Study on the Optimization of Water-alcohol Extraction Process of Chlorogenic Acids from Yunnan Green Coffee Beans by Response Surface Methodology

Nine chlorogenic acid isomers were extracted from Yunnan Catimor green coffee beans by water-alcohol extraction method. Single factor experiments were carried out to study the material number,ratio of liquid to material, water extraction temperature, extraction time, alcohol concentration and alcohol extraction temperature, and response surface design was used to optimize the water alcohol extraction process. The results showed that the extraction rate of water-alcohol extraction method (5.21%) was significantly higher than that of water extraction method (4.29%)；The alcohol concentration and the ratio of liquid to material had significant influence on the extraction rate of chlorogenic acids (P ≤ 0.01). The optimum extraction conditions of chlorogenic acids isomers by water-alcohol method optimized by single factor and response surface were: alcohol extraction temperature of 60 ℃, extraction time of 11.67 min,material mesh of 60, liquid to material ratio of 16.07, alcohol concentration of 20.16%, the extraction rate of chlorogenic acid isomers were of 5.31%.