The effect of mechanical processing on avenanthramide and phenol levels in two organically grown Italian oat cultivars.

Avenanthramides (AVNs), free and bound phenols and their antioxidant capacities (ORAC) were evaluated in two Avena sativa L. cultivars, Donata and Flavia. The cultivars (cvs.) were grown in loamy and medium texture soils and assessed after industrial dehulling and milling. Total dietary fiber, β-glucan, starch and proteins were also evaluated. Cv. Donata showed 2.8 fold higher AVN storage as compared to cv. Flavia, which was linked with genotype. The accumulation of AVN content was also influenced by the texture of the soil. Dehulling resulted in a 75 and 37% AVN decrease in cv. Donata and Flavia, respectively. The dehulled grains of cv. Donata showed 40% reduction in free phenolic content, whereas the dehulled grains of both cvs. showed 67% reduction in bound phenols. Milling affected the bound phenolics and their antioxidant capacity. Cv. Flavia showed 1.3 fold higher β-glucan than that of cv. Donata. Total dietary fiber was reduced by 50 and 12% after dehulling and milling, respectively, while marginal changes in proteins were observed after milling. The results suggest that the choice of genotype and the kind of dehulling processes that are employed are essential considerations in the production of oat-based products with high AVN content and extra health benefits.