低温预贮对猕猴桃果实糖代谢的影响

Effects of Low Temperature Conditioning the Sugar Metabolism of Kiwifruit

目的:研究低温预贮结合外源乙烯催熟对采后猕猴桃果实糖代谢的影响。方法:将猕猴桃在0,4,8,12℃4个温度下分别放置3,5,7 d后,在室温(25℃)采用乙烯催熟,以其为对照,分别测定12个不同处理组以及对照组猕猴桃果实中可溶性糖含量、单糖含量(葡萄糖、果糖、蔗糖)、淀粉含量、关键糖代谢酶活性和淀粉酶活性。结果:低温预贮能够提高后熟猕猴桃中可溶性糖的含量,保持较高的淀粉酶活性;同时,低温预贮能加快淀粉降解速率,有效维持中性转化酶与蔗糖磷酸合成酶活性,而对果实的酸性转化酶与蔗糖合成酶活性无显著影响。通过主成分分析及聚类分析分析发现低温预贮对后熟猕猴桃糖代谢影响的最佳预贮条件是4℃下预贮7 d。结论:低温预贮可调控采后猕猴桃糖代谢相关酶活性,从而使其在后熟过程中保持较高的可溶性糖含量和营养价值。

Objective:The effect of low temperature conditioning(LTC)combining with exogenous ethylene on the sugar metabolism of postharvest kiwifruit was studied.Methods:The kiwifruit was placed at four temperatures:0,4,8,12℃for 3,5,7 day,respectively,and then ripened at room temperature(25℃)with ethylene.The kiwifruit directly ripened at room temperature was as control group(CK).The soluble sugar content,monosaccharide content(glucose,fructose and sucrose),starch content,amylase activity,and sugar metabolism enzymes activities in 12 treatment groups and CK were determined.Results:LTC treatment could increase the soluble sugar content and starch degradation rate,maintain high amylase activity in kiwifruit.Neutral invertase(NI)and sucrose phosphate(SPS)enzyme activities were maintain effectively.However,the effect of LTC on AI and SS enzymes activities was not significant.Through principal component analysis(PCA)and cluster analysis(CA),it was found that the best time and temperature for LTC in kiwifruit was 7days and 4℃,respectively.Conclusion:These results indicated that LTC can maintain a higher soluble sugar content by regulating the activity of sugar metabolism-related enzymes during ripening,and kiwifruit has higher nutritional value.