Optimization of extraction process of proanthocyanidins from Zijuan tea ( Camellia sinensis var. kitmaura ) by response surface design

Abstract

In order to broaden the application field of proanthocyanidins (PCs) from Zijuan tea, it is necessary to establish an environmental and economic extraction method of PCs from Zijuan tea. Based on the single-factor experiment, Box-Behnken response surface methodology was used to study the effects of solid–liquid ratio, the concentration of citric acid solution, ultrasonic power, ultrasonic time, and ultrasonic temperature on the yield of PCs from Zijuan tea. The results showed that the optimum extraction conditions were as follows: 1:35.3 (m/V) solid–liquid ratio, 0.08% citric acid solution, 233.0 W ultrasonic power, 64.0°C ultrasonic temperature, and 48.6 min ultrasonic time. Under these conditions, the yield of PCs was 5.18 ± 0.13 mg/g. Meanwhile, the half inhibitory concentration (IC50) of PCs on 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) and hydroxyl radical (·OH) were 0.5417 and 0.4825 mg/mL, respectively; antimicrobial activity of PCs on several strains tested showed antimicrobial effect as follows: Bacillus subtilis >Staphylococcus aureus >Escherichia coli >Saccharomyces cerevisiae. Therefore, the results provided a theoretical basis for the application of PCs in food development. Novelty impact statement The extraction conditions significantly affected the yield of proanthocyanidins (PCs) from Zijuan tea. While Zijuan tea extracted with 0.08% the citric acid solution (1:35.3 [m/V] solid–liquid ratio) and ultrasonic instrument (233.0 W ultrasonic power, 64.0°C ultrasonic temperature, and 48.6 min ultrasonic time) could be used as a potential food additive, exhibiting a promising antioxidant potential for food product applications.