Ultrasonic-assisted Acidification Methanol Extraction of Anthocyanins from Sweet Cherry Fruit and Its Antioxidant Activity

To explore method of extracting anthocyanins, the ultrasonic-assisted acidified methanol method was used to extract anthocyanins of sweet cherry fruit in this study. The effects of methanol concentration, solid-liquid ratio, ultrasonic temperature and ultrasonic time on sweet cherry anthocyanin yield were investigated. The antioxidant activity and stability of anthocyanins were evaluated. Results showed that optimal extraction of sweet cherry anthocyanins was achieved with the following conditions: methanol concentration of 90%, solid-liquid ratio of 1:20, ultrasonic temperature of 35 ℃, ultrasonic time of 10 min, and the anthocyanin content obtained under these conditions was (61.48±0.81) mg/100 g. Conditions of darkness, 20 °C, and pH1.0 enhanced the stability of sweet cherry anthocyanins. The thermal degradation of cherry anthocyanins followed the first-order reaction kinetic model. The antioxidant capacity of cherry anthocyanins was evaluated by DPPH、ABTS⁺ and ·OH radical scavenging test. The results exhibited that cherry anthocyanins had significant scavenging effects on DPPH, ABTS⁺, and ·OH radicals. When the maximum mass concentration was 120 μg/mL, the scavenging rates respectively were 69.64%, 47.94%, 55.01%, thus demonstrating antioxidant activity.