两种抗性淀粉的结构特征及体外消化性研究

本实验对小麦抗性淀粉和马铃薯抗性淀粉结构特征及体外消化性进行研究。结果表明，与小麦抗性淀粉相比，马铃薯抗性淀粉直链淀粉含量更高，分子质量分布更集中，热稳定性更高。两种抗性淀粉粒径相差不大，均为C型结构，化学结构相似，没有基团差异。小麦抗性淀粉分子颗粒完整，表面光滑，呈不规则的椭圆形，马铃薯抗性淀粉分子为不规则多面体，分子表面粗糙，有凹陷，且有少量的层状起伏。体外消化试验表明:马铃薯抗性淀粉具有更强的抗消化能力，血糖指数分别为40.62、40.50（GI<55），属于低GI食品。相关性分析结果为抗性淀粉体外消化率与其直链淀粉含量、碘吸收峰负相关，与其结晶度、热焓值显著负相关，与比表面积正相关。

Structural Characteristics and in Vitro Digestibility of Two Resistant Starches

The structural characteristics and in vitro digestibility of wheat resistant starch and potato resistant starch were studied. The results showed that compared with wheat resistant starch, potato resistant starch had higher amylose content, more concentrated molecular weight distribution and higher thermal stability. The two resistant starches had little difference in particle size, with C-type structure and similar chemical structure without group difference. Wheat resistant starch particles were complete, the surface was smooth and irregular oval, potato resistant starch molecules were irregular polyhedron, the molecular surface was rough, concave, and a small amount of lamellar undulation. In vitro digestion test showed that potato resistant starch had stronger anti-digestion ability, and the glycemic index was 40.62 and 40.50 (GI<55), respectively, which was a low GI food. Correlation analysis showed that the in vitro digestibility of resistant starch was negatively correlated with amylose content and iodine absorption peak, significantly negatively correlated with crystallinity and enthalpy, and positively correlated with specific surface area.