Study On Extraction And Purification Of Phycocyanin From Spirulina Platensis And It's Application

China has the largest cultivation area of Spirulina and the largest production of Spirulina platensis(Arthrospira).Among them,Spirulina platensis is one of the most important breeding species and also the main commercial production species.Phycocyanin is an important active substance in Spirulina platensis(Arthrospira platensis).Phycocyanin is a precious natural blue pigment with high added value.How to extract and purify phycocyanin efficiently and conveniently is still a technical problem to be solved in industrial production.Therefore,this study mainly discussed the crushing extraction methods of phycocyanin from Spirulina platensis and the purification of phycocyanin in order to obtain better extraction efficiency and product purity.The research contents and experimental results were as follows:Comparisons were made between high-speed homogenization(SH),ultrasonic fragmentation(U),repeated freeze-thaw(F),high-pressure microjet homogenization(PH)and enzymatic treatment(E)on the cell fragmentation and phycocyanin release of Spirulina platensis.The results showed that PH>SH>U>F>E.The high-speed homogenization method has better effect on breaking spirulina cells and higher yield of phycocyanin.The effects of various factors on the yield and purity of phycocyanin extracted by high-speed homogenization were discussed.The optimum extraction conditions were determined by single factor and orthogonal test.The results showed that the highest yield of phycocyanin was 157.75 mg/g using PBS buffer at pH 7.0.The yield of phycocyanin reached 213.32 mg/g when the amount of solvent added was 20 times as much as spirulina powder and treated with high-speed homogenate for 40 minutes,three times at 30'C.The results show that ammonium sulfate precipitation method is better than ethanol precipitation method and acid precipitation method.50%ammonium sulfate precipitation can make the recovery of phycocyanin 97.10%and the purity of phycocyanin up to 1.0.Phycocyanin was recovered by fractional salting-out with 20%ammonium sulfate and 50%ammonium sulfate,The results showed that 80%of the phycocyanin could be recovered and the purity of the phycocyanin could reach 2.3 which reached the purity of the commercial phycocyanin.Compared with the two commercial phycocyanin products,the purity of 2.3 phycocyanin is better in color value,color,content of phycocyanin and purity of phycocyanin.The effect of two anion exchange chromatography on the further purification of phycocyanin was compared.The results showed that the weak anion exchange column DEAE Tanrose FF was superior to the strong anion exchange column.The purity of phycocyanin was over 3.0 when the pH value of 8.0 Tris-HCl was used as equilibrium buffer and 0.2 mol/L NaCl was eluted.SDS-PAGE gel electrophoresis analysis and spectroscopic analysis(UV Vis spectrophotometry and fluorescence spectrophotometry)identified the phycocyanin purified by chromatography which accords with the characteristics of phycocyanin.To evaluate the antioxidant activity of phycocyanin,free radical scavenging experiments were studied.The results showed that phycocyanin had good free radical scavenging ability.The higher the purity of phycocyanin was,the stronger the free radical scavenging ability became.The formula and technology of phycocyanin yoghurt product showed that the reconstituted milk contained 0.25 g/L phycocyanin,9%sugar,10%milk powder and 8 h fermentation time.The obtained phycocyanin yoghurt had light blue color,rich milk aroma and good taste.Compared with ordinary yoghurt,phycocyanin yoghurt had stronger reducing ability and free radical scavenging ability which greatly improved the antioxidant ability of yoghurt.Quality inspection of phycocyanin yoghurt:acidity 79.5°T,protein content 3.65 g/100 g,lactic acid bacteria number 1×107 cfu/mL.Phycocyanin yoghurt meets the national standard.