Optimization of the Microwave-Assisted Extraction of Simple Phenolic Compounds from Grape Skins and Seeds

A method for the extraction of phenolic compounds from grape seeds and skins using microwave-assisted (MAE) was developed. Optimization effects parameters in terms results obtained response surface methodology. The studied were solvent (methanol, ethanol, acetone, water), percentage methanol water, quantity sample relation to volume (solid:liquid, 10–50 mg mL−1), power (100–500 W), magnetic stirring speed (0–100%), time (5–20 min). Finally, repeatability intermediate precision determined. best conditions proved be: 65% water as an optimum solvent; 0.5 g skin or seed a 25 mL; 500 W with maximum (100%); 5 min. be stable optimized conditions. resulting showed relative standard deviation below 7%. new applied on Napoleon allowed determination catechin (453.2 (mg kg−1)), epicatechin (306.3 kg−1), caftaric acid (22.37 caffeic equivalents dihydrokaempferol-glycoside (11.13 kaempferol quercetin (18.28 quercetin-3-glucoside (20.09 kaempferol-3-glucoside (11.10 kg−1).