Optimization of ultrasonic-microwave assisted extraction process of polysaccharide from macadamia green husk and its antioxidant activity
To develop polysaccharide products from macadamia green husk,improve integrated utilization of macadamia green husk,the extraction rate of polysaccharide from different parts of macadamia fruit was com-pared.Effects of microwave power,extraction time,solid-to-liquid ratio and ultrasonic temperature on the ex-traction rate of polysaccharide were compared by ultrasonic-microwave assisted extraction methods using one-factor and orthogonal test to study the best extraction conditions.The scavenging capacity against 1,1-diphen-yl-2-picrylhydrazyl(DPPH)and hydroxyl radicals,and reducing power were investigated to evaluate its an-tioxidant activity by comparing with vitamin C as control.The results showed that the extraction rate of poly-saccharides from macadamia green husk was the highest in different parts of macadamia fruit.Effects of all factors of ultrasonic-microwave assisted extraction process on extraction rate could be ranked from high to low as following:extraction time,solid-to-liquid ratio,ultrasonic temperature and microwave power.There were extremely significant differences among all the factors.The optimal extraction condition was as following:ex-traction time of 90 min,ultrasonic temperature of 65℃,solid-to-liquid ratio of 1:25(g/mL),microwave power of 400 W.Under this condition,the extraction rate of polysaccharide from macadamia green husk was up to 1.96%.The antioxidant activities of macadamia green husk polysaccharide was extremely positive corre-lated to mass concentration(p＜0.01),with correlation coefficients of 0.970 7,0.981 3 and 0.991 2,respec-tively,with strong scavenging capacities against DPPH and hydroxyl radicals and reducing power,and with half maximal inhibitory concentration(IC50)of 38.55,20.38 and 41.51 μg/mL,respectively,which were lower than vitamin C at the same concentration.
macadamia nutpolysaccharide from green huskextractionultrasonicmicrowaveantioxidant activity
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维普
