Effect of thermosonication treatment on blueberry juice quality: Total phenolics, flavonoids, anthocyanin, and antioxidant activity

Abstract

To investigated the effects of thermosonication (TS) on blueberry juice quality. The raw juice (RJ), pasteurized juice (60 °C, 30 min, PJ), and TS treated juice (20 kHz, 200 W, 400 W, and 600 W at 60 °C for 15 min, TJ) were analysed for colour characteristics, total antioxidant contents, antioxidant capacity, and composition of anthocyanins. Results showed that TS treated juice had higher colour density (CD), L*, and ΔE values and lower values of chroma (C), hue angle (h), yellow index (YI). The content of total phenolics, flavonoids, and anthocyanins, were increased by 139.32%, 251.72%, and 94.12%, respectively, in TJ600 sample compared to the RJ samples. The 1,1-diphenyl-2-picrylhydrazyl (DPPH) and hydroxyl radical (▪OH) scavenging capacity were increased to 65.22%, 51.13%, significantly higher than PJ sample. The content of delphinidin-3-O-glucoside (Dp-G) and cyanidin-3-O-glucoside (Cy-G), were 54.40 mg/L, 28.75 mg/L in juice. Correlation analysis indicated that the antioxidant contents play an important role in CD, and Cy-G determines the brightness or darkness of the juice. Collectively, the findings suggested that TS could be a feasible alternative to pasteurization for improving the quality and antioxidant activity of blueberry juice.