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 salina in calcium alginate beads of di†erent alginate concentrations, followed by drying in a Ñuid-bed dryer. The drying process yielded b-carotene recoveries of between 79 and 89% and produced a change in the 9-cis/all-trans ratio of b-carotene isomers. The carotenoid stability of the product was dependant on both the storage conditions and alginate content (range 3É3È7É3 g litre~1) of the beads. In the presence of light and oxygen total carotenoid degraded following a Ðrst order kinetic model with degradation constants between 0É016 and 0É039 days~1, with the lowest degradation occurring with the lowest alginate concentration. Product stored in the dark and Ñushed with nitrogen produced Ðrst-order degradation constants of 0É012 and 0É020 days~1 for the two higher alginate concentrations ; that with the lowest alginate content showed no noticeable degradation after 58 days storage. During storage, the 9-cis isomer was signiÐcantly more unstable showing a relative loss under all conditions, degrading almost completely when stored in the presence of light and oxygen and reaching an equilibrium ratio with the all-trans isomer when stored in the dark and Ñushed with nitrogen