Volatile Compounds in Merlot Wine Pomace Extract Obtained by Supercritical Fluid Extraction

The valorisation of grape pomace, a major by-product of winemaking, presents both an environmental challenge and a resource opportunity.This study investigates the volatile compounds present in Merlot grape pomace extracts obtained by supercritical fluid extraction (SFE) using carbon dioxide as solvent.Extracts from whole grape pomace, seeds and skins were analysed.Volatile compounds were collected by headspace solid-phase microextraction (HS-SPME) and analysed using gas chromatography-mass spectrometry (GC-MS).A total of 29 different volatile compounds were identified across the three extracts, of which 11 were common to all fractions.The volatile profiles were dominated by alcohols, followed by esters, while carboxylic acids, ketones, and terpenoids were also detected.Butane-2,3-diol was the major constituent in terms of chromatogram peak area, followed by 2-phenylethanol and various esters.Many of the identified volatile compounds are recognised for their sensory and bioactive properties, possessing proven antioxidant, antimicrobial, and anti-inflammatory effects, making them of interest to the food, cosmetics, and pharmaceutical industries.The results of this study confirm the effectiveness of supercritical fluid extraction in recovering a broad range of volatile compounds from Merlot grape pomace, underscoring its value as a sustainable feedstock rather than agricultural waste.However, due to the limited efficiency of supercritical fluid extraction in mobilising polar compounds when carbon dioxide is used as the sole solvent, additional extraction strategies are required for more comprehensive pomace valorisation.This research supports the potential integration of grape pomace extracts into bio-based industry applications, contributing to the transformation of waste into value-added products.