ARS | Publication request: Characterisation of Oat Products with and Without Supercritical Carbon Dioxide Extraction

Submitted to: International Journal of Food Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 31, 2006
Publication Date: December 2, 2007
Citation: Stevenson, D.G., Eller, F.J., Radosavljevic, M., Jane, J., Inglett, G.E. 2007. Characterization of oat products with and without supercritical carbon dioxide extraction. International Journal of Food Science and Technology. 42:1489-1496.

Interpretive Summary: In this study, the properties of oat bran concentrate and Nutrim-OB, an enriched, oat fiber based, jet-cooked product, were examined with and without lipid extraction. During heating, Nutrim-OB had thicker paste, which thinned under constant shear. It also had higher water-holding capacity compared to oat bran concentrate. Lipid extraction resulted in thicker paste and higher water-holding capacity for both oat bran concentrate and Nutrim-OB. The development and use of these oat products will enable the manufacture of more healthy foods.

Technical Abstract: Thermal and pasting properties, starch structural properties, and oil fatty acid composition of oat bran concentrate (OBC) and Nutrim-OB (NOB), a jet-cooked oat-bran product, were examined to determine the effect of supercritical carbon dioxide extraction (SCC). DSC analysis showed that OBC had three thermal transitions in which two could be positively identified as starch gelatinization and an amylose-lipid complex transition. NOB only had an amylose-lipid complex transition. SCC significantly decreased gelatinization temperatures and enthalpy of OBC. Pasting properties, measured by RVA, showed that NOB had significantly higher peak viscosity and breakdown, with significantly lower final viscosity, setback, and pasting temperature compared to OBC. SCC resulted in an increased peak viscosity, breakdown, final viscosity, and setback, but lower pasting temperature for both OBC and NOB. Thermogravimetric analysis of oat products heated from 15 to 110 deg C showed that NOB had higher water-holding capacity (WHC) than OBC, while SCC decreased WHC throughout the entire temperature range. Amylopectin molecular weight, determined by HPSEC, was 6.8 x 10^7 for NOB and significantly lower for OBC (4.5 x 10^7). Predominant fatty acids present in both OBC and NOB oil obtained by SCC were: oleic (41%), linoleic (38%), and palmitic (16%). This study showed that jet-cooked NOB had markedly different properties from OBC, which expands the range of potential industrial applications for oat-bran products.