Impact of defatting method on oat protein isolate structure-function characteristics

Oat (Avena sativa) is valued for its high protein content of 15–20% and potential health benefits. Oat also contains a notable lipid content, ranging from 6% to 10%, which can lead to rapid oxidation and rancidity, lowering product shelf life. Thus, defatting is imperative for the production of high-quality oat-based ingredients. This study focuses on evaluating the impact of various defatting techniques, including hexane-based defatting, supercritical carbon dioxide extraction, and supercritical carbon dioxide extraction with ethanol, on the structural and functional characteristics of oat protein isolate. Oat protein isolate was produced through alkaline extraction-isoelectric precipitation and assessed for its proximate composition, structural characteristics, encompassing protein profile, surface hydrophobicity, denaturation, and functional properties, including solubility, foaming capacity, and emulsification. Our results indicate that supercritical fluid methods are promising in their effectiveness in defatting oat flour although characteristics such as protein purity and solubility need improvement. Nevertheless, supercritical carbon dioxide defatting methods were found to yield oat protein with functional and structural properties closely comparable to the hexane-based method. In conclusion, given the environmental impacts associated with hexane, supercritical defatting methods can be further optimized and used as an eco-friendly alternative to conventional solvent-based fat extraction techniques.