Impact of wheat grain selenium content variation on milling and bread baking

Authors: Garvin, David; Hareland, Gary; Gregoire, Brian; Finley, John

Submitted to: Cereal Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/5/2011
Publication Date: 4/1/2011
Citation: Garvin, D.F., Hareland, G.A., Gregoire, B.R., Finley, J.W. 2011. Impact of wheat grain selenium content variation on milling and bread baking. Cereal Chemistry. 88(2):195-200.

Interpretive Summary: U.S. wheat has higher levels of the mineral micronutrient selenium (Se) than wheat grown in many regions of the world, and it can be used in foods to improve the Se intake of populations at risk of Se deficiency. However, it is important to know if high Se levels in wheat affect food product quality. Thus, high and low Se wheat grain was compared for a range of quality traits associated with bread production. After milling, the majority of the grain Se was found in the flour. The bread-baking process did not alter Se levels in bread loaves; however, the size of loaves made from high Se wheat was moderately lower than loaves baked with low Se flour. This deleterious effect should be easily corrected by blending high Se flour with low Se flour until the desired level of Se is present. High Se wheat can be considered a natural value-added commodity because it is an efficient delivery vehicle for improving Se intake, and thus the health, of large numbers of individuals. Further, because there appears to be an association between adequate dietary Se intake and reduced cancer risk, consumption of food products naturally fortified with high Se wheat may also reduce cancer rates.

Technical Abstract: Selenium (Se) is an essential nutrient associated with reduced cancer risk. High levels of Se can accumulate in wheat grain, but it is not clear if this impacts milling or baking. Low and high Se hard red winter wheat grain from the same cultivar was milled and used for bread-baking studies and Se analysis. Mill stream yields from the low and high Se wheat were comparable, as were flour yields. The amount of total grain Se retained in the flour mill streams was 71.2% and 66.4% for the low and high Se wheat, respectively. Modest increases in relative Se concentrations were observed in the bran, shorts, and the largest flour mill stream in high Se wheat compared to low Se wheat. Flour quality parameters including protein content, ash content, and farinograph traits were similar in low and high Se mill streams. Bread-baking evaluations indicated that high Se has a modest deleterious effect on loaf volume. There was no evidence of significant Se loss after bread baking with either low or high Se flour. Thus, high Se wheat flour is not likely to impact end use quality when blended with low Se wheat flour to reach desired Se levels.