Design and evaluation of a smart microclimate storage system for reducing postharvest losses in onion

Design and evaluation of a smart microclimate storage system for reducing postharvest losses in onion | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Design and evaluation of a smart microclimate storage system for reducing postharvest losses in onion Mohammed Bukar Yunusa, Lawan Garba Abubakar², Gambo Bala This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7925926/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 8 You are reading this latest preprint version Abstract Purpose This study investigates the impact of varying storage conditions specifically temperature and relative humidity on the postharvest quality of Dadin-kowa red onions. Methods Onions were stored under combinations of three temperature levels (25, 30, and 35°C) and three relative humidity levels (60, 65, and 70%) for 8 weeks. The parameters evaluated were weight loss, rottenness percentage, and total soluble solids (TSS). Results Results indicate that higher temperatures significantly increase weight loss and rottenness, while higher humidity tends to reduce weight loss but may increase spoilage risk at elevated temperatures. TSS values remained relatively stable across treatments. The findings suggest that moderate humidity (65%) and lower temperature (25°C) offer optimal storage conditions for minimizing postharvest losses in onions. Conclusion This study demonstrates how affordable, sensor-based storage systems can reduce onion postharvest losses and support food security initiatives in sub-Saharan Africa. Physical sciences/Engineering Biological sciences/Plant sciences humidity onion storage rottenness temperature total soluble solids weight loss Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Introduction Onions ( Allium cepa L.) are among the most widely cultivated and consumed vegetables globally, forming a staple component of daily cooking. However, harvested onions, being living entities, undergo various physicochemical changes during storage, including respiration, weight loss, rotting, and sprouting (Suravi et al., 2024 . Onion is one of the most economically significant vegetables cultivated across Nigeria, particularly in the northern states of Kano, Kebbi, Sokoto, Bauchi, Borno, and Gombe. Kano and Kebbi serve as the major suppliers, contributing nearly 40% of the onions sold to other regions (Ibrahim, 2018 ). Collectively, these states account for about 79% of national onion production. Despite its high demand and nutritional value, onion production in Nigeria is constrained by postharvest losses, estimated at 30–50%, primarily due to inadequate storage practices, especially during the rainy season. According to (Falola et al., 2023 ) reported that losses were largely due to rot, pest and disease attacks, drying, and bruising, compounded by insufficient storage facilities, poor transportation networks, long market distances, weak extension services, and limited access to credit. Conventionally, onions are stored in cool, dark, and well-ventilated spaces such as sheds or underground cellars. However, these methods are not always effective in preserving onion quality and do not account for optimal microclimatic conditions (Karanja et al., 2020 ) Ensuring food security for a growing population therefore requires sustainable postharvest management systems that reduce losses and stabilize market prices(Tadesse, 2024 ) The postharvest performance of onions depends on factors such as curing methods, grading, packaging, and the storage environment (Chauhan et al., 2020 ) Moisture content also plays a critical role in determining onion quality, shelf life, processing characteristics, and nutritional value (Gupta et al., 2025 ). Minimizing mass loss during drying and storage without compromising quality is essential for maintaining onion marketability (Islam et al., 2019 ) A study by (Shehu et al., 2023 ) assessed traditional and improved storage systems in northern Nigeria and found that improved structures, such as the Ventilated Onion Safe, significantly reduced rotting and sprouting, enhancing food security and market stability. Similarly, (Sohany et al., 2016 ) observed that physiological changes in red onions during storage were closely correlated with storage temperature. This study, therefore, presents the design and evaluation of a sensor-controlled onion storage structure aimed at minimizing postharvest losses in Dadinkowa, Gombe State, Nigeria. The system integrates temperature and humidity sensors with automated control mechanisms to maintain optimal storage conditions. The research further investigates the relationship between environmental parameters and storage outcomes, providing insights into how technology can enhance efficiency and sustainability in agricultural storage systems. Materials and Methods The experiment was carried out at the Department of Agricultural Technology Laboratory, Federal College of Horticultural Technology, Dadin-Kowa, Gombe State. The Experiment took place between July and October 2023. The study area is characterized as tropical, 643m above sea level, with an annual temperature range of 24 o -48 o , and estimated annual rainfall range from 760-1110mm (Bello et al., 2024). Onion is one of the major crop crops grown in the area in commercial quantity, with an estimated production of 25 tons per hectare. Onion is grown in the rainy season from May to September, and in the dry season using irrigation from November to April. Varieties grown in the area are mostly local, and they include Yar Romi, Yar Gaidam, Fitsarin Godiya,Mai Faranti,Zobo and some adopted varieties like Red Creole, Sweet Yellow and Violet De Galma. 