Current IssueSpecial IssueEditorial BoardOnline First ArticlesArchive
Current IssueSpecial IssueEditorial BoardOnline First ArticlesArchive

Full Research Article

Effect of Preharvest Application of Melatonin for Maintaining Postharvest Quality and Shelf Life in Guava

R
R. Madhanraj1
https://orcid.org/0009-0007-1207-2334
K
K. Prakash2,*
https://orcid.org/0000-0001-9347-8182
A
A. Akino1
https://orcid.org/0000-0002-6759-6967
R
R. Nagajothi3
https://orcid.org/0009-0004-0630-7422
1Department of Fruit Science, SRM College of Agricultural Sciences, SRM Institute of Science and Technology, Baburayanpettai, Chengalpattu-603 201, Tamil Nadu, India.
2Department of Post Harvest Technology, SRM College of Agricultural Sciences, SRM Institute of Science and Technology, Baburayanpettai, Chengalpattu-603 201, Tamil Nadu, India.
3Section of Biochemistry and Crop Physiology, SRM College of Agricultural Sciences, SRM Institute of Science and Technology, Baburayanpettai, Chengalpattu-603 201, Tamil Nadu, India.

ABSTRACT

Background: Guava (Psidium guajava L.) is a highly perishable climacteric fruit characterized by a rapid ripening process and a short post-harvest life, which leads to significant economic losses. Melatonin has emerged as a potent antioxidant and signaling molecule capable of delaying senescence and preserving fruit quality.

Methods: A field experiment was conducted using a Randomized Block Design (RBD) with four replications. Guava trees were subjected to five preharvest treatments: T1 (Control), T2 (50 µM), T3 (100 µM), T4 (150 µM) and T5 (200 µM) melatonin. The treatments were applied as foliar sprays two weeks prior to the anticipated harvest date.

Result: Among the concentrations tested, fruits treated with 100 µM melatonin maintained significantly higher firmness, titratable acidity, ascorbic acid (Vitamin C) and total phenolic content compared to the control group. Furthermore, this treatment effectively minimized physiological loss in weight (PLW) and extended the shelf life of the fruits up to 9 (8.73) days under ambient conditions.

INTRODUCTION

Guava is a climacteric fruit enriched with bioactive compounds, yet its commercial utilization is constrained by rapid post-harvest deterioration driven by accelerated physicochemical processes. Such degradation contributes to pronounced quality losses and considerable economic implications across the supply chain (Labib et al., 2025). The crop exhibits seasonal flowering patterns influenced by climatic conditions, resulting in multiple harvests in southern India. However, fruits obtained during the rainy season are often of inferior quality compared to winter harvests, largely due to higher pest incidence and reduced storage potential (Sahu et al., 2025; Sharma, 2024). As a climacteric fruit, guava undergoes sharp increases in respiration and ethylene biosynthesis following harvest, which hastens ripening and senescence. These processes manifest as softening, loss of firmness, decline in nutritional attributes and substantial post-harvest losses (Yadav et al., 2022). Consequently, the development of effective strategies to delay ripening and preserve quality is critical for extending shelf life and ensuring market sustainability.
       
Melatonin (N-acetyl-5-methoxytryptamine) is a versatile signalling molecule that occurs ubiquitously across diverse plant taxa (Ze et al., 2021). In recent years, the use of eco-friendly natural compounds or bio stimulants, such as melatonin, has gained importance due to their ability to regulate biosynthetic pathways involved in the formation of key quality attributes of fruits during ripening and subsequent post-harvest storage (Mubarok et al., 2023). Melatonin has emerged as a promising bio regulator owing to its functions in plant growth regulation, enhancement of stress tolerance and modulation of fruit ripening (Gao et al., 2022). Exogenous application of melatonin has been reported to delay fruit ripening, suppress ethylene biosynthesis and strengthen antioxidant defence mechanisms, thereby prolonging shelf life in several fruit species (Onik et al., 2021). Melatonin exhibits antioxidant activity during postharvest storage, thereby contributing to the extension of shelf life in fruits and vegetables (Gurjar et al., 2022). Preharvest application of melatonin has been shown to delay climacteric ethylene peaks, thereby maintaining fruit firmness and modulating chlorophyll-carotenoid transitions, which collectively enhance post-harvest quality across diverse fruit species (Aghdam and Arnao, 2024). Multiple investigations have explored the role of melatonin in regulating fruit yield and quality (Xie et al., 2022a). Although melatonin has been widely studied for its regulatory roles in plants, comprehensive evaluations of its preharvest application in guava are lacking, underscoring the necessity for targeted investigations to optimize post-harvest quality and shelf life. Therefore, this study was conducted to assess the impact of melatonin on postharvest quality attributes and shelf life of guava fruits.

MATERIALS AND METHODS

The present investigation was carried out in the fruit orchard by the Department of Fruit Science, SRM College of Agricultural Sciences, Chengalpattu, Tamil Nadu, India, during 2025-2026. The experimental site is situated at 12°23′19.7″ N latitude and 79°44′37.4″ E longitude, with an elevation of approximately 50 m above the mean sea level. The region experiences a tropical climate, with ambient temperatures ranging between 23°C and 38°C. The soil at the site is predominantly clayey, characterized by moderate fertility and adequate drainage capacity, making it suitable for fruit crop cultivation.
       
Healthy guava trees were selected for the study and the experiment was conducted in a Randomized Block Design (RBD) with four replications. Five treatments were evaluated: T1 (control, water spray), T2 (melatonin 50 µM), T3 (melatonin 100 µM), T4 (melatonin 150 µM) and T5  (melatonin 200 µM). Melatonin solutions were freshly prepared by dissolving the required amount in a small volume of ethanol, followed by dilution with distilled water to obtain the desired concentrations (50-200 µM). Foliar sprays were applied uniformly two weeks before harvest using a battery-operated sprayer during early morning hours to ensure effective absorption and minimize evaporation. Fruits were harvested at physiological maturity and transported carefully to the laboratory for analysis (Dangwal et al., 2026). All laboratory analyses were conducted according to the standardized procedures outlined in Table 1.

Table 1: Parameters recorded during the study in guava fruit.


       
The recorded data were statistically analysed by using Analysis of Variance (ANOVA) appropriate for RBD to determine the significance of treatment effects with the help of the KAUGRAPES web-based statistical analysis software (Gopinath et al., 2021).

RESULT S AND DISCUSSION

Fruit firmness declined significantly as storage progressed, regardless of treatment. Fruit softening during storage mainly occurs due to the enzymatic breakdown of cell wall constituents such as pectin, cellulose and hemicellulose, mediated by enzymes like polygalacturonase and pectin methyl esterase (Kucuker et al., 2023). A gradual decline in fruit firmness was observed across all treatments throughout the storage period, indicating progressive softening during storage. However, fruits treated with 100 µM melatonin retained greater firmness, whereas the untreated controls exhibited the lowest firmness values (Table 2). Earlier studies have indicated that melatonin can inhibit the activity of cell wall degrading enzymes, thereby preserve cell wall integrity and delaying softening in papaya fruit (Borthakur et al., 2024). Thus, the improved firmness observed in melatonin treated fruits may be attributed to better preservation of structural polysaccharides and enhanced membrane stability during storage (Garrido Auñón  et al., 2025).

Table 2: Effect of preharvest melatonin on firmness and TSS content of guava.


       
Total soluble solids (TSS) serve as an indicator of fruit maturation or progression into advanced storage stages (Kasilingam et al., 2025). Data presented in Table 2 indicate significant differences in the effects of melatonin on fruit TSS content. The progression of ripening during storage was reflected by gradual increase in TSS as storage progressed across all treatment. Among the treatments, fruits treated with 100 µm of melatonin recorded the lowest TSS, while the control fruits exhibited the higher values. The rise in TSS during storage is a typical ripening response, mainly resulting from the breakdown of complex carbohydrates into soluble sugars. Application of melatonin (MT) effectively delays mango ripening by inhibiting starch to sugar conversion, maintaining cell wall integrity, modulating antioxidant metabolism and regulating the biosynthesis of ethylene and abscisic acid (Njie et al., 2022). Similar result was observed in banana (Devi et al., 2025) and Japanese plum (Cortes-Montana  et al., 2023).
       
