Evaluation of the Effect of Sodium Alginate Combined with Thyme Essential Oil on the Postharvest Shelf Life of Washington Navel Orange (Citrus sinensis cv. Washington Navel)

Evaluation of the Effect of Sodium Alginate Combined with Thyme Essential Oil on the Postharvest Shelf Life of Washington Navel Orange (Citrus sinensis cv. 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Washington Navel) Hessamuddin Hamzeh, Rasool Etamadipour, Mehrdad Babarabie This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6081586/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 Citrus fruits, belonging to the Rutaceae family, are among the most widely cultivated fruits worldwide. Oranges are one of the most consumed fruits globally; however, they are prone to postharvest issues such as weight loss, decay, and physiological disorders. In an effort to enhance the storability of oranges, extensive research has been conducted on the application of edible coatings in the postharvest phase. Sodium alginate and its derivatives exhibit numerous biological activities, including antioxidant, coagulating, antimicrobial, biocompatibility, wound healing, low toxicity, and tissue engineering effects. This study investigated the effect of sodium alginate coating enriched with thyme essential oil on the quality and postharvest shelf life of Washington Navel oranges. The results demonstrated that the combined coating of sodium alginate and thyme essential oil delayed the respiratory peak, thereby preventing weight loss. Additionally, it maintained acidity and soluble solid content during storage. Similarly, the combined coatings were effective in preserving fruit firmness. Furthermore, these coatings maintained cellular membrane integrity by reducing relative electrolyte leakage, which delayed fruit senescence during long-term storage. The coatings also enhanced the total phenolic content, flavonoids, and ascorbic acid, thereby increasing the antioxidant capacity. In conclusion, sodium alginate combined with thyme essential oil can serve as a promising, effective, and non-toxic strategy for preserving the nutritional quality and membrane integrity of oranges. Alginate Thyme Preservation Antioxidants Oranges Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Introduction Citrus fruits (Citrus spp.), belonging to the Rutaceae family, are among the most widely cultivated fruits worldwide (Suri et al., 2022 ). They are rich in various bioactive compounds, including flavonoids, essential oils, carotenoids, limonoids, and synephrine, which provide protection against various diseases such as cancer, inflammatory conditions, digestive disorders, and cardiovascular diseases (Lu et al., 2023 ). Washington Navel orange ( Citrus sinensis cv. Washington Navel) is one of the most important sweet orange varieties and is highly valued for its delicious taste, nutritional properties, and seedless nature (El-Khalifa et al., 2022 ). This cultivar originates from the Bahia orange (Bahia), which was selected and cultivated in Brazil. Washington Navel oranges are large, weighing between 200 and 500 grams, and have a thick peel (El-Gioushy & Eissa, 2019 ). Despite the high production volume of oranges, significant postharvest losses occur due to improper handling and storage methods (Barsha et al., 2021 ). Preserving the quality and quantity of fruits and vegetables after harvest is crucial for economic sustainability. A recent approach to extending shelf life, maintaining nutritional benefits, and preventing physical and textural deterioration of fruits involves the application of edible coatings. These coatings form a thin, consumable layer on the fruit’s surface, creating a barrier against moisture loss, oxygen exchange, and nutrient depletion (Wang et al., 2020 ). Edible coatings are an environmentally friendly innovation designed to maximize fruit quality and longevity (Prakash et al., 2020 ). Sodium alginate-based edible coatings have demonstrated significant potential in fruit preservation (Wang et al., 2019 ). Sodium alginate and its derivatives exhibit several biological activities, including antioxidant, coagulating, antimicrobial, biocompatibility, wound healing, low toxicity, and tissue engineering effects. Additionally, sodium alginate is considered an ideal edible coating due to its biocompatibility, biodegradability, non-toxicity, physicochemical properties, rheological behavior, and film-forming ability. Dulta et al. ( 2022 ) examined the effect of sodium alginate (1%) and chitosan (0.5%) coatings enriched with nano-zinc oxide (0.5 g/L) on orange quality and found that the coatings significantly improved quality parameters compared to uncoated oranges. The coated samples exhibited lower rates of pH change, total soluble solids variation, and titratable acidity reduction. In another study, cherries coated with 3% sodium alginate demonstrated delayed weight loss, acidity reduction, softening, and color change (Chiabrando & Giacalone, 2015 ). Similarly, an experiment on strawberries revealed that a sodium alginate-calcium chloride edible coating effectively reduced respiration rate and transpiration while delaying pH increase and soluble solids accumulation. Additionally, the coating preserved the sensory properties of sliced strawberries, such as color and texture (Alharaty & Ramaswamy, 2020 ). Garden thyme (Thymus vulgaris), belonging to the Lamiaceae family, is widely recognized in traditional medicine for its expectorant, antitussive, bronchodilatory, antispasmodic, carminative, and diuretic properties (Borug et al., 2014 ). Thyme essential oil contains over 40% phenolic compounds, primarily thymol and carvacrol, which possess strong antimicrobial properties. Key components of thyme essential oil include thymol, carvacrol, linalool, γ-terpinene, p-cymene, β-myrcene, and terpinen-4-ol (Nadi et al., 2023 ). In a study examining the effects of a sodium alginate (SA) and thyme essential oil (TEO) coating on fresh pistachios, treated samples exhibited lower weight loss and superior quality indices compared to untreated samples, with the highest sensory scores observed in the SA-TEO coated pistachios (Shakerardekani et al., 2021 ). Fatemi et al. ( 2011 ) investigated the impact of natural essential oils, including thyme and peppermint, on controlling green mold and improving postharvest orange quality. Their results indicated that thyme essential oil exhibited strong antifungal properties against citrus fungal diseases. Similarly, Akbari et al. ( 2024 ) evaluated the effects of thyme essential oil on the microbial and physiological quality of green bell peppers, finding that it minimized peroxidase activity and respiration rate without adversely affecting texture, total phenolic content, antioxidant activity, pH, or soluble solids. This treatment contributed to the extended shelf life and improved postharvest quality of bell peppers. Despite extensive research on sodium alginate and thyme essential oil-based edible coatings in postharvest fruit preservation, no study has specifically investigated the combined effect of sodium alginate and thyme essential oil coatings on the postharvest shelf life of Washington Navel oranges. Therefore, this study aims to evaluate the application of a sodium alginate-thyme essential oil edible coating on the postharvest quality and shelf life of Washington Navel oranges. Materials and Methods This study was conducted as a factorial experiment in a completely randomized design during the 2023–2024 period in the Plant Physiology Laboratory of the Department of Agriculture, Hormozgan University. In this research, edible sodium alginate coating (chemical formula: C₆H₉NaO₇) was purchased from Sigma Company. Thyme essential oil was obtained from Ayat Essences Company, Tehran. Experimental Treatments The experimental treatments included: AS1: Sodium alginate at a concentration of 1% AS2: Sodium alginate at a concentration of 2% E1: Thyme essential oil at a concentration of 150 mg/L E2: Thyme essential oil at a concentration of 300 mg/L E1 + AS1: 1% sodium alginate combined with 150 mg/L thyme essential oil E2 + AS1: 1% sodium alginate combined with 300 mg/L thyme essential oil E1 + AS2: 2% sodium alginate combined with 150 mg/L thyme essential oil E2 + AS2: 2% sodium alginate combined with 300 mg/L thyme essential oil C: Control Each treatment was conducted in three replications, with three oranges per replication, evaluated at three time intervals (0, 30, and 60 days). Measured Traits At the beginning of the experiment (T0), the following parameters were measured: fruit firmness, total soluble solids (TSS), ascorbic acid, titratable acidity (TA), total phenolic content, flavonoids, antioxidant capacity, and ion leakage. After 30 (T1) and 60 (T2) days, in addition to the mentioned traits, fruit decay and weight loss percentage were also evaluated. Weight Loss Percentage To determine the percentage of weight loss, the weight of all fruits in each container (three fruits together) was measured at the beginning of the experiment and again at 30 and 60 days using a digital scale with an accuracy of 0.01 g. Finally, weight loss percentage was calculated using Eq. (1). Equation 1: Weight loss percentage= (Initial weight / (Final weight - Initial weight) ×100 Firmness Fruit firmness was measured using a Lutron FS-1001 penetrometer equipped with a cylindrical probe (8 mm diameter). The applied force was recorded in Newtons. Total Soluble Solids (TSS) TSS content was determined using a Prismatic PTRP100 refractometer. A single drop of orange juice was placed on the device's prism, and the TSS value was recorded in Brix degrees (Ayala-Zavala et al., 2007 ). Titratable Acidity (TA) Titratable acidity was determined using the Ayala-Zavala method with slight modifications, and its value was calculated using Eq. 2 (Ayala-Zavala et al., 2007 ). Equation 2: $$\:\text{T}\text{A}=\:\left(\frac{\text{V}\text{o}\text{l}\text{u}\text{m}\text{e}\:\text{o}\text{f}\:\text{N}\text{a}\text{O}\text{H}\:\text{c}\text{o}\text{n}\text{s}\text{u}\text{m}\text{e}\text{d}\times\:\:\text{N}\text{o}\text{r}\text{m}\text{a}\text{l}\text{i}\text{t}\text{y}\:\text{o}\text{f}\:\text{a}\text{c}\text{i}\text{d}\:\text{e}\text{q}\text{u}\text{i}\text{v}\text{a}\text{l}\text{e}\text{n}\text{t}}{\text{S}\text{a}\text{m}\text{p}\text{l}\text{e}\:\text{v}\text{o}\text{l}\text{u}\text{m}\text{e}}\right)\times\:100$$ Ascorbic Acid Ascorbic acid (Vitamin C) was determined using the Etemadipoor method. A 100 µL sample of orange juice was added to a test tube containing 10 mL of 1% metaphosphoric acid and vortexed for 10 seconds. Then, 1000 µL (1 mL) of this mixture was transferred to 9 mL of indophenol solution and vortexed again for 10 seconds. The absorbance of the samples was read at 515 nm using an ELISA reader. In this experiment, 1% metaphosphoric acid was used as a blank (Etemadipoor et al., 2019 ). Antioxidant Capacity To prepare the methanolic extract of the juice, a 1:3 ratio of orange juice to 85% methanol was used. Antioxidant capacity was measured using the DPPH free radical scavenging assay. In this experiment, 85% methanol was used as a blank, and the DPPH solution served as the control (Sheng et al., 2018 ). The percentage of free radical inhibition was calculated using Eq. (3). Equation 3: Antioxidant capacity = [(AC - OD) / AC] × 100 Where AC represents the absorbance of the control and OD represents the absorbance of the samples. Total Phenols Total phenolic content was determined using the Folin-Ciocalteu reagent. A 150 µL sample of methanolic extract was transferred to a 2 mL microtube, and 750 µL of 10% Folin-Ciocalteu reagent (Merck) was added. After 5 minutes, 600 µL of 7% sodium carbonate was added. The samples were incubated for 90 minutes in the dark on a shaker (TSHAKER-M model). The total phenolic content was then measured at 760 nm using an ELISA reader (Singleton & Rossi, 1965 ). Flavonoids Flavonoid content was measured using the aluminum chloride (AlCl3) colorimetric method. A 100 µL methanolic extract was placed in a 2 mL microtube, and 300 µL of 85% methanol was added. Then, 20 µL of 10% aluminum chloride and 20 µL of 1 M potassium acetate were added. Finally, 560 µL of distilled water was added, and the mixture was shaken for 30 minutes in the dark. The absorbance was then measured at 415 nm using an ELISA reader (Chang et al., 2002 ). Ion Leakage Ion leakage was measured using the method described by Masoumi et al. ( 2012 ). A 0.5 g sample of orange peel was placed in a 50 mL Falcon tube with 20 mL of distilled water and left for 24 hours. After 24 hours, the initial electrical conductivity (EC1) was measured using a Temp AD3000 EC meter. The samples were then incubated in a water bath at 100°C for one hour. After cooling to 25°C, the final electrical conductivity (EC2) was recorded. Ion leakage percentage was calculated using Eq. (4). Equation 4: Ion leakage = (EC1 / EC2) × 100 Sensory Evaluation For sensory evaluation (panel test), three trained panelists were asked to score the juiciness, aroma, taste, and appearance of the oranges on a 1–5 scale at both evaluation times (Shah Beik, 1999). Statistical Analysis The final data were analyzed using SAS software. Mean comparisons were performed using LSD at a 5% probability level. Graphs were drawn using Excel software. Results and Discussion Effect of Treatments on Fruit Skin Firmness Variance analysis of the data indicated that the effect of sodium alginate, garden thyme essential oil, storage time, and their interaction was significant at the 1% level (Table 1 ). The results of mean comparisons showed that after 30 days, the lowest firmness was observed in the control group, and the highest firmness at this time was observed in the As1E1 treatment. After 60 days of storage, the lowest firmness was seen in the control treatment, and the highest firmness was also observed in the As1E1 treatment (Fig. 1 ). It appears that the treatments had a positive effect on the percentage of weight loss, which may be due to the role of sodium alginate in stabilizing the cell membrane. Sodium alginate enriched with essential oils significantly increases the shelf life of fruits. Sodium alginate containing essential oils acts as a barrier to reduce gas exchange, thus preventing tissue softening by slowing down respiration (Díaz-Mula et al., 2012 ). A study found that grapes treated with a combination of sodium alginate and essential oils showed higher firmness compared to untreated samples (Wang et al., 2020 ). In pineapple, fruit coated with sodium alginate along with lemongrass essential oil and sodium alginate enriched with antioxidants and olive oil showed higher firmness compared to the control group (Azarakhsh et al., 2014 ; Ramana Rao et al., 2016 ). Table 1 Analysis of variance for some traits evaluated in the study. Source of Variation df Mean Squares Firmness Ion Leakage Panel Test TSS TA Treatments 8 9.90 ** 268.56 ** 0.76 * 1.11 ** 0.23 ** Time 2 812.57 ** 3024.54 ** 6.02 ** 150.57 ** 0.93 ** Treatment × Time 16 3.11 ** 160.79 ** 0.52 ** 0.64 * 0.11 ** Error 54 0.49 21.28 0.47 0.32 0.16 Total Error 80 - - - - - CV (%) - 3.15 6.42 16.8 3.85 16.89 * Significant at 5% level, ** Significant at 1% level, ns non-significant Effect of Treatments on Ion Leakage According to the results in the analysis of variance table, the effect of the experimental treatments and their interaction on the ion leakage trait was significant at the 1% level. The results of mean comparisons showed that the highest ion leakage was observed in the control treatment at 60 days of storage, with significant differences compared to all other treatments at 30 days of storage, except for the control. The lowest ion leakage was observed in the As2E2 treatment (Fig. 2 ). Ion leakage is an indicator used to assess the integrity of the cell membrane and its permeability. Maintaining the structural integrity of cells during the fruit ripening process is crucial for cell survival. Increased ion leakage is mainly due to cell degradation and increased membrane permeability (Sinha et al., 2022 ). However, the sodium alginate coating with garden thyme essential oil, both individually and in combination, was effective in reducing ion leakage. Similar results were observed in peaches coated with sodium alginate along with rhubarb extract (Li et al., 2019 ). Effect of Treatments on Sensory Evaluation The results from the analysis of variance table indicated that the treatments of sodium alginate, garden thyme, and their combination were significant at the 5% level, while storage time and their interaction were significant at the 1% level for sensory evaluation (Table 1 ). The results of mean comparisons showed that the lowest score was observed in the control treatment at both 30 and 60 days of storage, while the highest score was observed in the As2E2 treatment at 30 days of storage, with a significant difference compared to the control (Fig. 3 ). The agricultural and food sectors are required to evaluate the organoleptic properties of oranges through sensory analysis. This type of analysis is related to consumer perception, as food is evaluated through the senses using organoleptic properties such as appearance, smell, aroma, texture, and taste (Villaseñor-Aguilar et al., 2024 ). In this experiment, the sensory properties of the oranges were evaluated using a panel test. The results showed that sensory scores decreased over time, and the application of treatments at all levels improved the overall quality of the samples. Furthermore, the results indicated that the combined treatments of sodium alginate and garden thyme essential oil were the most effective. These results are consistent with findings from research by Megha et al. on pears, Fatemi et al. on oranges, and Shabani et al. on oranges (Shabani et al., 2015, Fatemi et al., 2012; Megha et al., 2023). Effect of Treatments on Total Soluble Solids (TSS) Based on the results shown in the analysis of variance table, the effect of sodium alginate, garden thyme, and storage time was significant at the 1% level, while their interactions were significant at the 5% level on the total soluble solids (TSS) content (Table 1 ). The results of mean comparisons indicated that the control treatment at 60 days of storage had the highest TSS, while the lowest TSS was observed in the As1E1 treatment. In the 30-day storage samples, the control also had the highest TSS (Fig. 4 ). The treatments showed a slight increase in TSS compared to the control, which might be due to the formation of a physical barrier by the coating materials, reducing transpiration losses. The highest TSS in the control may be attributed to faster metabolic activities through respiration and transpiration in the control compared to the other treatments. Similar observations have been reported by Rokaya et al. ( 2016 ) for different mandarin orange varieties and Thapa et al. ( 2020 ) for sweet oranges. Effect of Treatments on Titratable Acidity (TA) According to the results from the analysis of variance, the effect of sodium alginate, garden thyme essential oil, storage time, and the interaction between the treatments and time were significant at the 1% level on titratable acidity (TA) (Table 1 ). Based on the results of mean comparisons, the highest titratable acidity was observed in the E2 and As1E1 treatments, which showed a significant difference compared to the control at both 30 and 60 days of storage (Fig. 5 ). In this study, the titratable acidity in all coated treatments was lower than in the control. This might be due to reduced acid utilization during respiration in fruits treated with sodium alginate and garden thyme essential oil, while faster acid utilization during respiration was observed in the control fruits during storage. Rokaya et al. ( 2016 ) and Khorram et al. ( 2017 ) reported the highest TA in the control compared to fruits treated with different coating materials in mandarin and Kinnow mandarin, respectively (Khorram et al., 2017 ; Rokaya et al., 2016 ). Effect of Treatments on Weight Loss According to the analysis of variance table, the effect of sodium alginate, garden thyme essential oil, storage time, and their interactions on the percentage of weight loss in oranges was significant at the 1% level (Table 2 ). The results of mean comparisons also showed that after 30 days of storage, the control sample had the highest weight loss, and the lowest percentage of weight loss was observed in the As2E1 treatment. In the samples after 60 days of storage, the highest weight loss was observed in the control, and the lowest weight loss was observed in the As2E2 treatment (Fig. 6 ). The edible coating of sodium alginate acts as a semi-permeable barrier to limit water exchange. This reduces moisture loss, respiration rate, oxidative reactions, and delays the physiological aging of fruits (A. Wang et al., 2020 ). Garden thyme essential oil was added to sodium alginate to delay moisture loss and preserve other sensory characteristics. Adding essential oils and surfactants improves the water retention ability of the coating (Shakerardekani et al., 2021 ). The results of this study are consistent with the findings of Shakerardekani et al. on pistachio (Pistacia vera), Utami et al. on strawberries (Fragaria sp), Linh et al. on Darabi (Citrus maxima), and Dulta et al. on oranges (Citrus sinensis L.) (Dulta et al., 2022 ; Linh et al., 2024 ; Shakerardekani et al., 2021 ; Utami et al., 2023 ). Table 2 Analysis of variance for some evaluated traits in the study Source of Variation df Mean Squares Weight Loss Total Phenols Flavonoids Antioxidant Capacity Ascorbic Acid Treatments 8 55.73 ** 1627.59 ** 0.23 ** 18.71 ** 11.43 ** Time 2 123967.26 ** 70370.73 ** 7.96 ** 6296.11 ** 1631.38 ** Treatment × Time 16 53.59 ** 1700.03 ** 0.14 ** 11.29 ** 10.23 ** Experimental Error 54 2.5 780.02 0.22 0.4 3.54 Total Error 80 - - - - - CV (%) - 1.99 22.49 19.41 1.82 1.99 * Significant at 5% level, ** Significant at 1% level, ns non-significant Effect of Treatments on Total Phenol Content The results of the analysis of variance showed that the effect of sodium alginate and garden thyme at the 5% level, as well as storage time and the interaction of time and treatments, was significant at the 1% level for total phenol content (Table 2 ). The mean comparison results indicated that in the samples after 30 days of storage, the highest phenol content was observed in the control treatment, and the lowest phenol content was in the E1 treatment. In the samples after 60 days, the highest total phenol content was observed in the control, while the lowest total phenol content was observed in the garden thyme treatment with a concentration of 150 mg/L (Fig. 7 ). Edible coatings reduce the loss of polyphenols and maintain a higher antioxidant capacity during post-harvest storage of cherries (Díaz-Mula et al., 2012 ). Studies on plums and apricots have reported that coatings reduce the ripening rate, thereby delaying the onset of aging and reducing cellular structural degradation. Additionally, coatings reduce respiration, decrease the available oxygen for metabolic activities in the fruit, and consequently reduce the activity of phenol oxidase and peroxidase (Ghasemnezhad et al., 2010 ; Kumar et al., 2017 ; Thakur et al., 2018 ). A continuous increase in phenolic compounds was observed in cherries coated with alginate during cold storage. Thus, the coating allows for the accumulation of phenolic compounds throughout storage without any reduction (Díaz-Mula et al., 2012 ). Effect of Treatments on Total