Development of a Green Extraction Process from Residues of Assyrtiko Wine Production for Cosmetic Applications

Vitis vinifera L. cultivar, “Assyrtiko”, is a famous grape variety native to Santorini island. Its wine production residues are rich in bioactive polyphenols, making them valuable for extraction and use in cosmetics. The aim of this work was the development and optimization of an extraction process from “Assyrtiko” Wine Production Residue (AWPR), using a Natural Deep Eutectic Solvent (NaDES) as the extraction medium. Four NaDESs were synthesized and screened for the extraction, and the extracts were evaluated for Total Phenolic Content (TPC) and Total Flavonoid Content (TFC). The NaDES comprising betaine and 1,3-propanediol was chosen for further analysis because of its effectiveness as an extraction solvent. The extraction process was optimized using a Box–Behnken experimental design. The NaDES %w/w content in the NaDES/water system was found to play the most statistically significant role in the quality of the extracts, assessed via TPC and TFC values. The quality of the extract obtained from the optimal conditions was practically stable with respect to TPC and TFC after long storage, suggesting that NaDESs have a potential “protective” effect for the extracted phytochemicals and give energy-efficient character to the process. This extract was also directly incorporated into a moisturizing cosmetic formulation, which remained homogeneous and stable after testing, demonstrating the extract’s potential for cosmetic applications.