The decline in titratable acidity of guava fruits during storage was markedly reduced by exogenous melatonin treatment. The observed decline in titratable acidity (TA) during storage can be attributed to the metabolism of organic acids within the fruit or their breakdown through respiratory activity (Wang et al., 2022 and Jiang et al., 2023).  However, fruits treated with melatonin retained significantly higher acidity compared to other treatments. Among the treatments, 100 µM recorded the highest acidity values, indicating the effectiveness of melatonin in delaying the decline of organic acids during storage (Fig 1). Melatonin application may have moderated the rate of respiration and related metabolic activities, thereby reducing the rapid consumption of organic acids. Similar findings have been reported where melatonin treatment helped maintain higher acidity levels in fruits by slowing ripening related biochemical changes in Japanese plum (Cortes-Montana et al., 2023).

Fig 1: Effects of preharvest melatonin on titratable acidity of guava.


       
Reduced sugar accumulation is a characteristic marker of delayed postharvest ripening and senescence, primarily associated with the inhibition of amylase and phosphorylase activities (Hanif et al., 2020). During storage, complex carbohydrates were converted into soluble sugars (Johari et al., 2023). Application of melatonin increased the total sugar compared with the control at the end of storage period indicating slower metabolic activity (Fig 2). Total sugar content showed a steady increase throughout the storage in all treatments, reflecting the normal ripening process. The reduced accumulation of sugars suggests that melatonin regulated carbohydrate metabolism and delayed the breakdown of polysaccharides into simple sugars, thereby slowing the ripening process. Similar findings were reported by Zhao et al., (2023), who observed that melatonin treatment can regulate sugar metabolism by influencing enzymes involved in carbohydrate transformation in pear fruits. Thus, the slower increase in total sugars in melatonin treated fruits indicates delayed ripening and better preservation of fruit quality during storage.

​

Fig 2: Effects of preharvest melatonin on total, reducing and non-reducing sugars of guava.


       
The contents of reducing and non-reducing sugars in guava fruits exhibited gradual changes throughout the storage period. At the end of the storage period, melatonin treated fruits showed considerably lower levels of both reducing and non-reducing sugars compared with the control fruits (Fig 2). This effect may be attributed to melatonin’s inhibition of ethylene biosynthesis and the concentration-dependent suppression of starch conversion to soluble sugars, thereby contributing to delayed ripening and the maintenance of fruit quality (Liu  et al., 2020). Similar results were observed in papaya (Wang et al., 2022) and peach (Zhou et al., 2023).
       
Ascorbic acid constitutes a fundamental antioxidant that governs the progression of fruit ripening by modulating reactive oxygen species metabolism and maintaining the intracellular redox equilibrium (Arabia et al., 2024). In this study, a consistent decline in ascorbic acid content was observed across all treatments throughout the storage period, reflecting the gradual degradation of vitamin C as ripening progressed. Among the treatments, fruit treated with 100 µM melatonin retained significantly higher ascorbic acid content, while the control fruits exhibited the lowest values (Fig 3). This effect may be attributed to the application of melatonin, which enhances the accumulation of metabolites during fruit ripening by elevating total flavonoid and phenolic contents as well as ascorbic acid levels (Fan et al., 2022a). Numerous investigations have demonstrated that melatonin significantly modulates fruit metabolite profiles by enhancing and sustaining levels of ascorbic acid (Zhang et al., 2020). Comparable outcomes were reported in guava (Fan et al., 2022b), kiwifruit (Luo et al., 2022) and pear (Liu et al., 2024).

Fig 3: Effects of preharvest melatonin on ascrobic acid and phenol of guava.


       
Melatonin is widely recognized as a potent antioxidant that limits free radical accumulation in plant tissues while supporting the preservation of non-enzymatic antioxidant metabolites, including anthocyanins, phenolics and flavonoids (Xie et al., 2022b). In present investigation, the total phenolic content declined progressively during storage irrespective of melatonin treatment; however, the reduction was more pronounced in control fruits compared to melatonin treated fruits. By the end of storage period, fruits treated with 100 µM melatonin exhibited the highest phenolic content (Fig 3). Comparable increases in phenolic compound concentrations following melatonin application have recently been reported in table grapes (Wang et al., 2020), litchi (Marak et al., 2024) and raspberry (Rahmanzadeh-Ishkeh  et al., 2024).
       
The percentage of physiological weight loss (PLW) in guava fruit exhibited a progressive increase throughout the storage period. At the end of storage, fruits treated with 100 µM melatonin exhibited the lowest percentage of physiological weight loss (PLW), whereas the untreated controls showed significantly higher weight loss (Table 3). Exogenous melatonin has been reported to stimulate endogenous melatonin biosynthesis, thereby attenuating PLW (Li et al., 2023). The mitigation of weight loss following melatonin application may be attributed to the downregulation of metabolic activity, resulting in reduced energy expenditure and diminished rates of transpiration and respiration in stored fruit (Padilla-González  et al., 2026; Bal, 2021). Concordant findings have been documented in other fruit species, including plum (Zhang et al., 2024), litchi (Xie et al., 2022b) and banana (Anchana et al., 2023).
       
Exogenous melatonin acts as an effective natural preservative that enhances postharvest fruit shelf life by mitigating physiological processes related to oxidative damage and strengthening antioxidant defences (Budiarto et al., 2025). In the present study, melatonin application extended fruit shelf life by up to 9 days (Table 3). The treatment effectively delayed the loss of firmness, suppressed the decline in soluble solids and titratable acids and enhanced the fruit’s antioxidant capacity, thereby contributing to prolonged freshness (Ze et al., 2021; Hei et al., 2025; Feng et al., 2022). Comparable outcomes have been reported in apples (Onik et al., 2021), mango (Njie et al., 2022), sweet cherries (Carrión-Antolí  et al., 2022) and banana (Lin et al., 2026). Melatonin plays an essential role in regulating fruit ripening through its interaction with ethylene and abscisic acid signalling pathways, thereby influencing the timing and synchrony of ripening while delaying senescence in fruit tissues (Aghdam et al., 2024).

Table 3: Effect of preharvest Melatonin on PLW and shelf life of guava.

CONCLUSION

The findings of the study reveal that preharvest application of melatonin had a positive influence on maintaining the post-harvest quality of guava fruits by delaying ripening and reducing the rate of physiological and biochemical changes during storage. Treated fruits exhibited better retention of firmness and nutritional components, along with lower weight loss compared to untreated fruits. The regulation of sugar metabolism and antioxidant systems further contributed to improved fruit stability and slower senescence. Among the treatments, 100 µM melatonin was identified as the most effective concentration for preserving quality attributes and extending shelf life. In conclusion, exogenous melatonin represents a promising natural preservative that extends postharvest fruit shelf life by mitigating oxidative damage and strengthening antioxidant defences in guava.

ACKNOWLEDGEMENT

This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.
 
Informed consent
 
This study did not involve any experiments on human participants or animals. Therefore, ethics approval and permits were not required.

CONFLICT OF INTEREST

The authors declare that there are no conflicts of interest regarding the publication of this article.

REFERENCES


  1. Abbott, J.A. (1999). Quality measurement of fruits and vegetables. Postharvest Biology and Technology. 15(3): 207-225. https://doi.org/10.1016/S0925-5214(98)00086-6.

  2. Aghdam, M.S. and Arnao, M.B. (2024). Phytomelatonin: From intracellular signaling to global horticulture market. Journal of Pineal Research. 76(5): e12990. https://doi.org/10.1111/jpi.12 990.

  3. Anchana, K., Kavitha, C., Shanmugasundaram, K.A., Djanaguiraman,  M. and Johnson, I. (2023). Role of exogenous melatonin in enhancing shelf life of traditional banana varieties. International Journal of Environment and Climate Change. 13(10): 992-998. DOI:10.9734/ijecc/2023/v13i102746. 

  4. AOAC. (2005). Official methods of analysis of AOAC International (18th ed.). Association of Official Analytical Chemists, Washington DC.

