[关键词]
[摘要]
以绿熟期杏果为材料,分析了热风干制和自然晒制过程中己糖激酶、果糖激酶、蔗糖相关酶活性及糖含量的变化规律,旨在明确干制过程中关键酶调控糖代谢的作用机制。结果表明,果糖、葡萄糖、蔗糖占可溶性总糖的比例在干制前分别为33.52%、47.25%、45.22%,干制后分别平均为9.70%、28.24%、54.16%,果糖、葡萄糖和蔗糖呈显著负相关,因此干制条件下杏果中蔗糖的积累主要来源于己糖的转化。干制期间杏果中分解类酶活性(NI、SSs、AI)降低,且与果糖、葡萄糖呈正相关,分解类酶的调控以NI和AI为主。蔗糖合成类酶(SPS、SSs)在蔗糖代谢中起到辅助调控作用且热风40~50 ℃温度处理能有效地提高其活性,使蔗糖含量及蔗糖占可溶性总糖的比例增大。果糖激酶和己糖激酶也在干制前期略有升高,高活性的果糖激酶和己糖激酶利于增加果实中己糖的消耗,为蔗糖的积累提供基础。
[Key word]
[Abstract]
Using apricot fruits at the green ripe stage, variations in the sugar content and activities of hexokinase, fructokinase, and sucrose-metabolizing enzymes during natural drying and hot air drying processes were analyzed to understand the mechanisms of action of key enzymes in the regulation of sugar metabolism. The results showed that the fructose, glucose, and sucrose content changed from 33.52, 47.25, and 45.22% of the total soluble sugars in apricots before drying to about 9.70, 28.24, and 54.16% after drying, respectively. The content of fructose and glucose had significantly negative correlations with sucrose content. Therefore, the accumulation of sucrose in apricots during drying was mainly due to the conversion from hexose. The activities of sucrose cleavage enzymes [neutral invertase (NI), sucrose synthase (SSc), and acid invertase (AI)] were decreased during the drying process and were correlated positively with the content of fructose and glucose; NI and AI were the dominant cleavage enzymes. Sucrose synthesis enzymes [sucrose phosphate synthase (SPS) and sucrose synthase (SSs)] played a supplementary role in sucrose metabolism, and their activities were effectively enhanced by hot-air treatment at temperatures of 40~50 ℃, so that the sucrose content and the sucrose percentage of total soluble sugar were increased. Fructokinase and hexokinase activities were increased slightly during the early stage of the drying process, and high fructokinase and hexokinase activity could increase hexose consumption in the fruits, providing the basis for the accumulation of sucrose.
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