Water migration and browning mechanisms in postharvest litchi pericarp: Insights from LF NMR

文献类型: 外文期刊

第一作者: Chen, Yongqi

作者: Chen, Yongqi;Li, Jingyi;Zhu, Difa;Zhou, Chulin;Li, Yao;Liu, Yiwen;Ma, Yuwei;Luo, Tao;Wu, Zhenxian;Han, Dongmei;Luo, Tao;Wu, Zhenxian;Wen, Bingyi

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关键词: Browning; Pericarp; Water migration

期刊名称:POSTHARVEST BIOLOGY AND TECHNOLOGY ( 影响因子:6.8; 五年影响因子:7.5 )

ISSN: 0925-5214

年卷期: 2025 年 230 卷

页码:

收录情况: SCI

摘要: Litchi (Litchi chinensis Sonn.) pericarp undergoes rapid postharvest browning, driven by physiological and biochemical changes, with water migration playing a critical role. This study employed low-field nuclear magnetic resonance (LF NMR) and biochemical analyses to explore these dynamics across five litchi cultivars: Jumeiren 'JMR' and Nuomici 'NMC' (rapid-loss cultivars) exhibited up to 70 % loss of free water within 24 h, accompanied by faster browning, increased activities of polyphenol oxidase (PPO) and peroxidase (POD), pronounced degradation of phenolic compounds, and elevated levels of oxidative stress markers including proline and malondialdehyde. In contrast, Huaizhi 'HZ', Xianjinfeng 'XJF', and Wuheli 'WHL' (slow-loss cultivars) showed slower water loss, delayed browning, and preserved antioxidant capacity. Combining LF NMR results, we discovered a three-phase water migration model driving browning a three-phase water migration model driving browning: (1) rapid free water loss disrupted vacuoles and initiated oxidative stress and phenolic oxidation; (2) sustained free water loss with increased semi-bound water temporarily boosted antioxidant capacity while perpetuating browning; and (3) bound water rebound stabilized the structure as senescence slowed browning due to substrate depletion Polyphenol oxidase and peroxidase activities, which are inversely related to moisture and phenolic levels, catalyzed browning. Water loss amplified oxidative stress, as evidenced by elevated proline and malondialdehyde levels. This stress triggers superoxide dismutase (SOD) oxidative responses. However, sustained water loss diminished SOD efficacy, promoting lipid peroxidation, i.e., MDA accumulation. Cultivarspecific water dynamics, primarily driven by free water loss, influence these processes. These insights support targeted postharvest strategies, including humidity control and antioxidant enhancement to preserve litchi quality.

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