  5. Arabia, A., Munné-Bosch, S. and Munoz, P. (2024). Ascorbic acid as a master redox regulator of fruit ripening. Postharvest Biology and Technology. 207: 112614. https://doi.org/ 10.1016/j.postharvbio.2023.112614. 

  6. Bal, E. (2021). Effect of melatonin treatments on biochemical quality and postharvest life of nectarines. Journal of Food Measurement and Characterization. 15(1): 288-295. https://doi.org/10.1007/s11694-020-00636-5. 

  7. Borthakur, P., Chinnasamy, K., Paramasivam, S.K., Venkatachalam, S., Alagarswamy, S., Iruthayasamy, J. and Muthusamy, S. (2024). Exogenous melatonin as pre-and postharvest application on quality attributes, antioxidant capacity and extension of shelf life of papaya. Horticulturae. 10(10): 1099. https://doi.org/10.3390/horticulturae10101099.

  8. Budiarto, R., Sholikin, M.M., Mubarok, S., Ujilestari, T., Adli, D.N., Ahmed, T. and Ali, H. M. (2025). Exogenous melatonin as a natural preservative: A meta-analysis of its effects on fruit shelf life and oxidative stress during storage. Chemical and Biological Technologies in Agriculture. 12(1): 61. 10.1186/s40538-025-00781-3. 

  9. Carrión-Antolí, A., Martínez-Romero, D., Guillén, F., Zapata, P.J., Serrano, M. and Valero, D. (2022). Melatonin pre-harvest treatments leads to maintenance of sweet cherry quality during storage by increasing antioxidant systems. Frontiers in Plant Science. 13: 863467. https://doi.org/10.3389/ fpls.2022.863467.

  10. Cortes-Montana, D., Bernalte-García, M.J., Serradilla, M.J. and Velardo-Micharet, B. (2023). Optimal preharvest melatonin applications to enhance endogenous melatonin content, harvest and postharvest quality of Japanese plum. Agriculture. 13(7): 1318. https://doi.org/10.3390/agriculture 13071318.

  11. Dangwal, V., Singh, V.P., Mishra, D.S., Rawat, M., Krishna, R.K., Ravat, P. and Jat, R. (2026). Foliar potassium-calcium nutrition enhances fruit yield, quality and mitigates cracking in guava (Psidium guajava L.) under humid subtropical conditions. Frontiers in Plant Science. 17: 1812647. https: //doi.org/10.3389/fpls.2026.1812647. 

  12. Devi, M., Jeyakumar, P., Ravichandran, V., Arul, L., Balakrishnan, M. and Kavino, M. (2025). Melatonin application extends banana shelf life by delayed ripening. Plant Science. doi: 10.14719/pst.6867. 

  13. DuBois, M., Gilles, K.A., Hamilton, J.K., Rebers, P.A. and Smith, F. (1956). Colorimetric method for determination of sugars and related substances. Analytical Chemistry. 28(3): 350-356. https://doi.org/10.1021/ac60111a017.

  14. Fan, S., Li, Q., Feng, S., Lei, Q., Abbas, F., Yao, Y. and Zhu, X. (2022a). Melatonin maintains fruit quality and reduces anthracnose in postharvest papaya via enhancement of antioxidants and inhibition of pathogen development. Antioxidants. 11(5): 804. https://doi.org/10.3390/antiox11050804. 

  15. Fan, S., Xiong, T., Lei, Q., Tan, Q., Cai, J., Song, Z. and Zhu, X. (2022b). Melatonin treatment improves postharvest preservation and resistance of guava fruit (Psidium guajava L.). Foods. 11(3): 262. https://doi.org/10.3390/foods11030 262. 

  16. Feng, B.S., Kang, D.C., Sun, J., Leng, P., Liu, L.X., Wang, L. and Liu, Y.G. (2022). Research on melatonin in fruits and vegetables and the mechanism of exogenous melatonin on postharvest preservation. Food Bioscience. 50: 102196. https://doi.org/10.1016/j.fbio.2022.102196. 

  17. Gao, T., Liu, X., Tan, K., Zhang, D., Zhu, B., Ma, F. and Li, C. (2022). Introducing melatonin to the horticultural industry: Physiological roles, potential applications and challenges. Horticulture Research. 9: uhac094.  https://doi.org/10.1093/hr/uhac 094. 

  18. Garrido Auñón, F., Padilla González, P.A., Serrano, M., Valero, D. and Agulló, V. (2025). Melatonin boosts the phytochemical profile of blood oranges, enhancing (Poly) phenol and endogenous melatonin content, through pre and postharvest treatments. Journal of Pineal Research. 77(5): e70078. https://doi.org/10.1111/jpi.70078. 

  19. Gopinath, P.P., Parsad, R., Joseph, B. and VS, A. (2021). grapesAgri1: Collection of shiny apps for data analysis in agriculture. Journal of Open-Source Software. 6(63): 3437. doi: 10. 21105/joss.03437.

  20. Gurjar, P.S., Killadi, B., Pareek, P.K. and Hada, T.S. (2022). Application of melatonin in maintaining post harvest quality of fruits and vegetables: A review. Agricultural Reviews. 43(2): 193-198. doi: 10.18805/ag.R-2092.

  21. Hanif, A., Ahmad, S., Jaskani, M.J. and Ahmad, R. (2020). Papaya treatment with putrescine maintained the overall quality and promoted the antioxidative enzyme activities of the stored fruit. Scientia Horticulturae. 268: 109367. https:/ /doi.org/10.1016/j.scienta.2020.109367. 

  22. Hei, H., Tang, H., Zhao, R., Li, G. and Shi, F. (2025). Effect of melatonin treatment on storage quality and antioxidant system of postharvest winter jujube (Zizyphus jujube Mill. cv. Dongzao). Foods. 14(4): 576.  https://doi.org/10.3390/ foods14040576. 

  23. Jiang, X., Liu, K., Peng, H., Fang, J., Zhang, A., Han, Y. and Zhang, X. (2023). Comparative network analysis reveals the dynamics of organic acid diversity during fruit ripening in peach [Prunus persica L. Batsch]. BMC Plant Biology. 23(1): 16.10.1186/s12870-023-04037-w. 

  24. Johari, N.H.F., Dolhaji, N.H., Shamsuri, S. and Abdol Latif, P. (2023). A review on sugar and organic profiles on the postharvest quality of fruits. Science Letters (ScL). 17(2): 91-108. https://ir.uitm.edu.my/id/eprint/79962. 

  25. Kasilingam, P., Shanmugavel, C., Athikesavan, R., Ramakrishnan, R. and Arumugam, V.A. (2025). Innovative postharvest treatments to enhance the shelf-life and quality of carica papaya. Agricultural Science Digest. 46(4): 614-621. doi: 10.18805/ag.D-6371. 

  26. Kucuker, E., Aglar, E., Sakaldaş, M., Şen, F. and Gundogdu, M. (2023). Impact of postharvest putrescine treatments on phenolic compounds, antioxidant capacity, organic acid contents and some quality characteristics of fresh fig fruits during cold storage. Plants. 12(6): 1291.https://doi.org/10.3390 /plants12061291.

  27. Labib, L.A., Ahmed, S. and Hasan, M.F.  (2025). Improving guava shelf life and preserving postharvest quality with edible coatings. Food Science and Nutrition. 13(6): e70491. https://doi.org/10.1002/fsn3.70491.

  28. Li, N., Zhai, K., Yin, Q., Gu, Q., Zhang, X., Melencion, M.G. and Chen, Z. (2023). Crosstalk between melatonin and reactive oxygen species in fruits and vegetables post-harvest preservation: An update. Frontiers in Nutrition. 10: 1143511. https://doi.org/10.3389/fnut.2023.1143511.  

  29. Lin, J., Zhang, R., Chen, Q., Liang, W., Wu, Y., Su, W. and Fan, Z. (2026). Melatonin alleviates chilling injury in postharvest banana fruit by modulating membrane lipid and phenolic metabolism. Postharvest Biology and Technology. 239: 114361. https://doi.org/10.1016/j.postharvbio.2026.114 361. 

