The effect of partially substituted lupin, soybean, and navy bean flours on wheat bread quality

Authors: Liu, Sean; Chen, Diejun; Xu, Jingyuan - James

Submitted to: Food and Nutrition Sciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/16/2018
Publication Date: 7/19/2018
Citation: Liu, S., Chen, D., Xu, J. 2018. The effect of partially substituted lupin, soybean, and navy bean flours on wheat bread quality. Food and Nutrition Sciences. 9:840-854.
DOI: https://doi.org/10.4236/fns.2018.97063

Interpretive Summary: The nutritional value of cereal products such as wheat bread can be enhanced by fortifying it with edible legumes. Edible legumes contain high amount of lysine, an essential amino acid that cereal crops such as wheat and corn are deficient. In addition, breads fortified with protein rich legumes generally make the breads more palatable; however, the effect of incorporation of legumes into wheat bread formulation on bread quality attributes and handling of flour mixture and bread dough was unknown. In this study, we evaluated breads made from wheat flour partially substituted with soybean, navy bean, and lupine flours at 10%, 20%, and 30% levels. The physicochemical properties of breads were measured and compared with the control (made from 100% wheat flour). It was found that bread fortified with legume tend to be firmer due to higher protein and fiber contents and comparable springiness. As the level of gluten in the breads declines, the bread volume decreases as well. Comparing to the wheat bread, all legume-substituted bread samples show a slightly darker crust and crumb colors with the exception of breads with the soybean flour substitution. Lupin –substituted breads appear to be the best overall among all legume-substituted breads. Lupin, with its high protein and high fiber, has the potential to be used in a number of commercial health food formulations.

Technical Abstract: Many edible legumes contain high amounts of proteins, fibers, minerals and vitamins. Their essential amino acid composition and concentration complements the amino acids in wheat and other cereals. In addition, breads fortified with protein rich legumes make the breads more palatable. In this study, we evaluated breads made from wheat flour partially substituted with soybean, navy bean, and lupine flours at 10%, 20%, and 30% levels. The physicochemical properties of breads were measured and compared with the control (made from 100% wheat flour). Statistical analysis was used to assess the significance of the differences. The breads fortified with soybean, lupine and navy bean flours showed remarkable springiness, similar to the breads made from wheat flour. However, the higher amount of substitution increased the firmness of the breads, probably due to the incorporation of additional fibers and proteins into the formulations. Comparing to the wheat bread, the volumes of 90:10 wheat-soybean, wheat-lupin, and wheat-navy bean breads decreased about 7%, 2%, and 10%, respectively. Higher substitution levels may result in a higher reduction in volume for all legumes tested. The volume reduction as a result of legume substitution appears to be navy bean flour > soybean flour > lupine flour. The inclusion of legumes in the bread formulations imparts a slightly darker crust color and crumb color with the exception of breads with the soybean flour substitution. Lupin appears to be the best substitution candidate among the legumes tested for fortified bread making. Lupin can be presented as a high-value protein source in developing marketable foods for health conscious consumers.