| Xanthophylls are members of carotenoids family, including lutein and zeaxanthin. As an excellent antioxidants, natural xanthophylls have some properties different from other carotenoids, such as protection of visual acuity, reductuction of incidence of cataract. Almost all the commercial xanthophylls products are taken from nature. Corn Gluten Meal (CGM) is a by-product from corn starch manufacturing. Natural xanthophylls can be obtained from CGM. which has a great annual output.Xanthophylls were determined by HPLC using YMC-Carotenoid C30 column 4.6mm×150mm (3μm). Mixture of methanol, methyl tertiary butyl ether and water (95:2:3) was used as elution solvent with flow rate of 1.OmL/min. The wavelength of UV detector was 450nm/260nm and the column temperature was 30℃.The separation of xanthophylls from CGM consists of three unit operation including extraction, preparative chromatography and crystallization. The proteolytic hydrolysis was explored to enhance the extraction yield of xanthophylls. And then the pigment was extracted by industrial alcohol for getting rid of the insoluble proteins and lipids. After that, ethyl ether was selected as extractant to extract pigment from raffinate with a proportion of ethyl ether:raffinate:water=5:5:6, and the content of xanthophylls in product was increased from 0.3% to 1.0% with a recovery of 98%. Before purification with column chromatography, the performance and separation characteristics relevant to xanthophylls were measured on ten different resins. It was found that macroporous adsorptive resin H offer the largest adsorption abilities among the tested adsorbents and thus was selected as the stationary phase. Using ethanol and water as mobile phase, the content of xanthophylls in product was increased to 5.76%, with a recovery of 97.2%. Finally through crystallization process in the mixture of chloroform and n-hexane at -4℃, the crystalline product was obtained with the purity higher than 64%. |
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