苦荞多酚对苦荞淀粉和小麦淀粉理化性质的影响

以苦荞淀粉和小麦淀粉为原料,研究低添加量(1%~4%)苦荞多酚与两种淀粉共糊化后的相互作用以及对其透明度、凝沉性、糊化特性、质构特性、抗性淀粉含量和微观结构的影响。结果表明:苦荞多酚与两种淀粉的共糊化显著降低了淀粉糊的透明度和沉降体积比,淀粉糊的凝沉加快;两种淀粉的糊化温度和糊化焓值一定程度上有所下降,淀粉更易糊化;同时两种淀粉胶质构参数显著降低,苦荞多酚添加量为4%时苦荞淀粉和小麦淀粉硬度分别下降了19.74%和54.18%;苦荞多酚的存在显著提高了淀粉中抗性淀粉含量(15%~30%)。电子显微镜结果显示,共糊化后苦荞多酚促进了淀粉颗粒的交联和聚合。苦荞多酚对淀粉理化性质的改变可视为一种提高抗性淀粉含量的物理改性方式,苦荞粉可作为高抗性淀粉食品的优质原料。

Effect of Tartary Buckwheat Polyphenols on Physicochemical Properties of Tartary Buckwheat Starch and Wheat Starch

The research was designed to investigate the interactions of tartary buckwheat starch (TBS) and wheat starch (WS) with tartary buckwheat polyphenols (TBP) at low levels (1%.4%) during gelatinization and their effect on starch paste transparency, retrogradation and pasting properties, textural properties, resistant starch content and microstructure. The results showed that adding TBP could significantly decrease the transparency and sedimentation volume of TBS and WS paste, and accelerate starch paste retrogradation. The pasting temperature and enthalpy of both starches were decreased, indicating that the starches were prone to be pasted. Compared with the control without added TBP, addition of 4% TBP led to a decrease in the hardness of TBS and WS gels by 19.74% and 54.18%, respectively, and a significant increase in resistant starch content (by 15%.30%). The scanning electronic micrographs (SEM) indicated that TBP could accelerate the aggregation and cross-linking of starch granules. The changes in physicochemical properties of starch after TBP addition can be regarded as a physical modification method to increase resistant starch. Tartary buckwheat flour can be used as a high quality ingredient of foods high in resistant starch.