Preparation And Functional Properties Of Spirulina Antioxidative Peptides

Spirulina is a kind of widely used functional food raw material, which was rated by FAO as ‘human best health care food of 21 st century' and ‘super nutritious food of the future'(Zhangwen et al., 2013). Spirulina is rich in phycobiliprotein, whose content is as high as 50-70% and amino acids composition is very ideal. The contents of the 8 kinds of essential amino acids is close to or more than the FAO's recommended standard. Spirulina can reduce the incidence of high cholesterol, high cholesterol, cardiovascular disease, inflammatory diseases, cancer and viral infections. Spirulina can also be used as a functional component in food manufacturing industry(Hemamalini, 2013). However, due to shortcomings of poor solubility and strong smell, the applications of Spirulina are subject to certain restrictions.The physical and chemical properties of phycobiliprotein can be improved and the scope of application can be expanded by using protease to hydrolysis. Compared with the phycobiliprotein, the hydrolysate of Spirulina peptide not only has lower molecular weight and good physical and chemical properties, more easily digested and absorbed by the body, but also enhance the body's immune function, eliminate and prevent the body from free radical damage, comprehensive regulation of the metabolism of human body, physiological function, especially the capacity of antioxidant which draws people's attention. In this paper, the method of breaking the Spirulina wall was studied. Also, optimization of hydrolysis conditions for antioxidant capacity of peptides from Spirulina using single and double enzyme method was discussed. The effect of degree of hydrolysis on emulsification, foaming capacity and antioxidant activity of Spirulina peptides and the pigment's production and prevention of the process of enzymatic hydrolysis and the preparation of Spirulina peptide functional beverage were researched.The methods of stirring, ultrasonic, repeat freezing and thawing can make the Spirulina wall broke. The results showed that, when the broken method was ultrasonic in the condition of the same ultrasonic mode, ultrasonic powder 5%, ultrasonic 7s and interval 3s, the content of soluble of protein in the cell can reach the highest. The repeat freezing and thawing, the sample thawed under 4? has more soluble protein than the sample thawed under 37?, and the content of soluble protein increased gradually with the increase of the number of freeze-thaw cycles. When the two methods are combined, the effect is better than using a single method alone. There is a linear relation between the content of soluble protein in solution and stirring time when the method was stirring, the content of soluble protein was increased, but the growth rate gradually slowed down. The soluble protein content was 25.8mg/m L when the stirring time was 3h.The hydrolysis conditions of antioxidant peptides from Spirulina powder using Alcalase were optimized by single factor methods and the Box-Behnken experiments, to improve the antioxidant abilities and the yield of Spirulina peptides. The results showed that Alcalase has the highest hydrolysis ability compared with other commercial proteases, incluing papain, trypsase and flavourzyme, and it's optimum hydrolysis conditions were 55.46?, pH6.71 and the solid liquid ratio was 1:10.83(v/w). When the Spirulina powder were hydrolyzed under the optimized conditions, the yield of the Spirulina peptides was 58.50%, increasing by 15.61% compared with the control. The DPPH radical scavenging ability of Spirulina peptides reached 77.60%, at the mass fraction of Spirulina peptides was 0.86g/L, increased by 7.62% compared with the control.The hydrolysis conditions of antioxidant peptides from Spirulina powder using double enzyme method were optimized by the Central Composite designs. The results showed that the optimum hydrolysis conditions of the double enzyme method was 54.89?, the ratio of alkaline protease to papaya protease was 2.23:1, and the time was 6.53 h. When the Spirulina powder were hydrolyzed under the optimized conditions, the yield and the DPPH radical scavenging ability of the Spirulina peptides was 57.94% and 78.00%.The effect of the degree of hydrolysis(DH) on the emulsification, foaming capacity and antioxidant activity of Spirulina peptides was investigated. The DH of the hydrolysate increased during the process of hydrolysis. In the process of hydrolysis, the foaming activity, DPPH radical scavenging ability, hydroxyl radical scavenging ability and reducing power of Spirulina peptides first increased then decreased with the increase of the DH, however the foaming stability, the emulsification, emulsifying stability decreased with the increase of the DH.The pigment was gradually accumulation in the process of enzymatic hydrolysis, add inhibitor or adsorbent appropriate can effectively inhibit the production of pigment. When the hydrolysis was complete, the amount of H2O2 addition was 1.5%, the inhibition rate of pigment was 31.07%; the amount of NaClO addition was 1.5%, the inhibition rate was 21.47%; the amount of active carbon was 3%, and the inhibition rate was 27.29%.In this article the formular of Spirulina peptides beverage in which the Spirulina peptide powder was the main raw material was researched. The studied showed that on the basis of single factor experiment, orthogonal experiment was used to optimize the preparation of the beverage. The factors that influenced the quality of beverage was the Spirulina peptide, the amount of citric acid and the amount of white granulated sugar. The best formula was like this: 0.5g Spirulina peptide powder, 0.05 g citric acid and 3g white granulated sugar in soybean peptide beverage per 100 mL.