Optimization of Polysaccharide from Okra by Slowfreezing-Microwave Assisted Extraction Method and Its Hypoglycemic Activity

Slow freezing-microwave assisted extraction optimized by single factor experiment and response surface methodology was implemented to extract polysacchrides from Okra. To explore the hypoglycemic effect of okra polysaccharides,the inhibitory effects on the activities of α-glycosidase were studied by the colorimetry of pNPG,the effects on blood glucose were studied in adrenaline-induced hyperglycemia model mices.Results showed that the optimal conditions were slow freezing time 16 h,liquid-solid ratio 40:1 (mL/g),extracting time 2.2 h,extracting temperature 65 ℃,microwave power 310 W.Under these conditions,the extraction rate of polysaccharide was 17.17%,which was significantly higher than a single extraction process. The polysaccharides from Okra could significantly inhibited the activity of α-glucosidase,the inhibition rate was 68.26% at 10 mg·mL^-1;and significantly reduced the blood glucose level of adrenaline-induced hyperglycemia mices(P<0.01). The extraction rate of okra polysaccharides was improved by slowfreezing-microwave assisted extraction method.Okra polysaccharides had better potential for the hypoglycemic effect,and might be developed to prevent and treat diabetes.