Valorization of grape pomace after distillation and its application in delaying oil oxidation

The Spent Grape Pomace (SGP) generated after Grappa elaboration is mainly considered a food waste. The aims of this study were to optimize an ultrasound assisted extraction (UAE) of antioxidant bioactive compounds from red and white SGP and to delay oil oxidation by employing the best extract obtained in each case. The optimization was carried out with the Response Surface Methodology (RSM), considering the amplitude, time, and solute: solvent ratio as assessed variables. The parameters used for obtaining the optimum value of TPC and AOA were the combinations (amplitude, time, and solute: solvent ratio) of 40%, 22 min, 1:38 and 40%, 25 min, 1:45 for red and white SGP, respectively. The oxidation was delayed up to 39% and 25% when employed the optimum red and white extracts grape pomace (EGPs), respectively. Therefore, both EGPs could be an alternative to synthetic antioxidants, which delayed the oxidation by 13%.