Optimization of pigment extracting conditions from red raspberry by response surface methodology

To optimize the pigment extracting conditions from red raspberry,response surface methodology was used through fractional factorial design and central composite design based on the single factor experiments.The results showed that the optimal conditons were: ethanol as solvent of 95 % concentration,extraction temperature of 72.4 ℃,extraction time of 60 min,substrate to solvent ratio of 1∶8.5,and pH of 2.0.Under these conditions,extraction rate of pigment reached 98.4 % after twice extraction,and yield of pigment was 5.61 %.pH,extraction temperature and substrate to solvent ratio affected the extraction rate of pigment significantly.