Melatonin Treatment Improves Postharvest Preservation and Resistance of Guava Fruit (Psidium guajava L.)

Abstract

Guava fruit has a short postharvest shelf life at room temperature. Melatonin is widely used for preservation of various postharvest fruit and vegetables. In this study, an optimal melatonin treatment (600 μmol·L−1, 2 h) was identified, which effectively delayed fruit softening and reduced the incidence of anthracnose on guava fruit. Melatonin effectively enhanced the antioxidant capacity and reduced the oxidative damage to the fruit by reducing the contents of superoxide anions, hydrogen peroxide and malondialdehyde; improving the overall antioxidant capacity and enhancing the enzymatic antioxidants and non-enzymatic antioxidants. Melatonin significantly enhanced the activities of catalase, superoxide dismutase, ascorbate peroxidase and glutathione reductase. The contents of total flavonoids and ascorbic acid were maintained by melatonin. This treatment also enhanced the defense-related enzymatic activities of chitinase and phenylpropanoid pathway enzymes, including phenylalanine ammonia lyase and 4-coumaric acid-CoA-ligase. The activities of lipase, lipoxygenase and phospholipase D related to lipid metabolism were repressed by melatonin. These results showed that exogenous melatonin can maintain the quality of guava fruit and enhance its resistance to disease by improving the antioxidant and defense systems of the fruit.

Attenuation of Postharvest Browning in Rambutan Fruit by Melatonin Is Associated With Inhibition of Phenolics Oxidation and Reinforcement of Antioxidative Process

“…In the present research, the activities of SOD and CAT in stored rambutan fruit were significantly enhanced by MT treatment, further indicating that MT could mitigate ROS-induced cellular oxidative stress by augmenting antioxidant enzyme activity and therefore contribute to the alleviation of postharvest browning. Parallel observations have also been reported in cassavas (53), strawberries (12), sweet cherries (54), litchis (18), guavas (55), and peaches (41).…”

Latest Advances in Preservation Technology for Fresh Fruit and Vegetables

“…Several preservation technologies can be used with fresh produce, such as chemical treatments, physical applications, and other approaches. This Special Issue aimed to collect the latest trends in diverse mechanisms of fresh product preservation and covered six chemical treatments: 1-Methylcyclopropene (1-MCP) [ 1 ], calcium chloride (CaCl 2 ) [ 2 ], melatonin [ 3 ], hydrogen sulfide (H 2 S) [ 4 ], essential oils [ 5 ], lactic acid and acetic acid [ 6 ], in a broader postharvest quality attribute. Other treatments, such as cold shock, modified atmospheric packaging [ 7 ], and chlorophyllin-based photodynamic inactivation [ 8 ], were utilized in postharvest conditions.…”

“…As an organic preservative, melatonin is a vital stress regulator in plants physiology, with a possible role in the postharvest life of fruit and vegetables. The application of melatonin (600 μmol L −1 ) remarkably improved quality in postharvest guava ( Psidium guajava L.) fruit [ 3 ]. The mechanisms involve enhancing enzymatic and non-enzymatic antioxidants, paralleled with regulating lipid metabolisms and defense-related enzymes such as chitinase, phenylalanine ammonia lyse, and 4-coumaric acid-CoA-ligase.…”

“…The mechanisms involve enhancing enzymatic and non-enzymatic antioxidants, paralleled with regulating lipid metabolisms and defense-related enzymes such as chitinase, phenylalanine ammonia lyse, and 4-coumaric acid-CoA-ligase. It further helps maintain cellular integrity and boosts disease resistance, which results in the improvement of storage quality in guava [ 3 ]. In another gaseous preservative, H 2 S is utilized in horticultural products with low concentrations.…”

Inhibitory Effect of Guava Leaf Polyphenols on Advanced Glycation End Products of Frozen Chicken Meatballs (−18 °C) and Its Mechanism Analysis

“…In industry, the fruit has been used to produce juice, preserved fruit, jam [ 13 ], and so on because of its abundant nutritional and functional constituents (such as minerals, vitamin C, polyphenols, dietary fiber, carotenoids, etc.) [ 14 , 15 ], which lead to an amount of industry residues including peels, seeds, and leaves [ 16 ]. About 80 kg of residue is produced after one ton of guava is processed [ 13 ].…”