color intensity, chroma (C*), and hue angle (hue\\u003csup\\u003e0\\u003c/sup\\u003e) were further computed from CIE a*b* values. Chroma (C*) was calculated using formula C* = (a \\u003csup\\u003e2\\u003c/sup\\u003e + b \\u003csup\\u003e\\u003cspan citationid=\\\"CR2\\\" class=\\\"CitationRef\\\"\\u003e2\\u003c/span\\u003e\\u003c/sup\\u003e) \\u003csup\\u003e\\u0026frac12;\\u003c/sup\\u003e, and hue angle (hue\\u003csup\\u003e0\\u003c/sup\\u003e) that provides insights into color perception by consumers was calculated using formula hue\\u003csup\\u003e0\\u003c/sup\\u003e\\u0026thinsp;=\\u0026thinsp;tan \\u003csup\\u003e1\\u003c/sup\\u003e(b/a)\\u003csup\\u003e19\\u003c/sup\\u003e.\\u003c/p\\u003e \\u003c/div\\u003e \\u003cdiv id=\\\"Sec9\\\" class=\\\"Section2\\\"\\u003e \\u003ch2\\u003eFruit firmness and pulp firmness\\u003c/h2\\u003e \\u003cp\\u003eThe fruit and pulp firmness of individual fruits at different developmental stages were evaluated using a texture analyzer (TA. HD plus, Stable Microsystems, England). A 2.5 mm stainless steel needle (P/2N) probe was used to puncture the fruits, and the pressure required was measured and expressed in Newtons (N). To determine fruit firmness, the whole fruit and pulp firmness and the fruit without peel were analyzed at three equidistant points on the radial axis to ensure standardized and precise firmness measurement across different stages of development.\\u003c/p\\u003e \\u003c/div\\u003e \\u003cdiv id=\\\"Sec10\\\" class=\\\"Section2\\\"\\u003e \\u003ch2\\u003eFruit peel characteristics\\u003c/h2\\u003e \\u003cp\\u003ePeel thickness and peel percentage were analyzed to determine the fruit peel characteristics. Peel thickness was measured using a Vernier Caliper (Mitutoyo 150 mm, resolution 0.02 mm) to record thickness in centimeters. Measurements were taken at different growth and developmental stages to capture changes in peel thickness over time. Peel percentage, representing the proportion of peel weight relative to total fruit weight, was calculated as Peel (%) = (Peel weight/ Fruit weight) x 100 to provide insights into the relative contribution of peel in the overall fruit structure.\\u003c/p\\u003e \\u003c/div\\u003e\"},{\"header\":\"Declarations\",\"content\":\"\\u003cp\\u003e \\u003ch2\\u003eConflict of interest:\\u003c/h2\\u003e \\u003cp\\u003eThe authors declare no conflicts of interest.\\u003c/p\\u003e \\u003c/p\\u003e\\u003ch2\\u003eAuthor Contribution\\u003c/h2\\u003e\\u003cp\\u003eConceptualisation and methodology, G.P.R, S.S and S.K.; software, validation, formal analysis, investigation, data curation, visualization, S.S., G.P.R., P.P.G., P.G. and S.K.; writing and original draft preparation, S.S., G.P.R., P.P.G., and P.G; review and editing, G.P.R., P.P.G., S.S., and S.K.; manuscript finalization, G.P.R., S.S. and S.K.; and project administration, G.P.R. and S.S. All authors have reviewed and approved the final version of the manuscript for publication.\\u003c/p\\u003e\\u003ch2\\u003eAcknowledgement\\u003c/h2\\u003e\\u003cp\\u003eThe authors gratefully acknowledge the support of commercial dragon fruit farmers for facilitating the research\\u003c/p\\u003e\\u003ch2\\u003eData Availability\\u003c/h2\\u003e\\u003cp\\u003eThe datasets used and/or analysed during the current study are available from the corresponding author on reasonable request.\\u003c/p\\u003e\"},{\"header\":\"References\",\"content\":\"\\u003col\\u003e\\u003cli\\u003e\\u003cspan\\u003eOrtiz-Hernandez, Y. D. \\u0026amp; Carilli, J. A. S. Pitahaya (\\u003cem\\u003eHylocereus\\u003c/em\\u003e spp): short review. Commun. Sci. 3(4), 220\\u0026ndash;237 (2012).\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eWakchaure, G. C., Kumar, S., Meena, K. K., Rane, J., \\u0026amp; Pathak, H. Dragon Fruit Cultivation in India: Scope, Constraints and Policy Issues. 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Foods, 11(21), 3518, DOI: \\u003cspan class=\\\"ExternalRef\\\"\\u003e\\u003cspan class=\\\"RefSource\\\"\\u003ehttps://doi.org/10.3390/foods11213518\\u003c/span\\u003e\\u003cspan address=\\\"10.3390/foods11213518\\\" targettype=\\\"DOI\\\" class=\\\"RefTarget\\\"\\u003e\\u003c/span\\u003e\\u003c/span\\u003e (2022).\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eErsan, K., Yalcin, C., \\u0026amp; Salih, A. Some physical fruit properties of cactus pear (\\u003cem\\u003eOpuntia\\u003c/em\\u003e spp.) that grow wild in the eastern Mediterranean region of Turkey. J Prof. Assoc. Cactus Dev. 1\\u0026ndash;8 (2004).