Improvement in quality of fast-frozen steamed bread by different gluten content and glutenin/gliadin ratio and its mechanism

The effect of frozen storage on the quality of fast-frozen steamed bread has not been explored. Meanwhile, gluten, as a key component of wheat, can be used as a quality improver for fast-frozen steamed bread due to its functional characteristics. Therefore, the effects of different gluten contents (0%, 0.5%, 1.0%, 1.5% on flour weight) and glutenin/gliadin (glu/gli) ratios (1:1, 1:2, and 2:1) on the quality of fast-frozen steamed bread were investigated, and the influence mechanism on its quality was also analyzed. Frozen storage induced the amount of SDS-soluble protein and freezable water increased, which further resulted in the reduction of specific volume, the increase of hardness and the destruction of microstructure. The results further indicated that 1.0%-1:1 gluten addition resulted in steamed bread with supreme specific volume and minimum hardness during frozen storage. By analyzing the mechanism of quality improvement, we determined that the SDS-soluble protein and freezable water content of steamed bread frozen for 60 d decreased by 8.45% and 9.63% following 1%-1:1 gluten addition, respectively. Adequate elasticity and extensibility of dough (specific alveograph index: P = 62, L = 55, P/L = 1.08) with 1.0%-1:1 of gluten addition resulted in the best quality and freeze stability of the fast-frozen steamed bread.