Flavonoids According to the results of the analysis of variance, the effect of sodium alginate, garden thyme, storage duration, and their interaction was significant at the 1% level for flavonoid content (Table 4). The mean comparison results showed that in the samples after 30 days of storage, the highest flavonoid content was observed in the As1E1 treatment, while the lowest flavonoid content was in the As1 treatment. In the samples after 60 days of storage, the highest flavonoid content was observed in the As2E2 treatment, and the lowest flavonoid content was in the E2 treatment (Fig. 8 ). Research has shown that flavonoid content can be influenced by fruit ripening, post-harvest treatments, and extraction processes (Addi et al., 2022 ; Tai et al., 2014 ). In the present study, the results showed that flavonoid content increased over time. This might be due to the increase in flavonoid levels during storage, which enhances antioxidant properties and helps combat oxidative stress. Additionally, sodium alginate coating combined with garden thyme essential oil maintains flavonoid content by controlling the activity of the mentioned enzymes. These results align with studies on flavonoids in citrus fruits (Addi et al., 2022 ; Díaz-Mula et al., 2012 ; Riva et al., 2020 ; Thakur et al., 2018 ). Effect of Treatments on Antioxidant Capacity and Ascorbic Acid Content The results from the analysis of variance indicated that the effect of sodium alginate, garden thyme essential oil, storage duration, and their interaction on the antioxidant capacity of the fruits was significant at the 1% level (Table 2 ). The mean comparison results showed that with the increase in storage time, the antioxidant capacity also increased, and at each time point, the control sample differed significantly from the other treatments (Fig. 9 ). According to the variance table, the effect of sodium alginate, garden thyme essential oil, storage duration, and their interaction on ascorbic acid (vitamin C) content in oranges was significant at the 1% level (Table 2 ). The mean comparison results indicated that after 60 days, the highest ascorbic acid content was observed in the As2E2 treatment, while the lowest content was in the control sample. For the 30-day storage samples, no significant differences were observed among the treatments (Fig. 10 ). Fruits are rich in minerals, vitamins, and antioxidants that protect against cancer and cardiovascular diseases. However, improper storage of fruits has adverse effects on their quality, such as browning, off-flavors, loss of soluble solids, and decreased antioxidant activity (Barzegar et al., 2018 ). Rahami et al. ( 2023 ) reported that during storage, ascorbic acid is highly susceptible to degradation due to oxidation compared to other nutrients. By maintaining membrane stability, the binding of free radicals and reactive oxygen species to the membrane surface can be prevented, thereby preserving antioxidants such as ascorbic acid. The reduction in antioxidant capacity of the fruits during storage can be explained by the fact that ascorbic acid is converted by the enzyme ascorbate oxidase into dehydroascorbate, and by phenol oxidase (Linh et al., 2024 ). A study on cherries showed that sodium alginate coating was effective in preserving antioxidants in cherries, with an increase in anthocyanins, phenolics, delayed loss of titratable acidity, and ascorbic acid content during 21 days of storage at 4°C. It was also reported that sodium alginate coating significantly reduced active oxygen levels, decreased the activity of defense enzymes, and preserved total soluble solids, titratable acidity, and ascorbic acid content, which resulted in increased antioxidant activity (Chiabrando & Giacalone, 2015 ). It was also reported that sodium alginate edible coatings combined with essential oils exhibited higher antioxidant activity. Similarly, sodium alginate coatings enriched with citral and eugenol helped preserve antioxidant activity, anthocyanins, and phenolics in raspberries and fresh apples during refrigeration storage. Sodium alginate, by creating a semi-permeable barrier around the fruit and inhibiting ethylene production, helps preserve the antioxidant activity of fruits (Guerreiro et al., 2016 ; A. Wang et al., 2020 ). Conclusion Washington Navel oranges, although a non-climacteric fruit, have a high rate of perishability. One of the strategies to increase shelf life and reduce decay in post-harvest processes is treating the fruits with edible coatings. Edible coatings are an innovative solution used to preserve the quality and shelf life of fruits. Sodium alginate coatings combined with plant essential oils can have a significant impact on the shelf life of fruits. In this study, a sodium alginate edible coating with garden thyme essential oil was used to preserve the quality of Washington Navel oranges during storage. The results showed that the combined sodium alginate coating and garden thyme essential oil delayed the increase in respiration rate, reduced the percentage of weight loss, firmness, and ion leakage. It also preserved the soluble solids content during storage and increased antioxidant activity by enhancing the content of flavonoids, phenolics, and ascorbic acid. Declarations Funding This research was not financially supported by any government or private organization. Author Contribution H.H: Conducting laboratory work and measuring factors.R.E: Owning the idea and paying for laboratory materials.M.B: Writing the article. Data Availability https://ostad.hormozgan.ac.ir/ostad/resualtfni?m=388016 References Addi, M., Elbouzidi, A., Abid, M., Tungmunnithum, D., Elamrani, A., & Hano, C. (2022). An Overview of Bioactive Flavonoids from Citrus Fruits. Applied Sciences (Switzerland) , 12 (1), 1–15. https://doi.org/10.3390/app12010029 Akbari, S., Radi, M., Hosseinifarahi, M., & Amiri, S. 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Journal of Polymers and the Environment , 30 (8), 3293–3306. https://doi.org/10.1007/s10924-022-02411-7 El-Gioushy, S. F., & Eissa, M. A. (2019). Effectiveness of Different NPK Fertilization Sources on Growth, Nutritional Status, Productivity and Fruit Quality of Washington Navel Orange Trees. Journal of Horticultural Science & Ornamental Plants , 11 (2), 134–143. https://doi.org/10.5829/idosi.jhsop.2019.134.143 El-Khalifa, Z. S., ElSheikh, M. H., Zahran, H. F., & Ayoub, A. (2022). Evaluation of Washington Navel Orange Economic Indicators. Open Journal of Applied Sciences , 12 (04), 481–490. https://doi.org/10.4236/ojapps.2022.124033 Etemadipoor, R., Ramezanian, A., Dastjerdi, A. M., & Shamili, M. (2019). The potential of gum arabic enriched with cinnamon essential oil for improving the qualitative characteristics and storability of guava (Psidium guajava L.) fruit. Scientia Horticulturae , 251 , 101–107. Fatemi, S., Jafarpour, M., Eghbalsaied, S., Rezapour, A., & Borji, H. (2011). 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Kumar, P., Sethi, S., Sharma, R. R., Srivastav, M., & Varghese, E. (2017). Effect of chitosan coating on postharvest life and quality of plum during storage at low temperature. Scientia Horticulturae , 226 , 104–109. Li, X., Du, X., Liu, Y., Tong, L., Wang, Q., & Li, J. (2019). Rhubarb extract incorporated into an alginate-based edible coating for peach preservation. Scientia Horticulturae , 257 , 108685. Linh, C. T. M., Ngoc, V. D., Phat, D. T., Phong, H. X., Quy, N. N., Tung, N. T. X., & Nhi, T. T. Y. (2024). Effectiveness of sodium alginate-based coating on the preservation of Da xanh pomelo fresh-cut. Applied Food Research , 4 (1), 100426. https://doi.org/10.1016/j.afres.2024.100426 Linh, C. T. M., Ngoc, V. D., Phat, D. T., Phong, H. X., Quy, N. N., Tung, N. T. X., & Nhi, T. T. Y. (2024). Effectiveness of sodium alginate-based coating on the preservation of Da xanh pomelo fresh-cut. Applied Food Research , 4 (1), 100426. https://doi.org/10.1016/j.afres.2024.100426 Lu, X., Zhao, C., Shi, H., Liao, Y., Xu, F., Du, H., Xiao, H., & Zheng, J. (2023). Nutrients and bioactives in citrus fruits: Different citrus varieties, fruit parts, and growth stages. Critical Reviews in Food Science and Nutrition, 63(14), 2018–2041. https://doi.org/10.1080/10408398.2021.1969891 Masoumi, A., Kafi, M., Nabati, J., Khazaei, H., Davari, K., Zarei Mehrjerdi, M. (2012). "Effect of drought stress on water status and electrolyte leakage of leaves, photosynthesis, and chlorophyll fluorescence in different growth stages of two Kochia (Kochia scoparia) populations under saline conditions," Iranian Agronomy Research, 10(3), pp. 476-484. doi: 10.22067/gsc.v10i3.17666 Nadi, A., Shiravi, A. A., Mohammadi, Z., Aslani, A., & Zeinalian, M. (2023). Thymus vulgaris, a natural pharmacy against COVID-19: A molecular review. Journal of Herbal Medicine , 38 (January). https://doi.org/10.1016/j.hermed.2023.100635 Prakash, A., Baskaran, R., & Vadivel, V. (2020). Citral nanoemulsion incorporated edible coating to extend the shelf life of fresh cut pineapples. Lwt , 118 , 108851. Rahami, M . , Nezaran, M H . , Abolghasemi, S . , Sedeqat, S., Zarei, M. (2023). Effect of postharvest hot water, calcium chloride, and calcium nanochelate fertilizer application on reducing frost damage and increasing the shelf life of 'Mahalli Darab' orange fruit. Horticultural Science; 37(3): 801-819. doi: 10.22067/jhs.2023.79650.1209. Ramana Rao, T. V, Baraiya, N. S., Vyas, P. B., & Patel, D. M. (2016). Composite coating of alginate-olive oil enriched with antioxidants enhances postharvest quality and shelf life of Ber fruit (Ziziphus mauritiana Lamk. Var. Gola). Journal of Food Science and Technology , 53 , 748–756. Riva, S. C., Opara, U. O., & Fawole, O. A. (2020). Recent developments on postharvest application of edible coatings on stone fruit: A review. Scientia Horticulturae , 262 (November 2019), 109074. https://doi.org/10.1016/j.scienta.2019.109074 Rokaya, P. R., Baral, D. R., Gautam, D. M., Shrestha, A. K., & Paudyal, K. P. (2016). Effect of postharvest treatments on quality and shelf life of mandarin (Citrus reticulata Blanco). American Journal of Plant Sciences , 7 (7), 1098–1105. Saini, R. K., Ranjit, A., Sharma, K., Prasad, P., Shang, X., Gowda, K. G. M., & Keum, Y.-S. (2022). Bioactive compounds of citrus fruits: A review of composition and health benefits of carotenoids, flavonoids, limonoids, and terpenes. Antioxidants , 11 (2), 239. Shabaniyan, Z., Fattahi Moghaddam, J., Alavi, S A. (2015). Investigation of the possibility of preserving the quality of Thomson Navel orange (Citrus sinensis cv. Thomson Navel) fruit using coating treatments in ordinary storage. Journal of Iranian Food Science and Technology Research; 11(4): 458-472. doi: 10.22067/ifstrj.v1394i11.31370 Shahbik, M A. (1999). Effects of heat quarantine treatment and modified atmosphere in fruit packaging on the storage life of 'Washington Navel' and 'Valencia' oranges. Agricultural Sciences, 30(1), 0-0. SID. https://sid.ir/paper/424705/fa Shakerardekani, A., Hashemi, M., Shahedi, M., & Dastjerdi, A. M. (2021). Enhancing the quality of fresh pistachio fruit using sodium alginate enriched with thyme essential oil. Journal of Agricultural Science and Technology , 23 (1), 65–82. Shakerardekani, A., Hashemi, M., Shahedi, M., & Dastjerdi, A. M. (2021). Enhancing the quality of fresh pistachio fruit using sodium alginate enriched with thyme essential oil. Journal of Agricultural Science and Technology , 23 (1), 65–82. Sheng, K., Zheng, H., Shui, S. S., Yan, L., Liu, C., & Zheng, L. (2018). Comparison of postharvest UV-B and UV-C treatments on table grape: Changes in phenolic compounds and their transcription of biosynthetic genes during storage. Postharvest Biology and Technology , 138 (August 2017), 74–81. https://doi.org/10.1016/j.postharvbio.2018.01.002 Singleton, V. L., & Rossi, J. A. (1965). Colorimetry of total phenolics with phosphomolybdic-phosphotungstic acid reagents. American Journal of Enology and Viticulture , 16 (3), 144–158. Sinha, A., Gill, P. P. S., Jawandha, S. K., Kaur, P., & Grewal, S. K. (2022). Salicylic acid enriched beeswax coatings suppress fruit softening in pears by modulation of cell wall degrading enzymes under different storage conditions. Food Packaging and Shelf Life , 32 , 100821. Suri, S., Singh, A., & Nema, P. K. (2022). Current applications of citrus fruit processing waste: A scientific outlook. Applied Food Research, 2(1), 100050.https://doi.org/10.1016/j.afres.2022.100050 Tai, D., Tian, J., Zhang, J., Song, T., & Yao, Y. (2014). A Malus crabapple chalcone synthase gene, McCHS, regulates red petal color and flavonoid biosynthesis. PLoS One , 9 (10), e110570. Thakur, R., Pristijono, P., Golding, J. B., Stathopoulos, C. E., Scarlett, C. J., Bowyer, M., Singh, S. P., & Vuong, Q. V. (2018). Development and application of rice starch based edible coating to improve the postharvest storage potential and quality of plum fruit (Prunus salicina). Scientia Horticulturae , 237 , 59–66. Thapa, S., Sapkota, S., & Adhikari, D. (2020). Sustainability in Food and Agriculture ( SFNA ) EFFECT OF DIFFERENT POSTHARVEST TREATMENTS ON PROLONGING SHELF LIFE AND MAINTAINING QUALITY OF SWEET ORANGE ( Citrus sinensis Osbeck .) . 