玉米蛋白粉中叶黄素的提取和纯化

Extraction and Purification of Xanthophyll from Corn Gluten Meal

为提高玉米蛋白粉的应用价值,对玉米蛋白粉中叶黄素碱性蛋白酶辅助提取工艺及叶黄素和玉米黄质的分离方法进行研究。分析酶解pH值、温度、酶添加量、底物质量浓度和酶解时间对总叶黄素得率的影响。结果表明,相比于常规溶剂提取,酶解辅助的方法显著提高了叶黄素的得率(P<0.05),考虑到提取效率、成本和可行性,得到的最佳工艺参数为pH7.0、酶解温度40℃、酶添加量4000U/g、底物质量浓度110g/L、酶解时间2h。在最佳工艺参数下,总叶黄素的得率为59.57μg/g。采用V(正己烷):V(乙酸乙酯):V(乙醇):V(水)=4:1:4:1的两相体系将所得的粗提物进行制备型高速逆流色谱的分离纯化,利用高效液相色谱检测得到的反式叶黄素和反式玉米黄质的纯度分别为90.85%和91.21%。实验证明制备型高速逆流色谱可以成功地将玉米黄粉中叶黄素和玉米黄质分离,但不能彻底分离叶黄素和玉米黄质与其各自的顺式异构体。

In order to improve the utilization of corn gluten meal （CGM）, the alcalase hydrolysis process of the material for the extraction of xanthophylls and zeaxanthin and the high speed counter current chromatographic （HSCCC） separation of xanthophylls and zeaxanthin from the residue left after alcalase hydrolysis were explored. The effects of pH, temperature, enzyme loading, substrate concentration and hydrolysis duration on the extraction efficiency of xanthophylls were examined. The results showed that the extraction efficiency of xanthophylls was increased significantly by enzyme treatment when compared with the traditional solvent extraction method （P〈 0.05）. Considering extraction efficiency, production cost and experimental feasibility, the optimum conditions for CGM hydrolysis were determined to be： pH 7.0, reaction temperature 40 ℃, enzyme loading 4000 U/g, substrate concentration 110 g/L and hydrolysis duration 2 h. Under these optimum conditions, the extraction efficiency of xanthophylls was 59.57μg/g. The binary phase system employed for the preparative HSCCC purification of the crude extract was composed of n-hexane, ethyl acetate, ethanol and water （4：1：4：1, V/V）. HPLC determination revealed that the purities of the trans-xanthophylls and the trans-zeaxanthin were 90.85% and 91.21%, respectively. Preparative HSCCC could not thoroughly separate the trans and cis isomers of xanthophylls and zeaxanthin, although the technique succeeded in separating the two compounds.