2.2 Materials Used Onion Variety : Dadinkowa Red Onion Locally call (Yar Yomi) Sensors : DHT22 for humidity and temperature Actuators : Heating bulb and extractor fans. Controller : Arduino and microcontroller unit Power Supply : A hybrid system combining solar panels and backup battery to ensure energy efficiency and uninterrupted operation. Measurement Tools : Digital weighing scale for loss in weight Refractro meter for Total Soluble Solids Observation sheet for rottenness assessment 2.3 Design of the Storage Structure: The structure was designed to store onions in a controlled environment to optimize their quality and shelf life, it consists of three storage compartments, each of which have a capacity of 10kg of onions. The compartment was independently controlled to maintain the desired storage conditions; the compartments were equipped with sensors to measure various storage conditions, such as temperature and relative humidity. These sensors were connected to a microcontroller, which controls and monitors the storage conditions and processes. The microcontroller was programmed to maintain the desired storage conditions and adjust them as needed based on the sensor readings. The compartments were also equipped with actuators, which is heating and cooling elements, to control the storage conditions. For example, the microcontroller would activate the heating element to maintain a specific temperature in the Microclimate structure compartment or turn on the fan to regulate the humidity. It also has a display or interface to allow the user to monitor and control the storage conditions and processes. Overall, the structure provides a controlled and standardized platform for storing onions in a way that maximizes their quality and shelf life. It was used to test and optimize different storage conditions and practices and would have a wide application in food industry of for home storage, Figure 1 and 2 shows the isometric view of the structure, while Plate I shows the front view of the storage structure. 2.4 Algorithm for storing onions within the microclimate structure An algorithm for storing onions in a controlled environment includes the following steps: i. Set the desired storage conditions: This include setting the desired temperature and relative humidity range which are 25, 30 and 35 0 C and 60, 65 and 70% as the desired storage conditions for the three compartments. ii. Measure the storage conditions: Using temperature and relative humidity sensors, it measures the current temperature and relative humidity within the compartments. iii. Compare the measured values to the desired values: The micro controller will compare the measured values with the desired values to determine if any adjustments are needed. iv. Activate the appropriate actuators: If the measured values are outside the desired range, the microcontroller will activate the appropriate actuators to bring the values back within the desired range. For example, if the temperature is too high, turn on the cooling fan; if it is too low, turn on the heater. 3.1 Experimental Design The experiment was carried out as factorial in a completely randomized design (CRD), using temperature, relative humidity and time as the independent variables, with onions attributes as dependent variables, which will include, rotting, and physiological loss in weight, total soluble solids. The independent variables, temperature T 1 , T 2 , and T 3 at (25, 30, and 35 0 C), relative humidity, H 1 , H 2 , and H 3 at (60, 65, and 70%) and time D 1- D 8 at 8 weeks. So, there will be 3x3x2=18 treatments each at 3 replications which gives 18x3=54 experiments. 3.2 Data Collection . Weight loss of onion was measured weekly and expressed as percent weight loss by taking the initial and final bulb weight after respective storage interval as shown in Equation (1). Where; PLW= Physiological Loss in Weight in % Pi = Initial Weight Pn =Weight, days after storage in % For onion to be declared rotten it has to exhibit any of these unpleasant qualities, external appearance and changes in colour, rotten onions may exhibit dark or discoloured patches. Surface texture, as rot often causes a breakdown in the texture of the onion skin. Rotten onions emit a foul or unpleasant odour. Presence of mould on the surface of the onion. Mould is a common indicator of decay. Rotten onion was measured by counting after physical observation of its texture and colour around the neck, and expressed as percentage. The rotted bulbs were discarded after each counting to avoid double counting as shown in Equation (2) below as reported by Sharma et al . (2013). Where, Number of rotted bulbs = number of bulbs that rotted Total number of bulbs = total number of bulbs The total soluble solids (TSS) were measured by hand held refractometer by placing 2 or 3 drops of clear juice of onion on the prism and the value is expressed as degree brix (˚Bx) as reported by Sohany et al . (2016) 3.3 . Data Analysis Microsoft excel software package was used to show graphically the relationship between two quantities; an independent variable plotted on the X - axis and a dependent on Y - axis. Temperature, relative humidity and time will be independent variable while TSS, rottenness, loss in weight as the dependent variables. The result was analysed using Analysis of Variance (ANOVA) to compare the difference. The test will show weather onion stored under controlled environment has effects on the physiological qualities. The Turkey’s method was employed to ascertain significant difference (α ≤0.05) between the samples mean using Statistical Analysis Software (SAS3. Experimental Design Results and Discussion 4.2 Weight Loss Figure 3 shows how onion weight loss varied under different combinations of humidity (60–70%) and temperature (25°C, 30°C, and 35°C) over different storage durations (7–49 days). Weight loss increased consistently with both storage duration and temperature. The highest losses occurred at 35°C and 60% humidity where weight loss exceeded 70% by day 49. In contrast, the least weight loss was recorded at 25°C and 70% humidity, remaining under 40%. This suggests that lower temperatures and higher humidity levels are effective in reducing moisture loss. 4.3 Rottenness Figure 4 presents the percentage of rotten onions under the same storage conditions. Rottenness generally increased with storage time. While higher humidity reduced weight loss, it also promoted decay, especially at elevated temperatures. Rottenness levels peaked around 13–14% at 35°C and 70% humidity. At 25°C, rottenness was consistently lower, regardless of humidity, indicating that cooler conditions discourage microbial spoilage. 