Optimization of Extraction of Proanthocyanidins from Skin of Red Locus Seed Using Response Surface Methodology

The extraction of proanthocyanidins from skin of red locus seed were investigated by the single experiments and response surface methodology.The single experiments were used to explore the effects of different extractant,extractant concentration,different acid,pH,liquid-to-material ratio,extraction temperature,extraction time and extraction times on the yield of proanthocyanidins.The best extraction temperature,extraction time and extraction times were determined as 40 ℃,90 min and one time,respectively.Then the extraction pH,liquid-to-material ratio,and acetone concentration were investigated through response surface experiment.Based on the regression analysis,the extractive conditions were optimized as follows: pH 2.6,liquid-to-material ratio 55 mL/g and acetone concentration 67%.The extraction rate of proanthocyanidins of this optimized procedure reached 9.57 %.