Carotenoid compound coming from plant and containing natural astaxanthin, preparation method therefor, and composition

A method of preparing a high-content carotenoid mixture by using adonis amurensis extract as raw material, characterized in that, comprising the following steps:

• (a) mixing Adonis amurensis extract with alcohols solvent and fully dissolving, to obtain a mixed solution;
• (b) heating the mixed solution of the step (a) to 25-75° C., and dropwise adding an alkali solution to the reaction, and the reaction time is 0.5˜ 6.0 hr, wherein a concentration of the alkali solution of the reaction is 0.01-2.50 mol/L after adding dropwise the alkali solution;
• (c) adding a mixture of alcohols solvent and water to obtain a reaction solution, after completion of the step (b), wherein a volume ratio of the alcohols solvent to water in the step (c) is 1:5-10;
• (d) filtering the reaction solution of the step (c) to obtain a filter cake, and then washing the filter cake with a mixture of alcohols solvent and water, wherein a volume ratio of the alcohols solvent to water in the step (d) is 2-3:1;
• and
• (e) drying the filter cake of the step (d) in vacuum to obtain a carotenoid mixture;
• wherein, in the high-content carotenoid mixture, the content of the total carotenoid is higher than 95 wt %, the proportion of the all-trans (3S, 3'S) astaxanthin in the carotenoid is higher than 80 wt %, the all-trans (3S, 3'S)-astaxanthin has the molecular structure as shown in formula (I):