Effects of Processing, Cultivar, and Environment on the Physicochemical Properties of Oat β-Glucan

Several food regulatory agencies around the world have approved health claims for oat-derived beta-glucan for cholesterol lowering and glycemic control. The biological efficacy of beta-glucan appears to depend both on daily intake and on physicochemical properties, such as molecular weight and viscosity. The objective of this study was to determine the effects of oat processing, genotype, and growing location on the physicochemical properties of beta-glucan. Five oat genotypes (HiFi, Leggett, CDC Dancer, Marion, and CDC Morrison) grown in two locations (Saskatoon and Kernen) were dehulled (untreated) and processed in a pilot facility through kilning (kilned, not flaked) and subsequent steaming and flaking (kilned, flaked). Untreated groats gave a relatively low Rapid Visco Analyzer (RVA) apparent viscosity (164 cP) and a low extractable beta-glucan molecular weight (332,440) but exhibited high beta-glucan solubility (90.49%). Compared with untreated groats, the kilned (not flaked) samples had significantly increased RVA apparent viscosity (314 cP) and extractable beta-glucan molecular weight (604,710). Additional processing into kilned and flaked products further increased RVA apparent viscosity (931 cP) and beta-glucan molecular weight (1,221,760), but beta-glucan solubility (63.83%) was significantly reduced. Genotype and growing environment also significantly affected beta-glucan viscosity and molecular weight, but no significant interaction effects between processing, genotype, and environment were found. Results indicate that there is potential for processors to improve the physicochemical and nutritional properties of oat end products through processing of specific oat genotypes from selected growing locations.