Effects of flour proteins, dough rheological properties, and flour extraction rates on northern-style Chinese steamed bread making

The relationships of protein quality and composition to resulting dough properties and steamed bread quality were studied by using twenty three wheat samples that covered a wide range of protein content and dough strength. Strong relationships between flour protein composition as measured with SE-HPLC, physical dough properties, and steamed bread quality were observed. The quantitative and compositional differences in wheat gluten proteins were determinants of the variations in steamed breadmaking quality among wheat varieties. Unlike pan breadmaking, however, flours with a medium dough development time and slightly longer dough stability were most desirable with regard to steamed bread specific volume and subjective score. Extremely strong dough strength should be avoided in order to prevent post-baking shrinkage and the formation of surface blisters and wrinkles. In a steamed bread wheat breeding program, it would be advisable to increase wheat protein content by increasing the total polymeric protein that contains moderately higher proportion of unextractable polymeric protein, but its amount should not be as high as that in wheats intended for pan bread.; Kansas HWW and HRW with moderate protein content and dough strength had superior performance compared to US soft wheat and Chinese wheats Yumai 18 (YM18) in steamed bread baking. On the other hand, Kansas HWW and HRW wheats at normal protein ranges are over-strong, which causes post-baking shrinkage and unsatisfactory steamed bread appearance (wrinkles and blisters). When the Kansas hard red winter wheat flour Jagger (11.8% protein content) was blended with the US soft (7.2% protein content) or Chinese hard winter YM 18 (9.7% protein content) wheat flours at ratios from 75:25 to 50:50, the quality of the steamed bread made with the blends was comparable to that made from the Chinese standard control. The results obtained in the current study suggest that flour blending provides a useful way to improve the Northern-style Chinese steamed bread (NCSB) making qualities of both Kansas and weaker Chinese wheats.; Kansas HWW showed a great color advantage over Kansas HRW at all extraction rates studied. NCSB made with HWW flours was substantially whiter than that made with HRW flours. Flour color and extraction rate has significant negative impact on NCSB color. The whiteness of both skin and crumb decreased considerably as flour extraction rate increased. Flour extraction rates at 70 and 80% did not significantly affect specific volume for all wheat varieties tested. However, texture, and spread-ratio were remarkably affected. Overall, flours at 70% extraction had the best performance. Flours at 80% extraction produced acceptable steamed bread, but flours at 90% extraction were unacceptable for NCSB.