College of Food Science and Technology, Huazhong Agricultural University, Wuhan 430070, China; Laboratory of Food Technology, Department of Microbial and Molecular Systems (M(2)S), KU Leuven 3001 Leuven, Belgium.
Laboratory of Food Technology, Department of Microbial and Molecular Systems (M(2)S), KU Leuven 3001 Leuven, Belgium.
Food Res Int. 2022 Sep;159:111423. doi: 10.1016/j.foodres.2022.111423. Epub 2022 May 27.
To extend the applications of glutinous rice bran, a by-product of the glutinous rice processing industry, soluble dietary fibers (SDF) isolated from Chinese white (WSDF) and black (BSDF) glutinous rice bran were compared for their structures, physicochemical properties, and hypoglycemic activities in this study. Results showed that BSDF had higher glucose content while lower rhamnose, arabinose, xylose, and mannose contents, similar molecular weight, and a particular presence of anthocyanin compared to WSDF. Owing to the smaller particle size, higher viscosity, and more abundant network structures, BSDF had higher glucose adsorption capacity and retarding glucose diffusion ability than WSDF. The evaluations in vitro kinetics showed that addition of BSDF in starch led to a smaller glucose absorption rate constant and expected glucose index than WSDF, although BSDF showed lower α-amylase inhibitory ability. Interactions between the SDF and α-amylase, which were mediated by van der Waals force and hydrogen bond (WSDF-α-amylase) and hydrophobic interaction (BSDF-α-amylase), induced partial transformation of α-amylase from α-helix and β-sheet to β-turn and random coil. In summary, both WSDF and BSDF could be used as natural food additives for the reduction of postprandial blood glucose level and the enhancement of antioxidant activity in food products, while BSDF may show better efficacy.
为了拓展糯米糠这一糯米加工业副产物的应用范围，本研究比较了来源于白糯米糠（WSDF）和黑糯米糠（BSDF）的可溶性膳食纤维（SDF）在结构、理化性质和降血糖活性方面的差异。结果表明，BSDF 的葡萄糖含量较高，鼠李糖、阿拉伯糖、木糖和甘露糖含量较低，分子量相似，但存在特定的花色苷。BSDF 具有较小的粒径、较高的黏度和更丰富的网络结构，因此其葡萄糖吸附能力和延缓葡萄糖扩散能力均高于 WSDF。体外动力学评价表明，BSDF 加入淀粉后，其葡萄糖吸收速率常数和预期血糖指数均小于 WSDF，尽管 BSDF 对α-淀粉酶的抑制能力较低。SDF 与α-淀粉酶之间的相互作用是由范德华力和氢键（WSDF-α-淀粉酶）以及疏水相互作用（BSDF-α-淀粉酶）介导的，这导致α-淀粉酶从α-螺旋和β-折叠部分转变为β-转角和无规卷曲。总之，WSDF 和 BSDF 均可作为天然食品添加剂，用于降低餐后血糖水平和增强食品的抗氧化活性，而 BSDF 可能具有更好的效果。