1 (2), 69–75. Utami, R., Annisa, R. R., Praseptiangga, D., Nursiwi, A., Sari, A. M., Ashari, H., Ikarini, I., & Hanif, Z. (2023). Effect of edible coating sodium alginate with addition of siam pontianak tangerine peel essential oil (Citrus suhuinensis cv Pontianak) on the physical quality of strawberries (Fragaria ananassa) during refrigeration temperature storage. IOP Conference Series: Earth and Environmental Science , 1200 (1), 0–8. https://doi.org/10.1088/1755-1315/1200/1/012058 Villaseñor-Aguilar, M. J., Cano-Lara, M., Lopez, A. R., Rostro-Gonzalez, H., Padilla-Medina, J. A., & Barranco-Gutiérrez, A. I. (2024). Fuzzy Classification of the Maturity of the Orange (Citrus × sinensis) Using the Citrus Color Index (CCI). Applied Sciences (Switzerland) , 14 (13). https://doi.org/10.3390/app14135953 Wang, A., Siddique, B., Wu, L., Ahmad, I., Liu, X., & Province, H. (2020). Sodium alginate edible coating augmented with essential oils maintains fruits postharvest physiology during preservation : A review . 135–140. Wang, X., Zhang, Y., Liang, H., Zhou, X., Fang, C., Zhang, C., & Luo, Y. (2019). Synthesis and properties of castor oil-based waterborne polyurethane/sodium alginate composites with tunable properties. Carbohydrate Polymers , 208 , 391–397. 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-6081586","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":421949504,"identity":"7b85d018-5294-4fec-91b1-6d3093f92e08","order_by":0,"name":"Hessamuddin Hamzeh","email":"","orcid":"","institution":"University of Hormozgan","correspondingAuthor":false,"prefix":"","firstName":"Hessamuddin","middleName":"","lastName":"Hamzeh","suffix":""},{"id":421949505,"identity":"c7b7aa59-7d80-4c24-abc8-160f23bc523a","order_by":1,"name":"Rasool Etamadipour","email":"data:image/png;base64,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","orcid":"","institution":"University of Hormozgan","correspondingAuthor":true,"prefix":"","firstName":"Rasool","middleName":"","lastName":"Etamadipour","suffix":""},{"id":421949506,"identity":"075be9c0-6ac0-48ec-b9eb-b7a99ce59cc1","order_by":2,"name":"Mehrdad Babarabie","email":"","orcid":"","institution":"University of Hormozgan","correspondingAuthor":false,"prefix":"","firstName":"Mehrdad","middleName":"","lastName":"Babarabie","suffix":""}],"badges":[],"createdAt":"2025-02-21 18:23:15","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6081586/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6081586/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":77616976,"identity":"078d4bbc-559d-47c1-99a6-35cc94cfd310","added_by":"auto","created_at":"2025-03-03 15:07:03","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":19002,"visible":true,"origin":"","legend":"\u003cp\u003eComparison of the mean interaction effects of treatments on fruit firmness.\u003cbr\u003e\nIn the figure above, the letters \"As\" and \"E\" represent sodium alginate and thyme essential oil, respectively. (Means with similar letters do not show a significant difference at the 5% level.)\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-6081586/v1/e8b9cd34eeafc8785a37d6ac.png"},{"id":77618353,"identity":"b18dc2d4-d097-4a40-b14d-fc8672ad7fe3","added_by":"auto","created_at":"2025-03-03 15:15:03","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":19049,"visible":true,"origin":"","legend":"\u003cp\u003eComparison of the mean interaction effects of treatments on ion leakage.\u003cbr\u003e\nIn the figure above, the letters \"As\" and \"E\" represent sodium alginate and thyme essential oil, respectively. (Means with the same letters are not significantly different at the 5% level.)\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-6081586/v1/7e6b1159d44dc123504c2d4c.png"},{"id":77616978,"identity":"2c268a3a-10a1-40b1-922b-af9f9a4a6ea0","added_by":"auto","created_at":"2025-03-03 15:07:03","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":19565,"visible":true,"origin":"","legend":"\u003cp\u003eComparison of the mean interaction effects of treatments on sensory evaluation.\u003cbr\u003e\nIn the figure above, the letters \"As\" and \"E\" represent sodium alginate and thyme essential oil, respectively. (Means with the same letters are not significantly different at the 5% level.)\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-6081586/v1/c6bca51795c23cbe674fb892.png"},{"id":77616979,"identity":"1a7ce0bf-a648-476a-b9c6-dcfe37ceb544","added_by":"auto","created_at":"2025-03-03 15:07:03","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":21782,"visible":true,"origin":"","legend":"\u003cp\u003eComparison of the mean interaction effects of treatments on total soluble solids. \u003cbr\u003e\nIn the figure above, the letters As and E represent sodium alginate and garden thyme essential oil, respectively (means with the same letters do not have a significant difference at the 5% level).\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-6081586/v1/cc0e5141d3ed96f6fcaf18ca.png"},{"id":77618354,"identity":"5f74dba3-d989-4774-86f5-0db2f5b27b22","added_by":"auto","created_at":"2025-03-03 15:15:03","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":19396,"visible":true,"origin":"","legend":"\u003cp\u003eComparison of the mean effect of the treatments on TA. \u003cbr\u003e\nIn the figure above, the letters As and E represent sodium alginate and garden thyme essential oil, respectively (means with similar letters do not show significant differences at the 5% level).\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-6081586/v1/a9b18b622aea6c1756e62c56.png"},{"id":77616982,"identity":"00bddd24-33a7-4b4a-99e8-8fb49059b595","added_by":"auto","created_at":"2025-03-03 15:07:04","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":16115,"visible":true,"origin":"","legend":"\u003cp\u003eComparison of the mean effect of the treatments on weight loss percentage. \u003cbr\u003e\nIn the figure above, the letters As and E represent sodium alginate and garden thyme essential oil, respectively (means with similar letters do not show significant differences at the 5% level).\u003c/p\u003e","description":"","filename":"6.png","url":"https://assets-eu.researchsquare.com/files/rs-6081586/v1/7f78d7dbc7ea702463646eaa.png"},{"id":77616985,"identity":"830aaa09-1855-42e9-8472-4a60deb6027b","added_by":"auto","created_at":"2025-03-03 15:07:04","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":19817,"visible":true,"origin":"","legend":"\u003cp\u003eComparison of the mean interaction effects of treatments on total phenol content.\u003cbr\u003e\nIn the figure above, the letters As and E represent sodium alginate and garden thyme essential oil, respectively (means with similar letters are not significantly different at the 5% level).\u003c/p\u003e","description":"","filename":"7.png","url":"https://assets-eu.researchsquare.com/files/rs-6081586/v1/bf9dc39636fe1fe58dd08414.png"},{"id":77618358,"identity":"a84d775b-4c53-466f-9cc3-5f9288a36fb2","added_by":"auto","created_at":"2025-03-03 15:15:04","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":17911,"visible":true,"origin":"","legend":"\u003cp\u003eComparison of the interaction effect of treatments on flavonoids.\u003cbr\u003e\nIn the figure above, the letters \"As\" and \"E\" represent sodium alginate and garden thyme essential oil, respectively (Means with similar letters are not significantly different at the 5% level).\u003c/p\u003e","description":"","filename":"8.png","url":"https://assets-eu.researchsquare.com/files/rs-6081586/v1/1b465c93dbf8fcecba5a977e.png"},{"id":77620005,"identity":"f9ded31b-b840-42f7-bfab-87b2d0bda5e5","added_by":"auto","created_at":"2025-03-03 15:31:04","extension":"png","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":15545,"visible":true,"origin":"","legend":"\u003cp\u003eComparison of the interaction effect of treatments on antioxidant capacity.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eIn the figure above, the letters \"As\" and \"E\" represent sodium alginate and garden thyme essential oil, respectively (Means with similar letters are not significantly different at the 5% level).\u003c/p\u003e","description":"","filename":"9.png","url":"https://assets-eu.researchsquare.com/files/rs-6081586/v1/b5f76eaacc34713d170fca15.png"},{"id":77618356,"identity":"ac177b19-0df9-4a75-9e4e-1241b55b1fb2","added_by":"auto","created_at":"2025-03-03 15:15:04","extension":"png","order_by":10,"title":"Figure 10","display":"","copyAsset":false,"role":"figure","size":17348,"visible":true,"origin":"","legend":"\u003cp\u003eComparison of mean interaction effects of treatments on ascorbic acid. \u003cbr\u003e\nIn the figure above, the letters \"As\" and \"E\" represent sodium alginate and thyme essential oil, respectively (means with similar letters do not show significant differences at the 5% level).\u003c/p\u003e","description":"","filename":"10.png","url":"https://assets-eu.researchsquare.com/files/rs-6081586/v1/ca034d6b7b23ac2de55060bf.png"},{"id":79581923,"identity":"b3e52c0c-2000-4309-9004-a8d8da19579f","added_by":"auto","created_at":"2025-03-31 12:01:57","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1158363,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6081586/v1/ad0cd1ab-197d-4731-bd24-ef8b7a8d4202.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Evaluation of the Effect of Sodium Alginate Combined with Thyme Essential Oil on the Postharvest Shelf Life of Washington Navel Orange (Citrus sinensis cv. Washington Navel)","fulltext":[{"header":"Introduction","content":"\u003cp\u003eCitrus fruits (Citrus spp.), belonging to the Rutaceae family, are among the most widely cultivated fruits worldwide (Suri et al., \u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). They are rich in various bioactive compounds, including flavonoids, essential oils, carotenoids, limonoids, and synephrine, which provide protection against various diseases such as cancer, inflammatory conditions, digestive disorders, and cardiovascular diseases (Lu et al., \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). Washington Navel orange (\u003cem\u003eCitrus sinensis\u003c/em\u003e cv. Washington Navel) is one of the most important sweet orange varieties and is highly valued for its delicious taste, nutritional properties, and seedless nature (El-Khalifa et al., \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). This cultivar originates from the Bahia orange (Bahia), which was selected and cultivated in Brazil. Washington Navel oranges are large, weighing between 200 and 500 grams, and have a thick peel (El-Gioushy \u0026amp; Eissa, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2019\u003c/span\u003e). Despite the high production volume of oranges, significant postharvest losses occur due to improper handling and storage methods (Barsha et al., \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). Preserving the quality and quantity of fruits and vegetables after harvest is crucial for economic sustainability.