17G-22 |
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A. SOOTTITANTAWAT1, J. Peigney2, Y. Uekaji1, H. Yoshii1, T. Furuta1, M. Ohkawara3, and P. Linko4. (1) Dept. of Biotechnology, Tottori University, 4-101 Koyamacho-minami, Tottori, 680-8552, Japan, (2) ENSBANA, Universite de Bourgogne, Dijon, France, (3) Ohkawara Kakouki Co. Ltd., Yokohama, 224-0053, Japan, (4) Department of Chemical Technology, Helsinki University of Technology, Espoo, Finland Spray drying is one of the most widely used processes in food industry for the formation of powder. It offers several advantages such as continuous, speedy processing, and low operation costs. The morphology of spray-dried particles is very important because of it influences the powder flowability, redispersibility, density and also the stability of the encapsulated compounds. The purpose was to investigate the internal and external morphology of various spray-dried powders as a function of the operating conditions of the spray-dryer by using confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM), respectively. The blend of arabia gum and maltodextrins solutions was prepared at 30% solid content with the respective proportions of 1 to 3. In order to make the powder particles visible by CLSM, fluorescein sodium was used to label the solid materials. The solutions were fed through an Ohkawara L-8 type spray dryer at different inlet air temperatures and atomization speeds. An increase in the vacuole size as well as the particle size were observed when the inlet air temperature was increased. Smaller vacuoles and lower yields of vacuoles were observed when using low atomization speeds. The density of powders decreased with increase of inlet air temperature as well as with increase of atomization speed. Furthermore, the surface morphology presented smooth and shriveled particles for all the powders but deeper surface grooving for low inlet air temperatures. More grooves were observed by using a low atomization speed. CLSM was shown to be a helpful tool for microparticle characterization with a non-destructive. These results suggest that powder spray-dried at higher temperatures shows the larger vacuole size and lower density of powder which provides an obvious packaging advantage for the industry. Furthermore, the relative lack of grooving will increase the flowability of the powder.
Session 17G, Food Engineering: Physical, chemical and electrical properties
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