4.4 Total Soluble Solids (TSS) TSS values serve as an indicator of sugar concentration and overall bulb quality. TSS remained relatively stable across all treatments. Slight increases were observed at higher temperatures, likely due to concentration effects from moisture loss rather than true increases in sugar content. This suggests that flavour quality is not heavily compromised by most storage conditions 4.5 Innovation and Practical Relevance The integration of low-cost sensors and a programmable microcontroller in a solar-powered structure demonstrated that affordable, scalable solutions for post-harvest storage are feasible in rural settings. The system's adaptability to local environmental conditions—particularly the focus on humidity reduction rather than elevation—enhanced its practical value and energy efficiency. The innovation bridges the gap between traditional storage methods and high-end cold storage technologies, offering a middle-ground solution that can be adopted by smallholder farmers, cooperatives, and extension agencies. Conclusion and Recommendations This study successfully demonstrated that the storage conditions significantly affect onion quality. Weight loss and rottenness are primarily driven by temperature, with humidity playing a secondary but important role. The developed sensor -controlled microclimate storage system effectively minimised postharvest losses compared with conventional methods. For optimal storage, it is recommended to maintain onions at 25°C and 65% humidity. These conditions help minimize weight loss and spoilage while preserving flavour quality as indicated by stable TSS levels. 5.2 Recommendations: 1. Scale-up and Field Trials: Broader trials across different agro-ecological zones should be conducted to test the robustness of the design under varying climatic conditions. 2. Policy and Extension Support: Government and agricultural extension services should promote sensor-controlled storage systems as part of post-harvest loss reduction strategies. 3. Training and Capacity Building: Training farmers and cooperative groups on the operation and maintenance of such systems is crucial for widespread adoption. 4. Further Research: Additional studies can integrate mobile alert systems, remote data logging, and modular designs for other perishable crops. Declarations Author Contribution Author Contributions- M.B. Yunusa: Conceptualization, Methodology, Writing Original Draft.- L.G. Abubakar: Supervision, Review & Validation.- B.G. Jahun: Data Analysis, Editing. Acknowledgement The authors wish to thank the Federal College of Horticulture, Dadinkowa, and Abubakar Tafawa Balewa University for their institutional support during this research. Data Availability The data that support the findings of this study are available from the corresponding author upon request. Ethical approval: Not applicable. No funding References Bello, M. Y., Bashir, B. M., & Abubakar, H. (2024). An assessment of characteristics of rainfall and temperature variability in Dadinkowa, Yamaltu Deba LGA of Gombe State, Nigeria. Science World Journal, 19 (3), 868–873. https://doi.org/10.4314/swj.v19i3.35 Chauhan, P., Joshi, R., & Rawat, S. (2020). Impact of post-harvest management on onion shelf-life. Postharvest Biology and Technology, 169 , 104276. https://doi.org/10.1016/j.postharvbio.2020.111276 Falola, A., Mukaila, R., Uddin, R. O. II, Ajewole, C. O., & Gbadebo, W. (2023). Postharvest losses in onion: Causes and determinants. KSU Journal of Agriculture and Nature, 26 (2), 346–354. https://doi.org/10.18016/ksutarimdoga.vi.1091225 Gupta, A. J., Kaldate, S., Volaguthala, S., & Mahajan, V. (2025). Onion nutritional and nutraceutical composition and therapeutic potential of its phytochemicals assessed through preclinical and clinical studies. Journal of Functional Foods, 129 , 106889. https://doi.org/10.1016/j.jff.2025.106889 Ibrahim, M. (2018). Economic analysis of onion (Allium cepa) marketing in Kano and Kebbi States, Nigeria . Retrieved from https://www.researchgate.net/publication/361446983 Islam, M. N., Körner, O., Skov Pedersen, J., Sørensen, J. N., & Edelenbos, M. (2019). Analyzing quality and modelling mass loss of onions during drying and storage. Computers and Electronics in Agriculture, 164 , 104865. https://doi.org/10.1016/j.compag.2019.104865 Karanja, E. K., KimaniMutiri, S. N., & Njenga, F. W. (2020). Improving onion storage techniques for sub-Saharan Africa: A review. In Advances in integrated soil fertility management in sub-Saharan Africa: Challenges and opportunities . https://doi.org/10.1007/978-1-4020-5760-1_45 Sharma, K., & Lee, Y. R. (2016). Effect of different storage temperature on chemical composition of onion ( Allium cepa L.) and its enzymes. Journal of Food Science and Technology, 53 (3), 1620–1632. https://doi.org/10.1007/s13197-015-2076-9 Shehu, K., Salau, I. A., & Kasimu, S. M. (2023). Enhancing onion preservation and storage through improved storage systems. Journal of Applied Sciences and Environmental Management, 27 (12), 2127–2133. Sohany, M., Sarker, M. K. U., & Mahomud, M. S. (2016). Physiological