Technology Research On Extraction And Seperation Of Fucoidan From Fermentation Of Kelp

This thesis summarized the extraction methods of fucoidan. Based on this, a novel procedure, solvent extraction, was put forward to extract and purify fucoidan from kelp fermentation. Kelp waste generated during the extraction was used to yield water insoluble dietary fiber, which is accord with green chemical industry. Phenol-sulfuric acid procedure and HPLC analysis was established to detect the content of polysaccharides. The thermodynamic and kinetic parameters were studied during the extraction process. The extraction progress of dietary fiber was optimized.The optimum reagent ratio of phenol-sulfuric acid method was 2:5:1(raw material/sulfuric acid/phenol), and color reaction was steady within 70 min. Fucoidan was hydrolyzed at 60℃ with 0.0050 M sulfuric acid for 3 h, then the L-fucose content was detected by HPLC.CS2, 50% amines+50% A1416, was chosen as extracting reagent. Raw material was extracted at 20℃ for 5 min with stirring speed 500 r/min, and its concentration was 0.3430 g/L. The p H and phase ratio was 0.46 and 5:2 respectively. Under this condition, 8 stages countercurrent extraction was conducted and total extraction rate was 95%. Then the saturated organic phase was used to separate fucoidan and its concentration was 0.4461 g/L. The saturated organic phase was back extracted at 60℃ for 5 min with stirring speed 700 r/min, the phase ratio was 1:1. After 8 stages countercurrent back extraction, the total back extraction ratio was 90%. The product was analyzed by FT-IR, and the spectrum proved it was fucoidan.Lewis cell was used to investigate the kinetics of extraction reaction. The reaction coefficient of fucoidan and extraction reagent was 1:1, extraction rate equation was R =5.408[P], apparent activation energy was 13.47 KJ/mol. The reaction was controlled by diffusion step, and was adapted to interface reaction model. Stirring speed and mass transfer coefficient was in line with 4K1.13 10 r 0.01986-= ′ +, temperature and mass transfer coefficient was in line with 4K5.066 10 T 0.18719-=- ′ +.The dewatering rate of kelp dregs was fitting by Cubic model, and the equation was in line with 3 2 tX =1.0187 t -15.2708 t +73.4104 t -16.0978, which means 3 h was enough for drying process. Kelp dregs were then digested by Na2CO3(20 g/L) at 80℃ for 12 min, while the solid-liquid ratio was 1:100(g/m L). Under such conditio, the digestibility was stable between 75-80%. After digesting, kelp residue was two-step bleached. Firstly bleached at 80℃ by H2O2(6%, p H 6.0) for 2 h, while the solid-liquid ratio was 1:75(g/m L). Then the solution bleached another 2 h after new H2O2(30%, 3 m L) was added. After digesting and bleaching, the product was creamy white and mainly composed by dietary fiber(80.53%). Wate holding capacity was 643.17%, expansion force was 1.50 m L/g and bulk density was 0.1672 g/m L.