Assessment Of Phenolics And Antioxidant Activities During Development And Storage In Sanhua Plum

Sanhua plum was collected as the research object,and the dynamic changes of antioxidants and antioxidant activities during plum development and storage were investigated.The main results of this study are presented as follows:(1)Sanhua plum in the purple-red stage has the highest soluble sugar content,the lowest titratable acid content,the highest sugar-acid ratio.The total phenolic content decreased while the total flavonoid content decreased first and then increased during plum development.(2)Four genes including C4 H,CHS,F3 H and ANS in Sanhua plum were upregulated during plum development;two genes including CHI and LAR were downregulated during plum development.The contents of individual phenolic compounds(epicatechin,myricetin,hesperetin)in plums increased.The content of cyanidin increased from the full-green stage to full-red stage,and differed insignificantly from purple-red to full-red;pelargonin was not detected in full-green and red-appeared plums,and its content was stable from the half-red stage to purple-red stage.(3)During the development of Sanhua plum,Sanhua plum in the purple-red stage has the highest polyphenol oxidase activity,the highest cellular antioxidant activity.(4)During the storage of Sanhua plum treated by hot air treatment,hot air treatment combined with chitosan coating: the total soluble sugar contents of the plums in each group showed upward trendencies.The titratable acid contents of each group in plums were lower than that of fresh Sanhua plum.The ratios of sugar to acid in plums of each group were higher than that in fresh Sanhua plum.(5)During the storage: the total phenolic contents in each group were higher than that of fresh Sanhua plum.Each treatment improved the total flavonoid content in plums.The content of individual phenolic compounds in plums of each group(epicatechin,myricetin,hesperetin)increased.The content of individual anthocyanin compounds(cyanidin and pelargonidin)in plums increased,and the effect of hot air treatment combined with chitosan coating on the content of anthocyanin compounds in plum was better than the other two groups.(6)During the storage: compared with fresh plum,the activity of polyphenol oxidase in all samples decreased.The PSC value in each group increased.The inhibition of hot air treatment combined with chitosan coating treatment on polyphenol oxidase activity was stronger than the other two groups.The improvement of hot air treatment combined with chitosan coating treatment on PSC value was better than the other two groups.The results showed that Sanhua plum in the purple-red stage has the best quality according to antioxidant quality,but considering the limitation in actual production(Sanhua plum in the purple-red stage is not resistant to storage and perishable),Sanhua plum in the full-red or half-red stage should be harvested,and appropriate treatment of the post-ripening technology should be applied to reduce the loss and improve economic efficiency.In addition,hot air treatment combined with chitosan coating treatment has a positive significance for maintaining the nutritional quality and antioxidant activity of Sanhua plum in the post-harvest storage process.