壳聚糖与臭氧对采后‘阳光玫瑰’香气及品质的影响

The effect of chitosan and ozone on the aroma and quality of postharvest‘Shine Muscat’

[目的]本文旨在探究壳聚糖与臭氧对采后葡萄果实保鲜的影响。[方法]以‘阳光玫瑰’葡萄为试材,采用10 g·L^(-1)的壳聚糖浸泡60 s以及通1 h浓度为4.288 mg·L^(-1)的臭氧处理葡萄果实,以不经任何处理的葡萄为对照,测定不同时间果实生理指标和挥发性香气成分,以及与类胡萝卜素、酸代谢和香气代谢相关基因的表达量。[结果]壳聚糖与臭氧处理能维持果实的硬度,抑制可溶性固形物的提升,影响果实着色并改善外观品质,在短期内(0~20 d)减缓‘阳光玫瑰’糖酸含量的降低。壳聚糖与臭氧处理可提高果实叶黄素含量,并维持醛类、醇类及萜烯类香气物质含量。基因表达分析结果显示,壳聚糖与臭氧处理能不同程度上调以下基因表达:类胡萝卜素相关基因ζ-胡萝卜素脱饱和酶基因(ZDS)、1-脱氧木酮糖-5-磷酸还原异构酶基因(DXR)和4-二磷酸胞苷-2-C-甲基赤藓糖激酶基因(CMK);香气代谢相关基因3-羟基-3-甲基戊二酰辅酶A还原酶基因(HMGR1、HMGR2、HMGR3),1-羟基-2-甲基-2-(E)-丁烯基-4-二磷酸还原酶基因(HDR);可溶性糖相关基因酸性转化酶基因(AI)、中性转化酶基因(NI)、转化酶基因(INV);有机酸代谢相关基因苹果酸脱氢酶基因(MDH)、异柠檬酸脱氢酶基因(IDH)和磷酸烯醇式丙酮酸羧化酶基因(PEPC)。[结论]壳聚糖与臭氧处理显著提高了葡萄果实的可溶性糖和有机酸含量,壳聚糖维持采后‘阳光玫瑰’的香气物质含量,尤其是醛类、醇类和萜烯类。

[Objectives]This article aimed to explore the effects of chitosan and ozone on the preservation of postharvest grape fruits.[Methods]‘Shine Muscat’grapes were used as the test material,and the grape fruits were soaked in 10 g·L^(-1)chitosan for 60 seconds and treated with ozone at a concentration of 4.288 mg·L^(-1)for 1 h,respectively.The grapes without any treatment were used as the control,the physiological indicators and volatile aroma components of the fruit at different time were measured,as well as the expression levels of genes related to carotenoid,acid metabolism,and aroma metabolism.[Results]Chitosan and ozone treatment could maintain the hardness of the fruit,inhibit the increase of soluble solids,affect fruit coloring,and improve appearance quality.In the short term(0-20 days),chitosan and ozone treatment slowed down the decrease in sugar and acid content of‘Shine Muscat’,increased the content of lutein and maintained the contents of aldehydes,alcohols,and terpenes in fruits.The gene expression analysis results showed that chitosan and ozone treatment could up-regulate carotenoid related genes expression to varying degrees,such as zeta-carotene desaturase gene(ZDS),1-deoxyxylulose-5-phosphate reductive isomerase gene(DXR)and 4-diphosphocytidine-2-C-methylerythritol kinase gene(CMK);aroma metabolism related genes 3-hydroxy-3-methylglutaryl-CoA reductase gene(HMGR1,HMGR2,HMGR3),1-hydroxy-2-methyl-2-(E)-butenyl-4-diphosphate reductase gene(HDR);soluble sugar related genes such as acid invertase gene(AI),neutral invertase gene(NI),invertase gene(INV);as well as organic acid metabolism related genes such as malate dehydrogenase gene(MDH),isocitrate dehydrogenase gene(IDH)and phosphoenolpyruvate carboxylase gene(PEPC).[Conclusions]Chitosan and ozone treatment significantly increased the soluble sugar and organic acid content of grape fruits,while the chitosan maintained the postharvest aroma contents of‘Shine Muscat’,especially aldehydes,alcohols,and terpenes.