The study aimed to identify the optimal concentration of exogenous melatonin for fresh-cut nectarines by evaluating their quality attributes during storage at 0 °C with relative humidity (RH) of 85 % - 90 % after treatments with different concentrations (0 mM, 0.05 mM, 0.1 mM, and 0.5 mM, with 0 mM as the control). Furthermore, the optimal melatonin treatment concentration and control were used to analyze its effects on antioxidant capacity and tissue microstructure of fresh-cut nectarines. The results indicated that 0.1 mM melatonin was the most effective treatment concentration for maintaining the primary physicochemical qualities of the fresh-cut nectarines. On 12 d of the storage, the 0.1 mM melatonin-treated group showed significant increases of 4.09 % in total phenolic content and 5.78 % in ascorbic acid compared to the control group, with more retained tissue microstructure. Additionally, the treatment was observed with a reduction of 23.82 % in MDA content, 39.31 % in H2O2 content, and 34.26 % in superoxide anion levels, compared with the control. Moreover, the melatonin treatment inhibited the microbial growth and enhanced the antioxidant capacity of fresh-cut nectarines. Furthermore, 0.1 mM melatonin treatment reduced the gene expression and activity of POD and PPO enzymes, while increased the gene expression and activity of PAL and CHS enzymes. These findings demonstrate that 0.1 mM melatonin not only delays browning in fresh-cut nectarines but also improves their antioxidant capacity and storage quality, highlighting its potential as an effective post-harvest treatment strategy for reducing the reliance on synthetic preservatives in commercial applications.

中文翻译：

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将鲜切油桃浸泡在褪黑激素浓度下的功效及其对抗氧化能力、微生物含量和储存质量的影响


该研究旨在通过评估不同浓度（0 mM、0.05 mM、0.1 mM 和 0.5 mM，以 0 mM 作为对照）处理后，在 0 °C、相对湿度 （RH） 为 85 % - 90 % 的条件下储存期间的质量属性，来确定鲜切油桃外源褪黑激素的最佳浓度。此外，采用最佳褪黑素处理浓度和对照分析其对鲜切油桃抗氧化能力和组织微观结构的影响。结果表明，0.1 mM 褪黑激素是维持鲜切油桃主要理化品质的最有效处理浓度。在储存 12 天后，与对照组相比，0.1 mM 褪黑激素处理组的总酚含量显着增加 4.09%，抗坏血酸含量显着增加 5.78%，保留的组织微观结构更多。此外，与对照相比，观察到处理的 MDA 含量降低了 23.82%，H2O2 含量降低了 39.31%，超氧阴离子水平降低了 34.26%。此外，褪黑激素处理抑制了微生物生长并增强了鲜切油桃的抗氧化能力。此外，0.1 mM 褪黑激素处理降低了 POD 和 PPO 酶的基因表达和活性，同时增加了 PAL 和 CHS 酶的基因表达和活性。这些发现表明，0.1 mM 褪黑激素不仅可以延缓鲜切油桃的褐变，还可以提高其抗氧化能力和储存质量，突出了其作为减少商业应用中对合成防腐剂依赖的有效收获后处理策略的潜力。