Microstructural, Physical, and Rehydration Properties of Maltodextrin Powders Obtained by Spray Drying

摘要

Operating conditions in spray drying have a strong influence in rehydration of food powders. Moisture content, bulk and tapped density, angle of repose, dispersability, wettability, and microstructure of powders are important in mixing, transport, storage, and rehydration. This work studied the influence of three different concentrations of maltodextrin solutions and two spray-drying air temperatures on rehydration and microstructure characteristics of powders. Maltodextrin solutions containing 20%, 30%, and 40% total solids (TS) were subjected to cocurrent two-nozzle atomization spray drying at 140° and 249°C inlet drying-air temperature, outlet drying-air tem-perature of 70° and 120°C, and feed rate of 1.2 L/h. Physical and rehydration properties of maltodextrin powders can be improved when they are obtained by spray-drying solutions at higher temperatures and the highest concentration of feed. High air-drying temperature (249°/120°C) and high feed concentrations (40% TS) have a strong influ-ence on the microstructure of particles produced during spray drying and improved the "instant" properties of powders.