Mechanism of promoting okara insoluble to soluble dietary fiber by high-pressure homogenization-microbial fermentation.

This study investigated the conversion of okara insoluble dietary fiber (IDF) to soluble dietary fiber (SDF) using high-pressure homogenization (HPH) combined with microbial fermentation. The conversion mechanism was analyzed from four aspects: correlation, proteomics, component and structure under. Results indicated a negative correlation between pH and SDF yield (r = -0.9885, p < 0.05), while cellulase and xylanase showed a positive correlation with SDF yield (p < 0.05). Proteomic analysis identified 22 key enzymes involved in IDF degradation. According to the composition and structure, the combined treatment effectively reduced the aggregation of IDF, promoting its transformation into SDF. HPH treatment primarily acted on the hemicellulose fractions in the amorphous region, while microbial fermentation broke hydrogen bonds between hydroxyl groups in the crystalline regions of cellulose, enhancing the conversion of more exposed cellulose. This study provided theoretical support for the development and utilization of okara IDF.