UPLC-ESI-MS/MS-based chemometric approach for investigating the effect of conventional versus modern extraction methods on polyphenols recovery from grape seed wastes.

Grape seed wastes are a rich source of bioactive polyphenols. This study compares the recovery efficiency of traditional maceration extraction (ME) with modern extraction techniques (ultrasound-assisted extraction (UAE), microwave-assisted extraction (MAE), and accelerated solvent extraction (ASE)), revealing the selective extraction of polyphenolic compounds by different methods. UPLC-ESI-MS/MS analysis was used to identify and quantify 24 polyphenols. ASE showed the highest efficiency for phenolic acids (e.g., gallic acid, 231.75 μg/g) and proanthocyanidins (e.g., procyanidin B1, 126.18 μg/g), while MAE was optimal for flavonoids recovery (e.g., myricetin, 41.52 μg/g). Multivariate chemometric analysis revealed co-extraction patterns among structurally related compounds (e.g., flavan-3-ols with galloylated derivatives), linking extraction parameters to the selectivity of polyphenols. Integrating UPLC-ESI-MS/MS profiling of 24 polyphenols, we suggest that MAE/ASE is most suitable for antioxidant-rich nutraceuticals, while ME is optimal for thermally labile pharmaceuticals. This study provides practical strategies for the sustainable utilization of grape seed by-products, offering industry-specific solutions to reduce waste and improve the recovery of bioactive compounds.