  30. Liu, G., Zhang, Y., Yun, Z., Hu, M., Liu, J., Jiang, Y. and Zhang, Z. (2020). Melatonin enhances cold tolerance by regulating energy and proline metabolism in litchi fruit. Foods. 9(4): 454. https://www.mdpi.com/2304-8158/9/4/454. 

  31. Liu, L., Huang, A., Wang, B., Zhang, H., Zheng, Y. and Wang, L. (2024). Melatonin mobilizes the metabolism of sugars, ascorbic acid and amino acids to cope with chilling injury in postharvest pear fruit. Scientia Horticulturae. 323: 112548. https://doi.org/10.1016/j.scienta.2023.112548. 

  32. Luo,Z., Zhang, J., Xiang, M., Zeng, J., Chen, J. and Chen, M. (2022). Exogenous melatonin treatment affects ascorbic acid metabolism in postharvest ‘Jinyan’kiwifruit. Frontiers in Nutrition. 9: 1081476. https://doi.org/10.3389/fnut.2022.1081476. 

  33. Marak, K.A., Mir, H., Siddiqui, M.W., Singh, P., Homa, F. and Alamri, S. (2024). Exogenous melatonin delays oxidative browning in litchi during cold storage by regulating biochemical attributes and gene expression. Frontiers in Plant Science. 15: 1402607. https://doi.org/10.3389/fpls.2024.1402607. 

  34. Miller, G.L. (1959). Use of dinitrosalicylic acid reagent for determination of reducing sugar. Analytical Chemistry. 31(3): 426-428.  https://doi.org/10.1021/ac60147a030. 

  35. Mubarok, S., Suminar, E., Abidat, A.H., Setyawati, C.A., Setiawan, E. and Buswar, A.S. (2023). Overview of melatonin’s impact  on postharvest physiology and quality of fruits. Horticulturae. 9(5): 586. https://doi.org/10.3390/horticulturae9050586.

  36. Njie, A., Zhang, W.E., Dong, X., Lu, C., Pan, X. and Liu, Q. (2022). Effect of melatonin on fruit quality via decay inhibition and enhancement of antioxidative enzyme activities and genes expression of two mango cultivars during cold storage. Foods. 11(20): 3209. https://www.mdpi.com/ 2304-8158/11/20/3209. 

  37. Onik, J.C., Wai, S.C., Li, A., Lin, Q., Sun, Q., Wang, Z. and Duan, Y. (2021). Melatonin treatment reduces ethylene production and maintains fruit quality in apple during postharvest storage. Food Chemistry. 337: 127753. https://doi.org/ 10.1016/j.foodchem.2020.127753.

  38. Padilla-González, P.A., Garrido-Auñón, F., García-Pastor, M.E., Guillén, F., Serrano, M., Valero, D. andAgulló, V. (2026). Melatonin as a Pre-and postharvest tool for enhancing fruit quality. Plants. 15(2): 331. https://doi.org/10.3390/ plants15020331. 

  39. Rahmanzadeh-Ishkeh, S., Shirzad, H., Tofighi, Z., Fattahi, M. and Ghosta, Y. (2024). Exogenous melatonin prolongs raspberry postharvest life quality by increasing some antioxidant and enzyme activity and phytochemical contents. Scientific Reports. 14(1): 11508. https://doi.org/10.1038/s41598- 024-62111-1. 

  40. Sahu, K., Khunte, S.D., Chandrakar, Y.K. and Singh, A. (2025). Advances in guava crop regulation: A review of recent research and developments. Plant Archives. 25(1): 557- 564. https://doi.org/10.51470/PLANTARCHIVES.2025. v25.supplement-1.075.  

  41. Sharma, A. (2024). Effect of PGRs Application on ‘mrig-bahar’of Guava under Sub-Himalayan Subtropical Growing Conditions    (Doctoral dissertation, Ph. D. Thesis, Dr. Yashwant Singh Parmar University of Horticulture and Forestry). https:// krishikosh.egranth.ac.in/server/api/core/bitstreams/b3b f6cf4-374d-459b-9c58-f97a9577d17b/content. 

  42. Singleton, V.L. and Rossi Jr, J.A. (1965). Colorimetry of total phenolics with phosphomolybdic-phosphotungstic acid reagents. American Journal of Enology and Viticulture. 16(3): 144-158.10.5344/ajev.1965.16.3.144. 

  43. Wang, D., Randhawa, M.S., Azam, M., Liu, H., Ejaz, S., Ilahy, R., Qadri, R. et al. (2022) Exogenous melatonin treatment reduces postharvest senescence and maintains the quality of papaya fruit during cold storage. Front. Plant Sci. 13: 1039373. https://doi.org/10.3389/fpls.2022.103 9373.

  44. Wang, L., Luo, Z., Yang, M., Li, D., Qi, M., Xu, Y. and Li, L.I. (2020). Role of exogenous melatonin in table grapes: First evidence on contribution to the phenolics-oriented response. Food Chemistry. 329: 127155. https://doi.org/10.1016/j.food chem.2020.127155. 

  45. Wills, R. and Golding, J. (2016). Postharvest: An Introduction to the Physiology and Handling of Fruit and Vegetables. UNSW press

  46. Xie, J., Qin, Z., Pan, J., Li, J., Li, X., Khoo, H.E. and Dong, X. (2022a).  Melatonin treatment improves postharvest quality and regulates reactive oxygen species metabolism in “Feizixiao” litchi based on principal component analysis. Frontiers in Plant Science. 13: 965345. https://doi.org/10.3389/ fpls.2022.965345. 

  47. Xie, J., Qin, Z., Pan, J., Li, J., Sun, J., Khoo, H.E. and Dong, X. (2022b). Melatonin retarded the browning process of litchi by regulating the metabolism of phenolic compounds and reactive oxygen species. Available at SSRN 3983088. doi: 10.2139/ssrn.3983088.

  48. Yadav, A., Kumar, N., Upadhyay, A., Fawole, O.A., Mahawar, M.K., Jalgaonkar, K. and Mekhemar, M. (2022). Recent advances in novel packaging technologies for shelf-life extension of guava fruits for retaining health benefits for longer duration. Plants. 11(4): 547. https://www.mdpi.com/ 2223-7747/11/4/547.  

  49. Ze, Y., Gao, H., Li, T., Yang, B. and Jiang, Y. (2021). Insights into the roles of melatonin in maintaining quality and extending shelf life of postharvest fruits. Trends in Food Science and Technology. 109: 569-578.https://doi.org/10.1016/ j.tifs.2021.01.051. 

  50. Zhang, M., Yang, X., Yin, C., Lin, X., Liu, K., Zhang, K. and Wang, Z. (2024). Effect of exogenous melatonin on antioxidant properties and fruit softening of ‘Fengtang’plum fruit (Prunus salicina Lindl.) during storage at room temperature. Frontiers in Plant Science. 15: 1348744.  https://doi.org/ 10.3389/fpls.2024.1348744. 

  51. Zhang, W., Cao, J., Fan, X. and Jiang, W. (2020). Applications of nitric oxide and melatonin in improving postharvest fruit quality and the separate and crosstalk biochemical mechanisms. Trends in Food Science and Technology.  99: 531-541. https://doi.org/10.1016/j.tifs.2020.03.024. 

  52. Zhao, L., Yan, S., Wang, Y., Xu, G. and Zhao, D. (2023). Evaluation of the effect of preharvest melatonin spraying on fruit quality of ‘Yuluxiang’ pear. Foods. 12: 3507. https://doi. org/10.3390/foods12183507.

