Abstract: The effects of microwave heating and air-drying of grapeseeds on the physic-chemical parameters and tocopherols in their oils were investigated. Microwave treatment improved oil yield and increased viscosity while reducing pigment contents (K410 and K670 values). Removal of tannin by washing grapeseeds with alcohol resulted in oil with low pigment content (K410 and K670 values). γ-Tocotrienol, the major tocopherol of grapeseed oil, and α-tocopherol,β-tocopherol,γ-tocopherol increased while δ-tocopherol concentrations decreased on heat treatment of grapeseeds. The negative effect of tannin removal was confirmed by the low tocopherol contents of its oil. The results demonstrated the impacts of using microwave heating in producing oil from grapeseeds.

Key words: Grapeseed oil Microwave Heating effect Oil quality Tocopherols