Spray drying of nopal mucilage (Opuntia ficus-indica): Effects on powder properties and characterization

Aqueous solutions of mucilage were spray dried without the use of carrier agents and the influence of drying conditions on mucilage powder properties was evaluated. The drying parameters studied were inlet air temperature, feed flow rate, and atomization speed. Statistical analysis carried out on the experimental data showed that the feed flow and atomization speed had significant effects on the dryer yield. Moisture content and yield had an inverse relationship to the inlet air temperature. Furthermore, some physical properties of Opuntia mucilage powder were evaluated. The particle morphology observed was of spheres with collapsed fragments and agglomerate structure. The glass transition temperature and water adsorption behavior indicated that powder is stable for room temperature <45 degrees C and relative humidity <50%. The GAB model gave good fit (R-2 > 0.99) for the experimental data of adsorption isotherms. Net and total sorption heats were determined. (C) 2010 Elsevier Ltd. All rights reserved.