  53. Zhou, K., Cheng, Q., Dai, J., Liu, Y., Liu, Q., Li, R. and Lin, L. (2023).  Effects of exogenous melatonin on sugar and organic acid metabolism in early-ripening peach fruits. Plos One. 18(10): e0292959. https://doi.org/10.1371/journal.pone. 0292959.
Published In
Asian Journal of Dairy and Food Research
Article Metrics
Metrics Icon
22
Views
0
Citations
Reviewed By
Share Article
Download Article
In this Article
    Contact us
    Follow us

    Full Research Article

    Effect of Preharvest Application of Melatonin for Maintaining Postharvest Quality and Shelf Life in Guava

    R
    R. Madhanraj1
    https://orcid.org/0009-0007-1207-2334
    K
    K. Prakash2,*
    https://orcid.org/0000-0001-9347-8182
    A
    A. Akino1
    https://orcid.org/0000-0002-6759-6967
    R
    R. Nagajothi3
    https://orcid.org/0009-0004-0630-7422
    1Department of Fruit Science, SRM College of Agricultural Sciences, SRM Institute of Science and Technology, Baburayanpettai, Chengalpattu-603 201, Tamil Nadu, India.
    2Department of Post Harvest Technology, SRM College of Agricultural Sciences, SRM Institute of Science and Technology, Baburayanpettai, Chengalpattu-603 201, Tamil Nadu, India.
    3Section of Biochemistry and Crop Physiology, SRM College of Agricultural Sciences, SRM Institute of Science and Technology, Baburayanpettai, Chengalpattu-603 201, Tamil Nadu, India.

    ABSTRACT

    Background: Guava (Psidium guajava L.) is a highly perishable climacteric fruit characterized by a rapid ripening process and a short post-harvest life, which leads to significant economic losses. Melatonin has emerged as a potent antioxidant and signaling molecule capable of delaying senescence and preserving fruit quality.

    Methods: A field experiment was conducted using a Randomized Block Design (RBD) with four replications. Guava trees were subjected to five preharvest treatments: T1 (Control), T2 (50 µM), T3 (100 µM), T4 (150 µM) and T5 (200 µM) melatonin. The treatments were applied as foliar sprays two weeks prior to the anticipated harvest date.

    Result: Among the concentrations tested, fruits treated with 100 µM melatonin maintained significantly higher firmness, titratable acidity, ascorbic acid (Vitamin C) and total phenolic content compared to the control group. Furthermore, this treatment effectively minimized physiological loss in weight (PLW) and extended the shelf life of the fruits up to 9 (8.73) days under ambient conditions.

    INTRODUCTION

    Guava is a climacteric fruit enriched with bioactive compounds, yet its commercial utilization is constrained by rapid post-harvest deterioration driven by accelerated physicochemical processes. Such degradation contributes to pronounced quality losses and considerable economic implications across the supply chain (Labib et al., 2025). The crop exhibits seasonal flowering patterns influenced by climatic conditions, resulting in multiple harvests in southern India. However, fruits obtained during the rainy season are often of inferior quality compared to winter harvests, largely due to higher pest incidence and reduced storage potential (Sahu et al., 2025; Sharma, 2024). As a climacteric fruit, guava undergoes sharp increases in respiration and ethylene biosynthesis following harvest, which hastens ripening and senescence. These processes manifest as softening, loss of firmness, decline in nutritional attributes and substantial post-harvest losses (Yadav et al., 2022). Consequently, the development of effective strategies to delay ripening and preserve quality is critical for extending shelf life and ensuring market sustainability.
           
    Melatonin (N-acetyl-5-methoxytryptamine) is a versatile signalling molecule that occurs ubiquitously across diverse plant taxa (Ze et al., 2021). In recent years, the use of eco-friendly natural compounds or bio stimulants, such as melatonin, has gained importance due to their ability to regulate biosynthetic pathways involved in the formation of key quality attributes of fruits during ripening and subsequent post-harvest storage (Mubarok et al., 2023). Melatonin has emerged as a promising bio regulator owing to its functions in plant growth regulation, enhancement of stress tolerance and modulation of fruit ripening (Gao et al., 2022). Exogenous application of melatonin has been reported to delay fruit ripening, suppress ethylene biosynthesis and strengthen antioxidant defence mechanisms, thereby prolonging shelf life in several fruit species (Onik et al., 2021). Melatonin exhibits antioxidant activity during postharvest storage, thereby contributing to the extension of shelf life in fruits and vegetables (Gurjar et al., 2022). Preharvest application of melatonin has been shown to delay climacteric ethylene peaks, thereby maintaining fruit firmness and modulating chlorophyll-carotenoid transitions, which collectively enhance post-harvest quality across diverse fruit species (Aghdam and Arnao, 2024). Multiple investigations have explored the role of melatonin in regulating fruit yield and quality (Xie et al., 2022a). Although melatonin has been widely studied for its regulatory roles in plants, comprehensive evaluations of its preharvest application in guava are lacking, underscoring the necessity for targeted investigations to optimize post-harvest quality and shelf life. Therefore, this study was conducted to assess the impact of melatonin on postharvest quality attributes and shelf life of guava fruits.

    MATERIALS AND METHODS

    The present investigation was carried out in the fruit orchard by the Department of Fruit Science, SRM College of Agricultural Sciences, Chengalpattu, Tamil Nadu, India, during 2025-2026. The experimental site is situated at 12°23′19.7″ N latitude and 79°44′37.4″ E longitude, with an elevation of approximately 50 m above the mean sea level. The region experiences a tropical climate, with ambient temperatures ranging between 23°C and 38°C. The soil at the site is predominantly clayey, characterized by moderate fertility and adequate drainage capacity, making it suitable for fruit crop cultivation.
           
    Healthy guava trees were selected for the study and the experiment was conducted in a Randomized Block Design (RBD) with four replications. Five treatments were evaluated: T1 (control, water spray), T2 (melatonin 50 µM), T3 (melatonin 100 µM), T4 (melatonin 150 µM) and T5  (melatonin 200 µM). Melatonin solutions were freshly prepared by dissolving the required amount in a small volume of ethanol, followed by dilution with distilled water to obtain the desired concentrations (50-200 µM). Foliar sprays were applied uniformly two weeks before harvest using a battery-operated sprayer during early morning hours to ensure effective absorption and minimize evaporation. Fruits were harvested at physiological maturity and transported carefully to the laboratory for analysis (Dangwal et al., 2026). All laboratory analyses were conducted according to the standardized procedures outlined in Table 1.

    Table 1: Parameters recorded during the study in guava fruit.


           
    The recorded data were statistically analysed by using Analysis of Variance (ANOVA) appropriate for RBD to determine the significance of treatment effects with the help of the KAUGRAPES web-based statistical analysis software (Gopinath et al., 2021).

    RESULT S AND DISCUSSION

    Fruit firmness declined significantly as storage progressed, regardless of treatment. Fruit softening during storage mainly occurs due to the enzymatic breakdown of cell wall constituents such as pectin, cellulose and hemicellulose, mediated by enzymes like polygalacturonase and pectin methyl esterase (Kucuker et al., 2023). A gradual decline in fruit firmness was observed across all treatments throughout the storage period, indicating progressive softening during storage. However, fruits treated with 100 µM melatonin retained greater firmness, whereas the untreated controls exhibited the lowest firmness values (Table 2). Earlier studies have indicated that melatonin can inhibit the activity of cell wall degrading enzymes, thereby preserve cell wall integrity and delaying softening in papaya fruit (Borthakur et al., 2024). Thus, the improved firmness observed in melatonin treated fruits may be attributed to better preservation of structural polysaccharides and enhanced membrane stability during storage (Garrido Auñón  et al., 2025).

    Table 2: Effect of preharvest melatonin on firmness and TSS content of guava.


           
    Total soluble solids (TSS) serve as an indicator of fruit maturation or progression into advanced storage stages (Kasilingam et al., 2025). Data presented in Table 2 indicate significant differences in the effects of melatonin on fruit TSS content. The progression of ripening during storage was reflected by gradual increase in TSS as storage progressed across all treatment. Among the treatments, fruits treated with 100 µm of melatonin recorded the lowest TSS, while the control fruits exhibited the higher values. The rise in TSS during storage is a typical ripening response, mainly resulting from the breakdown of complex carbohydrates into soluble sugars. Application of melatonin (MT) effectively delays mango ripening by inhibiting starch to sugar conversion, maintaining cell wall integrity, modulating antioxidant metabolism and regulating the biosynthesis of ethylene and abscisic acid (Njie et al., 2022). Similar result was observed in banana (Devi et al., 2025) and Japanese plum (Cortes-Montana  et al., 2023).
           