changes in red onion bulbs at different storage temperature. World Journal of Engineering and Technology, 4 (2), 261–266. https://doi.org/10.4236/wjet.2016.42025) Suravi, T. I., Hasan, M. K., Jahan, I., Shopan, J., Saha, M., Debnath, B., & Ahammed, G. J. (2024). An update on post-harvest losses of onion and employed strategies for remedy. Scientia Horticulturae , 113794 . https://doi.org/10.1016/j.scienta.2024.113794 . Tadesse, K. T. (2024). The role of post-harvest management in ensuring food security in a changing world: Review article. Journal of Clinical Research and Case Studies, 2 (4), Article 41. https://doi.org/10.61440/JCRCS.2024.v2.41 Plate Plate 1 is available in the Supplementary Files section. Additional Declarations No competing interests reported. Supplementary Files PlateI.docx Cite Share Download PDF Status: Under Review Version 1 posted Reviewers agreed at journal 27 Mar, 2026 Reviews received at journal 18 Nov, 2025 Reviewers agreed at journal 04 Nov, 2025 Reviewers invited by journal 04 Nov, 2025 Editor invited by journal 29 Oct, 2025 Editor assigned by journal 24 Oct, 2025 Submission checks completed at journal 24 Oct, 2025 First submitted to journal 22 Oct, 2025 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. 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2","display":"","copyAsset":false,"role":"figure","size":94258,"visible":true,"origin":"","legend":"\u003cp\u003eOnion storage structure\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-7925926/v1/404d4415d6798db25906e17b.png"},{"id":95916239,"identity":"fa2103db-d7cd-44fa-b40f-4ba8e78e64ea","added_by":"auto","created_at":"2025-11-14 11:49:02","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":26708,"visible":true,"origin":"","legend":"\u003cp\u003eEffects of Temperature, relative humidity and time on weight loss of onions\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-7925926/v1/c54dd5828305d27ed060bf35.png"},{"id":96244672,"identity":"2b94cebb-1342-4c1a-8b77-d45c8cb9a4dc","added_by":"auto","created_at":"2025-11-19 07:19:03","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":23605,"visible":true,"origin":"","legend":"\u003cp\u003eEffects of Temperature, relative humidity and time on rottenness of onions\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-7925926/v1/91759c52e9e30ca3758cdf3d.png"},{"id":95916236,"identity":"d5b1b708-d380-4f97-840d-5225b7578f89","added_by":"auto","created_at":"2025-11-14 11:49:02","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":23700,"visible":true,"origin":"","legend":"\u003cp\u003eFigure 3: Effects of Temperature, relative humidity and time on Total soluble solids of onions\u003c/p\u003e","description":"","filename":"03.png","url":"https://assets-eu.researchsquare.com/files/rs-7925926/v1/43512169226a55d2938e3617.png"},{"id":96255324,"identity":"de2088a7-cb5f-481e-8133-6d9f0f95a678","added_by":"auto","created_at":"2025-11-19 07:48:28","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":883338,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7925926/v1/8885589f-04a6-4ea8-a71c-05a17dc8fb0c.pdf"},{"id":95916235,"identity":"6b090a17-5bbb-4906-9eeb-cd59c057c0cc","added_by":"auto","created_at":"2025-11-14 11:49:02","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":430622,"visible":true,"origin":"","legend":"","description":"","filename":"PlateI.docx","url":"https://assets-eu.researchsquare.com/files/rs-7925926/v1/3b1a2bade28fabc1461c0fe3.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Design and evaluation of a smart microclimate storage system for reducing postharvest losses in onion","fulltext":[{"header":"Introduction","content":"\u003cp\u003eOnions (\u003cem\u003eAllium cepa\u003c/em\u003e L.) are among the most widely cultivated and consumed vegetables globally, forming a staple component of daily cooking. However, harvested onions, being living entities, undergo various physicochemical changes during storage, including respiration, weight loss, rotting, and sprouting (Suravi et al., \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e2024\u003c/span\u003e. Onion is one of the most economically significant vegetables cultivated across Nigeria, particularly in the northern states of Kano, Kebbi, Sokoto, Bauchi, Borno, and Gombe. Kano and Kebbi serve as the major suppliers, contributing nearly 40% of the onions sold to other regions (Ibrahim, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e2018\u003c/span\u003e). Collectively, these states account for about 79% of national onion production. Despite its high demand and nutritional value, onion production in Nigeria is constrained by postharvest losses, estimated at 30\u0026ndash;50%, primarily due to inadequate storage practices, especially during the rainy season. According to (Falola et al., \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e2023\u003c/span\u003e) reported that losses were largely due to rot, pest and disease attacks, drying, and bruising, compounded by insufficient storage facilities, poor transportation networks, long market distances, weak extension services, and limited access to credit. Conventionally, onions are stored in cool, dark, and well-ventilated spaces such as sheds or underground cellars. However, these methods are not always effective in preserving onion quality and do not account for optimal microclimatic conditions (Karanja et al., \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e2020\u003c/span\u003e) Ensuring food security for a growing population therefore requires sustainable postharvest management systems that reduce losses and stabilize market prices(Tadesse, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e2024\u003c/span\u003e) The postharvest performance of onions depends on factors such as curing methods, grading, packaging, and the storage environment (Chauhan et