SPRAY-DRYING OF DUNALIELLA-SALINA TO PRODUCE A BETA-CAROTENE RICH POWDER

Powders of Dunaliella salina biomass were obtained by spray drying a c ell concentrate under different drying regimes, A three-factor, two-le vel experimental design was employed to investigate the influence of i nlet temperature, outlet temperature and feed solids on beta-carotene recovery. The effect of microencapsulation in a polymer matrix of malt odextrin and gum arabic was also studied, All powders were stored unde r specific conditions to assess the stability of the native beta-carot ene, There was a trend indicating that lower outlet temperature yielde d higher carotenoid recoveries, beta-carotene recovery varying between 57% and 91%, Micrroencapsulated biomass yielded 100% recoveries. AII non-microencapsulated powders were unstable in terms of beta-carotene content in the presence of natural light and oxygen showing 90% degrad ation over a I-day period, The incorporation of a microencapsulating a gent had a significant increase in the storage stability, Results indi cated a first-order degradation of the beta-carotene in microencapsula ted powders with kinetic constants of 0.06 day(-1) and 0.10 day(-1). H PLC analysis showed no effect of drying processes on isomer compositio n (9-cis-beta-carotene and all-trans-beta-carotene ratio), This behavi our was also observed during storage of the microencapsulated powders.