Abstract：
Okara, as a by-product of soybean processing, is rich in insoluble dietary fiber (IDF), which is a carbohydrate polymer with various insoluble polysaccharides. Nowadays, the extraction of IDF with excellent functional properties has become a research hotspot. In this work, we further proposed an alternating alkali/ultrasound method for the efficient extraction of IDF. The sequential treatments of alkali (A-ISF), alkali-ultrasonic (AU-ISF), ultrasonic-alkali (UA-ISF), ultrasonic-alkali-ultrasonic (UAU-ISF) and alkali-ultrasonic-alkali (AUA-ISF) were applied to extract insoluble soybean fiber (ISF). FTIR and XRD results proved the typical structure of ISFs, and TGA results demonstrated the improved thermal stability of UAU-ISF and AUA-ISF. Chemical composition measurement showed that UAU-ISF and AUA-ISF exhibited higher cellulose content (>83 %). SEM results revealed that ultrasonic treatment led to a decomposition of okara matrix and significant porous structure in ISFs with an amplified collapse effect, resulting in an increase of the pore size of ISFs, and strengthening the properties of UAU-ISF and AUA-ISF in higher water (>15 g/g)/oil (>12 g/g) holding capacities, cholesterol binding capacity (>36 mg/g), and cation exchange capacity (>0.3 mmol/g), thus providing new insights for the preparation of ISF with high functional properties that are beneficial for human intestinal health.
摘要：
Okara,作为大豆加工的副产品，富含不溶性膳食纤维(IDF)，它是一种含有各种不溶性多糖的碳水化合物聚合物。如今,具有优异功能特性的IDF的提取成为研究热点。在这项工作中,我们进一步提出了一种高效提取IDF的交替碱/超声方法。碱的顺序处理(A-ISF)，碱性超声波（AU-ISF），超声波碱(UA-ISF)，采用超声-碱-超声（UAU-ISF）和碱-超声-碱（AUA-ISF）提取不溶性大豆纤维（ISF）。FTIR和XRD结果证明了ISFs的典型结构,和TGA结果表明UAU-ISF和AUA-ISF的热稳定性提高。化学组成测量显示UAU-ISF和AUA-ISF表现出更高的纤维素含量(>83%)。SEM结果表明，超声处理导致豆渣基质的分解和ISFs中明显的多孔结构，并具有放大的塌陷效应，导致ISF的孔径增加，并加强UAU-ISF和AUA-ISF在较高的水（>15g/g）/油（>12g/g）保持能力的性能，胆固醇结合能力（>36毫克/克），和阳离子交换容量（>0.3mmol/g），从而为制备有益于人体肠道健康的具有高功能特性的ISF提供了新的见解。