al., \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2020\u003c/span\u003e) Moisture content also plays a critical role in determining onion quality, shelf life, processing characteristics, and nutritional value (Gupta et al., \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2025\u003c/span\u003e). Minimizing mass loss during drying and storage without compromising quality is essential for maintaining onion marketability (Islam et al., \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2019\u003c/span\u003e) A study by (Shehu et al., \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e2023\u003c/span\u003e) assessed traditional and improved storage systems in northern Nigeria and found that improved structures, such as the Ventilated Onion Safe, significantly reduced rotting and sprouting, enhancing food security and market stability. Similarly, (Sohany et al., \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2016\u003c/span\u003e) observed that physiological changes in red onions during storage were closely correlated with storage temperature. This study, therefore, presents the design and evaluation of a sensor-controlled onion storage structure aimed at minimizing postharvest losses in Dadinkowa, Gombe State, Nigeria. The system integrates temperature and humidity sensors with automated control mechanisms to maintain optimal storage conditions. The research further investigates the relationship between environmental parameters and storage outcomes, providing insights into how technology can enhance efficiency and sustainability in agricultural storage systems.\u003c/p\u003e"},{"header":"Materials and Methods","content":"\u003cp\u003eThe experiment was carried out at the Department of Agricultural Technology Laboratory, Federal College of Horticultural Technology, Dadin-Kowa, Gombe State. The Experiment took place between July and October 2023. The study area is characterized as tropical, 643m above sea level, with an annual temperature range of 24\u003csup\u003eo\u003c/sup\u003e-48\u003csup\u003eo\u003c/sup\u003e, and estimated annual rainfall range from 760-1110mm (Bello et al., 2024). Onion is one of the major crop crops grown in the area in commercial quantity, with an estimated production of 25 tons per hectare. Onion is grown in the rainy season from May to September, and in the dry season using irrigation from November to April. Varieties grown in the area are mostly local, and they include Yar Romi, Yar Gaidam, Fitsarin Godiya,Mai Faranti,Zobo and some adopted varieties like Red Creole, Sweet Yellow and Violet De Galma.\u003c/p\u003e\n\u003ch3\u003e\u003cstrong\u003e2.2\u003c/strong\u003e \u003cstrong\u003eMaterials Used\u003c/strong\u003e\u003c/h3\u003e\n\u003cp\u003e\u003cstrong\u003eOnion Variety\u003c/strong\u003e: Dadinkowa Red Onion Locally call (Yar Yomi)\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eSensors\u003c/strong\u003e: DHT22 for humidity and temperature\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eActuators\u003c/strong\u003e: Heating bulb and extractor fans.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eController\u003c/strong\u003e: Arduino and microcontroller unit\u0026nbsp;\u003c/p\u003e\n\u003ch2\u003e\u003cstrong\u003ePower Supply\u003c/strong\u003e:\u0026nbsp;\u003c/h2\u003e\n\u003cp\u003eA hybrid system combining solar panels and backup battery to ensure energy efficiency and uninterrupted operation.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMeasurement Tools\u003c/strong\u003e\u003cstrong\u003e:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDigital weighing scale\u003c/strong\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003efor loss in weight\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eRefractro meter\u003c/strong\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003efor Total Soluble Solids\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eObservation sheet\u003c/strong\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003efor rottenness assessment\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.3 Design of the Storage Structure: \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u0026nbsp;\u003c/strong\u003e\u003cbr\u003eThe structure was designed to store onions in a controlled environment to optimize their quality and shelf life, it consists of three storage compartments, each of which have a capacity of 10kg of onions. The compartment was independently controlled to maintain the desired storage conditions; the compartments were equipped with sensors to measure various storage conditions, such as temperature and relative humidity. These sensors were connected to a microcontroller, which controls and monitors the storage conditions and processes. The microcontroller was programmed to maintain the desired storage conditions and adjust them as needed based on the sensor readings. The compartments were also equipped with actuators, which is heating and cooling elements, to control the storage conditions. For example, the microcontroller would activate the heating element to maintain a specific temperature in the Microclimate structure compartment or turn on the fan to regulate the humidity. It also has a display or interface to allow the user to monitor and control the storage conditions and processes. Overall, the structure provides a controlled and standardized platform for storing onions in a way that maximizes their quality and shelf life. It was used to test and optimize different storage conditions and practices and would have a wide application in food industry of for home storage, Figure 1 and 2 shows the isometric view of the structure, while Plate I shows the front view of the storage structure.