\\u003c/span\\u003e\\u003c/li\\u003e\\u003c/ol\\u003e\"}],\"fulltextSource\":\"\",\"fullText\":\"\",\"funders\":[],\"hasAdminPriorityOnWorkflow\":false,\"hasManuscriptDocX\":true,\"hasOptedInToPreprint\":true,\"hasPassedJournalQc\":\"\",\"hasAnyPriority\":false,\"hideJournal\":true,\"highlight\":\"\",\"institution\":\"\",\"isAcceptedByJournal\":false,\"isAuthorSuppliedPdf\":false,\"isDeskRejected\":\"\",\"isHiddenFromSearch\":false,\"isInQc\":false,\"isInWorkflow\":true,\"isPdf\":false,\"isPdfUpToDate\":true,\"isWithdrawnOrRetracted\":false,\"journal\":{\"display\":true,\"email\":\"info@researchsquare.com\",\"identity\":\"researchsquare\",\"isNatureJournal\":false,\"hasQc\":true,\"allowDirectSubmit\":true,\"externalIdentity\":\"\",\"sideBox\":\"\",\"snPcode\":\"\",\"submissionUrl\":\"/submission\",\"title\":\"Research Square\",\"twitterHandle\":\"researchsquare\",\"acdcEnabled\":true,\"dfaEnabled\":false,\"editorialSystem\":\"\",\"reportingPortfolio\":\"\",\"inReviewEnabled\":false,\"inReviewRevisionsEnabled\":true},\"keywords\":\"\",\"lastPublishedDoi\":\"10.21203/rs.3.rs-4839398/v1\",\"lastPublishedDoiUrl\":\"https://doi.org/10.21203/rs.3.rs-4839398/v1\",\"license\":{\"name\":\"CC BY 4.0\",\"url\":\"https://creativecommons.org/licenses/by/4.0/\"},\"manuscriptAbstract\":\"\\u003cp\\u003eThe purple-fleshed dragon fruit (\\u003cem\\u003eHylocereus costaricensis\\u003c/em\\u003e) is rapidly emerging as a \\u0026lsquo;superfruit\\u0026rsquo; due to its striking color, exotic appearance, refreshing taste, exceptional nutritional and medicinal benefits, vast adaptability, and ease of cultivation. The fruit undergoes dynamic color transformations and changes in the physical attributes throughout its maturation stages, which are influenced by species and growth conditions. The study comprehensively examined color parameters and their correlation with peel characteristics and fruit and pulp firmness in the purple-fleshed dragon fruit grown under humid tropical conditions. The detailed analysis of color parameters, such as L*, a*, b*, and C* values, and hue angle, provides a clear depiction of the fruit's progression from green to purplish-red hues during maturation, with a distinct shift in color intensity and purity. The asynchronous color transition in the fruit and pulp highlights the complex nature of fruit maturation, with the pulp exhibiting an earlier color change at 25 days after flowering, followed by fruit peel at 27 days after flowering. Additionally, the investigation documented a reduction in peel thickness, peel percentage, and firmness during fruit development that emphasized the importance of these parameters in determining optimal harvest maturity. By elucidating these changes and their interrelationships, the research offers valuable insights for optimizing the harvest with better quality and marketability of purple-fleshed dragon fruit.\\u003c/p\\u003e\",\"manuscriptTitle\":\"Dynamic transformations in fruit color and textural characteristics of purple-fleshed dragon fruit (Hylocereus costaricensis) across fruit developmental stages under humid tropical climate\",\"msid\":\"\",\"msnumber\":\"\",\"nonDraftVersions\":[{\"code\":1,\"date\":\"2024-09-05 09:19:15\",\"doi\":\"10.21203/rs.3.rs-4839398/v1\",\"editorialEvents\":[{\"type\":\"communityComments\",\"content\":0}],\"status\":\"published\",\"journal\":{\"display\":true,\"email\":\"info@researchsquare.com\",\"identity\":\"researchsquare\",\"isNatureJournal\":false,\"hasQc\":true,\"allowDirectSubmit\":true,\"externalIdentity\":\"\",\"sideBox\":\"\",\"snPcode\":\"\",\"submissionUrl\":\"/submission\",\"title\":\"Research Square\",\"twitterHandle\":\"researchsquare\",\"acdcEnabled\":true,\"dfaEnabled\":false,\"editorialSystem\":\"\",\"reportingPortfolio\":\"\",\"inReviewEnabled\":false,\"inReviewRevisionsEnabled\":true}}],\"origin\":\"\",\"ownerIdentity\":\"6a217326-4b7b-47b0-b84b-9722bbb9110c\",\"owner\":[],\"postedDate\":\"September 5th, 2024\",\"published\":true,\"recentEditorialEvents\":[],\"rejectedJournal\":[],\"revision\":\"\",\"amendment\":\"\",\"status\":\"posted\",\"subjectAreas\":[{\"id\":37070649,\"name\":\"Biological sciences/Plant sciences\"},{\"id\":37070650,\"name\":\"Biological sciences/Plant sciences/Plant development\"},{\"id\":37070651,\"name\":\"Biological sciences/Plant sciences/Plant physiology\"}],\"tags\":[],\"updatedAt\":\"2024-09-30T08:39:08+00:00\",\"versionOfRecord\":[],\"versionCreatedAt\":\"2024-09-05 09:19:15\",\"video\":\"\",\"vorDoi\":\"\",\"vorDoiUrl\":\"\",\"workflowStages\":[]},\"version\":\"v1\",\"identity\":\"rs-4839398\",\"journalConfig\":\"researchsquare\"},\"__N_SSP\":true},\"page\":\"/article/[identity]/[[...version]]\",\"query\":{\"redirect\":\"/article/rs-4839398\",\"identity\":\"rs-4839398\",\"version\":[\"v1\"]},\"buildId\":\"qtupq5eGEP_6zYnWcrvyt\",\"isFallback\":false,\"isExperimentalCompile\":false,\"dynamicIds\":[84888],\"gssp\":true,\"scriptLoader\":[]}","source_license":"CC-BY-4.0","license_restricted":false}