Abstract
The objective of this study was to determine the most suitable extraction conditions from Red cardinal grape pomace using deep eutectic solvents (DES). Factors influencing the extraction process were investigated, including DES type, the ratio of hydrogen bond acceptor (HBA) to hydrogen bond donor (HBD), water addition, solvent-to-material ratio, extraction temperature, and time. The best results were obtained with choline chloride: glycerol: citric acid (1:1:1, w/w/w) DES, adding 25 % water, using a 25:1 (v/w) solvent-to-material ratio, 60 °C, and 2.5 h extraction. The grape pomace extract showed substantial levels of bioactive compounds, with the highest recorded values being 65.49 ± 1.30 mg GAE/g DW for total polyphenol content, 177.88 ± 5.17 mg AE/g DW for total triterpenoid saponin content, and 36.22 ± 0.77 mg CE/g DW for proanthocyanidin content. The concentrations of specific compounds were quantified, revealing DES's superior extraction compared to ethanol and methanol, highlighting DES's effectiveness as an alternative extraction solvent.
