This study investigated the effects of melatonin (MT) treatment on the edible qualities and lignification in loquat fruit during cold storage (4 °C) for 25 days. The results exhibited that 50 μM MT treatment effectively maintained the external quality of loquat fruit by reducing weight loss and firmness. MT treatment suppressed the decline of sucrose while slowing the changes in glucose and fructose contents. MT application to loquat fruit also increased the contents of phenolic compounds (chlorogenic acid and neochlorogenic acid) and organic acids (malic acid, oxalic acid, and tartaric acid), thereby maintaining the flavor and nutritional quality of loquat fruit. Compared to untreated fruit, MT treatment reduced the accumulation of malondialdehyde (MDA) and improved antioxidant capacity in loquat fruit, as indicated by higher ABTS, DPPH, and FRAP. Furthermore, MT treatment heavily regulated lignin biosynthesis-related enzyme activities during cold storage, including phenylalanine ammonia-lyase (PAL), 4-coumarate: coenzyme A ligase (4CL), cinnamate dehydrogenase (CAD), and peroxidase (POD). Our results suggest that MT treatment could be an effective approach to alleviate lignification and maintaining the nutrition quality of loquat fruit during cold storage.

这项研究调查了褪黑素（MT）处理对冷藏（4°C）25天的fruit果实的食用品质和木质化的影响。结果表明，50μMMT处理可通过减少体重减轻和硬度来有效保持maintained果实的外部品质。MT处理抑制了蔗糖的下降，同时减缓了葡萄糖和果糖含量的变化。在to果上施用MT还增加了酚类化合物（绿原酸和新绿原酸）和有机酸（苹果酸，草酸和酒石酸）的含量，从而保持了fruit果的风味和营养品质。与未处理的水果相比，MT处理减少了lon果实中的丙二醛（MDA）积累并提高了抗氧化能力，这可以通过较高的ABTS，DPPH和FRAP来表明。此外，MT处理在冷藏期间严重调节了木质素生物合成相关的酶活性，包括苯丙氨酸解氨酶（PAL），4-香豆酸盐：辅酶A连接酶（4CL），肉桂酸脱氢酶（CAD）和过氧化物酶（POD）。我们的结果表明，MT处理可能是减轻冷藏过程中木质化和保持lo果实营养质量的有效方法。