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.4 Algorithm for storing onions within the microclimate structure\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAn algorithm for storing onions in a controlled environment includes the following steps:\u003c/p\u003e\n\u003cp\u003ei. \u0026nbsp; \u0026nbsp; \u0026nbsp;Set the desired storage conditions: This include setting the desired temperature and relative humidity range which are 25, 30 and 35\u003csup\u003e0\u003c/sup\u003eC and 60, 65 and 70% as the desired storage conditions for the three compartments.\u003c/p\u003e\n\u003cp\u003eii. \u0026nbsp; \u0026nbsp; Measure the storage conditions: Using temperature and relative humidity sensors, it measures the current temperature and relative humidity within the compartments.\u003c/p\u003e\n\u003cp\u003eiii. \u0026nbsp; \u0026nbsp;Compare the measured values to the desired values: The micro controller will compare the measured values with the desired values to determine if any adjustments are needed.\u003c/p\u003e\n\u003cp\u003eiv. \u0026nbsp; \u0026nbsp;Activate the appropriate actuators: If the measured values are outside the desired range, the microcontroller will activate the appropriate actuators to bring the values back within the desired range. For example, if the temperature is too high, turn on the cooling fan; if it is too low, turn on the heater.\u003c/p\u003e\n\u003ch3\u003e\u003cstrong\u003e3.1 Experimental Design\u003c/strong\u003e\u003c/h3\u003e\n\u003cp\u003eThe experiment was carried out as factorial in a completely randomized design (CRD), using temperature, relative humidity and time as the independent variables, with onions attributes as dependent variables, which will include, rotting, and physiological loss in weight, total soluble solids. The independent variables, temperature T\u003csub\u003e1\u003c/sub\u003e, T\u003csub\u003e2\u003c/sub\u003e, and T\u003csub\u003e3\u003c/sub\u003e at (25, 30, and 35\u003csup\u003e0\u003c/sup\u003eC), relative humidity, H\u003csub\u003e1\u003c/sub\u003e, H\u003csub\u003e2\u003c/sub\u003e, and H\u003csub\u003e3\u003c/sub\u003e at (60, 65, and 70%) and time D\u003csub\u003e1-\u003c/sub\u003eD\u003csub\u003e8\u003c/sub\u003e at 8 weeks. So, there will be 3x3x2=18 treatments each at 3 replications which gives 18x3=54 experiments.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.2\u003c/strong\u003e \u003cstrong\u003eData Collection\u003c/strong\u003e.\u003c/p\u003e\n\u003cp\u003eWeight loss of onion was measured weekly and expressed as percent weight loss by taking the initial and final bulb weight after respective storage interval as shown in Equation (1).\u003c/p\u003e\n\u003cp\u003e\u003cimg 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Physiological Loss in Weight in %\u003c/p\u003e\n\u003cp\u003ePi = Initial Weight\u0026nbsp;\u003c/p\u003e\n\u003cp\u003ePn =Weight, days after storage in %\u003c/p\u003e\n\u003cp\u003eFor onion to be declared rotten it has to exhibit any of these unpleasant qualities, external appearance and changes in colour, rotten onions may exhibit dark or discoloured patches. Surface texture, as rot often causes a breakdown in the texture of the onion skin. Rotten onions emit a foul or unpleasant odour. Presence of mould on the surface of the onion. Mould is a common indicator of decay. Rotten onion was measured by counting after physical observation of its texture and colour around the neck, and expressed as percentage. The rotted bulbs were discarded after each counting to avoid double counting as shown in Equation (2) below as reported by Sharma \u003cem\u003eet al\u003c/em\u003e. (2013).\u003c/p\u003e\n\u003cp\u003e\u003cimg src=\"data:image/png;base64,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\"\u003e\u003c/p\u003e\n\u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n\u003cp\u003eWhere,\u003c/p\u003e\n\u003cp\u003eNumber of rotted bulbs = number of bulbs that rotted\u003c/p\u003e\n\u003cp\u003eTotal number of bulbs = total number of bulbs\u003c/p\u003e\n\u003cp\u003eThe total soluble solids (TSS) were measured by hand held refractometer by placing 2 or 3 drops of clear juice of onion on the prism and the value is expressed as degree brix (˚Bx) as reported by Sohany \u003cem\u003eet al\u003c/em\u003e. (2016)\u003c/p\u003e\n\u003ch3\u003e\u003cstrong\u003e3.3\u003c/strong\u003e. \u003cstrong\u003eData Analysis\u003c/strong\u003e\u003c/h3\u003e\n\u003cp\u003eMicrosoft excel software package was used to show graphically the relationship between two quantities; an independent variable plotted on the X - axis and a dependent on Y - axis. Temperature, relative humidity and time will be independent variable while TSS, rottenness, loss in weight as the dependent variables. The result was analysed using Analysis of Variance (ANOVA) to compare the difference. The test will show weather onion stored under controlled environment has effects on the physiological qualities. The Turkey\u0026rsquo;s method was employed to ascertain significant difference (\u0026alpha; \u0026le;0.05) between the samples mean using Statistical Analysis Software (SAS3. Experimental Design\u003c/p\u003e"},{"header":"Results and Discussion","content":"\u003ch4\u003e\u003cstrong\u003e4.2 Weight Loss\u003c/strong\u003e\u003c/h4\u003e\n\u003cp\u003eFigure 3 shows how onion weight loss varied under different combinations of humidity (60\u0026ndash;70%) and temperature (25\u0026deg;C, 30\u0026deg;C, and 35\u0026deg;C) over different storage durations (7\u0026ndash;49 days). Weight loss increased consistently with both storage duration and temperature. The highest losses occurred at 35\u0026deg;C and 60% humidity where weight loss exceeded 70% by day 49. In contrast, the least weight loss was recorded at 25\u0026deg;C and 70% humidity, remaining under 40%. This suggests that lower temperatures and higher humidity levels are effective in reducing moisture loss.