Conventional and ultrasound-assisted extraction of anthocyanins from blackberry and sweet cherry cultivars

Abstract

Blackberry and sweet cherry are important plant foods rich in anthocyanins well-known for their pharmacological and antioxidant effects. The aim of the present paper was to comparatively investigate conventional and ultrasound-assisted extraction procedures in order to isolate an enriched crude anthocyanin extract from blackberry (Thornfree cultivar) and sweet cherry (Black Gold cultivar). Hydroethanolic solution and acidified ethanol were used to conventionally extract anthocyanins by a discontinuous process at 4 degreeC for 2/ 24 hours. Added hydrochloric acid in ethanol of different concentrations proved to be more efficient in both type of samples. In the ultrasound-assisted extraction, the highest recovered anthocyanin content in blackberry (107.81 mg 100 g(-1) FM) was obtained with a 10/1 solvent/solid ratio (v/w) at 30 degreeC for 5 minutes, while a 15/1 solvent/solid ratio (v/w) at 30 degreeC for 20 minutes lead to an increased antioxidant capacity as determined by ferric reducing antioxidant power in the extract using 0.1% HCI in 80% ethanol. The optimum conditions obtained for ultrasound-assisted extraction from sweet cherry in 0.1% HCI in 60% ethanol at 30 degree C include a 15/1 solid/solvent ratio (w/v) and 5 minutes for the maximum yield (36.05 mg 100(-1) FM). The final crude anthocyanin extracts may find useful application as dietary supplements, or may be further purified for application as food ingredients.