Characterisation of oat bran products with and without supercritical carbon dioxide extraction

Abstract

Morphology, starch structures and thermal and pasting properties of oat bran concentrate (OBC) and Nutrim-OB (NOB), a jet-cooked oat bran product, with or without supercritical carbon dioxide extraction (SCD) were studied. Oil composition was analysed. OBC had three thermal transitions, starch gelatinisation and two amylose-lipid complex transitions. NOB only had amorphous amylose-lipid transition. SCD significantly decreased gelatinisation temperatures of OBC. Pasting properties, showed NOB had significantly higher peak viscosity and breakdown, with significantly lower final viscosity, setback and pasting temperature compared with OBC. SCD increased peak viscosity for NOB and final viscosity for OBC. Thermogravimetric analysis showed NOB had higher water-holding capacity (WHC) than OBC, while SCD decreased WHC. Amylopectin molecular weight was 3.4 x 10(8) for OBC and was significantly lower for NOB (1.4 x 10(8)). Predominant fatty acids were oleic (41%), linoleic (38%) and palmitic (16%). Study showed NOB had different properties from OBC thereby expanding industrial applications.