In the Mediterranean area, grape is one of the main cultivated fruit crops and is mostly used in winemaking, a process that generates large amounts of by-products, mainly consisting of grape pomace. Due to its well-known richness in bioactive compounds and its relevant properties, including strong radical-scavenging power and antimicrobial activity, grape pomace may represent a valuable secondary raw material to be reused as a resource. In the present work, natural deep eutectic solvents (NADESs) were used to extract polyphenols from different varieties of grape pomace collected in Apulia, Italy. After a preliminary HPLC-DAD screening, selected samples were further investigated through LC-QTOF-MS metabolomic characterization. In particular, conventional Sangiovese and organic Merlot grape pomaces extracted with betaine hydrochloride/lactic acid 1:4, mol/mol + 40% water, Bet/LA, and choline chloride/ascorbic acid 2:1, mol/mol + 40% water, ChCl/AA, were analyzed. The results showed that betaine-based extracts, from both cultivars, achieved approximately three-fold higher polyphenol recovery. Further analyses also revealed higher antimicrobial activity and good antioxidant power for these extracts. For this reason, subsequent in vitro digestion experiments were carried out on Bet/LA extracts, with metabolomic profile, antioxidant activity, and total polyphenol content determined in each digestion phase. Glycoside content increased up to the duodenal phase, followed by an enrichment of free polyphenols during the colon phase, probably due to the metabolic activity of lactic acid bacteria. The introduction of Lactobacillus plantarum from the beginning of the experiments significantly reduced the original grape pomace-like polyphenols, while maintaining high antioxidant activity and total phenolic content, suggesting the formation of new probiotic derived compounds. Together with further results from dietary supplementation studies in quails, these findings support the potential use of NADES-based grape pomace extracts in supplement formulations with nutraceutical properties.
NADES-based green extraction of grape pomace polyphenols: a sustainable approach to novel dietary supplements
Roselli, Vincenzo;Leuci, Rosalba;Paparella, Marco;Pugliese, Gianluca;Laghezza, Antonio;Tufarelli, Vincenzo;Gambacorta, Lucia;Piemontese, Luca.
2026-01-01
Abstract
In the Mediterranean area, grape is one of the main cultivated fruit crops and is mostly used in winemaking, a process that generates large amounts of by-products, mainly consisting of grape pomace. Due to its well-known richness in bioactive compounds and its relevant properties, including strong radical-scavenging power and antimicrobial activity, grape pomace may represent a valuable secondary raw material to be reused as a resource. In the present work, natural deep eutectic solvents (NADESs) were used to extract polyphenols from different varieties of grape pomace collected in Apulia, Italy. After a preliminary HPLC-DAD screening, selected samples were further investigated through LC-QTOF-MS metabolomic characterization. In particular, conventional Sangiovese and organic Merlot grape pomaces extracted with betaine hydrochloride/lactic acid 1:4, mol/mol + 40% water, Bet/LA, and choline chloride/ascorbic acid 2:1, mol/mol + 40% water, ChCl/AA, were analyzed. The results showed that betaine-based extracts, from both cultivars, achieved approximately three-fold higher polyphenol recovery. Further analyses also revealed higher antimicrobial activity and good antioxidant power for these extracts. For this reason, subsequent in vitro digestion experiments were carried out on Bet/LA extracts, with metabolomic profile, antioxidant activity, and total polyphenol content determined in each digestion phase. Glycoside content increased up to the duodenal phase, followed by an enrichment of free polyphenols during the colon phase, probably due to the metabolic activity of lactic acid bacteria. The introduction of Lactobacillus plantarum from the beginning of the experiments significantly reduced the original grape pomace-like polyphenols, while maintaining high antioxidant activity and total phenolic content, suggesting the formation of new probiotic derived compounds. Together with further results from dietary supplementation studies in quails, these findings support the potential use of NADES-based grape pomace extracts in supplement formulations with nutraceutical properties.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
