PRODUCTION METHOD FOR ASTAXANTHIN-CONTAINING COMPOSITION
The present invention relates to a method for reducing the relative ratio of 3-hydroxy-3′,4′-didehydro- β, Ψ-caroten-4-one (HDCO) to astaxanthin in a composition containing astaxanthin and HDCO by contacting the composition with an acidic medium having a pH of 3 or less and/or a basic medium having a pH of 9 or greater, and also relates to a method for producing an astaxanthin-containing composition which includes reducing the relative ratio of HDCO by the above method. By means of the method of the present invention, the relative ratio of HDCO, the biological function of which is not known, in an astaxanthin-containing composition can be easily reduced.
1 . A method for producing an astaxanthin-containing composition, comprising:
contacting a composition containing astaxanthin and 3-hydroxy-3′,4′-didehydro-β, Ψ- caroten-4-one (HDCO) with an acidic medium having a pH of 3 or less and/or a basic medium having a pH of 9 or greater to reduce a relative ratio of HDCO to astaxanthin in the composition.
2 . The method according to claim 1 ,
wherein the composition containing astaxanthin and HDCO is at least one selected from the group consisting of cells capable of producing astaxanthin, parts of the cells, extracts of the cells, and partially purified products of these.
3 . The method according to claim 2 ,
wherein the cells capable of producing astaxanthin are cells of a microorganism of the genus Xanthophyllomyces, Brevundimonas, Haematococcus, Chlamydomonas, Monoraphidium, Erythrobacter, Agrobacterium , or Paracoccus , or a microorganism of Labyrinthulea.
4 . The method according to claim 2 ,
wherein the cells capable of producing astaxanthin are cells of a microorganism of the genus Xanthophyllomyces .
5 . The method according to claim 4 ,
wherein the microorganism cells of the genus Xanthophyllomyces have an astaxanthin content of not less than 2000 μg/g dry cell weight.
6 . The method according to claim 1 ,
wherein the composition containing astaxanthin and HDCO has an relative ratio of HDCO to astaxanthin of not less than 1%.
7 . The method according to claim 1 ,
wherein the acidic medium has a pH of 2 or less.
8 . The method according to claim 1 ,
wherein the basic medium has a pH of 10 or greater.
9 . The method according to claim 1 ,
wherein the relative ratio of HDCO to astaxanthin is reduced by 0.1 percentage points or more through the contact with the acidic medium and/or the basic medium.
10 . A feed, a food, a food additive, or a medicament, comprising an astaxanthin-containing composition obtained by the method according to claim 1 .
11 . The method according to claim 2 , wherein the composition containing astaxanthin and HDCO has an relative ratio of HDCO to astaxanthin of not less than 1%.
12 . The method according to claim 3 , wherein the composition containing astaxanthin and HDCO has an relative ratio of HDCO to astaxanthin of not less than 1%.
13 . The method according to claim 4 , wherein the composition containing astaxanthin and HDCO has an relative ratio of HDCO to astaxanthin of not less than 1%.
14 . The method according to claim 5 , wherein the composition containing astaxanthin and HDCO has an relative ratio of HDCO to astaxanthin of not less than 1%.
15 . The method according to claim 2 , wherein the acidic medium has a pH of 2 or less.
16 . The method according to claim 3 , wherein the acidic medium has a pH of 2 or less.
17 . The method according to claim 4 , wherein the acidic medium has a pH of 2 or less.
18 . The method according to claim 5 , wherein the acidic medium has a pH of 2 or less.
19 . The method according to claim 6 , wherein the acidic medium has a pH of 2 or less.
20 . The method according to claim 2 , wherein the basic medium has a pH of 10 or greater.