\u003c/p\u003e \u003cp\u003eA recent approach to extending shelf life, maintaining nutritional benefits, and preventing physical and textural deterioration of fruits involves the application of edible coatings. These coatings form a thin, consumable layer on the fruit\u0026rsquo;s surface, creating a barrier against moisture loss, oxygen exchange, and nutrient depletion (Wang et al., \u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). Edible coatings are an environmentally friendly innovation designed to maximize fruit quality and longevity (Prakash et al., \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e2020\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eSodium alginate-based edible coatings have demonstrated significant potential in fruit preservation (Wang et al., \u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e2019\u003c/span\u003e). Sodium alginate and its derivatives exhibit several biological activities, including antioxidant, coagulating, antimicrobial, biocompatibility, wound healing, low toxicity, and tissue engineering effects. Additionally, sodium alginate is considered an ideal edible coating due to its biocompatibility, biodegradability, non-toxicity, physicochemical properties, rheological behavior, and film-forming ability. Dulta et al. (\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e2022\u003c/span\u003e) examined the effect of sodium alginate (1%) and chitosan (0.5%) coatings enriched with nano-zinc oxide (0.5 g/L) on orange quality and found that the coatings significantly improved quality parameters compared to uncoated oranges. The coated samples exhibited lower rates of pH change, total soluble solids variation, and titratable acidity reduction. In another study, cherries coated with 3% sodium alginate demonstrated delayed weight loss, acidity reduction, softening, and color change (Chiabrando \u0026amp; Giacalone, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2015\u003c/span\u003e). Similarly, an experiment on strawberries revealed that a sodium alginate-calcium chloride edible coating effectively reduced respiration rate and transpiration while delaying pH increase and soluble solids accumulation. Additionally, the coating preserved the sensory properties of sliced strawberries, such as color and texture (Alharaty \u0026amp; Ramaswamy, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e2020\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eGarden thyme (Thymus vulgaris), belonging to the Lamiaceae family, is widely recognized in traditional medicine for its expectorant, antitussive, bronchodilatory, antispasmodic, carminative, and diuretic properties (Borug et al., \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2014\u003c/span\u003e). Thyme essential oil contains over 40% phenolic compounds, primarily thymol and carvacrol, which possess strong antimicrobial properties. Key components of thyme essential oil include thymol, carvacrol, linalool, γ-terpinene, p-cymene, β-myrcene, and terpinen-4-ol (Nadi et al., \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). In a study examining the effects of a sodium alginate (SA) and thyme essential oil (TEO) coating on fresh pistachios, treated samples exhibited lower weight loss and superior quality indices compared to untreated samples, with the highest sensory scores observed in the SA-TEO coated pistachios (Shakerardekani et al., \u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). Fatemi et al. (\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e2011\u003c/span\u003e) investigated the impact of natural essential oils, including thyme and peppermint, on controlling green mold and improving postharvest orange quality. Their results indicated that thyme essential oil exhibited strong antifungal properties against citrus fungal diseases. Similarly, Akbari et al. (\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2024\u003c/span\u003e) evaluated the effects of thyme essential oil on the microbial and physiological quality of green bell peppers, finding that it minimized peroxidase activity and respiration rate without adversely affecting texture, total phenolic content, antioxidant activity, pH, or soluble solids. This treatment contributed to the extended shelf life and improved postharvest quality of bell peppers.\u003c/p\u003e \u003cp\u003eDespite extensive research on sodium alginate and thyme essential oil-based edible coatings in postharvest fruit preservation, no study has specifically investigated the combined effect of sodium alginate and thyme essential oil coatings on the postharvest shelf life of Washington Navel oranges. Therefore, this study aims to evaluate the application of a sodium alginate-thyme essential oil edible coating on the postharvest quality and shelf life of Washington Navel oranges.\u003c/p\u003e"},{"header":"Materials and Methods","content":"\u003cp\u003eThis study was conducted as a factorial experiment in a completely randomized design during the 2023\u0026ndash;2024 period in the Plant Physiology Laboratory of the Department of Agriculture, Hormozgan University. In this research, edible sodium alginate coating (chemical formula: C₆H₉NaO₇) was purchased from Sigma Company. Thyme essential oil was obtained from Ayat Essences Company, Tehran.\u003c/p\u003e \u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eExperimental Treatments\u003c/h2\u003e \u003cp\u003eThe experimental treatments included:\u003c/p\u003e \u003cp\u003eAS1: Sodium alginate at a concentration of 1%\u003c/p\u003e \u003cp\u003eAS2: Sodium alginate at a concentration of 2%\u003c/p\u003e \u003cp\u003eE1: Thyme essential oil at a concentration of 150 mg/L\u003c/p\u003e \u003cp\u003eE2: Thyme essential oil at a concentration of 300 mg/L\u003c/p\u003e \u003cp\u003eE1\u0026thinsp;+\u0026thinsp;AS1: 1% sodium alginate combined with 150 mg/L thyme essential oil\u003c/p\u003e \u003cp\u003eE2\u0026thinsp;+\u0026thinsp;AS1: 1% sodium alginate combined with 300 mg/L thyme essential oil\u003c/p\u003e \u003cp\u003eE1\u0026thinsp;+\u0026thinsp;AS2: 2% sodium alginate combined with 150 mg/L thyme essential oil\u003c/p\u003e \u003cp\u003eE2\u0026thinsp;+\u0026thinsp;AS2: 2% sodium alginate combined with 300 mg/L thyme essential oil\u003c/p\u003e \u003cp\u003eC: Control\u003c/p\u003e \u003cp\u003eEach treatment was conducted in three replications, with three oranges per replication, evaluated at three time intervals (0, 30, and 60 days).\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eMeasured Traits\u003c/h3\u003e\n\u003cp\u003eAt the beginning of the experiment (T0), the following parameters were measured: fruit firmness, total soluble solids (TSS), ascorbic acid, titratable acidity (TA), total phenolic content, flavonoids, antioxidant capacity, and ion leakage. After 30 (T1) and 60 (T2) days, in addition to the mentioned traits, fruit decay and weight loss percentage were also evaluated.\u003c/p\u003e\n\u003ch3\u003eWeight Loss Percentage\u003c/h3\u003e\n\u003cp\u003eTo determine the percentage of weight loss, the weight of all fruits in each container (three fruits together) was measured at the beginning of the experiment and again at 30 and 60 days using a digital scale with an accuracy of 0.01 g. Finally, weight loss percentage was calculated using Eq.\u0026nbsp;(1).\u003c/p\u003e \u003cp\u003eEquation 1:\u003c/p\u003e \u003cp\u003eWeight loss percentage= (Initial weight / (Final weight - Initial weight) \u0026times;100\u003c/p\u003e\n\u003ch3\u003eFirmness\u003c/h3\u003e\n\u003cp\u003eFruit firmness was measured using a Lutron FS-1001 penetrometer equipped with a cylindrical probe (8 mm diameter). The applied force was recorded in Newtons.\u003c/p\u003e\n\u003ch3\u003eTotal Soluble Solids (TSS)\u003c/h3\u003e\n\u003cp\u003eTSS content was determined using a Prismatic PTRP100 refractometer. A single drop of orange juice was placed on the device's prism, and the TSS value was recorded in Brix degrees (Ayala-Zavala et al., \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2007\u003c/span\u003e).\u003c/p\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eTitratable Acidity (TA)\u003c/h2\u003e \u003cp\u003eTitratable acidity was determined using the Ayala-Zavala method with slight modifications, and its value was calculated using Eq.\u0026nbsp;2 (Ayala-Zavala et al., \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2007\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eEquation 2:\u003cdiv id=\"Equa\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equa\" name=\"EquationSource\"\u003e\n$$\\:\\text{T}\\text{A}=\\:\\left(\\frac{\\text{V}\\text{o}\\text{l}\\text{u}\\text{m}\\text{e}\\:\\text{o}\\text{f}\\:\\text{N}\\text{a}\\text{O}\\text{H}\\:\\text{c}\\text{o}\\text{n}\\text{s}\\text{u}\\text{m}\\text{e}\\text{d}\\times\\:\\:\\text{N}\\text{o}\\text{r}\\text{m}\\text{a}\\text{l}\\text{i}\\text{t}\\text{y}\\:\\text{o}\\text{f}\\:\\text{a}\\text{c}\\text{i}\\text{d}\\:\\text{e}\\text{q}\\text{u}\\text{i}\\text{v}\\text{a}\\text{l}\\text{e}\\text{n}\\text{t}}{\\text{S}\\text{a}\\text{m}\\text{p}\\text{l}\\text{e}\\:\\text{v}\\text{o}\\text{l}\\text{u}\\text{m}\\text{e}}\\right)\\times\\:100$$\u003c/div\u003e\u003c/div\u003e\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eAscorbic Acid\u003c/h3\u003e\n\u003cp\u003eAscorbic acid (Vitamin C) was determined using the Etemadipoor method. A 100 \u0026micro;L sample of orange juice was added to a test tube containing 10 mL of 1% metaphosphoric acid and vortexed for 10 seconds. Then, 1000 \u0026micro;L (1 mL) of this mixture was transferred to 9 mL of indophenol solution and vortexed again for 10 seconds. The absorbance of the samples was read at 515 nm using an ELISA reader. In this experiment, 1% metaphosphoric acid was used as a blank (Etemadipoor et al., \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e2019\u003c/span\u003e).\u003c/p\u003e\n\u003ch3\u003eAntioxidant Capacity\u003c/h3\u003e\n\u003cp\u003eTo prepare the methanolic extract of the juice, a 1:3 ratio of orange juice to 85% methanol was used. Antioxidant capacity was measured using the DPPH free radical scavenging assay. In this experiment, 85% methanol was used as a blank, and the DPPH solution served as the control (Sheng et al., \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e2018\u003c/span\u003e). The percentage of free radical inhibition was calculated using Eq.\u0026nbsp;(3).\u003c/p\u003e \u003cp\u003eEquation 3:\u003c/p\u003e \u003cp\u003eAntioxidant capacity = [(AC - OD) / AC] \u0026times; 100\u003c/p\u003e \u003cp\u003eWhere AC represents the absorbance of the control and OD represents the absorbance of the samples.