Spirulina is a microalgae species currently cultivated on a large scale in China, and phycocyanin is a unique photosynthetic pigment of Spirulina, with a content of over 20% of its dry mass. Therefore, Spirulina is an economical and effective preferred raw material for producing phycocyanin.
The physicochemical properties of phycocyanin
1. Solubility
Phycocyanin has strong fluorescence, emitting orange-red fluorescence, while it itself appears blue and is soluble in polar solvents such as water and ethanol. In high concentrations of ethanol, the pigment will coagulate. Insoluble in non-polar solvents such as ether and chloroform.
2. Stability at different pH values
Phycocyanin was prepared into pigment solutions with different pH values, and after being left for 1 hour, the color change of the solution was observed. The results showed that at pH 6-9, the phycocyanin solution appeared blue and transparent, with good stability.
3. Thermostability
Thermal stability studies have shown that phycocyanin is very stable below 40 ℃, but its stability decreases significantly when the temperature exceeds 60 ℃, and the solution color changes from blue-green to yellow-green.
4. Photostability
Take two solutions of phycocyanin and place them in natural light and strong sunlight indoors for a certain period of time, and measure the changes in absorbance. The results showed that the absorbance value remained basically unchanged after being placed under natural light indoors for 6 hours, but the color faded significantly after 18 hours; After 1 hour of strong sunlight exposure, the pigment solution faded to near colorless, indicating poor photostability of phycocyanin.
5. Oxidative resistance
An oxidant was added to the phycocyanin solution to prepare pigment solutions with H₂O₂ contents of 0.3%, 0.6%, and 1%, respectively. After 3 hours, the blue-green color of the three pigment solutions remained unchanged, indicating that phycocyanin has a certain degree of oxidation resistance.
6. The influence of metal ions on the stability of phycocyanin solution
Among all metal ions, it has been found that calcium and potassium ions have no effect on pigments, while in the presence of zinc and iron ions, pigments slowly precipitate. As the amount of zinc and iron ions increases, the color of pigments changes from blue to green and then to yellow.
The nutritional and health benefits of phycocyanin
1. Nutritive function
Domestic and foreign studies have shown that phycocyanin belongs to protein binding pigments, and its amino acid composition ratio is very reasonable. The content of eight essential amino acids is close to or exceeds the standards recommended by FAO. Phycocyanin used for food fortification can improve the biological efficiency of grains and the utilization of protein; Used in cosmetics, it can provide various nutritional active ingredients such as amino acids that the skin needs, and can play a role in surface and deep nutrition and care of the skin. It is also very safe to use and has no irritating or sensitizing effects on the skin.
2. Help the human body absorb iron
The availability of iron in food is related to its binding mode. Heme iron is the most effective absorbable iron, with 60% of iron in animal tissues being heme iron, while only 13% to 35% of iron in plant-based foods can be absorbed by the human body. Under similar digestive conditions, Japanese researchers have found that phycocyanin, similar to heme, can form soluble compounds with iron, greatly enhancing the body’s absorption of iron.
3. Enhancing immune function
Animal experiments have shown that after oral administration of phycocyanin to experimental mice injected with liver tumor cells, the survival rate of the experimental group mice is significantly higher than that of the control group mice; Further research found that the lymphocyte activity of the experimental group of mice was significantly higher than that of the control group and normal mice. Therefore, the researchers believe that phycocyanin can increase lymphocyte activity, enhance the body’s immunity through the lymphatic system, and enhance the body’s ability to prevent and resist diseases.
4. Promote the regeneration of animal blood cells
In 1988, Morcos et al. treated mouse myeloma cells with phycocyanin containing 0.25mg/mL, and compared with laser irradiation control cells, the cell survival rate increased from 15% to 71%. The study also showed that phycocyanin has a stimulating effect on bone marrow hematopoiesis and can be used as a clinical adjuvant therapy for various blood diseases. It also has therapeutic effects on blood cancer.
5. Antioxidation
Peroxidized lipids are formed by the oxidation of polyunsaturated fatty acids on the cell membrane by superoxide anions (LPO), which are important factors leading to tissue damage, cellular dysfunction, and muscle aging. Experiments have shown that phycocyanin can generate free radicals under light and eliminate them in the dark. Therefore, phycocyanin has a dual function of generating and scavenging free radicals. After undergoing specific treatment to denature phycocyanin, its ability to produce free radicals disappears, while its ability to scavenge free radicals is significantly enhanced. Used in food and cosmetics to eliminate tissue damage, cell aging, and other pathological changes caused by harmful substances and free radicals generated during physiological and metabolic processes in the human body.
