| Spirulina contains a lot of protein and a variety of nutrients, including active polysaccharides and phycocyanin which have the physiological functions of antitumor, antioxidation and improving immunity, so it is increasingly being developed for health products and functional foods. In addition, phycocyanin used as natural pigment or fluorescent reagents has high economic value. With the improvement of the living standard, people’s concepts of health gradually increased, and the demand for nutritional supplements and health products has gradually increased, therefor spirulina products have great market potential.In2012, it was reported that the lead of several well-known brands of spirulina exceeded the national standard. Although later the experimental results of SFDA (State Food And Drug Administration) showed that the lead of these spirulina did not exceed the national standard, consumers’confidence in the quality of Spirulina products had been affected, and the development of the spirulina industry had been hindered. At present, there are two major problems in the spirulina industry. One problem is that the quality control is not standardized, embodying in the unqualified tracking process of lead pollution, as well as the indeterminacy of the controlling ingredients of the important activity index. The other problems is the lack of deep-processed products, and the low material utilization ratio.At present, the spirulina powder is the main product form, or made into capsules, tablets, and added to other foods. The Spirulina polysaccharide, phycocyanin and other ingredients could be extracted and separated, and developed into series of spirulina products, such as functional foods, food additives, pigments or fluorescent reagents. In this way, the products could adapt to the market demands better, and the economic benefits of product could improve.The experimental material was spirulina, provided by the Fujian Shenzhou VI Health Products Co., Ltd.. The spirulina was tested that the lead content was below the national standard. Considering the yield and purity of polysaccharides and proteins (including phycocyanin), the complexity of the process, production costs, the paper discussed and evaluated the separation methods of polysaccharide and phycocyanin, and the purification process of phycocyanin. The experimental results proposed a variety of production process, which could be chose promptly to meet the market demand and improve market competitiveness. In addition, the spirulina polysaccharides obtained in this process were applied to mice hypoglycemic activity experiments, providing the the basis for quality control of polysaccharide products.The research compares two-step ammonium sulfate precipitation method, aqueous two-phase extraction method, resin method and hydrochloric acid precipitation method. Ammonium sulfate two-stage precipitation method and aqueous two-phase extraction method require a lot of ammonium sulfate, making the subsequent operations (such as desalination) more complicated. Resin method has good separation effect, low resin cost and simple process, but the high pH lead to protein denaturation and destroy the activity of polysaccharide. Hydrochloric acid method has better separation effect, and it has advantages such as easy operation, low equipment requirements, low cost. Water extract of spirulina is adjusted to pH3.5and stand5min at rom temperature, then the suspension is centrifugated. The yield of polysaccharide in the top phase is70.14%, and the yield of protein in the precipitation is98.07%(the recovery of phycocyanin in the sedimentation is99.23%). The alloxan-inducing hyperglycemic mice experiment indicates that the polysaccharides obtained by this process has hypoglycemic effect.Ammonium sulfate precipitation method and aqueous two-phase extraction method can be used to purify phycocyanin. They have simple processes, and are easy to be applied to industrial scale production. After30-60%two-step ammonium sulfate precipitation method, about70%of the phycocyanin is yielded, and its purity is increased from0.34to0.72. After optimized aqueous two-phase extraction (14%MgSO4,6%PEG2000,0.5%KCl) of spirulina water extract, the top phase is collected. Then it is reverse extracted using12%PEG,6%MgSO4aqueous two-phase system. The recovery rate of phycocyanin is92.66%, and the purity is increased to2.64from1.42. The stability tests show that foods or pigments containing phycocyanin should be used or stored at low temperature, acidic and dark conditions. |
PDF Full Text Request