\u003c/p\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003eTotal Phenols\u003c/h2\u003e \u003cp\u003eTotal phenolic content was determined using the Folin-Ciocalteu reagent. A 150 \u0026micro;L sample of methanolic extract was transferred to a 2 mL microtube, and 750 \u0026micro;L of 10% Folin-Ciocalteu reagent (Merck) was added. After 5 minutes, 600 \u0026micro;L of 7% sodium carbonate was added. The samples were incubated for 90 minutes in the dark on a shaker (TSHAKER-M model). The total phenolic content was then measured at 760 nm using an ELISA reader (Singleton \u0026amp; Rossi, \u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e1965\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003eFlavonoids\u003c/h2\u003e \u003cp\u003eFlavonoid content was measured using the aluminum chloride (AlCl3) colorimetric method. A 100 \u0026micro;L methanolic extract was placed in a 2 mL microtube, and 300 \u0026micro;L of 85% methanol was added. Then, 20 \u0026micro;L of 10% aluminum chloride and 20 \u0026micro;L of 1 M potassium acetate were added. Finally, 560 \u0026micro;L of distilled water was added, and the mixture was shaken for 30 minutes in the dark. The absorbance was then measured at 415 nm using an ELISA reader (Chang et al., \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e2002\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec13\" class=\"Section2\"\u003e \u003ch2\u003eIon Leakage\u003c/h2\u003e \u003cp\u003eIon leakage was measured using the method described by Masoumi et al. (\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e2012\u003c/span\u003e). A 0.5 g sample of orange peel was placed in a 50 mL Falcon tube with 20 mL of distilled water and left for 24 hours. After 24 hours, the initial electrical conductivity (EC1) was measured using a Temp AD3000 EC meter. The samples were then incubated in a water bath at 100\u0026deg;C for one hour. After cooling to 25\u0026deg;C, the final electrical conductivity (EC2) was recorded. Ion leakage percentage was calculated using Eq.\u0026nbsp;(4).\u003c/p\u003e \u003cp\u003eEquation 4:\u003c/p\u003e \u003cp\u003eIon leakage = (EC1 / EC2) \u0026times; 100\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec14\" class=\"Section2\"\u003e \u003ch2\u003eSensory Evaluation\u003c/h2\u003e \u003cp\u003eFor sensory evaluation (panel test), three trained panelists were asked to score the juiciness, aroma, taste, and appearance of the oranges on a 1\u0026ndash;5 scale at both evaluation times (Shah Beik, 1999).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec15\" class=\"Section2\"\u003e \u003ch2\u003eStatistical Analysis\u003c/h2\u003e \u003cp\u003eThe final data were analyzed using SAS software. Mean comparisons were performed using LSD at a 5% probability level. Graphs were drawn using Excel software.\u003c/p\u003e \u003c/div\u003e"},{"header":"Results and Discussion","content":"\u003cdiv id=\"Sec17\" class=\"Section2\"\u003e \u003ch2\u003eEffect of Treatments on Fruit Skin Firmness\u003c/h2\u003e \u003cp\u003eVariance analysis of the data indicated that the effect of sodium alginate, garden thyme essential oil, storage time, and their interaction was significant at the 1% level (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). The results of mean comparisons showed that after 30 days, the lowest firmness was observed in the control group, and the highest firmness at this time was observed in the As1E1 treatment. After 60 days of storage, the lowest firmness was seen in the control treatment, and the highest firmness was also observed in the As1E1 treatment (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). It appears that the treatments had a positive effect on the percentage of weight loss, which may be due to the role of sodium alginate in stabilizing the cell membrane. Sodium alginate enriched with essential oils significantly increases the shelf life of fruits. Sodium alginate containing essential oils acts as a barrier to reduce gas exchange, thus preventing tissue softening by slowing down respiration (D\u0026iacute;az-Mula et al., \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e2012\u003c/span\u003e). A study found that grapes treated with a combination of sodium alginate and essential oils showed higher firmness compared to untreated samples (Wang et al., \u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). In pineapple, fruit coated with sodium alginate along with lemongrass essential oil and sodium alginate enriched with antioxidants and olive oil showed higher firmness compared to the control group (Azarakhsh et al., \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e2014\u003c/span\u003e; Ramana Rao et al., \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e2016\u003c/span\u003e).\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\u003eAnalysis of variance for some traits evaluated in the study.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"7\"\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 \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSource of Variation\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003edf\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"5\" nameend=\"c7\" namest=\"c3\"\u003e \u003cp\u003eMean Squares\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eFirmness\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eIon Leakage\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003ePanel Test\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eTSS\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eTA\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eTreatments\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e9.90\u003csup\u003e\u003cspan type=\"SmallCaps\" class=\"SmallCaps\" name=\"Emphasis\"\u003e**\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e268.56\u003csup\u003e\u003cspan type=\"SmallCaps\" class=\"SmallCaps\" name=\"Emphasis\"\u003e**\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.76\u003csup\u003e\u003cspan type=\"SmallCaps\" class=\"SmallCaps\" name=\"Emphasis\"\u003e*\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1.11\u003csup\u003e\u003cspan type=\"SmallCaps\" class=\"SmallCaps\" name=\"Emphasis\"\u003e**\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.23\u003csup\u003e\u003cspan type=\"SmallCaps\" class=\"SmallCaps\" name=\"Emphasis\"\u003e**\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eTime\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e812.57\u003csup\u003e\u003cspan type=\"SmallCaps\" class=\"SmallCaps\" name=\"Emphasis\"\u003e**\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3024.54\u003csup\u003e\u003cspan type=\"SmallCaps\" class=\"SmallCaps\" name=\"Emphasis\"\u003e**\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e6.02\u003csup\u003e\u003cspan type=\"SmallCaps\" class=\"SmallCaps\" name=\"Emphasis\"\u003e**\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e150.57\u003csup\u003e\u003cspan type=\"SmallCaps\" class=\"SmallCaps\" name=\"Emphasis\"\u003e**\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.93\u003csup\u003e\u003cspan type=\"SmallCaps\" class=\"SmallCaps\" name=\"Emphasis\"\u003e**\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eTreatment \u0026times; Time\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3.11\u003csup\u003e\u003cspan type=\"SmallCaps\" class=\"SmallCaps\" name=\"Emphasis\"\u003e**\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e160.79\u003csup\u003e\u003cspan type=\"SmallCaps\" class=\"SmallCaps\" name=\"Emphasis\"\u003e**\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.52\u003csup\u003e\u003cspan type=\"SmallCaps\" class=\"SmallCaps\" name=\"Emphasis\"\u003e**\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.64\u003csup\u003e\u003cspan type=\"SmallCaps\" class=\"SmallCaps\" name=\"Emphasis\"\u003e*\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.11\u003csup\u003e\u003cspan type=\"SmallCaps\" class=\"SmallCaps\" name=\"Emphasis\"\u003e**\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eError\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e54\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.49\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e21.28\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.47\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.32\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.16\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eTotal Error\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e80\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eCV (%)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3.15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6.42\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e16.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e3.85\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e16.89\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"7\" nameend=\"c7\" namest=\"c1\"\u003e \u003cp\u003e\u003csup\u003e\u003cem\u003e*\u003c/em\u003e\u003c/sup\u003eSignificant at 5% level,\u003csup\u003e**\u003c/sup\u003eSignificant at 1% level, \u003csup\u003ens\u003c/sup\u003e non-significant\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e\u003c/div\u003e \u003cdiv id=\"Sec18\" class=\"Section2\"\u003e \u003ch2\u003eEffect of Treatments on Ion Leakage\u003c/h2\u003e \u003cp\u003eAccording to the results in the analysis of variance table, the effect of the experimental treatments and their interaction on the ion leakage trait was significant at the 1% level. The results of mean comparisons showed that the highest ion leakage was observed in the control treatment at 60 days of storage, with significant differences compared to all other treatments at 30 days of storage, except for the control. The lowest ion leakage was observed in the As2E2 treatment (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). Ion leakage is an indicator used to assess the integrity of the cell membrane and its permeability. Maintaining the structural integrity of cells during the fruit ripening process is crucial for cell survival. Increased ion leakage is mainly due to cell degradation and increased membrane permeability (Sinha et al., \u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). However, the sodium alginate coating with garden thyme essential oil, both individually and in combination, was effective in reducing ion leakage. Similar results were observed in peaches coated with sodium alginate along with rhubarb extract (Li et al., \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e2019\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec19\" class=\"Section2\"\u003e \u003ch2\u003eEffect of Treatments on Sensory Evaluation\u003c/h2\u003e \u003cp\u003eThe results from the analysis of variance table indicated that the treatments of sodium alginate, garden thyme, and their combination were significant at the 5% level, while storage time and their interaction were significant at the 1% level for sensory evaluation (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). The results of mean comparisons showed that the lowest score was observed in the control treatment at both 30 and 60 days of storage, while the highest score was observed in the As2E2 treatment at 30 days of storage, with a significant difference compared to the control (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). The agricultural and food sectors are required to evaluate the organoleptic properties of oranges through sensory analysis. This type of analysis is related to consumer perception, as food is evaluated through the senses using organoleptic properties such as appearance, smell, aroma, texture, and taste (Villase\u0026ntilde;or-Aguilar et al., \u003cspan citationid=\"CR48\" class=\"CitationRef\"\u003e2024\u003c/span\u003e). In this experiment, the sensory properties of the oranges were evaluated using a panel test. The results showed that sensory scores decreased over time, and the application of treatments at all levels improved the overall quality of the samples. Furthermore, the results indicated that the combined treatments of sodium alginate and garden thyme essential oil were the most effective. These results are consistent with findings from research by Megha et al. on pears, Fatemi et al. on oranges, and Shabani et al. on oranges (Shabani et al., 2015, Fatemi et al., 2012; Megha et al., 2023).