Addition of micronized oat husk fiber to gluten-free bread - Effects on chemical, physical and physiolgical properties

Abstract

Gluten-free (GF) breads available on the market are still mainly produced from refined flours or starch, thus they lack nutritional quality, like dietary fiber, minerals and vitamins. Incorporation of micronized oat husk (MOH) could improve these properties. MOH is a dietary fiber and a food by-product, rich in polyphenols exhibiting antioxidant properties. This study investigated the addition of 0–20% MOH (in 5% steps) to GF breads baked conventionally (deck oven) and by ohmic heating (OH). Incorporation of ≤20% MOH had only a slight effect on the bread texture properties (specific volume, pore properties, crumb firmness and relative elasticity), and was less pronounced for OH baked breads. Both, the crumb and crust color, darkened proportionally to the added amount of MOH. Total phenolic content (TPC) and antioxidative properties were significantly increased by MOH addition, as well as the ability to protect lipids from oxidation. In vitro starch digestibility was improved with MOH addition for OH-baked breads. GF breads containing ≥15% MOH can be claimed as “source of fiber”, ≥20% MOH as “high in fiber”. Overall, this study demonstrated that micronized oat husks have a good potential to enhance the quality of GF breads.