外源EGCG对采后龙眼果肉品质的影响

Effect of exogenous EGCG on postharvest longan pulp quality and its underlying mechanism

为探究表没食子儿茶素没食子酸酯(EGCG)对采后龙眼的保鲜效果,用浓度为1 mmol/L的EGCG溶液浸泡采后龙眼果实5min,于25℃条件下贮藏,分别在贮藏的第2、4、6、8天取样测定果肉自溶指数、抗氧化物质含量、抗氧化酶活性等。结果表明:外源EGCG处理采后龙眼果实的第6和第8天时,果肉自溶指数分别较对照下降22.56%、11.70%;第8天时果肉可溶性固形物和可滴定酸的含量分别是对照的1.16、1.17倍;EGCG处理显著提高脱氢抗坏血酸还原酶和谷胱甘肽还原酶活性,且上调DlDHAR和Dl GR等酶基因的相对表达。

In order to explore the fresh-keeping effect of EGCG on postharvest longan,the fruits of postharvest longan were soaked in 1 mmol/L EGCG solution for 5 minutes and stored at 25℃.On the 2,4,6 and 8 days of the storage period,samples were taken to determine the autolysis index of the pulp,the content of endogenous antioxidants,and the activity of antioxidant enzymes.The results showed that at 6 and 8 days after exogenous EGCG treatment,the autolysis index of longan fruits after harvest decreased by 22.56%and 11.70%respectively,compared with the control group;at 8 day after exogenous EGCG treatment,TSS and TA in the pulp were respectively 1.16 and 1.17 times than that in the control.Furthermore,EGCG treatment significantly increased the activities of DHAR and GR,and up-regulated the relative expression of enzyme genes such as DlDHAR and DlGR.