Recovery of anthocyanins from residues of Rubus fruticosus, Vaccinium myrtillus and Eugenia brasiliensis by ultrasound assisted extraction, pressurized liquid extraction and their combination

- Extracts from blackberry, blueberry and grumixama residues are obtained by PLE and UAE.
- The combination of UAE and PLE improves the extraction of total phenolic compounds.
- GY, TPC, MAC and AC of the extracts vary with the solvent and extraction method.
- The extracts contain anthocyanins, identified and quantified by UHPLC.
- There is high correlation between phenolic content and antioxidant capacity of the extracts.

This work investigated the extraction efficiency of polyphenols (anthocyanins) from blackberry, blueberry and grumixama residues using combined ultrasonic assisted extraction (UAE) and pressurized liquid extraction (PLE) (UAE + PLE). The performance of UAE + PLE was compared to those achieved by the isolated PLE and UAE methods and conventional Soxhlet extraction. The effects of the extraction methods and solvents (acidified water pH 2.0, ethanol + water 50% v/v and ethanol + water 70% ethanol v/v) on total phenolics content, anthocyanin composition and antioxidant capacity of extracts were investigated by a full factorial design. The extraction efficiency for total phenolics and antioxidant capacity in decreasing order was: UAE + PLE > PLE ≈ Soxhlet > UAE, and for anthocyanins it was: Soxhlet ≈ UAE > UAE + PLE > PLE, using hydroethanolic mixtures as solvents. Extractions with acidified water and ultrasound were not effective to recover phenolics. Two, four and fourteen anthocyanins were identified in the extracts from grumixama, blackberry and blueberry, respectively.