RESUMO
The removal of plant pigments such as ß-carotene is an aspect of vegetable oil processing often desired by the food and pharmaceutical industries. Adsorption of ß-carotene to acid-activated clay (AAC) is a well-established method for purification. Despite this, the removal mechanism of ß-carotene is not well understood. UPLC-MS/MS analysis of surface compounds extracted from ß-carotene-AAC (BC-AAC) complexes show that AAC acts as an oxidiser. Oxidation products detected included canthaxanthin and 3',4'-didehydro-ß-caroten-4-one. AAC had surface water exchanged with an 18O labelled water and was then exposed to ß-carotene. Carotenoids labelled with 18O were produced from this reaction, suggesting surface water is necessary for ß-carotene removal.
