Study On The Preparation Of Ulva Lactuca L Soluble Dietary Fiber And The Product’s Related Properties

In this study,the cellulose enzymatic method was adopted to extract soluble dietary fiber(SDF)from raw material of Ulva lactuca L and the effect of main factors on extraction rate of U.lactuca SDF were studied.The response surface methodology(RMS)was applied to optimize the key parameters of extracting process.The protein was removed from U.lactuca SDF by ultrasound-assisted enzymatic method and the key technological conditions of deproteinization were optimized through the orthogonal test of L9(34)design.In addition,the related physico-chemical properties and hypoglycemic activities in vitro of deproteinization and without deproteinization of U.lactuca SDF were analyzed and discussed.The specific results showed as follows:(1)Study on the technology of cellulose enzymatic extracting SDF from U.lactuca LSDF was extracted from U.lactuca L by cellulose enzymatic method.The effect of enzyme hydrolysis conditions on U.lactuca SDF extraction rate were investigated through the single factor experiments,and the enzymatic extraction technology of U.lactuca SDF was optimized by response surface methodology(RMS).The results showed that the optimized technological parameters combinations of the enzymatic extraction of U.lactuca SDF were:cellulase dosage 670 U/g U.lactuca,pH of enzymatic solution 6.0,solid-to-liquid ratio 1:35(g/mL),enzymolysis time 2.0 h.Under this condition,the maximum extraction ratio of U.lactuca SDF was 14.05%.(2)Study on the technology of deproteinization of the U.lactuca SDF by ultrasound-assisted enzymatic methodThe protein was removed from crude U.lactuca SDF by ultrasound-assisted enzymatic method.The effects of alkaline proteinase dosage and its enzymolysis processing parameters on protein removal rate and SDF retention rate were mainly studied.L9(34)orthogonal experiment design was adopted to optimize key technology parameters of deproteinization of U.lactuca SDF by ultrasound-assisted enzymatic method.The results showed the optimized key technology parameters of deproteinization of U.lactuca SDF by ultrasound-assisted enzymatic method were as follow:alkaline proteinase dosage 1400 U/g,U.lactuca SDF solution pH 11.0,ultrasonic temperature 50℃,ultrasonic time 1.5 h.The verification experiments had been carried out under these conditions with other ideal factors,and the protein removal rate of U.lactuca SDF was(83.91±0.18)%and the retention rate of U.lactuca SDF was(86.23±0.25)%,which were higher than the nine orthogonal experiment groups respectively.(3)Study the effect of deproteinization treatment on related properties of U.lactuca SDFThe U.lactuca SDF of deproteinization and without deproteinization was taken as materials to determinate and contrast their hydration properties,the rheological properties,the adsorption capacities of oil and cholesterol in vitro,the inhibitory activities of alpha glycosidase enzyme and alpha amylase.The results showed hydration properties,rheological properties and the oil adsorption capacities in vitro of the U.lactuca SDF of deproteinization were extremely significant(p<0.01)better than without deproteinization samples.However,the cholesterol adsorptive abilities and hypoglycemic activities of U.lactuca SDF were significantly stronger than it’s deproteinization samples(p<0.01).