POST MILLING EFFECT OF STORAGE ,TEMPERATURE ON BREAD BAKING QUALITY OF REFINED WHITE FLOUR,WHEAT BREAD AND THE ROLE OF FLOUR LIPIDS

1.1INTRODUCTION  The USDA issued a Dietary Guidelines recommendation on June 12th, 2005 for consumers to increase whole grain consumption. However, it is generally recognized that wheat flours containing the germ can develop problems due to lipid changes. White flour, especially soft wheat flour destined for use in cakes, increases in quality with time after harvest and milling, as indicated by a desirable drop in batter specific gravity and increase in batter viscosity, distilled water binding capacity (DWBC), minimum batter viscosity during heating, and cake volume. Quality increases with post-milling aging of flour up to a certain duration of storage, after which these parameters reach a plateau (Shelke et al., 1992a; Shelke et al., 1992b). However, in the baking industry, wheat flour is thought to decline in quality with storage time after milling (Jon Faubion, personal communication). The goals of this research were to rigorously test for and document any post milling effect of storage, temperature on bread baking quality of refined white flour, wheat bread and the role of flour lipids, mainly lipid oxidation and breakdown, as monitored by Thin Layer Chromatography (TLC). Lipid changes are expected to accompany deleterious changes in bread baking quality (such as volume, crumb grain, and dough handling properties). A second objective was to test for relationships between any changes in bread baking quality and changes in the glycolipid, phospholipid, and neutral lipid fractions of the flour. The research conducted here should prove useful to the food industry by providing information for controlling quality and processing variability in wheat flour based products.