PRODUCTION OF A CAROTENOID-RICH PRODUCT BY ALGINATE ENTRAPMENT AND FLUID-BED DRYING OF DUNALIELLA-SALINA

A new carotenoid-rich product was formed by entrapment of Dunaliella s alina in calcium alginate beads of different alginate concentrations, followed by drying in a fluid-bed dryer. The drying process yielded be ta-carotene recoveries of between 79 and 89% and produced a change in the 9-cis/all-trans ratio of beta-carotene isomers. The carotenoid sta bility of the product was dependant on both the storage conditions and alginate content (range 3.3-7.3 g litre(-1)) of the beads. In the pre sence of light and oxygen total carotenoid degraded following a first order kinetic model with degradation constants between 0.016 and 0.039 days(-1), with the lowest degradation occurring with the lowest algin ate concentration. Product stored in the dark and flushed with nitroge n produced first-order degradation constants of 0.012 and 0.020 days(- 1) for the two higher alginate concentrations; that with the lowest al ginate content showed no noticeable degradation after 58 days storage. During storage, the 9-cis isomer was significantly more unstable show ing a relative loss under all conditions, degrading almost completely when stored in the presence of light and oxygen and reaching an equili brium ratio with the all-trans isomer when stored in the dark and flus hed with nitrogen. (C) 1998 SCI.