Optimization of Enzyme-assisted Extraction Conditions in Water for Garlic Polysaccharide by Response Surface Methodology and Its Antioxidant Activity Against Oil

In order to improve the garlic polysaccharide extraction yield,the garlic polysaccharide was extracted with compound cellulase and pectinase and the main factors and optimum technological parameters of garlic polysaccharide extraction were studied by single factor experiments,Plackett-Burman(PB)experiment design and response surface methodology. The antioxidative effect of garlic polysaccharide on oil was evaluated by Schaal oven accelerated oxidation method.The results showed that the most significant factors were the extraction time,temperature and the ratio of material to liquid. The Box-Behnken response surface experiment results showed that the optimum conditions for the highest extraction rate of garlic polysaccharide were:The extraction temperature 67.2℃,the extraction time 59.9 min,and the ratio of material to liquid 1:28.8. Under these conditions,the prediction value of the extraction yield of garlic polysaccharide was 33.8%,and after three repeated verification tests,the average garlic polysaccharide extraction yield was 33.6%.The extraction rate of garlic polysaccharide extracted by compound enzyme method increased by 52.1%.The polynomial regression model could be used accurately to predict the extraction rate of garlic polysaccharides.Adding 0.5% of garlic polysaccharide into vegetable oil,the POV value was 10.38 meq/kg,which was 30% of the blank control group after acceleration oxidation of 10 d. It demonstrated that the extracted garlic polysaccharide had significant anti-lipid oxidation effects.