Studies On Extraction And Properties Of Konjac Flying Powder Protein

Our country annual output of konjac flying powder is 1500～2000 tons,the crude protein content between 15%and 21%.Now konjac flying powder is mainly used as cheap feed or desiccant,has low utilization.At present,there is no systematic study on extraction and functional properties of konjac flying powder protein.In this paper,with konjac flying powder as the raw material,extracting protein and determining the optimum extraction conditions.Then the konjac flying powder protein physicochemical properties and optimum enzyme solution process conditions had been studied.Specific conclusions were as follows:1、The optimum extraction condition of konjac flying powder protein was:the extraction temperature 40℃,the extraction time 40 min,pH 10.0,the ratio of solid and liquid 1:30.At this condition,the rate of extraction was 36.59%,the protein purity was 74.73%.By the experiment of SDS-PAGE electrophoresis,the molecular weight distribution of konjac flying powder protein was 17～26 kDa.2、The studies on physicochemical properties showed that the NSI of konjac flying powder protein was reasonably maintain at about 60%.The protein FA could reach 61.50%,the FS could reach 74.36%.When pH9,temperature 40℃,NaCl concentration 0.1 mol/L,protein concentration 3%respectively,the emulsibility reached the highest level,and the ES average 43.62%.The WHC average 2.33%.The fat absorption capability decreased with temperature rise.The protein moisture regain and moisture retaining quality were poor.The gel strength and protein consistency were good.3、The results of konjac flying powder proteolysis by ultrasonic treatment:Choosing alkaline protease as the optimum protease from six kinds of protease to hydrolyze konjac fly powder protein.Ultrasonic preteatment was the best pre-processing method.Degree of hydrolysis(DH)was taken as index,the optimum condition of ultrasonic pretreatment by BBD test was as follows:ultrasonic temperature 60℃,ultrasonic time 40 min,ultrasonic power 200W.Proteolysis process condition was:substrate concentration 2%,pH 8,dosage of alkaline protease was 3000U/g protein,temperature 60℃,proteolysis time 2h.At these conditions,the DH was 21.93%.The optimum condition of ultrasonic assisted synchronous proteolysis was as follows:ultrasonic temperature 70℃,ultrasonic time 80 min,ultrasonic power 200W,enzyme concentration 3000 U/g.In this condition,the DH was 21.38%.The DH of two kinds of ultrasonic assisted proteolysis methods was higher than un-ultrasonic proteolysis.