发酵过程中原花青素对大米淀粉多尺度结构及体外消化特性的调控

为了调控发酵米制品的消化性能，采用小角X射线散射、凝胶渗透色谱及体外模拟消化等多种现代分析技术，系统考察原花青素在大米淀粉发酵过程中对淀粉结构和消化性能的影响。研究表明，在发酵过程中原花青素与淀粉分子间存在相互作用，进而提高大米淀粉颗粒的抗消化性能，且在原花青素的添加量为8%时RS含量可达66.85%。在原花青素协同微生物发酵过程中，原花青素抑制微生物胞外酶活性并降低了淀粉分子被降解及聚集态结构无序化的程度；原花青素与淀粉分子形成淀粉分子-原花青素-淀粉分子的复合结构，促使淀粉半结晶层状结构中半结晶层厚度增大、无定型层厚度降低及聚集态结构紧密程度和表面短程有序化结构比例增加，且其在消化过程中释放原花青素并抑制淀粉酶活性，最终显著降低淀粉的消化性能。研究结果为发酵米制品消化性能的调控提供了依据。

Procyanidins Regulatethe Multi-scale Structures and in Vitro Digestibility of Rice Starch during Fermentation

To regulate the digestibility of fermented rice products, the effects of procyanidins on digestibility and multi-scale structures of rice starch during fermentation were systematically examined by small-angle X-ray scattering, gel penetration chromatography and in vitro simulated digestion. Research results showed that the digestive resistance of rice starch granules increased due to the interactions between the procyanidin and starch molecules during the fermentation process. The resistant starch (RS) content reached 66.85% when the amount of added procyanidins was 8%. During the synergistic fermentation by procyanidins and microbes, procyanidin inhibited the activities of microbial extracellular enzymes and reduced the degrees of starch degradation and disorder of aggregated structure. The procyanidins and starch molecules formed starch-procyanidin-starch complexes, which increased the thickness of the semi-crystalline layer in starch semi-crystalline layered structure, decreased the thickness of the amorphous layer, and raised the degree of compactness of aggregated structures and the proportion of short-range ordered structures on the surface. The starch-procyanidin-starch complexes also allowed the release of procyanidins and inhibition of amylase activity during digestion, which ultimately significantly decreased the digestibility of rice starch. The research results provide a basis for regulating the digestibility of fermented rice products.