UV-C处理对采后香蕉贮藏防御性成分和品质的影响

Effects of UV-C treatment on defensive components and quality of postharvest banana during storage

为了提高香蕉的贮藏品质,研究短波紫外线(UV-C)对香蕉贮藏过程中主要酶活性和抗氧化性的影响,用0.02 kJ/m^(2)剂量的UV-C处理香蕉后,于25℃贮藏18 d,研究UV-C处理对香蕉果实腐烂率、失质量率、总叶绿素含量、总酚(TP)含量、总黄酮(TF)含量、纤维素酶(CL)活性、2,2′-联氮-双-3-乙基苯并噻唑啉-6-磺酸(ABTS)自由基清除率、1,1-二苯基-2-三硝基苯肼(DPPH)自由基清除率、铁离子抗氧化能力(FRAP值)、苯丙氨酸解氨酶(PAL)活性、超氧化物歧化酶(SOD)活性、过氧化物酶(POD)活性的影响。结果表明,UV-C处理显著降低了香蕉果实的腐烂率,减少了失质量,同时显著减缓了香蕉皮中叶绿素的降解,抑制了纤维素酶活性,激活了PAL、SOD和POD的活性,提高了多酚、总黄酮含量。通过对12个指标的相关性和聚类分析发现,经UV-C处理后,PAL的激活,对诱导增加防御性成分TF、TP、SOD和POD有显著影响,有利于维持香蕉果实在贮藏过程中的品质。由此可见,0.02 kJ/m^(2)剂量UV-C处理可以提高香蕉果实抗病相关酶活性和抗氧化能力,延缓香蕉成熟,增强香蕉的抗病性,提升香蕉在贮藏期间的品质。

In order to improve the storage quality of banana,the effects of short wave ultraviolet(UV-C)on the main enzyme activity and antioxidant activity of banana during storage were studied.Bananas were stored at 25℃for 18 days after being treated with 0.02 kJ/m^(2) UV-C.The effects of UV-C treatment on decay rate,weight loss rate,total chlorophyll content,total phenol(TP)content,total flavonoids(TF)content,cellulase(CL)activity,2,2′-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid(ABTS)radical scavenging rate,1,1-diphenyl-2-picrylhydrazyl(DPPH)radical scavenging rate,ferric reducing antioxidant power(FRAP)value,phenylalanine ammonia lyase(PAL)activity,superoxide dismutase(SOD)activity,peroxidase(POD)activity in banana fruits were investigated.The results showed that UV-C treatment significantly reduced the decay rate and the weight loss rate,slowed down the degradation of chlorophyll significantly,inhibited the cellulase activity,promoted the activities of PAL,SOD,POD,and improved the contents of total polyphenols and flavonoids.The correlation and cluster analysis of 12 indices showed that the activation of PAL after UV-C treatment had a significant effect on the induction of the increase of defensive components TF,TP,SOD and POD,which was beneficial to the quality maintenance of banana fruit during storage.In conclusion,0.02 kJ/m^(2) UV-C treatment can improve the activity of disease resistant-related enzymes and antioxidant capacity of banana fruit,delay the ripening,enhance the disease resistance,improve the quality of banana during storage.