Natural antioxidant of rosemary extract used as an additive in the ultrasound-assisted extraction of anthocyanins from lingonberry (Vaccinium vitis-idaea L.) pomace

Abstract

The effects of natural antioxidant rosemary extracts with different carnosic acid concentrations (30%, 60%, and 90%) and of three synthetic antioxidants in the extraction of anthocyanins from lingonberry (Vaccinium vitis-idaea L.) pomace under ultrasound irradiation conditions were compared. The optimum extraction conditions were selected: antioxidant rosemary extract with carnosic acid of 30% (purity), 0.02% (carnosic acid to lingonberry pomace sample mass ratio); ethanol volume fraction, 40%; pH 1.5; liquid–solid ratio, 20 mL/g; ultrasound frequency, 80 kHz; ultrasound irradiation power, 170 W; reaction temperature, 55 °C; and ultrasound irradiation time, 35 min. Compared with traditional extraction techniques (no addition of rosemary extract), we obtained satisfactory yields of anthocyanins of 4.12 ± 0.18 mg/g (cyanidin-3-galactoside yield of 3.36 ± 0.14 mg/g, cyanidin-3-glucoside yield of 0.15 ± 0.01 mg/g and cyanidin-3-arabinoside yield of 0.61 ± 0.03 mg/g). The supplement of natural antioxidant rosemary extract was first added to inhibit the oxidation of anthocyanins, and the proposed natural antioxidant rosemary extract exhibited potential to replace synthetic antioxidants with greater security.