Location: Wheat, Sorghum and Forage ResearchTitle: Volume, texture, and molecular mechanism behind the collapse of bread made with different levels of hard waxy wheat flours Author
|Garimella Purna, Shivananda|
|Graybosch, Robert - Bob|
Submitted to: Journal of Cereal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/21/2011
Publication Date: 3/1/2011
Citation: Garimella Purna, S.K., Miller, R., Seib, P., Graybosch, R.A., Shi, Y. 2011. Volume, texture, and molecular mechanism behind the collapse of bread made with different levels of hard waxy wheat flours. Journal of Cereal Science. http://www.sciencedirect.com/science/article/pii/S0733521011000439. Interpretive Summary: American consumers prefer their bread soft textured and fresh-tasting, but also want loaves that remain so for several days after purchase. To achieve these characteristics, bakers employ a number of additives, including glycerol monostearate, methylcellulose, or lecithin. They also may treat the flour with enzymes known as amylases. These approaches are not necessarily detrimental to human health. However, many consumers are upset by the appearance of such bizarre sounding ingredients on food labels, and would prefer to consume products that are totally “natural”. Waxy wheat flour, or flour with starch that contains only amylopectin and no amylose, was explored as a means of extending shelf-life of bread. Waxy wheat flour is an “all-natural” ingredient from non-GMO wheat. Blending of waxy wheat flour at addition rates of less than 30% to normal flour resulted in larger loaves with softer texture. Addition rates above 30% reduced product quality. Thus, waxy wheat may serve as a natural means of improving the quality of baked goods.
Technical Abstract: Physico-chemical properties of bread baked by partially replacing wild type wheat (Triticum aestivum L.) flour (15, 30, and 45%) with two waxy wheat flours having different dough properties were investigated. Substitution with waxy wheat flour resulted in higher loaf volume and softer loaves. However, substitution at > 30% resulted in excessive post-bake shrinkage and a ‘key-hole’ shape with open and porous crumb structure; their bread crumb microstructure indicated loss of starch granule rigidity and fusing of starch granules. Soluble starch content was significantly higher in bread crumb containing waxy wheat flour than in control bread crumbs. Debranching studies indicated that soluble starch was mostly amylopectin. Incorporation of waxy wheat did not retard staling upon storage.