Sustainable grape seed oil processing: Green solvent extraction and byproduct valorisation

The extraction of grape seed oil (GSO) for food and cosmetic applications was performed with 2-methyloxolane (2-MeOx) as a green solvent. The oil extraction yield, the tocopherol and tocotrienol content, the fatty acid and polyphenol profiles of the oils were analysed and compared with hexane. The entire extraction process, including the oil chemical refining, was further investigated on a pilot scale (15-litre extractor). Oil refining had a negative effect on the micronutrient content. The content of sterols, tocols and polyphenols was reduced by 19.78 %, 47.6 % and 99 % respectively. High amounts of polyphenols were recovered in refining by-products, with approximately 80 % found in gums and 10 % in soap-stock. The polyphenols contained in the crude oil and gums demonstrated effective intracellular ROS inhibition in HaCaT keratinocytes and BJ fibroblasts, as well as an anti-melanogenic effect on B16-F10 murine melanoma cells. Consequently, these products are proposed as valuable cosmetic ingredients for treating hyperpigmentation disorders. In conclusion, 2-MeOx is an excellent alternative to hexane for GSO extraction, offering high extraction efficiency, a safer toxicological profile, and the production of oil and byproducts with promising food and cosmetic applications.