Changes of carbohydrate contents and amylase activities in bulb of Lilium davidii var. unicolor during cooling storage preservation process

In order to investigate the relationship between carbohydrate content and amylase activities in bulb of L. davidii var. unicolor, the dynamic changes of the contents of soluble sugar, reducing sugar, starch and the activities of total amylase, α-amylase, β-amylase in bulb of L. davidii var. unicolor during cooling storage at-2℃ were measured using UV-VIS spectrophotometry method. The results showed that the starch content in the bulb of L. davidii var. unicolor decreased by 62.29% within the whole 60 d cooling storage preservation periods at-2℃, whereas the content of soluble sugar and reducing sugar increased by 2.22% and 1.39%, respectively. β-amylase was the major enzyme in L. davidii var. unicolor bulb. Prolonged cold storage preservation time, the activity of β-amylase decreased;the activity of α-amylase first fell and then rose;the activity of total amylase showed a decreasing trend on the basis of high activity. Analysis of correlation showed that the correlation between carbohydrate contents and amylase activities in bulb was different. The activities of total amylase and β-amylase showed significant and negative correlation with the contents of soluble sugar and reducing sugar, whereas a significant and positive correlation with the contents of starch. The increase of the content of soluble sugar and reducing sugar during the cold storage process was correlated with the starch enzymolysis by β-amylase under low temperature induced condition.