PPO Activity Analysis During Browning Of Potato Tuber

Potato(Solanum tuberosum L.)is an important crop for both grain and vegetable feeding in China.The crop has strong adaptability to natural environmental conditions,high yield,rich nutritional value and great development potential.For a long time,enzymatic browning is a common problem in potato fresh-cut processing,and one of the factors that cause potato browning is polyphenol oxidase(PPO).Polyphenol oxidase is a copper ion-containing oxidoreductase,widely present in nature,and is an important measurement index for the enzymatic browning of fruits and vegetables.In this study,by comparing the PPO activity of 16 kinds of potatoes cultivated in Qinghai Province,the differences in PPO enzyme activity between varieties were compared in order to select excellent browning-resistant potato varieties.1.The tuber of potato by enzyme-linked immunoassay PPO activity was measured during storage period,and during the growth of potato PPO activity determination,analysis and comparison of the PPO activity trends between different varieties in different periods,the results found that the PPO activity in the storage period of no consistent trend,with differences between species,among them,the least reactive qing11-2-3,qingshu no.11 is maximum;In the growing period,the change trend of PPO activity can be divided into three categories: high-low-high-low,high-low-high and continuously rising.2.The luminance value L* of potato tuber slices of different varieties was detected with color difference instrument,and it was found that the luminance value L* changed regularly with time.The varieties with the highest luminance rate of L* were longshu no.6 and qingshu no.9,and the lowest was 11-19-4.3.Real-time fluorescence quantitative technique(q PCR)was used to detect the expression levels of POT32 gene in different growing stages of potato tubers of different varieties,so as to analyze the differences of gene expression among varieties,according to the results of POT32 reached significant difference between the varieties,and the growth period of PPO activity of correlation analysis,in 16 varieties,longshu no.7,xiazhai 65,qing11-2-3,D0602-10,Q072625,L0227-18 and qing2-4 varieties PPO activity and PPO gene expression quantity has significant correlation,11-19-4 and qing 3-2 had no significant correlation with gene expression.