Effect of manufacturing methods on the quality and storage stability of whole wheat flour

To clarify the effect of manufacturing methods on the quality characteristics and storage stability of whole wheat flour (WWF), six groups of WWF samples were prepared using two methods: direct grinding and re-addition. The specific groups were as follows: direct grinding with a cyclone mill; re-addition after milling with a Bühler experimental mill; re-addition of germ and regular bran; re-addition of regular bran;re-addition of germ and extruded bran; re-addition of extruded bran. The physicochemical properties, color parameters, particle size distribution, pasting viscosity, and storage stability of the WWF samples were determined, and the specific volume and texture characteristics of whole wheat steamed bread made from these flours were analyzed. Results indicated that WWF produced by direct grinding with a hammer mill had the largest average particle size. Samples with germ re-addition (WWF₃ and WWF₅) exhibited significantly higher crude fat and crude protein contents compared with those without germ (WWF₂, WWF₄, WWF₆), while no significant differences were observed in other quality indices. The moisture contents of WWFs with regular bran re-addition (WWF₃ and WWF₄) were 13.76% and 13.64%, respectively, which were significantly higher than those of the other four groups. WWFs samples with extruded bran re-addition (WWF₅ and WWF₆) had significantly higher contents of soluble dietary fiber and total phenolic compounds than other groups and yielded higher-quality steamed bread. After 6 weeks of re-addition accelerated storage, the fatty acid values of WWF₁ (direct grinding), WWF₅ (germ and extruded bran re-addition), and WWF₆ (both with extruded bran re-added) were 103.24, 92.27, and 86.99 mg/100 g, respectively, while their malondialdehyde contents were 3.01, 3.06, and 3.01 mg/kg—significantly lower than those of the other three samples—indicating enhanced storage stability. In summary, the WWF₁ (direct grinding), WWF₅, and WWF₆ (both with extruded bran re-added) exhibited greater storage stability. Moreover, WWFs with extruded bran re-addition produced higher-quality steamed bread.