Study On Protein Extraction From Kelp And Its Physicochemical Properties

China, as the largest producer of kelp, though kelp was widely used in food,utilization of kelp was only stay on the stage of primary product, further processing ofkelp is basically a blank in China. At present, there are a lot of kelp processingenterprises, but they are mainly extract alginate and iodine, mannitol from kelp.Theremaining of kelp which still containing a lot of useful content(protein, fiber, and so on)is throwed away. It not only wastes a lot of natural resoulces，but also bring a series ofenvironmental problems.So it was necessary to strengthen the study of kelp,to carry onmulti-level development and utilization of kelp and improve its economic value.Kelp is large edible perennial brown algae, containing little calorie, some protein,much mineral, and is an economic algae liked by people of China, Japan, Korea, andother oriental countries. Studies have shown that, kelp has the biological functions oflowering blood lipid and blood sugar, adjusting immunity, anticoagulant, antitumor,antioxidant and so on. In recent years, people around the world attached greatimportance to the study on health function of kelp. The most studied aspects of kelpwere polysaccharide iodine and dietary fiber, while there were little report about proteinin kelp.In this paper, kelp proteins were prepared from kelp powder, and their functionalproperties and bacteriostatic activity, the major finding result were as follows:(1) This paper first analyzed the component characteristics of kelp, and foundthat glutelin content (5.8%) is largest, followed by globulin (4.9%)，content ofprolamine and albumin is lower,3.2and1.9, respectively. According to thecharacteristics of protein, alkaline method assisted by cellulose was employed to extractprotein from kelp. Effects of ratio of water to stuff, pH, extraction time, extractiontemperature, and the enzy me additive amount on protein extraction was studied.Orthogonal test were employed to optimize the extraction technique. The optimumconditions for enzymatic extraction were as follows: ratio of water to stuff75:1, pH11,extraction time5hours, cellulase additive amount320u/g. The influencing factors haddifferent effects on protein extraction in the following order: ratio of water to stuff>enzyme additive amount> pH> time. And then using response surface method test toget a optimized parameters of pH, enzyme additive amount, time, and the result waspH11, enzyme additive amount335u/ml, extraction time5h. By all the experimentwecan get that,the best extraction parameters were temperature50℃, ratio of water to stuff 75:1, pH11, extraction time5h, enzyme additive amount335u/ml.(2) Based on kelp protein prepared in our own lab, its functional properties(including solubility, water and oil holding capacity, emulsifying and foamingproperties) were determined under different pH.(3) Distribution of kelp protein molecular weight was determined bypolyacrylamide gel electrophoresis.Kelp protein was preliminarily separated bySephadex G-75gel chromatography filtering, and four peak were got. The two peak gotfirstly were large and overlapped. The last peak got later was small, which were someprotein of large molecular weight. The protein of peak were collected and for the nextuse. protein purification system were used to separated the sample,and found that,everyprotein peak also contained a variety of protein.(4) By MIC experiment, we can get that minimum inhibitory concentration of kelpprotein to Escherichia coli, Staphylococcus aureus and Pseudomonas were15mg/mL,10mg/mL,10mg/mL, respectively. Antibacterial effect of kelp protein was also studied,and found that the best inhibitory concentration of kelp protein to Escherichia coli,Staphylococcus aureus and Pseudomonas was90mg/ml,80mg/ml and80mg/ml,respectively.