Recovery of phenolic compounds from wild bilberry, blackcurrant and blackberry pomaces by maceration and ultrasound-assisted extraction

Wild bilberry, blackcurrant and blackberry fruit pomaces obtained after industrial juice processing were extracted in water, 1% citric acid, 40%, 60% and 80% (v/v) aqueous ethanol using two extraction methods: maceration and ultrasound-assisted extraction.The total phenolics content (TPC), total anthocyanins content (TAC), and DPPH radical scavenging activity (RSA) were quantified in the extracts.TPC was about 2.3-3.2 times higher in ethanolic extracts as compared with the water extracts.The extracts made in 60% aqueous ethanol showed the highest values of TPC, TAC and RSA irrespective of extraction method and pomace matrix while water and 1% aqueous citric acid were very little effective in recovering anthocyanins and phenolic compounds.Bilberry pomace extracts made in 60% ethanol using maceration presented the highest TAC (585.21 mg CGE/L), TPC (3381.82mg GAE/L) and RSA (2.05 mmol Trolox/l).The results showed that bilberry, blackcurrant and blackberry fruit pomaces can be a valuable source of bioactive compounds to be used in food supplements and functional foods.