    The decline in titratable acidity of guava fruits during storage was markedly reduced by exogenous melatonin treatment. The observed decline in titratable acidity (TA) during storage can be attributed to the metabolism of organic acids within the fruit or their breakdown through respiratory activity (Wang et al., 2022 and Jiang et al., 2023).  However, fruits treated with melatonin retained significantly higher acidity compared to other treatments. Among the treatments, 100 µM recorded the highest acidity values, indicating the effectiveness of melatonin in delaying the decline of organic acids during storage (Fig 1). Melatonin application may have moderated the rate of respiration and related metabolic activities, thereby reducing the rapid consumption of organic acids. Similar findings have been reported where melatonin treatment helped maintain higher acidity levels in fruits by slowing ripening related biochemical changes in Japanese plum (Cortes-Montana et al., 2023).

    Fig 1: Effects of preharvest melatonin on titratable acidity of guava.


           
    Reduced sugar accumulation is a characteristic marker of delayed postharvest ripening and senescence, primarily associated with the inhibition of amylase and phosphorylase activities (Hanif et al., 2020). During storage, complex carbohydrates were converted into soluble sugars (Johari et al., 2023). Application of melatonin increased the total sugar compared with the control at the end of storage period indicating slower metabolic activity (Fig 2). Total sugar content showed a steady increase throughout the storage in all treatments, reflecting the normal ripening process. The reduced accumulation of sugars suggests that melatonin regulated carbohydrate metabolism and delayed the breakdown of polysaccharides into simple sugars, thereby slowing the ripening process. Similar findings were reported by Zhao et al., (2023), who observed that melatonin treatment can regulate sugar metabolism by influencing enzymes involved in carbohydrate transformation in pear fruits. Thus, the slower increase in total sugars in melatonin treated fruits indicates delayed ripening and better preservation of fruit quality during storage.

    ​

    Fig 2: Effects of preharvest melatonin on total, reducing and non-reducing sugars of guava.


           
    The contents of reducing and non-reducing sugars in guava fruits exhibited gradual changes throughout the storage period. At the end of the storage period, melatonin treated fruits showed considerably lower levels of both reducing and non-reducing sugars compared with the control fruits (Fig 2). This effect may be attributed to melatonin’s inhibition of ethylene biosynthesis and the concentration-dependent suppression of starch conversion to soluble sugars, thereby contributing to delayed ripening and the maintenance of fruit quality (Liu  et al., 2020). Similar results were observed in papaya (Wang et al., 2022) and peach (Zhou et al., 2023).
           
    Ascorbic acid constitutes a fundamental antioxidant that governs the progression of fruit ripening by modulating reactive oxygen species metabolism and maintaining the intracellular redox equilibrium (Arabia et al., 2024). In this study, a consistent decline in ascorbic acid content was observed across all treatments throughout the storage period, reflecting the gradual degradation of vitamin C as ripening progressed. Among the treatments, fruit treated with 100 µM melatonin retained significantly higher ascorbic acid content, while the control fruits exhibited the lowest values (Fig 3). This effect may be attributed to the application of melatonin, which enhances the accumulation of metabolites during fruit ripening by elevating total flavonoid and phenolic contents as well as ascorbic acid levels (Fan et al., 2022a). Numerous investigations have demonstrated that melatonin significantly modulates fruit metabolite profiles by enhancing and sustaining levels of ascorbic acid (Zhang et al., 2020). Comparable outcomes were reported in guava (Fan et al., 2022b), kiwifruit (Luo et al., 2022) and pear (Liu et al., 2024).

    Fig 3: Effects of preharvest melatonin on ascrobic acid and phenol of guava.


           
    Melatonin is widely recognized as a potent antioxidant that limits free radical accumulation in plant tissues while supporting the preservation of non-enzymatic antioxidant metabolites, including anthocyanins, phenolics and flavonoids (Xie et al., 2022b). In present investigation, the total phenolic content declined progressively during storage irrespective of melatonin treatment; however, the reduction was more pronounced in control fruits compared to melatonin treated fruits. By the end of storage period, fruits treated with 100 µM melatonin exhibited the highest phenolic content (Fig 3). Comparable increases in phenolic compound concentrations following melatonin application have recently been reported in table grapes (Wang et al., 2020), litchi (Marak et al., 2024) and raspberry (Rahmanzadeh-Ishkeh  et al., 2024).
           
    The percentage of physiological weight loss (PLW) in guava fruit exhibited a progressive increase throughout the storage period. At the end of storage, fruits treated with 100 µM melatonin exhibited the lowest percentage of physiological weight loss (PLW), whereas the untreated controls showed significantly higher weight loss (Table 3). Exogenous melatonin has been reported to stimulate endogenous melatonin biosynthesis, thereby attenuating PLW (Li et al., 2023). The mitigation of weight loss following melatonin application may be attributed to the downregulation of metabolic activity, resulting in reduced energy expenditure and diminished rates of transpiration and respiration in stored fruit (Padilla-González  et al., 2026; Bal, 2021). Concordant findings have been documented in other fruit species, including plum (Zhang et al., 2024), litchi (Xie et al., 2022b) and banana (Anchana et al., 2023).
           
    Exogenous melatonin acts as an effective natural preservative that enhances postharvest fruit shelf life by mitigating physiological processes related to oxidative damage and strengthening antioxidant defences (Budiarto et al., 2025). In the present study, melatonin application extended fruit shelf life by up to 9 days (Table 3). The treatment effectively delayed the loss of firmness, suppressed the decline in soluble solids and titratable acids and enhanced the fruit’s antioxidant capacity, thereby contributing to prolonged freshness (Ze et al., 2021; Hei et al., 2025; Feng et al., 2022). Comparable outcomes have been reported in apples (Onik et al., 2021), mango (Njie et al., 2022), sweet cherries (Carrión-Antolí  et al., 2022) and banana (Lin et al., 2026). Melatonin plays an essential role in regulating fruit ripening through its interaction with ethylene and abscisic acid signalling pathways, thereby influencing the timing and synchrony of ripening while delaying senescence in fruit tissues (Aghdam et al., 2024).

    Table 3: Effect of preharvest Melatonin on PLW and shelf life of guava.

    CONCLUSION

    The findings of the study reveal that preharvest application of melatonin had a positive influence on maintaining the post-harvest quality of guava fruits by delaying ripening and reducing the rate of physiological and biochemical changes during storage. Treated fruits exhibited better retention of firmness and nutritional components, along with lower weight loss compared to untreated fruits. The regulation of sugar metabolism and antioxidant systems further contributed to improved fruit stability and slower senescence. Among the treatments, 100 µM melatonin was identified as the most effective concentration for preserving quality attributes and extending shelf life. In conclusion, exogenous melatonin represents a promising natural preservative that extends postharvest fruit shelf life by mitigating oxidative damage and strengthening antioxidant defences in guava.

    ACKNOWLEDGEMENT

    This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.
     
    Informed consent
     
    This study did not involve any experiments on human participants or animals. Therefore, ethics approval and permits were not required.

    CONFLICT OF INTEREST

    The authors declare that there are no conflicts of interest regarding the publication of this article.

    REFERENCES


    1. Abbott, J.A. (1999). Quality measurement of fruits and vegetables. Postharvest Biology and Technology. 15(3): 207-225. https://doi.org/10.1016/S0925-5214(98)00086-6.

    2. Aghdam, M.S. and Arnao, M.B. (2024). Phytomelatonin: From intracellular signaling to global horticulture market. Journal of Pineal Research. 76(5): e12990. https://doi.org/10.1111/jpi.12 990.

    3. Anchana, K., Kavitha, C., Shanmugasundaram, K.A., Djanaguiraman,  M. and Johnson, I. (2023). Role of exogenous melatonin in enhancing shelf life of traditional banana varieties. International Journal of Environment and Climate Change. 13(10): 992-998. DOI:10.9734/ijecc/2023/v13i102746. 

