软枣猕猴桃果实发育期品质指标及抗氧化能力的变化

Changes of quality characteristics and antioxidant capacities during fruit development of hardy kiwifruit

目的:为软枣猕猴桃品质提升及合理开发利用提供理论依据。方法:以龙成2号及海佳2个品种(系)为试材,分析了软枣猕猴桃果实发育期间基本品质指标、总酚及类黄酮含量的变化,采用FRAP法、ABTS法和DPPH法动态测定其抗氧化能力,进一步比较了总酚含量与抗氧化能力在果实不同部位的分布差异。结果:①2个品种(系)果实的可溶性固形物、可滴定酸及维生素C含量在果实发育过程中整体表现出持续上升的趋势。②在色素方面,2个品种(系)的叶绿素含量均表现为高—低—高的变化趋势;自盛花后64 d起,2个品种(系)的类胡萝卜素含量持续增加,同时海佳的花青苷含量也逐步上升。③总酚、类黄酮含量及3种抗氧化能力均随果实的成熟而呈下降趋势;相关性分析表明,在所有品质指标中,总酚、类黄酮与3种抗氧化能力均呈极显著正相关。④在成熟果实中,果皮的总酚、类黄酮含量均远高于果肉,表现出较强的抗氧化能力。结论:2个品种(系)软枣猕猴桃的抗氧化能力均随果实发育而下降,而总酚特别是类黄酮是果实发育过程中影响抗氧化能力的重要物质。果皮是软枣猕猴桃果实抗氧化能力较高的部位,同时也是涩味的主要来源。

Objective:This study aimed to provide theoretical basis for hardy kiwifruit quality improvement and rational utilization.Methods:Taking the main variety'Longcheng No.2'and line'Haijia'as experimental materials,the changes of basic quality indexes,contents of total phenolics and flavonoids were analyzed during fruit development.On this basis,the antioxidant capacities were comprehensively evaluated by three assays(FRAP iron reducing ability,ABTS radical scavenging ability and DPPH radical scavenging ability).Furthermore,the differences of total phenolics and antioxidant capacities in different parts of fruit were compared.Results:①The contents of soluble solids,titratable acids and Vc in the fruits of the two varieties(lines)showed a trend of continuous increasing during fruit development.②The chlorophyll contents of two varieties(lines)both declined constantly at the early stage of fruit development,and then increased continuously from 64 days after blooming.The carotenoids of two varieties(lines)also increased continuously from 64 days after blooming,meanwhile,the anthocyanins of'Haijia'increased gradually.③The contents of total phenolics,flavonoids and three antioxidant capacities all decreased significantly during fruits ripening.The correlation analysis showed that among all quality indexes,total phenolics and flavonoids had extremely significant positive correlations with the three antioxidant capacities.④In mature fruits,the contents of total phenolics and flavonoids in the peel were significantly higher than those in the flesh,which indicated strong antioxidant capacities.Conclusion:The antioxidant capacities of two varieties(lines)of hardy kiwifruit decreased significantly during fruit development.Moreover,the content of total phenolics,especially flavonoids are the main components to affect antioxidant capacities during fruit development.In the different fruit parts,the peel has higher antioxidant capacities,but it is also the main source of astringency.