葡甘聚糖酶改性麦麸可溶性膳食纤维及其对小麦粉流变学特性的影响

Structural Characteristics of Soluble Dietary Fiber Derived from Wheat Bran Following Glucomannanase Modification and Its Influence on the Rheological Properties of Wheat Flour

将来源于解淀粉芽孢杆菌的葡甘聚糖酶用于提高麦麸中可溶性膳食纤维(soluble dietary fiber,SDF)的产量,结果表明,固态酶解(pH7.0,50℃,4 h)使SDF的产量提高了34.2%。通过凝胶渗透色谱、扫描电子显微镜和热重分析发现酶解后SDF的分子量降低,分支较多、更细,核磁共振分析、傅里叶变换红外光谱显示出部分半纤维素发生降解。同时,经酶解处理的SDF表现出更高的持水能力和抗氧化活性。进一步研究添加SDF对小麦粉流变学特性的影响,其中储能模量(G′)、损耗模量(G″)和触变性降低,这可能是由于SDF抑制了淀粉的膨胀能力,淀粉糊化过程中的峰值黏度、峰谷黏度和最终黏度显著降低进一步证明这一点。

Glucomannanase from Bacillus amyloliquefaciens was used to enhance the yield of soluble dietary fiber(SDF)in wheat bran.The results indicated that enzymolysis in a solid-state treatment system(pH7.0,50 ℃,4 h)achieved a 34.2% increase in the yield of SDF compared to the yield with no treatment.The SDF derived by glucomannanase treatment was structurally characterized by a lower molecular weight,finer bifurcation,an amorphous structure,and partial hemicellulose degradation,as determined by gel permeation chromatography,scanning electron microscopy,nuclear magnetic resonance analysis,thermo-gravimetric analysis,and Fourier transform-infrared spectroscopy.Meanwhile,the SDF derived by glucomannanase treatment demonstrated increased water-holding and antioxidant capacities.The influence of the addition of SDF on the rheological properties of dough was further investigated.A lower storage modulus(G′),loss modulus(G″),and thixotropy of the dough was achieved,which may have contributed to its reduced starch swelling capacity,as further supported by significantly reduced peak viscosity,trough viscosity,and final viscosity during the starch pasting progress.This study highlights a novel approach for the utilization of the wheat bran as a food ingredient.