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Nutritional Profile of Whole-Grain Soft Wheat Flour

¹United States Department of Agriculture, Agricultural Research Service, Soft Wheat Quality Laboratory, Wooster, OH 44691. ²Corresponding author. E-mail: edward.souza@bayer.com ³Ohio State University, Ohio Agricultural Research and Development Center, Wooster, OH 44691.

Whole-grain wheat flour is used in baking to increase fiber content and to provide vitamins from the bran layers of the kernel. We surveyed whole-grain soft flour samples from North America to determine the nutritional profile using recently revised fiber quantification protocols, Codex 2009.1. Standard compositional and vitamin analyses were also included in the survey. Three separate studies were included in the survey: sampling of commercial whole-grain soft wheat flour, a controlled study of two cultivars across three years and two locations, and a regional study of soft white and soft red grain from commercial grain production. The Codex method for fiber measurement estimated total fiber concentration in the commercial sampling at 15.1 g/100 g, dry weight basis (dwb). In the controlled research trial, the largest source of variation in total fiber concentration was attributed to year effects, followed by genotype effects. For the two locations used in this study, location effects on fiber concentration were significant but an order of magnitude less important than the year and genotype effects. The third study of regional variation within North America found limited variation for total fiber, with the resistant oligosaccharide fraction having the greatest variation in concentration. When all three studies were combined into a meta-analysis, the average total fiber concentration was 14.8 g/100 g dwb. In the meta-analysis, concentrations of folate, thiamin, riboflavin, niacin, and pyridoxine were lower than in previous summary reports. Vitamin E and pantothenic acid were the exceptions, with concentrations that were nearly identical to previous standard reports. Several other recent studies also point to current cultivars and production systems as producing lower concentrations of the essential vitamins than previously reported. The results suggest that vitamin concentrations in diets of populations using grain-based diets from modern cereal-production systems may require review to determine if previous assumptions of vitamin consumption are accurate.