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec20\" class=\"Section2\"\u003e \u003ch2\u003eEffect of Treatments on Total Soluble Solids (TSS)\u003c/h2\u003e \u003cp\u003eBased on the results shown in the analysis of variance table, the effect of sodium alginate, garden thyme, and storage time was significant at the 1% level, while their interactions were significant at the 5% level on the total soluble solids (TSS) content (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). The results of mean comparisons indicated that the control treatment at 60 days of storage had the highest TSS, while the lowest TSS was observed in the As1E1 treatment. In the 30-day storage samples, the control also had the highest TSS (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e). The treatments showed a slight increase in TSS compared to the control, which might be due to the formation of a physical barrier by the coating materials, reducing transpiration losses. The highest TSS in the control may be attributed to faster metabolic activities through respiration and transpiration in the control compared to the other treatments. Similar observations have been reported by Rokaya et al. (\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e2016\u003c/span\u003e) for different mandarin orange varieties and Thapa et al. (\u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e2020\u003c/span\u003e) for sweet oranges.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec21\" class=\"Section2\"\u003e \u003ch2\u003eEffect of Treatments on Titratable Acidity (TA)\u003c/h2\u003e \u003cp\u003eAccording to the results from the analysis of variance, the effect of sodium alginate, garden thyme essential oil, storage time, and the interaction between the treatments and time were significant at the 1% level on titratable acidity (TA) (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Based on the results of mean comparisons, the highest titratable acidity was observed in the E2 and As1E1 treatments, which showed a significant difference compared to the control at both 30 and 60 days of storage (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e). In this study, the titratable acidity in all coated treatments was lower than in the control. This might be due to reduced acid utilization during respiration in fruits treated with sodium alginate and garden thyme essential oil, while faster acid utilization during respiration was observed in the control fruits during storage. Rokaya et al. (\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e2016\u003c/span\u003e) and Khorram et al. (\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e2017\u003c/span\u003e) reported the highest TA in the control compared to fruits treated with different coating materials in mandarin and Kinnow mandarin, respectively (Khorram et al., \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e2017\u003c/span\u003e; Rokaya et al., \u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e2016\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec22\" class=\"Section2\"\u003e \u003ch2\u003eEffect of Treatments on Weight Loss\u003c/h2\u003e \u003cp\u003eAccording to the analysis of variance table, the effect of sodium alginate, garden thyme essential oil, storage time, and their interactions on the percentage of weight loss in oranges was significant at the 1% level (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). The results of mean comparisons also showed that after 30 days of storage, the control sample had the highest weight loss, and the lowest percentage of weight loss was observed in the As2E1 treatment. In the samples after 60 days of storage, the highest weight loss was observed in the control, and the lowest weight loss was observed in the As2E2 treatment (Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e). The edible coating of sodium alginate acts as a semi-permeable barrier to limit water exchange. This reduces moisture loss, respiration rate, oxidative reactions, and delays the physiological aging of fruits (A. Wang et al., \u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). Garden thyme essential oil was added to sodium alginate to delay moisture loss and preserve other sensory characteristics. Adding essential oils and surfactants improves the water retention ability of the coating (Shakerardekani et al., \u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). The results of this study are consistent with the findings of Shakerardekani et al. on pistachio (Pistacia vera), Utami et al. on strawberries (Fragaria sp), Linh et al. on Darabi (Citrus maxima), and Dulta et al. on oranges (Citrus sinensis L.) (Dulta et al., \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e2022\u003c/span\u003e; Linh et al., \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e2024\u003c/span\u003e; Shakerardekani et al., \u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Utami et al., \u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e2023\u003c/span\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\u003eAnalysis of variance for some evaluated traits in the study\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"7\"\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 \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSource of Variation\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003edf\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"5\" nameend=\"c7\" namest=\"c3\"\u003e \u003cp\u003eMean Squares\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eWeight Loss\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eTotal Phenols\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eFlavonoids\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eAntioxidant Capacity\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eAscorbic Acid\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eTreatments\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e55.73\u003csup\u003e**\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1627.59\u003csup\u003e**\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.23\u003csup\u003e**\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e18.71\u003csup\u003e**\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e11.43\u003csup\u003e**\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eTime\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e123967.26\u003csup\u003e**\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e70370.73\u003csup\u003e**\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e7.96\u003csup\u003e**\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e6296.11\u003csup\u003e**\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e1631.38\u003csup\u003e**\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eTreatment \u0026times; Time\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e53.59\u003csup\u003e**\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1700.03\u003csup\u003e**\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.14\u003csup\u003e**\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e11.29\u003csup\u003e**\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e10.23\u003csup\u003e**\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eExperimental Error\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e54\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e780.02\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e3.54\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eTotal Error\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e80\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eCV (%)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.99\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e22.49\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e19.41\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1.82\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e1.99\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"7\" nameend=\"c7\" namest=\"c1\"\u003e \u003cp\u003e\u003csup\u003e\u003cem\u003e*\u003c/em\u003e\u003c/sup\u003eSignificant at 5% level,\u003csup\u003e**\u003c/sup\u003eSignificant at 1% level, \u003csup\u003ens\u003c/sup\u003e non-significant\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cdiv id=\"Sec23\" class=\"Section3\"\u003e \u003ch2\u003eEffect of Treatments on Total Phenol Content\u003c/h2\u003e \u003cp\u003eThe results of the analysis of variance showed that the effect of sodium alginate and garden thyme at the 5% level, as well as storage time and the interaction of time and treatments, was significant at the 1% level for total phenol content (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). The mean comparison results indicated that in the samples after 30 days of storage, the highest phenol content was observed in the control treatment, and the lowest phenol content was in the E1 treatment. In the samples after 60 days, the highest total phenol content was observed in the control, while the lowest total phenol content was observed in the garden thyme treatment with a concentration of 150 mg/L (Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e). Edible coatings reduce the loss of polyphenols and maintain a higher antioxidant capacity during post-harvest storage of cherries (D\u0026iacute;az-Mula et al., \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e2012\u003c/span\u003e). Studies on plums and apricots have reported that coatings reduce the ripening rate, thereby delaying the onset of aging and reducing cellular structural degradation. Additionally, coatings reduce respiration, decrease the available oxygen for metabolic activities in the fruit, and consequently reduce the activity of phenol oxidase and peroxidase (Ghasemnezhad et al., \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e2010\u003c/span\u003e; Kumar et al., \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e2017\u003c/span\u003e; Thakur et al., \u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e2018\u003c/span\u003e). A continuous increase in phenolic compounds was observed in cherries coated with alginate during cold storage. Thus, the coating allows for the accumulation of phenolic compounds throughout storage without any reduction (D\u0026iacute;az-Mula et al., \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e2012\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec24\" class=\"Section2\"\u003e \u003ch2\u003eEffect of Treatments on Total Flavonoids\u003c/h2\u003e \u003cp\u003eAccording to the results of the analysis of variance, the effect of sodium alginate, garden thyme, storage duration, and their interaction was significant at the 1% level for flavonoid content (Table\u0026nbsp;4). The mean comparison results showed that in the samples after 30 days of storage, the highest flavonoid content was observed in the As1E1 treatment, while the lowest flavonoid content was in the As1 treatment. In the samples after 60 days of storage, the highest flavonoid content was observed in the As2E2 treatment, and the lowest flavonoid content was in the E2 treatment (Fig.\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e8\u003c/span\u003e). Research has shown that flavonoid content can be influenced by fruit ripening, post-harvest treatments, and extraction processes (Addi et al., \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2022\u003c/span\u003e; Tai et al., \u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e2014\u003c/span\u003e). In the present study, the results showed that flavonoid content increased over time. This might be due to the increase in flavonoid levels during storage, which enhances antioxidant properties and helps combat oxidative stress. Additionally, sodium alginate coating combined with garden thyme essential oil maintains flavonoid content by controlling the activity of the mentioned enzymes. These results align with studies on flavonoids in citrus fruits (Addi et al., \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2022\u003c/span\u003e; D\u0026iacute;az-Mula et al., \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e2012\u003c/span\u003e; Riva et al., \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e2020\u003c/span\u003e; Thakur et al., \u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e2018\u003c/span\u003e).