Research On Extraction, Stability And Biological Activity Of Anthocyanin In Black Rice, Black Beans

Anthocyanin is a kind of water-soluble pigments that is widely distributed in flowers, fruits and leaves of plants, which belongs to polyphenolic compounds. There are many studies shown that, natural anthocyanins have antioxidant, antimutagenic, anticancer, anti-inflammatory, anti-aging and many other biological activity. Domestic research shows that, black rice and black beans are rich of anthocyanins. In this thesis, the extraction of anthocyanins in the black rice and black beans, impact of various factors on its stability, antioxidant and hepatoprotection in vivo function are researched systematically.Total anthocyanins were extracted from black rice, black beans with moderate distilled water, adjusted pH to 2.0 by 1.0 mol/L HCL. Material was extracted for 5 times at 60℃water bath until the extraction is achromatic. Collected all extraction, and its total volume was determined. After centrifugation, its absorbance value was measured at 530 nm, the total anthocyanin contents in the black rice, black beans were 6.75 mg/g and 4.70 mg/g respectively. The way similar to family cooking black rice and black beans, absorbance values of the extracts was determined, anthocyanin content was 3.22 mg/g in the black rice, the extraction yield rate was 47.72%of total anthocyanins; anthocyanin content of black beans was 2.17 mg/g, the extraction yield rate was 46.21%of total anthocyanins.Anthocyanins of black rice and black beans were extracted by ethanol and water. Concentration of ethanol, extraction time, extraction temperature and solid to liquid ratio as single factor were reseached in the ethanol extraction experiments, Extraction time, extraction temperature and solid to liquid ratio as single factor were reseached in the water extraction experiments. According to the results of single factor experiments, absorbancy and yield rate were used as index, the orthogonal test were desighed, the optimum extraction process of anthocyanins by ethanol and water extraction were as follows:ethanol concentration 40%, extraction time 80min, extracted temperature 70℃, solid to liquid ratio 1:8 for ethanol extraction of black rice, and its yield rate reached 85.63%; extraction time 120 min, extraction temperature 60℃, solid to liquid ratio 1:4 for aqueous extract of black rice, its yield rate was 87.13%. Ethanol concentration 60%, extraction time 80 min, extraction temperature 50℃, solid to liquid ratio of 1:6 for ethanol extract of black beans, and its yield rate was 84.21%; extraction time 100 min, extraction temperature 60℃, solid to liquid ratio 1:6 for aqueous extract of black beans, its yield rate was 89.04%.Effects of different temperature, pH, light, metal ions (Mg2+, Al3+, Ca2+, Cu2+, Fe3+, Fe2+, Zn2+) and different types of food additives on anthocyanin stability in black rice, black beans were reseached too. The results showed that both two anthocyanins were poor in heat resistance and light resistance, and they were relatively stable under acidic conditions. Under the same light conditions, black beans anthocyanin was more stable than black rice anthocyanin. All treaments of Al3+,Ca2+,Zn2+ had a protective effect to the black beans and black rice anthocyanins, and The treatments of Cu2+,Fe2+,Fe3+ could weaken the stability of anthocyanins. Add 20.0 mg EDTA to the different metal ions anthocyanin solution, the subdued effect of Cu2+ on the two anthocyanin stability was significantly inhibited, while the protective effect of Zn2+ on the anthocyanin stability was destroyed; EDTA increased the destruction of Fe3+ on the black rice anthocyanin stability and inhibition of the destruction of Fe3+ on the black beans anthocyanin stability, Fe2+ had the contrary effect. Black rice anthocyanin addingβ-cyclodextrin and potassium sorbate was treated with high-temperature water bath, anthocyanin retention were 89.6%and 85.7%, higher than the 74.9%of control group; CMC was not significant impact on the stable of anthocyanins from black rice; Fumaric acid, and gelatin undermine its stability in a certain extent, and The maintain rate was 64.2%and 69.0% after high temperature treatment respectively. The degradation of anthocyanins in black beans was largely inhibited by addingβ-cyclodextrin, fumaric acid and potassium sorbate, maintain rate of anthocyanins reached more than 87%after high temperature treatment, and protected the stability of anthocyanins in solution water; CMC and gelatin made stability of anthocyanin from black beans slightly debilitated, and the reduce rate was no more than 5%, which isn't significant.Antioxidant and hepatoprotection in vivo function of anthocyanins in black rice and black beans was studied by animal experiments.The results showed that anthocyanin in black rice and black beans could significantly increase total SOD activity and CAT activity (p<0.05), while extremely significantly reduce MDA content (p<0.01) in serum of mice, which indicated that two kinds of anthocyanins has significant effects of vivo antioxidant. The mice mortality of three groups were 20%; Anthocyanin in black rice and black beans both extremely significantly reduced AST activity (p<0.01) in serum from alcoholic liver injury mice, and significantly reduced the ALT activity (p<0.05), which showed that both black rice and black beans anthocyanin have a certain function of hepatoprotection in vivo. But due to operational errors, the individual differences of experimental mice and other reasons, the mortality of model mice was 40%, the mortality of black rice group and black death group was 20%. The small number of samples in model group, and the differences of the sample number in each group leaded to results little statistically significance, so further research is needed.