Nutritional profile of whole grain soft wheat flour

Authors: GUTTIERI, MARY - The Ohio State University; Souza, Edward; SNELLER, CLAY - The Ohio State University

Submitted to: Cereal Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/1/2011
Publication Date: 9/1/2011
Citation: Guttieri, M., Souza, E.J., Sneller, C. 2011. Nutritional profile of whole grain soft wheat flour. Cereal Chemistry. 88(5):473-479.

Interpretive Summary: We conducted a comprehensive survey of whole grain soft wheat flour to determine the nutritional profile for fiber and vitamins for which grains are considered vital sources. We found that current levels of fiber concentration in standard reference literature were accurate but that vitamin concentration for thiamine (B1), riboflavin (B2), niacin (B3) and, particularly, pyridoxine (B6) were too large in the standard reference. Current crop production practices, cultivars, or analytical methods have changed sufficiently from the early small studies upon which the standard references were based, that we may be overestimating of the amount of vitamins provided by whole grains. Other recent literature in wheat is consistent with our findings, which suggests that the topic should be carefully reviewed for recommendations on future action. The USDA National Nutrient Database for Standard Reference previously has not listed a separate category for nutritional profiles for whole grain soft wheat flour. A number of the values in the whole grain wheat flour entry were imputed (that is not measured but inferred by other data). The most recent method for measuring fiber, CODEX 2009.1, included a category of small fiber molecules not previously classified as fiber. Therefore, it was necessary to provide a new standard reference for soft wheat with complete analysis of the most current methods. Manufacturers rely on this information for formulation and labeling of food products.

Technical Abstract: Whole grain wheat flour is used in baking products 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-1, 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 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 14.9 g 100 g-1 dwb. In the meta-analysis, concentrations of most vitamins were smaller 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 smaller 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 need a new review to determine if previous assumptions of vitamin consumption are accurate.