Abstract：
Rice bran was modified by steam explosion (SE) treatment to investigate the impact of different steam pressure (0.4, 0.8, 1.2, 1.6, and 2.0 MPa) with rice bran through 60 mesh and rice bran pulverization (60, 80, and 100 mesh) with the steam pressure of 1.2 MPa on the structure, thermal stability, physicochemical and functional characteristics of insoluble dietary fiber (IDF) extracted from rice bran. IDF with SE treatment from scanning electron microscopy images showed a porous honeycomb structure, and lamellar shape in IDF became obvious with the increase of steam pressure. The relative crystallinity and polymerization degree of crystalline regions in IDF from rice bran with SE treatment from X-ray diffraction analysis were decreased. Differential scanning calorimetry results showed that thermal stability of IDF with SE treatment increased with the increase of crushing degree. The results of FT-IR also suggested that some glycosidic and hydrogen bonds in IDF could be broken, and some cellulose and hemicellulose were degraded during SE process. The physicochemical and functional characteristics of IDF, including water-holding capacity, oil-holding, glucose adsorption capacity, α-amylase and pancreatic lipase inhibition capacity were decreased with the increase of steam pressure and crushing degree. The swelling and nitrite adsorption capacities of IDF were increased first and then decreased with the increase of steam pressure. The physicochemical and functional characteristics of IDF from rice bran were improved after SE treatment, which might provide references for the utilization of IDF from rice bran with SE treatment.
摘要：
通过蒸汽爆炸（SE）处理对米糠进行改性，以研究不同蒸汽压力（0.4、0.8、1.2、1.6和2.0MPa）与米糠通过60目和米糠粉碎（60、80和100目）在1.2MPa的蒸汽压力下对结构的影响。热稳定性，从米糠中提取的不溶性膳食纤维（IDF）的理化和功能特性。用SE处理的IDF从扫描电子显微镜图像显示多孔蜂窝结构，随着蒸汽压力的增加，IDF中的层状形状变得明显。通过X射线衍射分析，经过SE处理的米糠中IDF结晶区的相对结晶度和聚合度降低。差示扫描量热分析结果表明，SE处理的IDF的热稳定性随破碎度的增加而增加。FT-IR的结果还表明，IDF中的一些糖苷和氢键可以被破坏，部分纤维素和半纤维素在SE过程中被降解。IDF的物理化学和功能特性，包括持水能力，持油,葡萄糖吸附能力，α-淀粉酶和胰脂肪酶的抑制能力随着蒸汽压力和粉碎程度的增加而降低。随着蒸汽压力的增加，IDF的溶胀能力和亚硝酸盐吸附能力呈先增大后减小的趋势。SE处理后米糠IDF的理化特性和功能特性得到改善，为SE处理米糠中IDF的利用提供参考。
