两种贮藏温度下“黑琥珀”李果实品质及不同部位抗氧化活性的变化规律

研究不同贮藏温度下李果实品质以及近果皮与近果核部位果肉抗氧化能力的变化。结果表明，在20℃贮藏时，李果实硬度、超氧阴离子自由基、羟自由基和DPPH 自由基清除能力不同程度降低，而pH 值、总抗氧化能力、总酚和总黄酮含量升高，2℃贮藏可显著延缓李果实硬度、超氧阴离子自由基、羟自由基和DPPH 自由 基清除能力的降低，以及pH 值、总抗氧化能力、总酚和总黄酮含量的升高；相关性分析的结果表明，李果实中酚类、黄酮类物质含量与总抗氧化能力具有极显著相关性(P ＜ 0.01)；李果实近果皮及近果核处果肉的总抗氧化能力、羟自由基清除能力、总酚及总黄酮含量均存在显著性差异；李果实SSC 与近果皮果肉总抗氧化能力、清除超氧阴离子自由基及DPPH 自由基能力、总酚含量的相关系数大于近果核，而pH 值与近果核处总抗氧化能力、清除超氧阴离子自由基及羟自由基能力、总酚及总黄酮含量的相关系数大于近果皮果肉。李果采后品质劣变可能与清除超氧阴离子自由基、羟自由基及DPPH 自由基能力的降低有关。

Changes of Quality and Antioxidant Capacity of Different Parts of Plum Fruit at Two Storage Temperatures

The quality changes of plum fruit (Prunus salicina cv. Black amber) during storage at 20 ℃ and 2 ℃ were evaluated and the antioxidant capacity of different parts of plum pulp were determined. Plum fruits stored at 20 ℃ showed a significant decline in firmness, along with the scavenging activity of superoxide, DPPH radical and hydroxyl radical, whereas fruit pH value, along with total antioxidant activity, total phenol and total flavonoid concentration increased with time. In contrast, the low temperature alleviated these trends of fruit quality and antioxidant activity parameters simultaneously, Correlation analysis revealed that both total phenolic and flavonoid content were highly correlated (P ＜ 0.01) with total antioxidant capacity of plum fruit. In addition, the significant difference between outer and inner part of plum fruit was observed in terms of total antioxidant activity, hydroxyl radical scavenging activity, total phenol and total flavonoid contents, as well as the correlation between their antioxidant capacity and fruit quality attributes, expressed as the antioxidant activity of outer part of plum showed stronger correlation with SSC, whereas the inner part correlated more highly with pH value. The results indicated that postharvest quality deterioration of plum fruit may be attributed to the decrease of superoxide, DPPH radical, and hydroxyl radical scavenging activity.