不同淀粉脱支酶对菠萝蜜种子淀粉分子结构的影响及糊化特性研究

采用普鲁兰酶和异淀粉酶制备脱支菠萝蜜种子淀粉(debranched jackfruit seed starch,DS)及脱支菠萝蜜种子支链淀粉(debranchedjackfruitseedamylopectin,DAP),旨在研究所得DS和DAP之间的差异。结果表明,DS具有较宽的分子量分布,而DAP具有较窄的分子量分布。普鲁兰酶水解α-1,6糖苷键更完全,所以普鲁兰酶DS和DAP平均分子量更低。普鲁兰酶水解较短侧链更有效,异淀粉酶则可水解外分支链。异淀粉酶DAP具有高比例B2链、B3链和长平均链长,导致其具有低的峰值黏度、谷值黏度、崩解值、最终黏度和回生值,但糊化温度高。因此,淀粉脱支酶的选择和直链/支链淀粉组成均能导致淀粉分子结构和糊化特性显著不同(p<0.05),可根据特定需要选择合适制备方法增强或抑制菠萝蜜种子淀粉固有性质或赋予其新的特定性质。

Effect of Different Starch Debranching Enzymes on the Molecular Structure of Jackfruit Seed Starch and Pasting Properties

Debranched jackfruit seed starch (DS) and debranched jackfruit seed amylopectin (DAP) were prepared by pullulanase or isoamylase, and the differences between the DS and DAP was investigated. The results showed that DS had a broad molecular weight distribution while DAP had a narrow molecular weight distribution. Pullulanase DS and DAP had a lower average molecular weight due to more complete hydrolysis of the α-1,6 glycosidic bonds. Pullulanase hydrolysis was more effective for shorter lateral chains, whereas isoamylase could hydrolyze outer branching linkages of amylopectin. Isoamylase DAP had a higher proportion of B2, B3 chains and the longest average chain length, resulting in a lower peak viscosity, trough viscosity, breakdown, final viscosity and setback, but a higher gelatinization temperature. Therefore, both the selection of starch debranching enzymes and the amylose/amylopectin composition could lead to the significant differences (p<0.05) in the molecular structure and pasting properties. According to the specific needs, the appropriate methods could be used to enhance or inhibit the inherent properties of jackfruit seed starch or endow it new specific properties.