Combining eutectic solvents and food-grade silica to recover and stabilize anthocyanins from grape pomace

Concentrated in the skins of red grapes are the anthocyanins, the primary colorants responsible for the fruits' reddish-purple color. These colorants are recognized for their significant antioxidant properties and potent nutraceutical and pharmaceutical ingredients. Nevertheless, their widespread use is compromised by the (i) need for more efficient yet sustainable downstream processes for their recovery and (ii) by the challenges imposed by their poor stability. In this work, these drawbacks were overcome by applying eutectic solvents and stabilizing agents. Besides, the anthocyanins were successfully loaded into a solid host material (approved in both food and pharmaceutical sectors) based on silicon dioxide (SiO₂, loading capacity: 1_extract:7_silica m/m). Summing up, with the process developed, the extraction yield (21 mg_anthocyanins.g_biomass^-1) and the stability (under 55, 75, and 95 °C) of the recovered anthocyanins were over three times better than with the conventional process. Finally, the raw materials and solvents were recycled, allowing an economical and environmentally friendly downstream process.