title: Modification of official method for analysis of carotenes and xanthophylls in dried plant materials and mixed feeds.
abstract: The official method (43.018-43.023) for extraction and separation of carotenes and xanthophylls in dried plant materials and mixed feeds is modified. These pigments are extracted from samples lacking xanthophyll esters by stirring 2 hr, followed by 1-hr cold saponification. The official method recommends 16-hr static extraction preceding the cold saponification. For samples containing xanthophyll esters, we preceded the 20-min hot saponification step by 2 hr stirring. This extra step increased the yield of mono- and dihydroxy pigments, especially from marigold meal. For separation, Merck silica gel 60 plus Hyflo Supercel is substituted for silica gel G in adsorbent I, resulting in 30-min separation. Also, at least 4 separations can be performed using the same adsorbent, and the column is more easily cleaned between separations. Results of the modified method were comparable to those of the official method.
mesh_terms: D000821:Animal Feed / Q000032:analysis*; D002338:Carotenoids / Q000032:analysis*; D002845:Chromatography; D014975:Lutein / Q000032:analysis*; D008722:Methods; D010944:Plants / Q000032:analysis*
chemical_list: D002338:Carotenoids; D014975:Lutein