Extration, identification and stability ananlysis of anthocyanins from organic Guizhou blueberries in China

Guizhou Majiang organic blueberries from China are a prevalent fruit in the health industry and have high anthocyanin contents. This study used the ethanol extraction method, ultrasonic-assisted extraction, AB 8 macroporous resin adsorption purification, and the addition of 3% citric acid to extract anthocyanins, and through single-factor tests and orthogonal tests, the optimum extraction conditions of anthocyanins from blueberries was determined. The optimal extraction conditions were as follows: the extraction temperature was 40 °C, the ethanol volume fraction was 80%, the solid-liquid ratio was 1:10, the ultrasonic extraction time was 60 min, and the extraction amount was 2.56 mg/g. Anthocyanins were identified by HPLC, and the effects of storage conditions on their contents were investigated. K+, Cu2+, and Fe2+ had little influence on anthocyanin contents, while hydrogen peroxide had a highly destructive effect. With increasing illumination time, the retention rate of anthocyanins decreased gradually; the higher the temperature was, the stronger the damaging effect on anthocyanin contents, and the appropriate storage temperature was determined to be -4 °C or below. The absorbance was the highest when pH =2. Taken together, the results of our study revealed the optimal extraction process and appropriate preservation conditions of anthocyanins from organic Guizhou blueberries.