| Edible pigments are widely used in all trades and professions. Compared with synthetic pigments, natural edible pigments posses their advantages for the characteristics of edibleness, innocuousness and free of side effects.The Chenopodiaceae Suaeda salsa L., a C3 plant, is a succulent euhalophyte. Shoots of S. salsa are violet-red throughout the whole growth period under hypoxia, high salinity and low temperature conditions in the intertidal zone, but green on saline inland far from the seaside. Nowadays, the red pigment in Suaeda salsa has been firstly identified as betacyanin in our laboratory. In view of its extensive application in food, medicine and daily-use chemical industry, the nutrient analysis of red-violet phenotype Suaeda Salsa L. leaves grown in the Yellow River Delta was performed, we investigated the extraction, separation and purification techniques of betacyanin, screened best prescription of stabilizer and contrasted research experiment of its stability, and found the appropriate conditions of its storage and application. The main results are as follows:(1) The content of coarse protein, crude fiber, crude fat and total sugar in the leaves were lower in the red-violet phenotype, compared with that of the green phenotype, but the content of antioxidants such as betacyanins, vitamin c, carotenoids were higher than that of the green phenotype.(2) By studying the effect factors such as extracting solvent, extracting time, temperature, the ratio of materials/liquid and the times of extraction, an optimal extraction method was carried out: The distilled water of pH5.0 should be the best extracting solvent; If materials were ground into powder, extracting time had no significant effect on betacyanin extraction rate; In a range of temperature, with the increase of temperature, the extraction rate of betacyanin was gradually increased; The ratio of materials/liquid at 1:6 was the best for the betacyanin extraction; Different extraction time had no significant effect on betacyanin extraction rate. In addition, the effect of different solvent extraction on betacyanin's extraction efficiency was also studied. The results showed that neither MeOH pre-extraction nor EtOH pre-extraction gave rise to significant effect on betacyanin's extraction efficiency, but more impurities were removed by MeOH pre-extraction than by EtOH pre-extraction.(3) Betacyanin was extracted only by water from Suaeda Salsa L. leaves, marked as the obtained pigment powder 1, the color value was 1.068; After MeOH pre-extraction,the precipitation was extracted by water, as the obtained pigment powder 2, the color value was 1.544; After MeOH pre-extraction,the precipitation was extracted by 80% methanol, as the obtained pigment powder 3 color value was 1.544; Pigment powder 3 was further purifified by Sephadex G-25 , as the obtained pigment powder 8, its color value was 3.536; Pigment powder 3 was further purified by LH-20 Chromatogram elution, the fractions were collected.Through analyzing collected sample solution using HPLC, we hypothesized that the structural types of betacyanin from Suaeda Salsa leaves are more than three.(4) The best prescription of the stabilizer is 0.06% vitamin C, 0.06% sodium benzoate and 0.02% of the L-sodium ascorbate.The stabilizer can improve the resistance to the temperature, light, pH value, reducing agent. But the resistance to the effect of sucrose, oxidant was not improved.(5) Different dry methods had different effects on the content of betacyanin, Suaeda Salsa L. leaves should be dried with low-temperature-hot-air dryer.Because of the instability of betacyanin, it should be used in caution.Through studing the stability of pigment after which was added into several common beverages, it found that betacyanin was not suitable for the white vinegar and white wine.
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