Quality, Stability, and Bioactive Compound Composition of Virgin and Refined Organic Grape Seed Oil

Samples of virgin and refined organic grape seed oil were studied for their physicochemical quality, oxidative stability, and the bioactive compounds they contained. All of the samples were within the limits established by the Codex Alimentarius with regard to their quality parameters. Lutein, zeaxanthin, β-carotene, α-tocopherol, and catechin were the bioactive compounds analyzed, and the virgin oil afforded more significant results. No measurable amounts of zeaxanthin and β-carotene were observed in the refined oil, most likely due to the refining process that was carried out at high temperatures. The oxidative stability index decreased with increasing temperature, whereas the air flow had no effect on the stability index. The optimal parameters for the oxidative stability are 80 °C and a flow rate of 15 L h⁻¹, and the virgin oil sample showed the best oxidative stability, possibly because it was not subjected to any treatment after extraction. The results from this study suggest that it would be preferable to consume virgin instead of refined grape oil because it is a better source of bioactive compounds and has a higher stability when heated.