The composition and structure of the food matrix can have a major impact on the digestion. The aim of this work was to investigate the effects of endogenous proteins and lipids on starch digestibility in rice flour, with an emphasis on establishing the underlying physicochemical mechanisms involved. Native long-grain indica rice flour and rice flour with the lipids and/or proteins removed were subjected to a simulated digestion in vitro. A significant increase in starch digestibility was observed after removal of proteins, lipids, or both. The starch digestibility of the rice flour without lipids was slightly lower than that without proteins, even though the proteins content was about 10-fold higher than the lipids content. Microstructural analysis suggested that the proteins and lipids were normally attached to the surfaces of the starch granules in the native rice flour, thus inhibiting their contact with digestive enzymes. Moreover, the proteins and lipids restricted the swelling of the starch granules, which may have decreased their digestion by reducing their surface areas. In addition, amylose-lipid complex was detected in the rice flour, which is also known to slow down starch digestion. These results have important implications for the design of foods with improved nutritional profiles.

食物基质的组成和结构会对消化产生重大影响。这项工作的目的是研究内源性蛋白质和脂质对米粉淀粉消化率的影响，重点是建立涉及的潜在物理化学机制。天然长粒籼稻米粉和米粉与除去脂类和/或蛋白质进行一个模拟消化在体外。去除蛋白质，脂质或两者后，观察到淀粉消化率显着提高。没有蛋白质的米粉的淀粉消化率比没有蛋白质的米粉的淀粉消化率略低，即使蛋白质含量比脂质的含量高约10倍。微观结构分析表明，蛋白质和脂质通常附着在天然米粉中淀粉颗粒的表面，从而抑制了它们与消化酶的接触。此外，蛋白质和脂质限制了淀粉颗粒的溶胀，这可能通过减少淀粉颗粒的表面积而降低了它们的消化。此外，在米粉中检测到直链淀粉-脂质复合物，这也已知会减慢淀粉的消化。