Study On Chlorophyll Extraction Process From Mango Leaves, Chlorophyll Properties And Measurement Of Mangiferin Contents

In the thesis, chlorophyll was extracted by the ultrasonic-assisted method from mango leaves. The conditions of extraction techniques of chlorophyll were optimized. And the stability of the extracted chlorophyll was studied. A method was developed for determination of chlorophyll and mangiferin in mango leaves by UV-Vis, which could be used to evaluate the quality of mango leaves as medicinal materials. The contents of chlorophyll and mangiferin in mango leaves of the11mango cultivars in Baise City were determined. The chlorophyll was preliminarily purified with D101macroporous resin, which was analysed by UV-Vis, FT-IR, and TG-DTG-DSC.(1) Studying on the extraction process of chlorophyll in mango leaves. Chlorophyll was extracted by ultrasonic-assisted organic solvent method with mango leaves as raw material. Based on single-factor research, the impact of ultrasonic temperature, ultrasonic power, solid-liquid ratio, and ultrasonic time on the extraction effects were explored by orthogonal test. The optimized extraction conditions were95%ethanol as extractant, solid-liquid ratio of1:8(g/mL), ultrasonic temperature, power and time as60℃,160W and30min respectively. The extraction efficiency ration was23.6%higher than the conventional dipping extraction method.(2) Studying on the stability of chlorophyll in mango leaves. Chlorophyll in mango leaves was extracted with95%ethanol. Then its tolerance towards light, temperature, pH value and oxidant, as well as the impact of different metal ions on the stability were studied. The results were as follows:the stability of chlorophyll in mango leaves apparently was affected by Light, pH, value and high temperature. Hydrogen peroxide could cause decolorization and degradation of chlorophyll in mango leaves. The impact of different metal ions on the stability was significantly different. Copper, Zinc and magnesium ion, especially copper ion, had a good function of color protection for chlorophyll in mango leaves, while ferrous ion and ferric ion could rapidly destroy the stability and turned the color black.(3) Determination of the contents of chlorophyll and mangiferin in mango leaves of the11mango cultivars in Baise City:A method was developed for determination of chlorophyll and mangiferin in mango leaves by UV-Vis. In this established method, good linearities (R2>0.9998) in wide linear range (4.12～41.20μg/mL) with the good average recoveries were obtained. The chlorophyll content was calculated by Arnon’s equation.(4) Spectral analysis and thermal analysis for mango leaves extractions. The chlorophyll was preliminarily purified with D101macroporous resin, which was analysed by UV-Vis, FT-IR, and TG-DTG-DSC. The analytical result of UV-Vis showed that mango leaves extract was similar characteristic absorption peak with chlorophyll a and mangiferin. The analytical result of TG-DTG-DSC showed that pyrolytic reaction proceeds was steadily with releasing CO2, et al.