Melatonin‐mediated postharvest quality and antioxidant properties of fresh fruits: A comprehensive meta‐analysis

Abstract

At postharvest, fruits have a short shelf life. Recently, there has been much literature on the effects of melatonin on the postharvest quality of horticultural crops.However, reports of various findings comprise mixed claims and product-specific conclusions. Therefore, a meta-analysis systematically dissects the comprehensive effect on several fruits. In this meta-analysis, standard mean difference (SMD) was adopted using a random-effect model. The study used 36 articles and isolated 24 indicator parameters of postharvest quality and antioxidant properties based on the inclusion criteria. As exhibited in the forest plot, melatonin reduced chilling injury, weight loss, respiration rate, and ethylene content (SMD −0.90, 95% CI [−1.14, −0.65]; I 2 = 81%; p < .00001). Similarly, the application of melatonin significantly suppressed electrolyte leakage, malondialdehyde (MDA), hydrogen peroxide, superoxide anion, lipoxygenase, and polyphenol oxidase (SMD −0.89, 95% CI [−1.09, −0.69]; I 2 = 70%; p < .00001). In addition, exogenous melatonin application induced endogenous melatonin content, phenolic content, and flavonoid and anthocyanin contents (SMD 1.15, 95% CI [0.91, 1.39]; I 2 = 71%; p = .01). Moreover, melatonin treatment enhanced antioxidant activities (catalase, superoxide dismutase, peroxidase, ascorbate peroxidase, and phenylalanine ammonia-lyse) (SMD 1.37, 95% CI [1.03, 1.71]; I 2 = 86%; p < .00001). Thus, in the whole study, the overall effect was significantly high in treated fruit (p < .0001), and the overall heterogeneity was above (I 2 ) > 70%.In addition, the funnel plot showed symmetry in the most selected studies. To sum up, the result gives a further understanding of melatonin's capabilities in reducing postharvest losses and maintaining the quality of fresh fruits.

Melatonin: A biomolecule for mitigating postharvest chilling injury in fruits and vegetables

“…A study by Madebo et al. (2022) evaluated 36 published articles and identified 24 major parameters responsible for postharvest quality and shelf‐life. They found MT to be effective in reducing CI by 95%, by lowering weight loss and ethylene production by 81% when compared to control.…”

Melatonin Treatments Reduce Chilling Injury and Delay Ripening, Leading to Maintenance of Quality in Cherimoya Fruit

“…Then, serotonin is converted into melatonin through two different pathways involving the intermediates N-acetyl serotonin and 5-methoxy-tryptamine [ 18 ]. Melatonin has been reported to reduce CI in a wide range of fruit species when applied as a postharvest treatment, with additional effects on delaying ripening and senescence processes, leading to maintenance of fruit quality traits [ 19 , 20 , 21 ]. For instance, CI symptoms were delayed by 1 and 2.5 mM melatonin dipping treatment for 15 min in ‘Friar’ plum [ 22 ], and delays were also achieved with 0.1 mM melatonin dipping for 2 h in several mango cultivars [ 23 ].…”

“…Melatonin treatment has been also reported to be effective in increasing zucchini fruit tolerance to CI, although this effect was enhanced when melatonin and 1-methylcyclopropene treatments were combined [ 25 ]. In addition, melatonin has been reported to extend the shelf life of fruit when stored at non-chilling temperatures in a wide range of fruit species, including mango, banana and pear, among other [ 19 , 20 , 21 , 26 , 27 , 28 ]…”