\u003c/p\u003e\u003cdiv id=\"Sec25\" class=\"Section3\"\u003e \u003ch2\u003eEffect of Treatments on Antioxidant Capacity and Ascorbic Acid Content\u003c/h2\u003e \u003cp\u003eThe results from the analysis of variance indicated that the effect of sodium alginate, garden thyme essential oil, storage duration, and their interaction on the antioxidant capacity of the fruits was significant at the 1% level (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). The mean comparison results showed that with the increase in storage time, the antioxidant capacity also increased, and at each time point, the control sample differed significantly from the other treatments (Fig.\u0026nbsp;\u003cspan refid=\"Fig9\" class=\"InternalRef\"\u003e9\u003c/span\u003e). According to the variance table, the effect of sodium alginate, garden thyme essential oil, storage duration, and their interaction on ascorbic acid (vitamin C) content in oranges was significant at the 1% level (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). The mean comparison results indicated that after 60 days, the highest ascorbic acid content was observed in the As2E2 treatment, while the lowest content was in the control sample. For the 30-day storage samples, no significant differences were observed among the treatments (Fig.\u0026nbsp;\u003cspan refid=\"Fig10\" class=\"InternalRef\"\u003e10\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eFruits are rich in minerals, vitamins, and antioxidants that protect against cancer and cardiovascular diseases. However, improper storage of fruits has adverse effects on their quality, such as browning, off-flavors, loss of soluble solids, and decreased antioxidant activity (Barzegar et al., \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e2018\u003c/span\u003e). Rahami et al. (\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e2023\u003c/span\u003e) reported that during storage, ascorbic acid is highly susceptible to degradation due to oxidation compared to other nutrients. By maintaining membrane stability, the binding of free radicals and reactive oxygen species to the membrane surface can be prevented, thereby preserving antioxidants such as ascorbic acid. The reduction in antioxidant capacity of the fruits during storage can be explained by the fact that ascorbic acid is converted by the enzyme ascorbate oxidase into dehydroascorbate, and by phenol oxidase (Linh et al., \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e2024\u003c/span\u003e). A study on cherries showed that sodium alginate coating was effective in preserving antioxidants in cherries, with an increase in anthocyanins, phenolics, delayed loss of titratable acidity, and ascorbic acid content during 21 days of storage at 4\u0026deg;C. It was also reported that sodium alginate coating significantly reduced active oxygen levels, decreased the activity of defense enzymes, and preserved total soluble solids, titratable acidity, and ascorbic acid content, which resulted in increased antioxidant activity (Chiabrando \u0026amp; Giacalone, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2015\u003c/span\u003e). It was also reported that sodium alginate edible coatings combined with essential oils exhibited higher antioxidant activity. Similarly, sodium alginate coatings enriched with citral and eugenol helped preserve antioxidant activity, anthocyanins, and phenolics in raspberries and fresh apples during refrigeration storage. Sodium alginate, by creating a semi-permeable barrier around the fruit and inhibiting ethylene production, helps preserve the antioxidant activity of fruits (Guerreiro et al., \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e2016\u003c/span\u003e; A. Wang et al., \u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e2020\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e "},{"header":"Conclusion","content":"\u003cp\u003eWashington Navel oranges, although a non-climacteric fruit, have a high rate of perishability. One of the strategies to increase shelf life and reduce decay in post-harvest processes is treating the fruits with edible coatings. Edible coatings are an innovative solution used to preserve the quality and shelf life of fruits. Sodium alginate coatings combined with plant essential oils can have a significant impact on the shelf life of fruits. In this study, a sodium alginate edible coating with garden thyme essential oil was used to preserve the quality of Washington Navel oranges during storage. The results showed that the combined sodium alginate coating and garden thyme essential oil delayed the increase in respiration rate, reduced the percentage of weight loss, firmness, and ion leakage. It also preserved the soluble solids content during storage and increased antioxidant activity by enhancing the content of flavonoids, phenolics, and ascorbic acid.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eFunding\u003c/h2\u003e \u003cp\u003eThis research was not financially supported by any government or private organization.\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eH.H: Conducting laboratory work and measuring factors.R.E: Owning the idea and paying for laboratory materials.M.B: Writing the article.\u003c/p\u003e\u003ch2\u003eData Availability\u003c/h2\u003e\u003cp\u003ehttps://ostad.hormozgan.ac.ir/ostad/resualtfni?m=388016\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eAddi, M., Elbouzidi, A., Abid, M., Tungmunnithum, D., Elamrani, A., \u0026amp; Hano, C. (2022). An Overview of Bioactive Flavonoids from Citrus Fruits. \u003cem\u003eApplied Sciences (Switzerland)\u003c/em\u003e, \u003cem\u003e12\u003c/em\u003e(1), 1\u0026ndash;15. https://doi.org/10.3390/app12010029\u003c/li\u003e\n\u003cli\u003eAkbari, S., Radi, M., Hosseinifarahi, M., \u0026amp; Amiri, S. (2024). Microbial and physicochemical changes in green bell peppers treated with ultrasonic-assisted washing in combination with Thymus vulgaris essential oil nanocapsules. \u003cem\u003eScientific Reports\u003c/em\u003e, \u003cem\u003e14\u003c/em\u003e(1), 16584.\u003c/li\u003e\n\u003cli\u003eAlharaty, G., \u0026amp; Ramaswamy, H. S. (2020). The effect of sodium alginate-calcium chloride coating on the quality parameters and shelf life of strawberry cut fruits. \u003cem\u003eJournal of Composites Science\u003c/em\u003e, \u003cem\u003e4\u003c/em\u003e(3), 123\u003c/li\u003e\n\u003cli\u003eAyala-Zavala, J. F., Wang, S. Y., Wang, C. Y., \u0026amp; Gonz\u0026aacute;lez-Aguilar, G. A. (2007). 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(2020). \u003cem\u003eSustainability in Food and Agriculture ( SFNA ) EFFECT OF DIFFERENT POSTHARVEST TREATMENTS ON PROLONGING SHELF LIFE AND MAINTAINING QUALITY OF SWEET ORANGE ( Citrus sinensis Osbeck .)\u003c/em\u003e. \u003cem\u003e1\u003c/em\u003e(2), 69\u0026ndash;75.\u003c/li\u003e\n\u003cli\u003eUtami, R., Annisa, R. R., Praseptiangga, D., Nursiwi, A., Sari, A. M., Ashari, H., Ikarini, I., \u0026amp; Hanif, Z. (2023). Effect of edible coating sodium alginate with addition of siam pontianak tangerine peel essential oil (Citrus suhuinensis cv Pontianak) on the physical quality of strawberries (Fragaria ananassa) during refrigeration temperature storage. \u003cem\u003eIOP Conference Series: Earth and Environmental Science\u003c/em\u003e, \u003cem\u003e1200\u003c/em\u003e(1), 0\u0026ndash;8. https://doi.org/10.1088/1755-1315/1200/1/012058\u003c/li\u003e\n\u003cli\u003eVillase\u0026ntilde;or-Aguilar, M. J., Cano-Lara, M., Lopez, A. R., Rostro-Gonzalez, H., Padilla-Medina, J. A., \u0026amp; Barranco-Guti\u0026eacute;rrez, A. I. (2024). Fuzzy Classification of the Maturity of the Orange (Citrus \u0026times; sinensis) Using the Citrus Color Index (CCI). \u003cem\u003eApplied Sciences (Switzerland)\u003c/em\u003e, \u003cem\u003e14\u003c/em\u003e(13). https://doi.org/10.3390/app14135953\u003c/li\u003e\n\u003cli\u003eWang, A., Siddique, B., Wu, L., Ahmad, I., Liu, X., \u0026amp; Province, H. (2020). \u003cem\u003eSodium alginate edible coating augmented with essential oils maintains fruits postharvest physiology during preservation : A review\u003c/em\u003e. 135\u0026ndash;140.\u003c/li\u003e\n\u003cli\u003eWang, X., Zhang, Y., Liang, H., Zhou, X., Fang, C., Zhang, C., \u0026amp; Luo, Y. (2019). Synthesis and properties of castor oil-based waterborne polyurethane/sodium alginate composites with tunable properties. \u003cem\u003eCarbohydrate Polymers\u003c/em\u003e, \u003cem\u003e208\u003c/em\u003e, 391\u0026ndash;397.\u003c/li\u003e\n\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":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","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":"Alginate, Thyme, Preservation, Antioxidants, Oranges","lastPublishedDoi":"10.21203/rs.3.rs-6081586/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6081586/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eCitrus fruits, belonging to the Rutaceae family, are among the most widely cultivated fruits worldwide. Oranges are one of the most consumed fruits globally; however, they are prone to postharvest issues such as weight loss, decay, and physiological disorders. In an effort to enhance the storability of oranges, extensive research has been conducted on the application of edible coatings in the postharvest phase. Sodium alginate and its derivatives exhibit numerous biological activities, including antioxidant, coagulating, antimicrobial, biocompatibility, wound healing, low toxicity, and tissue engineering effects. This study investigated the effect of sodium alginate coating enriched with thyme essential oil on the quality and postharvest shelf life of Washington Navel oranges. The results demonstrated that the combined coating of sodium alginate and thyme essential oil delayed the respiratory peak, thereby preventing weight loss. Additionally, it maintained acidity and soluble solid content during storage. Similarly, the combined coatings were effective in preserving fruit firmness. Furthermore, these coatings maintained cellular membrane integrity by reducing relative electrolyte leakage, which delayed fruit senescence during long-term storage. The coatings also enhanced the total phenolic content, flavonoids, and ascorbic acid, thereby increasing the antioxidant capacity. In conclusion, sodium alginate combined with thyme essential oil can serve as a promising, effective, and non-toxic strategy for preserving the nutritional quality and membrane integrity of oranges.\u003c/p\u003e","manuscriptTitle":"Evaluation of the Effect of Sodium Alginate Combined with Thyme Essential Oil on the Postharvest Shelf Life of Washington Navel Orange (Citrus sinensis cv. Washington Navel)","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-03-03 15:06:59","doi":"10.21203/rs.3.rs-6081586/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","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":"0a17e487-ae08-4493-8486-19c785d0c02c","owner":[],"postedDate":"March 3rd, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-03-31T11:53:52+00:00","versionOfRecord":[],"versionCreatedAt":"2025-03-03 15:06:59","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-6081586","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6081586","identity":"rs-6081586","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}