Abstract Juice sac granulation is a serious problem in pummelo (Citrus grandis L. Osbeck) fruits during postharvest storage owing to various abiotic stress conditions, which greatly reduces their attractiveness and commercial value. Hence, measures to alleviate the postharvest juice sac granulation of pummelo are of great importance. The current study was designed to investigate the effects of 1.5 % chitosan treatment on the granulation index, fruit color, nutrient contents, hydrogen peroxide (H2O2) content, malondialdehyde (MDA) content, antioxidant enzymatic activities and related gene expressions in pummelo fruits stored at room temperature (20 ± 2 °C) for 150 d. The results showed that chitosan treatment significantly maintained the appearance of pummelo fruits by delaying postharvest granulation and color variation, retarded the degradation of total soluble solid (TSS), titratable acids (TA) and total sugars. The O2−· production rate, H2O2 content and MDA content in the fruit pulp were significantly decreased whereas the contents of lycopene, ascorbic acid (AsA) and glutathione (GSH) were enhanced following chitosan treatment. The alleviation of postharvest granulation of pummelo was attributed to the higher levels of active antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) and glutathione reductase (GR) both at the transcriptional and translational levels. The evidence from this study shows that postharvest chitosan treatment can efficiently reduce juice sac granulation and prolong the postharvest storage period of pummelo fruits by mitigating ROS accumulation, delayed fruit senescence under storage at room temperature.

中文翻译：

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壳聚糖涂层通过减轻室温储存期间收获的柚子 (Citrus grandis L. Osbeck) 中 ROS 的积累来减轻采后汁囊颗粒化

摘要 由于各种非生物胁迫条件，柚子（Citrus grandis L. Osbeck）果实在采后贮藏过程中，汁囊造粒是一个严重的问题，大大降低了其吸引力和商业价值。因此，减轻柚子采后汁囊造粒的措施具有重要意义。本研究旨在研究 1.5% 壳聚糖处理对贮藏于 1.5% 的柚子果实的制粒指数、果实颜色、营养成分、过氧化氢 (H2O2) 含量、丙二醛 (MDA) 含量、抗氧化酶活性和相关基因表达的影响。室温 (20 ± 2 °C) 150 天。结果表明，壳聚糖处理通过延迟采后造粒和颜色变化显着保持了柚子果实的外观，延缓总可溶性固体 (TSS)、可滴定酸 (TA) 和总糖的降解。壳聚糖处理后果肉中的O2-·产率、H2O2 含量和MDA 含量显着降低，而番茄红素、抗坏血酸（AsA）和谷胱甘肽（GSH）的含量增加。柚子收获后颗粒化的缓解归因于较高水平的活性抗氧化酶，如超氧化物歧化酶 (SOD)、过氧化氢酶 (CAT)、抗坏血酸过氧化物酶 (APX) 和谷胱甘肽还原酶 (GR) 在转录和翻译水平。本研究的证据表明，采后壳聚糖处理可以通过减轻 ROS 的积累，有效减少柚子的汁囊造粒，延长采后贮藏期，