微波对膳食纤维结构和功能特性的影响

采用微波对甘薯渣、苹果渣、大豆渣中的膳食纤维进行改性，通过扫描电镜、X-射线衍射及热重分析，研究微波对3种膳食纤维结构的影响，并对比处理前后膳食纤维持水力、持油力、胆固醇吸附力、亚硝酸根离子吸附力的变化。结果表明：微波改性可以使膳食纤维的可及性边缘暴露，结晶度升高，热稳定性加强，且3种膳食纤维的功能特性均有不同程度改善，是一种优良的膳食纤维改性方法。此外，改性后3种膳食纤维中的可溶性纤维质量分数分别提高63.11%，4.51%，358.79%，与功能特性综合提高幅度并非正相关，改性后膳食纤维功能性质的提升是可溶性膳食纤维增加与不溶性膳食纤维可及性边缘的增加共同作用的结果。

Effects of microwave on the structural and functional properties of dietary fibers from different sources

The microwave was used to modify the dietary fibers (DFs) in sweet potato pomace, apple pomace, and soybean pomace. The changes in the structural properties of three kinds of DFs by microwave were investigated by scanning electron microscopy, X-ray diffraction and thermogravimetric analysis. Moreover, the functional properties, including water holding capacity, oil holding capacity, cholesterol adsorption capacity and nitrite ions adsorption capacity, were evaluated in this study. The results showed that microwave was an excellent modification method that could expose the accessibility margin, increase crystallinity, strengthen thermal stability, and improve the functional properties of three dietary fibers to varying degrees. In addition, after modification, the soluble dietary fiber mass fractions of the three dietary fibers were increased by 63.11%, 4.51% and 358.79%, respectively, which was not positively correlated with the improvement of functional properties. The improvement of functional properties was related to the mass fraction of SDF, but the exposure of the accessibility margin on IDF also promoted an important influence for the improvement of DFs functional properties.