兰州百合鳞茎冷藏保鲜过程中碳水化合物含量及淀粉酶活性的变化

摘要

以兰州百合为试材,采用紫外-可见分光光度法测定了-2℃冷藏保鲜过程中百合鳞茎内可溶性糖、还原糖、淀粉的含量与淀粉酶活性的动态变化,分析了碳水化合物含量与淀粉酶活性之间的关系.结果表明,在-2 ℃、60 d的冷藏保鲜期内,随着冷藏时间的延长,兰州百合鳞茎内淀粉含量明显下降,其下降幅度达62.29％,可溶性糖与还原糖含量呈上升趋势,分别上升了2.22％和1.39％.β-淀粉酶是兰州百合鳞茎中的主要淀粉酶,其活性随冷藏时间的延长而有所降低,α-淀粉酶的活性随冷藏时间的延长先降低后升高,总淀粉酶在高活性的基础上整体呈现降低的趋势.相关性分析表明,鳞茎中碳水化合物含量及淀粉酶活性之间的相关性差异水平有所不同.总淀粉酶、β-淀粉酶活性与可溶性糖、还原糖含量具有极显著负相关性,而与淀粉含量具有极显著正相关性.可溶性糖和还原糖含量的增加与低温诱导下淀粉在β-淀粉酶的作用下分解有关.%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 thai 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 ofβ-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 byβ-amylase under low temperature induced condition.