Department of Biological and Chemical Engineering, Chongqing University of Education, Chongqing 400067, China; Key Laboratory of Lipid Resources Utilization and Children's Daily Chemicals, Chongqing University of Education, Chongqing 400067, China.
Department of Plant Sciences, North Dakota State University, Fargo, ND 58108, USA.
Food Chem. 2022 Aug 1;384:132526. doi: 10.1016/j.foodchem.2022.132526. Epub 2022 Feb 22.
Soy okara contains high levels of insoluble dietary fiber (IDF). The objective of this work is to investigate the composition, structure changes, and functionality of okara residues after the modification by ultracentrifugal milling (M), milling + steam heating (M + S), or milling + steam heating + enzymatic (M + S + E) treatment. The results showed that the combination of M + S could significantly convert okara IDF into soluble ones, and the highest conversion rate (59%) was achieved with the smallest size (147 µm). The structural characterization revealed that size reduction altered the functional groups and crystallinity of the modified okara residues with irregular and enlarged morphology. More importantly, the functionalities, including water and oil holding capacities, swelling capacity, as well as cholesterol and bile acid binding capacities were improved remarkably in okara residues pretreated by M + S prior to cellulase hydrolysis. The findings provide new insights on the effective biotransformation of okara into valuable food ingredients.
豆渣含有高水平的不可溶性膳食纤维（IDF）。本工作旨在研究超离心磨（M）、磨+蒸汽加热（M+S）或磨+蒸汽加热+酶处理（M+S+E）改性后豆渣残渣的组成、结构变化和功能。结果表明，M+S 的组合可显著将豆渣 IDF 转化为可溶性膳食纤维，转化率最高（59%），粒径最小（147µm）。结构表征表明，粒径减小改变了改性豆渣残渣的功能基团和结晶度，使其形态不规则且增大。更重要的是，经过 M+S 预处理后再用纤维素酶水解，豆渣残渣的水和油保持能力、膨胀能力以及胆固醇和胆汁酸结合能力显著提高。这些发现为豆渣有效生物转化为有价值的食品成分提供了新的思路。
