Location: Corn, Soybean and Wheat Quality ResearchTitle: Quality characteristics of northern-style Chinese steamed bread prepared from soft red winter wheat flours with waxy wheat flour substitution
Submitted to: Journal of Cereal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/12/2016
Publication Date: 1/1/2017
Publication URL: https://handle.nal.usda.gov/10113/5632748
Citation: Ma, F., Ji, T., Baik, B.V. 2017. Quality characteristics of northern-style Chinese steamed bread prepared from soft red winter wheat flours with waxy wheat flour substitution. Journal of Cereal Science. 73:99-107. https://dx.doi.org/10.1016/j.jcs.2016.12.002.
Interpretive Summary: Soft red winter wheat produces grain of relatively low protein content, but of diverse gluten protein strengths. Varieties producing grain with weak gluten proteins are suitable for making cookies, cakes and pastries, while those producing strong gluten proteins are more appropriate for making products requiring gluten development during dough mixing. A previous study conducted by the ARS scientists in the Soft Wheat Quality Laboratory identified a large number of soft red winter wheat varieties that produce Chinese steamed bread (CSB) of good to excellent quality even though their flour protein content was less than 10%, owing to their strong gluten protein. While starch constitutes 80 to 90% of wheat flour and is known to heavily influence the textural properties and shelf life of wheat food products, we have little understanding of its role in making CSB. With development of waxy wheat, whose starch is composed mainly of amylopectin molecules, it has been possible to prepare wheat flour of variable amylose content by blending waxy and normal what flours in an effort to improve the textural attributes and shelf life of wheat foods. We prepared soft red wheat flour blends of varying starch amylose content using waxy wheat flours to elucidate the role of starch amylose content on CSB quality attributes. The reduction of starch amylose content with increasing proportions of waxy wheat flour in blends increased the dough mixing absorption and showed positive effects, including increased loaf volume and crumb softness, while causing only slight changes in surface smoothness and total quality score. Wheat flour blends containing 15-20% waxy wheat flour, with amylose contents ranging from 20.5-22.7%, produced CSB with improved crumb texture and reduced staling during storage for 3 days without decreasing the total score of fresh and re-steamed CSB. The results of this study suggest that the production of CSB with improved crumb texture, volume and shelf life could be achieved by the incorporation of waxy wheat flour into wheat flour of normal starch amylose content, or by the development of wheat varieties producing wheat grain of reduced starch amylose content.
Technical Abstract: Quality characteristics of Chinese steamed bread (CSB) prepared from two soft red winter (SRW) wheat flours blended with 0-30% waxy wheat flour (WWF) were determined to estimate the influence of starch amylose content. The increased proportion of WWF in blends raised mixograph absorption with insignificant changes in protein content and dough strength-related parameters. The incorporation of WWF generally increased specific volume and crumb softness of CSB. The analysis of covariance evidenced that quality attributes of CSB were little affected by protein content and dough strength-related parameters, indicating that starch amylose content was largely responsible for the changes in CSB quality. Flour blends with 5-10% WWF, of which starch amylose content is 22.4-24.7%, produced CSB with superior crumb structure to other flour blends, but slight changes in surface smoothness, stress relaxation and total score compared with the respective control wheat flours. Flour blends with 15-20% WWF to produce starch amylose content of 20.5-22.7% exhibited reduced staling of CSB with comparable total score to the respective control wheat flours. CSB prepared with more than 10% WWF exhibited a higher soluble starch content, indicative of reduced starch retrogradation, than that prepared from wheat flours without WWF during storage for 3 days.