Extraction of Soluble Dietary Fiber from Passiflora edulis Peel by Ultrasonic Assisted Enzymatic Method and Its Physicochemical Properties

In order to improve the utilization rate of Passiflora edulis peel wastes,this study using Passiflora edulis peel as raw material,the effects of solid/solvent ratio,enzymatic hydrolysis temperature,ultrasonic power and mixed enzyme content(the ratio of α-amylase to papain was 1:1)on the the yield of passion peel soluble dietary fiber(PSDF)were investigated parameters through single factor testusing. The extraction process was optimized ocombined with orthogonal array. The physicochemical properties of passion peel flour(PPF)and PSDF were evaluated. The results indicated that the optimum conditions of ultrasonic assisted enzyme extraction of PSDF were as follows:Solid/solvent ratio of 1:26 g/mL,hydrolysis temperature of 70℃,ultrasonic power of 250 W,and mixed enzyme content of 0.6%. Under the optimal extraction conditions,the yield of PSDF was 14.82%. Compared with PPF,the swelling property and WHC of PSDF were significantly increased by 52.29% and 19.66%(P<0.01),respectively. The apparent density was decreased by 24.18%(P<0.05). The binding capacity of saturated fatty acid and unsaturated fatty acid were increased by 1.97% and 8.4%(P>0.05),respectively. And the adsorption capacity of cholesterol in simulated gastric environment(pH=2.0)and intestinal environment(pH=7.0)were increased by 16.15% and 10.47%(P<0.05),respectively. The characteristic absorption peaks of two kinds of samples were characterized by infrared spectrum,these two samples were indicative of the presence of the typical structure of polysaccharides.