\u003c/p\u003e\n\u003ch4\u003e\u003cstrong\u003e4.3 Rottenness\u003c/strong\u003e\u003c/h4\u003e\n\u003cp\u003eFigure 4 presents the percentage of rotten onions under the same storage conditions. Rottenness generally increased with storage time. While higher humidity reduced weight loss, it also promoted decay, especially at elevated temperatures. Rottenness levels peaked around 13\u0026ndash;14% at 35\u0026deg;C and 70% humidity. At 25\u0026deg;C, rottenness was consistently lower, regardless of humidity, indicating that cooler conditions discourage microbial spoilage.\u003c/p\u003e\n\u003ch4\u003e\u003cstrong\u003e4.4 Total Soluble Solids (TSS)\u003c/strong\u003e\u003c/h4\u003e\n\u003cp\u003eTSS values serve as an indicator of sugar concentration and overall bulb quality. TSS remained relatively stable across all treatments. Slight increases were observed at higher temperatures, likely due to concentration effects from moisture loss rather than true increases in sugar content. This suggests that flavour quality is not heavily compromised by most storage conditions\u003c/p\u003e\n\u003ch4\u003e\u003cstrong\u003e4.5\u003c/strong\u003e \u003cstrong\u003eInnovation and Practical Relevance\u003c/strong\u003e\u003c/h4\u003e\n\u003cp\u003eThe integration of low-cost sensors and a programmable microcontroller in a solar-powered structure demonstrated that affordable, scalable solutions for post-harvest storage are feasible in rural settings. The system\u0026apos;s adaptability to local environmental conditions\u0026mdash;particularly the focus on humidity reduction rather than elevation\u0026mdash;enhanced its practical value and energy efficiency. The innovation bridges the gap between traditional storage methods and high-end cold storage technologies, offering a middle-ground solution that can be adopted by smallholder farmers, cooperatives, and extension agencies.\u003c/p\u003e"},{"header":"Conclusion and Recommendations","content":"\u003cp\u003eThis study successfully demonstrated that the storage conditions significantly affect onion quality. Weight loss and rottenness are primarily driven by temperature, with humidity playing a secondary but important role. The developed sensor -controlled microclimate storage system effectively minimised postharvest losses compared with conventional methods. For optimal storage, it is recommended to maintain onions at 25°C and 65% humidity. These conditions help minimize weight loss and spoilage while preserving flavour quality as indicated by stable TSS levels.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e5.2 Recommendations:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e1.\u0026nbsp; \u0026nbsp; \u0026nbsp;Scale-up and Field Trials: Broader trials across different agro-ecological zones should be conducted to test the robustness of the design under varying climatic conditions.\u003c/p\u003e\n\u003cp\u003e2.\u0026nbsp; \u0026nbsp; \u0026nbsp;Policy and Extension Support: Government and agricultural extension services should promote sensor-controlled storage systems as part of post-harvest loss reduction strategies.\u003c/p\u003e\n\u003cp\u003e3.\u0026nbsp; \u0026nbsp; \u0026nbsp;Training and Capacity Building: Training farmers and cooperative groups on the operation and maintenance of such systems is crucial for widespread adoption.\u003c/p\u003e\n\u003cp\u003e4. \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; Further Research: Additional studies can integrate mobile alert systems, remote data logging, and modular designs for other perishable crops. \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eAuthor Contributions- M.B. Yunusa: Conceptualization, Methodology, Writing Original Draft.- L.G. Abubakar: Supervision, Review \u0026amp; Validation.- B.G. Jahun: Data Analysis, Editing.\u003c/p\u003e\u003ch2\u003eAcknowledgement\u003c/h2\u003e\u003cp\u003eThe authors wish to thank the Federal College of Horticulture, Dadinkowa, and Abubakar Tafawa Balewa University for their institutional support during this research.\u003c/p\u003e\u003ch2\u003eData Availability\u003c/h2\u003e\u003cp\u003eThe data that support the findings of this study are available from the corresponding author upon request.\u003c/p\u003e\n\u003cp\u003eEthical approval: Not applicable. No funding\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eBello, M. Y., Bashir, B. M., \u0026amp; Abubakar, H. (2024). \u003cem\u003eAn assessment of characteristics of rainfall and temperature variability in Dadinkowa, Yamaltu Deba LGA of Gombe State, Nigeria.\u003c/em\u003e \u003cstrong\u003eScience World Journal, 19\u003c/strong\u003e(3), 868\u0026ndash;873. https://doi.org/10.4314/swj.v19i3.35\u003c/li\u003e\n\u003cli\u003eChauhan, P., Joshi, R., \u0026amp; Rawat, S. (2020). \u003cem\u003eImpact of post-harvest management on onion shelf-life.\u003c/em\u003e \u003cstrong\u003ePostharvest Biology and Technology, 169\u003c/strong\u003e, 104276. https://doi.org/10.1016/j.postharvbio.2020.111276\u003c/li\u003e\n\u003cli\u003eFalola, A., Mukaila, R., Uddin, R. O. II, Ajewole, C. O., \u0026amp; Gbadebo, W. (2023). \u003cem\u003ePostharvest losses in onion: Causes and determinants.\u003c/em\u003e \u003cstrong\u003eKSU Journal of Agriculture and Nature, 26\u003c/strong\u003e(2), 346\u0026ndash;354. https://doi.org/10.18016/ksutarimdoga.vi.1091225\u003c/li\u003e\n\u003cli\u003eGupta, A. J., Kaldate, S., Volaguthala, S., \u0026amp; Mahajan, V. (2025). \u003cem\u003eOnion nutritional and nutraceutical composition and therapeutic potential of its phytochemicals assessed through preclinical and clinical studies.\u003c/em\u003e \u003cstrong\u003eJournal of Functional Foods, 129\u003c/strong\u003e, 106889. https://doi.org/10.1016/j.jff.2025.106889\u003c/li\u003e\n\u003cli\u003eIbrahim, M. (2018). \u003cem\u003eEconomic analysis of onion (Allium cepa) marketing in Kano and Kebbi States, Nigeria\u003c/em\u003e. Retrieved from https://www.researchgate.net/publication/361446983\u003c/li\u003e\n\u003cli\u003eIslam, M. N., K\u0026ouml;rner, O., Skov Pedersen, J., S\u0026oslash;rensen, J. N., \u0026amp; Edelenbos, M. (2019). \u003cem\u003eAnalyzing quality and modelling mass loss of onions during drying and storage.