Spray-drying optimization for <i>Dunaliella salina</i> and <i>Porphyridium cruentum</i> biomass

In this study, Dunaliella salina and Porphyridium cruentum biomass were encapsulated by using a spray-dryer (SD) and combined D-optimal method. The independent variables were SD inlet temperature (170-190 & DEG;C), maltodextrin (25-75%, w/w, in dm), and microalgae biomass (25-75%, w/w, in dm). Prior to spray drying, P. cruentum and D. salina were cultivated in a pilot scale tubular photobioreactor and than harvested using a conical plate centrifuge. Significant models were determined for the effects of independent variables on total carotenoids, chlorophyll-a, crude protein, moisture contents and encapsulation yield (EY), water activity, average particle size, wettability, hygroscopicity, L* and C* properties for both microalgae species (p < .05). Due to the low EY (11.1-33.1%), we recommend encapsulation and drying of P. cruentum biomass with alternative methods to SD. The extracellular, as well as the cell wall and storage polysaccharides released into the culture medium of these microalgae are possible reasons for the low EY.