Modifiers based on natural deep eutectic mixtures to enhance anthocyanins isolation from grape pomace by pressurized hot water extraction

Abstract

Anthocyanins are regarded as treasured compounds due to their potential health claims, as well as their industrial food applications. They are usually found in large quantities in food by-products such as grape pomace. Consequently, research interest has been triggered to the recovery of anthocyanins remaining in grape pomace after winemaking process. In an attempt to find more effective and environmentally friendly extraction procedure, natural deep eutectic solvents (NADESs) have been postulated as modifiers to carry out the anthocyanins extraction by means of pressurized hot water (PHWE). The implementation of pressurized hot water extraction with NADESs as modifiers enhanced significantly the anthocyanins extraction compared to the sole use of hot water extraction. Different NADESs were screened, being choline chloride and oxalic acid (ChOx) as the most promising one. Modifier percentage and extraction temperature were also optimized. The best extraction results were obtained with 30% of ChOx at 60 °C. Therefore, the implementation of PHWE with NADESs opens the feasibility of enhancing extraction efficiency fulfilling with the requirements of a green and sustainable approach.