| In order to study the changes of quality index and enzyme activity of potato at different storage temperature,the best storage method of potato was determined.The quality indexes of 52 different varieties of potato were determined at the beginning of storage,and the indexes were evaluated by fuzzy membership function.According to the specific requirements of special potato,36 potato varieties with different uses were selected for storage test,and the differences of quality index and related enzyme activities under different storage conditions were compared The expression levels of starch and reducing sugar related genes were analyzed.The results are as follows:1.The best comprehensive quality of the common potato was shepody,and the worst comprehensive quality index was V7.The comprehensive quality(x ≥0.65,x is the overall value)accounted for 6.8% of the number of varieties tested,the comprehensive quality was in the middle part(0.54≤ x ≤0.65)and the comprehensive quality was in the middle part(0.43≤ x ≤0.54)and accounted for 36.4% of the tested varieties,the comprehensive quality was lower(0.32≤ x ≤0.43)and the comprehensive quality was lower(0.32≤ x ≤0.43),accounting for 22.7% and 15.9% respectively.Huasong 66 was the best color potato,and Hongcai was the worst color potato.2.The content of dry matter and starch in potato tuber were significantly and positively correlated.Dry matter content was positively correlated with reducing sugar content and vitamin C content,starch content was positively correlated with reducing sugar content and vitamin C content,and vitamin C content was positively correlated with protein content The dry matter content,the starch content and the protein content were negative correlation,the reducing sugar content and the vitamin C content,the protein content were negative correlation,all did not reach the significant level.3.Compared with the early stage of storage,the content of dry matter and starch had the same change and the whole content of dry matter had a decreasing trend.The decreasing extent of the content of dry matter in potato stored at 10 °C was slower than that at 20 °C.The dry matter content of some cultivars increased at 30 days and 20 °C compared with the initial stage.The content of vitamin and protein decreased during the whole storage period.After 30 days of storage,the content of vitamin C decreased significantly.With the change of storage time and temperature, the content of vitamin C,dry matter and starch in fried chip potato decreased the most in any condition.The reduced sugar content of the French fries was lower than that of the other two kinds of potatoes at any time.According to the above results,the conclusions are as follows: The fried chip potato can not endure storage,so short-term storage should be selected as far as possible;The fresh-eating potato should be stored in low temperature,and the short-term storage,its edible value is higher.4.The amylase activity,starch phosphorylase activity and Peroxidase activity of different potato varieties increased with time.And the temperature has a great influence on the activity of potato amylase.The higher the temperature,the higher the Peroxidase activity,and the longer the storage time at the same temperature,the higher the Peroxidase activity.Xisen 6 was more resistant than other varieties.5.In the research of potato starch and reducing sugar related gene expression,except st Amy23,all other genes expressed in the same quantity as corresponding quality index,moreover,different genes expressed differently in the same variety.st Amy23 was not involved in the process of starch decomposition in potato leaves,and the amount of gene expression had a direct effect on the quality index of potato.Moreover,the regulation of genes on the variety was affected by the variety characteristics.This study provides a certain reference for the popularization and application of potato varieties and storage conditions of potato for different uses in North Shanxi,and also provides a certain theoretical basis for individual consumers to select potatoes with good nutritional quality. |
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