Comparison of Two Soy Globulins on the Dynamic-Mechanical Properties of the Dough and the Quality of Steamed Bread

Abstract

To investigate the effect of the soy protein concentrate (CSP) and 7S and 11S soy globulin on wheat dough and steamed bread (SB), mixing properties of the dough were assessed by farinograph and dynamic-mechanical analyzer (DMA). The quality attributes of SB were assessed by texture profile analyzer (TPA), sensory analysis, and scanning electron microscope (SEM). The results showed that CSP, 7S, or 11S (each from 2.0 to 4.0%) significantly decreased gluten content (from 29.4 to 26.0, 36.7 to 31.8, and 31.6 to 30.7%), when those were added to wheat flour. The CSP/wheat dough stability was increased (from 6.5 to 8.4, 6.5 to 8.5, and 6.5 to 8.3 min) and the degree of softening was decreased (from 71.0 to 68.0, 71.0 to 64.0, and 71.0 to 62.0 min), but 7S or 11S had the opposite result. Moreover, the ratio of 7S and 11S has a significant effect on the quality of the dough. The storage modulus and loss modulus of soy/wheat dough decreased in the order of CSP, control, 11S soy globulin, and 7S soy globulin. The hardness, chewiness, and cohesiveness of SB decreased in the order of control, CSP, 11S soy globulin, and 7S soy globulin. Microstructure demonstrated that gluten network was interfered by SPC, 7S, and 11S soy protein, which was in agreement with the texture analysis index. The quality of SB with 3% 11S was the best in texture, microstructure, and sensory. These findings indicate that 11S has the potential to be used as a special soy protein for SB making.