    4. AOAC. (2005). Official methods of analysis of AOAC International (18th ed.). Association of Official Analytical Chemists, Washington DC.

    5. Arabia, A., Munné-Bosch, S. and Munoz, P. (2024). Ascorbic acid as a master redox regulator of fruit ripening. Postharvest Biology and Technology. 207: 112614. https://doi.org/ 10.1016/j.postharvbio.2023.112614. 

    6. Bal, E. (2021). Effect of melatonin treatments on biochemical quality and postharvest life of nectarines. Journal of Food Measurement and Characterization. 15(1): 288-295. https://doi.org/10.1007/s11694-020-00636-5. 

    7. Borthakur, P., Chinnasamy, K., Paramasivam, S.K., Venkatachalam, S., Alagarswamy, S., Iruthayasamy, J. and Muthusamy, S. (2024). Exogenous melatonin as pre-and postharvest application on quality attributes, antioxidant capacity and extension of shelf life of papaya. Horticulturae. 10(10): 1099. https://doi.org/10.3390/horticulturae10101099.

    8. Budiarto, R., Sholikin, M.M., Mubarok, S., Ujilestari, T., Adli, D.N., Ahmed, T. and Ali, H. M. (2025). Exogenous melatonin as a natural preservative: A meta-analysis of its effects on fruit shelf life and oxidative stress during storage. Chemical and Biological Technologies in Agriculture. 12(1): 61. 10.1186/s40538-025-00781-3. 

    9. Carrión-Antolí, A., Martínez-Romero, D., Guillén, F., Zapata, P.J., Serrano, M. and Valero, D. (2022). Melatonin pre-harvest treatments leads to maintenance of sweet cherry quality during storage by increasing antioxidant systems. Frontiers in Plant Science. 13: 863467. https://doi.org/10.3389/ fpls.2022.863467.

    10. Cortes-Montana, D., Bernalte-García, M.J., Serradilla, M.J. and Velardo-Micharet, B. (2023). Optimal preharvest melatonin applications to enhance endogenous melatonin content, harvest and postharvest quality of Japanese plum. Agriculture. 13(7): 1318. https://doi.org/10.3390/agriculture 13071318.

    11. Dangwal, V., Singh, V.P., Mishra, D.S., Rawat, M., Krishna, R.K., Ravat, P. and Jat, R. (2026). Foliar potassium-calcium nutrition enhances fruit yield, quality and mitigates cracking in guava (Psidium guajava L.) under humid subtropical conditions. Frontiers in Plant Science. 17: 1812647. https: //doi.org/10.3389/fpls.2026.1812647. 

    12. Devi, M., Jeyakumar, P., Ravichandran, V., Arul, L., Balakrishnan, M. and Kavino, M. (2025). Melatonin application extends banana shelf life by delayed ripening. Plant Science. doi: 10.14719/pst.6867. 

    13. DuBois, M., Gilles, K.A., Hamilton, J.K., Rebers, P.A. and Smith, F. (1956). Colorimetric method for determination of sugars and related substances. Analytical Chemistry. 28(3): 350-356. https://doi.org/10.1021/ac60111a017.

    14. Fan, S., Li, Q., Feng, S., Lei, Q., Abbas, F., Yao, Y. and Zhu, X. (2022a). Melatonin maintains fruit quality and reduces anthracnose in postharvest papaya via enhancement of antioxidants and inhibition of pathogen development. Antioxidants. 11(5): 804. https://doi.org/10.3390/antiox11050804. 

    15. Fan, S., Xiong, T., Lei, Q., Tan, Q., Cai, J., Song, Z. and Zhu, X. (2022b). Melatonin treatment improves postharvest preservation and resistance of guava fruit (Psidium guajava L.). Foods. 11(3): 262. https://doi.org/10.3390/foods11030 262. 

    16. Feng, B.S., Kang, D.C., Sun, J., Leng, P., Liu, L.X., Wang, L. and Liu, Y.G. (2022). Research on melatonin in fruits and vegetables and the mechanism of exogenous melatonin on postharvest preservation. Food Bioscience. 50: 102196. https://doi.org/10.1016/j.fbio.2022.102196. 

    17. Gao, T., Liu, X., Tan, K., Zhang, D., Zhu, B., Ma, F. and Li, C. (2022). Introducing melatonin to the horticultural industry: Physiological roles, potential applications and challenges. Horticulture Research. 9: uhac094.  https://doi.org/10.1093/hr/uhac 094. 

    18. Garrido Auñón, F., Padilla González, P.A., Serrano, M., Valero, D. and Agulló, V. (2025). Melatonin boosts the phytochemical profile of blood oranges, enhancing (Poly) phenol and endogenous melatonin content, through pre and postharvest treatments. Journal of Pineal Research. 77(5): e70078. https://doi.org/10.1111/jpi.70078. 

    19. Gopinath, P.P., Parsad, R., Joseph, B. and VS, A. (2021). grapesAgri1: Collection of shiny apps for data analysis in agriculture. Journal of Open-Source Software. 6(63): 3437. doi: 10. 21105/joss.03437.

    20. Gurjar, P.S., Killadi, B., Pareek, P.K. and Hada, T.S. (2022). Application of melatonin in maintaining post harvest quality of fruits and vegetables: A review. Agricultural Reviews. 43(2): 193-198. doi: 10.18805/ag.R-2092.

    21. Hanif, A., Ahmad, S., Jaskani, M.J. and Ahmad, R. (2020). Papaya treatment with putrescine maintained the overall quality and promoted the antioxidative enzyme activities of the stored fruit. Scientia Horticulturae. 268: 109367. https:/ /doi.org/10.1016/j.scienta.2020.109367. 

    22. Hei, H., Tang, H., Zhao, R., Li, G. and Shi, F. (2025). Effect of melatonin treatment on storage quality and antioxidant system of postharvest winter jujube (Zizyphus jujube Mill. cv. Dongzao). Foods. 14(4): 576.  https://doi.org/10.3390/ foods14040576. 

    23. Jiang, X., Liu, K., Peng, H., Fang, J., Zhang, A., Han, Y. and Zhang, X. (2023). Comparative network analysis reveals the dynamics of organic acid diversity during fruit ripening in peach [Prunus persica L. Batsch]. BMC Plant Biology. 23(1): 16.10.1186/s12870-023-04037-w. 

    24. Johari, N.H.F., Dolhaji, N.H., Shamsuri, S. and Abdol Latif, P. (2023). A review on sugar and organic profiles on the postharvest quality of fruits. Science Letters (ScL). 17(2): 91-108. https://ir.uitm.edu.my/id/eprint/79962. 

    25. Kasilingam, P., Shanmugavel, C., Athikesavan, R., Ramakrishnan, R. and Arumugam, V.A. (2025). Innovative postharvest treatments to enhance the shelf-life and quality of carica papaya. Agricultural Science Digest. 46(4): 614-621. doi: 10.18805/ag.D-6371. 

    26. Kucuker, E., Aglar, E., Sakaldaş, M., Şen, F. and Gundogdu, M. (2023). Impact of postharvest putrescine treatments on phenolic compounds, antioxidant capacity, organic acid contents and some quality characteristics of fresh fig fruits during cold storage. Plants. 12(6): 1291.https://doi.org/10.3390 /plants12061291.

    27. Labib, L.A., Ahmed, S. and Hasan, M.F.  (2025). Improving guava shelf life and preserving postharvest quality with edible coatings. Food Science and Nutrition. 13(6): e70491. https://doi.org/10.1002/fsn3.70491.

    28. Li, N., Zhai, K., Yin, Q., Gu, Q., Zhang, X., Melencion, M.G. and Chen, Z. (2023). Crosstalk between melatonin and reactive oxygen species in fruits and vegetables post-harvest preservation: An update. Frontiers in Nutrition. 10: 1143511. https://doi.org/10.3389/fnut.2023.1143511.  

    29. Lin, J., Zhang, R., Chen, Q., Liang, W., Wu, Y., Su, W. and Fan, Z. (2026). Melatonin alleviates chilling injury in postharvest banana fruit by modulating membrane lipid and phenolic metabolism. Postharvest Biology and Technology. 239: 114361. https://doi.org/10.1016/j.postharvbio.2026.114 361. 

