Bioprocessing of Grape Pomace for the Development of a Nutraceutical Formulation: Bridging Winemaking By-Products and Functional Innovation

Grape pomace, the main by-product of winemaking, represents a promising source of anthocyanins for sustainable food applications. This study reports their low-impact aqueous extraction, yielding a two-step isolation of malvidin 3-O-hexoside (94% purity) characterized by spectroscopic and mass spectrometric analyses. The pure molecule was embedded into a jelly candy to develop a nutraceutical prototype, whose colorimetric analysis revealed a stable red hue. The jelly showed time-dependent release of the anthocyanin and strong antiradical capacity. The in vitro digestion confirmed 37% release in the oral phase, 55% in the gastric phase, and complete degradation in the intestinal phase, offering key insights for developing a further advanced strategy to enhance the bioaccessibility throughout the entire gastrointestinal tract. A consumer test (n = 116) indicated good acceptability, particularly among younger and more experienced supplement users. Overall, the study contributes to circular economy strategies towards a more resilient, responsible, and sustainable production system.