Enhancing Anthocyanin Bioavailability Unlocks the Cardiovascular Potential of Grape Pomace: A Review

Grape pomace (GP) is a major byproduct of the wine industry, rich in bioactive compounds such as polyphenols, anthocyanins (ACYs), and fiber, all of which have important functional properties. GP is composed of stalks, seeds, and skins. ACYs, a major component of GP, are key contributors to its functional properties, particularly in supporting cardiovascular health. However, a significant challenge with ACYs is their limited stability and bioavailability. This review explores the chemistry, extraction, and purification of ACYs, primarily from GP, where they are often bound within the plant cell wall. The cell wall matrix hinders the release and absorption of ACYs in the gastrointestinal tract, resulting in low natural bioavailability. Nonthermal extraction techniques designed to liberate ACYs from this matrix are highlighted for their potential to enhance bioavailability. The review also discusses encapsulation methods and novel approaches such as electrospinning, which may further improve ACY stability and controlled release. In addition, the antioxidant and anti-inflammatory effects of GP, its influence on short-chain fatty acid production, and findings from recent in vitro, in vivo, and human studies are summarized. Finally, the potential mechanisms by which ACYs in GP may benefit cardiovascular health are explored. Nevertheless, further research is needed to clarify the specific metabolites, underlying mechanisms, and unique properties of ACYs found in GP.