Extraction of γ-oryzanol from rice bran using diverse edible oils: enhancement in oxidative stability of oils

Diverse edible oils including perilla, corn, soybean, canola, sunflower, olive, and grape seed oils were mixed with heat-stabilized rice bran to extract γ-oryzanol from the rice bran. The oxidative stabilities of the oils with or without extraction were compared by analyzing the headspace oxygen content, conjugated dienoic acid (CDA) values, and p-anisidine values (p-AV). Grape seed oil extracted significantly high γ-oryzanol content while canola oil extracted lowest γ-oryzanol content (p < 0.05). All the solvent oils except corn oil possessed enhanced oxidative stability at 100 °C after extracting γ-oryzanol from stabilized rice bran, based on the results of the headspace oxygen depletion and CDA methods. However, all the recovered oils had high p-AV than vegetable oils. Especially, perilla oil had an exceptionally high p-AV, which may be due to its high linolenic acid content.