Wan Jiahui, Wu Yanting, Tong Zhihong, Su Wenbing, Lin Hetong, Fan Zhongqi
Institute of Postharvest Technology of Agricultural Products, College of Food Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
Key Laboratory of Postharvest Biology of Subtropical Special Agricultural Products, Fujian Province University, Fuzhou 350002, China.
Foods. 2024 Sep 25;13(19):3050. doi: 10.3390/foods13193050.
Cold storage is one of the most effective methods to maintain postharvest fruit quality. However, loquat fruits are prone to chilling injury (CI) during cold storage, appearing as symptoms such as browning and pitting, which leads to quality deterioration and economic losses. In this study, the effects of melatonin on CI alleviation and the potential role of reactive oxygen species (ROS) metabolism in loquat fruit were investigated. The results showed that 50 μM melatonin was the optimal concentration to inhibit the increase in CI index and cell membrane permeability. Moreover, compared to control fruits, 50 μM melatonin inhibited the malonaldehyde (MDA) content, O production rate and HO content (ROS accumulation) by 17.8%, 7.2% and 11.8%, respectively, during cold storage. Compared to non-treated loquats, 50 μM melatonin maintained higher levels of 1-diphenyl-2-picrylhydrazyl radical-scavenging ability and reducing power, as well as the contents of ascorbic acid (AsA) and glutathione (GSH). Additionally, 50 μM melatonin enhanced the activities of antioxidant enzymes, such as superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) by increasing relevant gene expressions. The activities of SOD, CAT and APX were increased by up to 1.1-, 1.1- and 1.1-times (16 d) by melatonin, as compared with the control fruits. These findings indicate that melatonin mitigation of CI is involved in maintaining cellular redox apphomeostasis in loquat fruit during cold storage.
冷藏是保持采后果实品质最有效的方法之一。然而，枇杷果实冷藏期间易发生冷害，出现褐变和麻点等症状，导致品质下降和经济损失。本研究探讨了褪黑素对减轻枇杷果实冷害的作用以及活性氧（ROS）代谢的潜在作用。结果表明，50 μM褪黑素是抑制冷害指数增加和细胞膜通透性增加的最佳浓度。此外，与对照果实相比，50 μM褪黑素在冷藏期间分别抑制了丙二醛（MDA）含量、O产生速率和H₂O₂含量（ROS积累）17.8%、7.2%和11.8%。与未处理的枇杷相比，50 μM褪黑素保持了较高水平的1,1-二苯基-2-苦基肼自由基清除能力和还原力，以及抗坏血酸（AsA）和谷胱甘肽（GSH）的含量。此外，50 μM褪黑素通过增加相关基因表达增强了抗氧化酶如超氧化物歧化酶（SOD）、过氧化氢酶（CAT）和抗坏血酸过氧化物酶（APX）的活性。与对照果实相比，褪黑素使SOD、CAT和APX的活性在16 d时分别提高了1.1倍、1.1倍和1.1倍。这些结果表明，褪黑素减轻枇杷果实冷害与冷藏期间维持细胞氧化还原稳态有关。
