Effects of Wheat Bran Dietary Fiber and Raw Wheat Bran on the Quality of Steamed Bread

In order to study the difference effects of wheat bran dietary fiber (WBDF) and raw wheat bran (RWB) on the quality of steamed bread, WBDF was prepared by complex enzyme hydrolysis (moderate temperature α-amylase, cellulase, and alkaline protease), the sensory quality, textural property, in vitro starch digestibility and microstructure of steamed bread with different WBDF and RWB addition level were determined by millet replacement method, colorimeter, texture analyzer, in vitro simulated total starch hydrolysis method and SEM. The different effects between WBDF and RWB on the quality and property of steamed bread were compared under the same total dietary fiber content in the mixed flour. The results showed that both WBDF and RWB could affect the quality of steamed bread, but they could also inhibit the in vitro digestion of starch in steamed bread. When the total dietary fiber content was same, the steamed bread in WBDF group had larger specific volume, deeper color, rounder and plumper appearance, less separation of skin and pulp, higher bulkiness, lower internal structure density, better texture (low hardness, high springiness, low chewiness, and high resilience), more continuous and smooth microstructure, besides the damage of gluten network was lower than that of the steamed bread of RWB group. RWB had a slightly more ability to inhibit starch digestion than WBDF. The results suggested that compared with raw wheat bran, the relatively pure wheat bran dietary fiber was a more potential form of dietary fiber supplement under the condition of achieving the same dietary fiber supplement requirements, which was more conducive to developing good quality high-fiber wheat products.