    30. Liu, G., Zhang, Y., Yun, Z., Hu, M., Liu, J., Jiang, Y. and Zhang, Z. (2020). Melatonin enhances cold tolerance by regulating energy and proline metabolism in litchi fruit. Foods. 9(4): 454. https://www.mdpi.com/2304-8158/9/4/454. 

    31. Liu, L., Huang, A., Wang, B., Zhang, H., Zheng, Y. and Wang, L. (2024). Melatonin mobilizes the metabolism of sugars, ascorbic acid and amino acids to cope with chilling injury in postharvest pear fruit. Scientia Horticulturae. 323: 112548. https://doi.org/10.1016/j.scienta.2023.112548. 

    32. Luo,Z., Zhang, J., Xiang, M., Zeng, J., Chen, J. and Chen, M. (2022). Exogenous melatonin treatment affects ascorbic acid metabolism in postharvest ‘Jinyan’kiwifruit. Frontiers in Nutrition. 9: 1081476. https://doi.org/10.3389/fnut.2022.1081476. 

    33. Marak, K.A., Mir, H., Siddiqui, M.W., Singh, P., Homa, F. and Alamri, S. (2024). Exogenous melatonin delays oxidative browning in litchi during cold storage by regulating biochemical attributes and gene expression. Frontiers in Plant Science. 15: 1402607. https://doi.org/10.3389/fpls.2024.1402607. 

    34. Miller, G.L. (1959). Use of dinitrosalicylic acid reagent for determination of reducing sugar. Analytical Chemistry. 31(3): 426-428.  https://doi.org/10.1021/ac60147a030. 

    35. Mubarok, S., Suminar, E., Abidat, A.H., Setyawati, C.A., Setiawan, E. and Buswar, A.S. (2023). Overview of melatonin’s impact  on postharvest physiology and quality of fruits. Horticulturae. 9(5): 586. https://doi.org/10.3390/horticulturae9050586.

    36. Njie, A., Zhang, W.E., Dong, X., Lu, C., Pan, X. and Liu, Q. (2022). Effect of melatonin on fruit quality via decay inhibition and enhancement of antioxidative enzyme activities and genes expression of two mango cultivars during cold storage. Foods. 11(20): 3209. https://www.mdpi.com/ 2304-8158/11/20/3209. 

    37. Onik, J.C., Wai, S.C., Li, A., Lin, Q., Sun, Q., Wang, Z. and Duan, Y. (2021). Melatonin treatment reduces ethylene production and maintains fruit quality in apple during postharvest storage. Food Chemistry. 337: 127753. https://doi.org/ 10.1016/j.foodchem.2020.127753.

    38. Padilla-González, P.A., Garrido-Auñón, F., García-Pastor, M.E., Guillén, F., Serrano, M., Valero, D. andAgulló, V. (2026). Melatonin as a Pre-and postharvest tool for enhancing fruit quality. Plants. 15(2): 331. https://doi.org/10.3390/ plants15020331. 

    39. Rahmanzadeh-Ishkeh, S., Shirzad, H., Tofighi, Z., Fattahi, M. and Ghosta, Y. (2024). Exogenous melatonin prolongs raspberry postharvest life quality by increasing some antioxidant and enzyme activity and phytochemical contents. Scientific Reports. 14(1): 11508. https://doi.org/10.1038/s41598- 024-62111-1. 

    40. Sahu, K., Khunte, S.D., Chandrakar, Y.K. and Singh, A. (2025). Advances in guava crop regulation: A review of recent research and developments. Plant Archives. 25(1): 557- 564. https://doi.org/10.51470/PLANTARCHIVES.2025. v25.supplement-1.075.  

    41. Sharma, A. (2024). Effect of PGRs Application on ‘mrig-bahar’of Guava under Sub-Himalayan Subtropical Growing Conditions    (Doctoral dissertation, Ph. D. Thesis, Dr. Yashwant Singh Parmar University of Horticulture and Forestry). https:// krishikosh.egranth.ac.in/server/api/core/bitstreams/b3b f6cf4-374d-459b-9c58-f97a9577d17b/content. 

    42. Singleton, V.L. and Rossi Jr, J.A. (1965). Colorimetry of total phenolics with phosphomolybdic-phosphotungstic acid reagents. American Journal of Enology and Viticulture. 16(3): 144-158.10.5344/ajev.1965.16.3.144. 

    43. Wang, D., Randhawa, M.S., Azam, M., Liu, H., Ejaz, S., Ilahy, R., Qadri, R. et al. (2022) Exogenous melatonin treatment reduces postharvest senescence and maintains the quality of papaya fruit during cold storage. Front. Plant Sci. 13: 1039373. https://doi.org/10.3389/fpls.2022.103 9373.

    44. Wang, L., Luo, Z., Yang, M., Li, D., Qi, M., Xu, Y. and Li, L.I. (2020). Role of exogenous melatonin in table grapes: First evidence on contribution to the phenolics-oriented response. Food Chemistry. 329: 127155. https://doi.org/10.1016/j.food chem.2020.127155. 

    45. Wills, R. and Golding, J. (2016). Postharvest: An Introduction to the Physiology and Handling of Fruit and Vegetables. UNSW press

    46. Xie, J., Qin, Z., Pan, J., Li, J., Li, X., Khoo, H.E. and Dong, X. (2022a).  Melatonin treatment improves postharvest quality and regulates reactive oxygen species metabolism in “Feizixiao” litchi based on principal component analysis. Frontiers in Plant Science. 13: 965345. https://doi.org/10.3389/ fpls.2022.965345. 

    47. Xie, J., Qin, Z., Pan, J., Li, J., Sun, J., Khoo, H.E. and Dong, X. (2022b). Melatonin retarded the browning process of litchi by regulating the metabolism of phenolic compounds and reactive oxygen species. Available at SSRN 3983088. doi: 10.2139/ssrn.3983088.

    48. Yadav, A., Kumar, N., Upadhyay, A., Fawole, O.A., Mahawar, M.K., Jalgaonkar, K. and Mekhemar, M. (2022). Recent advances in novel packaging technologies for shelf-life extension of guava fruits for retaining health benefits for longer duration. Plants. 11(4): 547. https://www.mdpi.com/ 2223-7747/11/4/547.  

    49. Ze, Y., Gao, H., Li, T., Yang, B. and Jiang, Y. (2021). Insights into the roles of melatonin in maintaining quality and extending shelf life of postharvest fruits. Trends in Food Science and Technology. 109: 569-578.https://doi.org/10.1016/ j.tifs.2021.01.051. 

    50. Zhang, M., Yang, X., Yin, C., Lin, X., Liu, K., Zhang, K. and Wang, Z. (2024). Effect of exogenous melatonin on antioxidant properties and fruit softening of ‘Fengtang’plum fruit (Prunus salicina Lindl.) during storage at room temperature. Frontiers in Plant Science. 15: 1348744.  https://doi.org/ 10.3389/fpls.2024.1348744. 

    51. Zhang, W., Cao, J., Fan, X. and Jiang, W. (2020). Applications of nitric oxide and melatonin in improving postharvest fruit quality and the separate and crosstalk biochemical mechanisms. Trends in Food Science and Technology.  99: 531-541. https://doi.org/10.1016/j.tifs.2020.03.024. 

    52. Zhao, L., Yan, S., Wang, Y., Xu, G. and Zhao, D. (2023). Evaluation of the effect of preharvest melatonin spraying on fruit quality of ‘Yuluxiang’ pear. Foods. 12: 3507. https://doi. org/10.3390/foods12183507.

    53. Zhou, K., Cheng, Q., Dai, J., Liu, Y., Liu, Q., Li, R. and Lin, L. (2023).  Effects of exogenous melatonin on sugar and organic acid metabolism in early-ripening peach fruits. Plos One. 18(10): e0292959. https://doi.org/10.1371/journal.pone. 0292959.
    In this Article
      Contact us
      Follow us
      Published In
      Asian Journal of Dairy and Food Research

      Editorial Board

      View all (0)