Advanced Extraction of Blackcurrant Pomace Polyphenols: Chemical Characterization and Biological Insights

This study evaluated the efficiency of advanced extraction techniques for recovering polyphenols from blackcurrant pomace (BP), with particular emphasis on anthocyanins. Pressurized liquid extraction (PLE), microwave-assisted extraction (MAE), ultrasound-assisted extraction (UAE), and the use of cryogrinding (CG) as a pretreatment were investigated under selected experimental conditions and compared with the conventional extraction technique (CT). Among the investigated extraction techniques, UAE provided relatively high anthocyanin recovery, while CG significantly enhanced extraction efficiency. Under the investigated conditions, CT yielded the highest total phenolic content (TPC) among the extraction techniques compared, but not the highest total monomeric anthocyanin content (TMAC), whereas CG combined with UAE (CG + UAE; 2 min CG, 75% amplitude, 5 min, 1:60 g/mL) provided a favorable balance between TPC and TMAC. UPLC–ESI–MS2 profiling confirmed high recovery of delphinidin- and cyanidin-based glycosides, flavonols, phenolic acids, and flavan-3-ols. The optimized extract showed strong antioxidant capacity in FRAP, DPPH, ABTS, and ORAC assays. Zebrafish embryotoxicity and cell-based assays showed concentration-dependent effects, indicating that further assessment is needed before conclusions regarding extract safety can be drawn. Overall, CG + UAE showed potential for improving the recovery of bioactive compounds from BP under the investigated conditions.