\u003c/em\u003e \u003cstrong\u003eComputers and Electronics in Agriculture, 164\u003c/strong\u003e, 104865. https://doi.org/10.1016/j.compag.2019.104865\u003c/li\u003e\n\u003cli\u003eKaranja, E. K., KimaniMutiri, S. N., \u0026amp; Njenga, F. W. (2020). Improving onion storage techniques for sub-Saharan Africa: A review. In \u003cem\u003eAdvances in integrated soil fertility management in sub-Saharan Africa: Challenges and opportunities\u003c/em\u003e. https://doi.org/10.1007/978-1-4020-5760-1_45\u003c/li\u003e\n\u003cli\u003eSharma, K., \u0026amp; Lee, Y. R. (2016). Effect of different storage temperature on chemical composition of onion (\u003cem\u003eAllium cepa\u003c/em\u003e L.) and its enzymes. \u003cem\u003eJournal of Food Science and Technology, 53\u003c/em\u003e(3), 1620\u0026ndash;1632. https://doi.org/10.1007/s13197-015-2076-9\u003c/li\u003e\n\u003cli\u003eShehu, K., Salau, I. A., \u0026amp; Kasimu, S. M. (2023). Enhancing onion preservation and storage through improved storage systems. \u003cem\u003eJournal of Applied Sciences and Environmental Management, 27\u003c/em\u003e(12), 2127\u0026ndash;2133.\u003c/li\u003e\n\u003cli\u003eSohany, M., Sarker, M. K. U., \u0026amp; Mahomud, M. S. (2016). Physiological changes in red onion bulbs at different storage temperature. \u003cem\u003eWorld Journal of Engineering and Technology, 4\u003c/em\u003e(2), 261\u0026ndash;266. https://doi.org/10.4236/wjet.2016.42025)\u003c/li\u003e\n\u003cli\u003eSuravi, T. I., Hasan, M. K., Jahan, I., Shopan, J., Saha, M., Debnath, B., \u0026amp; Ahammed, G. J. (2024). \u003cem\u003eAn update on post-harvest losses of onion and employed strategies for remedy.\u003c/em\u003e \u003cem\u003eScientia Horticulturae\u003c/em\u003e, \u003cem\u003e113794\u003c/em\u003e. https://doi.org/10.1016/j.scienta.2024.113794\u003cstrong\u003e.\u003c/strong\u003e\u003c/li\u003e\n\u003cli\u003eTadesse, K. T. (2024). \u003cem\u003eThe role of post-harvest management in ensuring food security in a changing world: Review article.\u003c/em\u003e \u003cstrong\u003eJournal of Clinical Research and Case Studies, 2\u003c/strong\u003e(4), Article 41. https://doi.org/10.61440/JCRCS.2024.v2.41\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Plate","content":"\u003cp\u003ePlate 1 is available in the Supplementary Files section.\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"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":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"humidity, onion storage, rottenness, temperature, total soluble solids, weight loss","lastPublishedDoi":"10.21203/rs.3.rs-7925926/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7925926/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003ePurpose\u003c/h2\u003e\u003cp\u003eThis study investigates the impact of varying storage conditions specifically temperature and relative humidity on the postharvest quality of Dadin-kowa red onions.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e\u003cp\u003eOnions were stored under combinations of three temperature levels (25, 30, and 35\u0026deg;C) and three relative humidity levels (60, 65, and 70%) for 8 weeks. The parameters evaluated were weight loss, rottenness percentage, and total soluble solids (TSS).\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e\u003cp\u003eResults indicate that higher temperatures significantly increase weight loss and rottenness, while higher humidity tends to reduce weight loss but may increase spoilage risk at elevated temperatures. TSS values remained relatively stable across treatments. The findings suggest that moderate humidity (65%) and lower temperature (25\u0026deg;C) offer optimal storage conditions for minimizing postharvest losses in onions.\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e\u003cp\u003eThis study demonstrates how affordable, sensor-based storage systems can reduce onion postharvest losses and support food security initiatives in sub-Saharan Africa.\u003c/p\u003e","manuscriptTitle":"Design and evaluation of a smart microclimate storage system for reducing postharvest losses in onion","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-11-14 11:48:58","doi":"10.21203/rs.3.rs-7925926/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"reviewerAgreed","content":"102576296553672946576768959962477436617","date":"2026-03-27T11:04:07+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-11-18T10:19:38+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"116209430143702709380827275494326459965","date":"2025-11-04T15:30:04+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-11-04T12:30:29+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2025-10-29T06:14:44+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-10-24T10:23:16+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-10-24T10:21:52+00:00","index":"","fulltext":""},{"type":"submitted","content":"Scientific Reports","date":"2025-10-22T17:37:02+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"c9fccc5a-8f10-48fb-b28e-0f0281cfea4a","owner":[],"postedDate":"November 14th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[{"id":57429652,"name":"Physical sciences/Engineering"},{"id":57429653,"name":"Biological sciences/Plant sciences"}],"tags":[],"updatedAt":"2025-11-14T11:48:58+00:00","versionOfRecord":[],"versionCreatedAt":"2025-11-14 11:48:58","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7925926","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7925926","identity":"rs-7925926","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}