Extraction And Purification Technology Research Of Laminaria Gel

Laminaria jiaponica was a large seaweed with edible and medicinal value, it was abundant in biological active components which was directly related to the function of health care.The purposes of this paper were to optimise the extration conditions, determine the pHysical and chemical properties, come to understand the bioactive functions of algin, provide the basic datas for the comprehensive development and utilization of algin.The study selected pH,extract temperature,and extract time as the influencing factors, builds the corresponding two-order polynomial equation by Box-Behnken experiment design method.obtained the optimum extract conditions and other results:The main research contents and results were as follows:(1) The optimum extract conditions were: pH5.6, temperature 55℃,extract time 2h and solid-liquid ratio 1:60. the highest extraction yield of alginate in the optimum condition was 27.56%,under the same conditions, the extraction yield of fucoidan was 4.3%.(2) The crude algin extrated from Laminaria jiaponica were purificated by DEAE-52 cellulose ion exchange column through elution,obtained two components L1, L2.the L2 was proved to be the algin single component after elution by G-75 gel column chromatograpHy .the sulfate and uronic acid content of algin were 26.67% and 38.23% respectively throuhg the measurement by barium sulfate turbidimetry and a sulfuric acid carbazole.(3) The alginate was found to be a typical pseudo-plastic fluid by rheometer scan experiment,the viscosity of alginate decreased with the shear rate increased,turned out to be shear-thinning pHenomenon.(4) The apparent viscosity of the storage modulus (Storage Modulus) G 'and loss modulus (Loss Modulus) G showed that the critial elastic change value of alginate was 55℃.when the temperature reached 63℃alginate solution began to show the characteristics of the solid type.therefore the apparent viscosity had a great depend on temperature.(5) The study of molecular weight and intrinsic viscosity showed that the alginate intrinsic viscosity and molecular weiht of alginate were 0.7136 and 8940Da in the condition of 0.1molNaCl,the molecular weight determined by high performance liquid chromatograpHy was 9034Da which was closed to the result abtained by intrinsic viscosity ways. The result proved that the enzymatic extractions can abtain the low molecular weight alginate.(6) According to infrared spectroscopy, the sodium alginate and fucoidan contain hydroxyl, carboxyl and pyranose, fucoidan contains a lot of sulfate sodium, and alginate molecule contained a large number of -COO- and OH group.αandβglucosidic bonds were co-exist in sodium alginate,but onlyβglucosidic bond was found in fucoidan.(7) In vitro antioxidant study found that both sodium alginate and fucoidan had significantly inhibited on hydroxyl radical superoxide anion radical and lipid peroxidation.espasically the alginate had best effectiveness of scavenging hydroxyl radical,the concentration of alginate 22.03mg/mL could reached 58.78%,while the same concentration of fucoidan had a good inhibition on the superoxide anion radical, lipid peroxide free,the inhibition ratio were 38.19% and 57.01% respectively the result came to conclusion that Laminaria japonica gum was a good free radical scavenger which could inhibit free radical effctively.