Microscopy spray drying

A recent study has been performed on various spray dried orange flavors(20% oil fixed in the powder) encapsulated on various Acacia gums and on mixtures of Acacia gums and malto-dextrins. The aromas in powder were tested by chromatography and then examined by electronic microscopy. This clearly shows the regular and uniform film covering each particle 10 to 40 microns in diameter. Prints of broken particles reveal numerous oil droplets (1 micron in diameter) spread in a gum nucleus. Protection of the oil phase then becomes fully effective. 

Particle size of the oil droplets after emulsification was determined by microscopy. This was accomplished prior to spray-drying. A typical good emulsion would have an oil particle size of less than 2 microns (urn). 

Eldem, T. Speiser, P. Hincal, A. Optimization of spray-dried and -congealed lipid micropellets and characterization of the surface morphology by scanning electron microscopy. Pharm. Res. 1991, 8, 47-54. 

Roetman, K. Crystalline lactose and the structure of spray-dried milk products as observed by scanning electron microscopy, Neth. Milk Dairy J., 33,1,1979. 

Inner Structural Analysis ol Spray-Dried Particle BY Conlocal Laser Scanning Microscopy... 

Soottitantawat A, Peigney 1, Uekaji U, Yoshii H, Furuta T, Ohgawara M, Linko P. 2007. Structural analysis of spray-dried powders by confocal laser scanning microscopy. Asia-Pacific Journal of Chemical Engineering 2 41 6. 

Yoshii H, Kawamura D, Neoh T-L, Furuta T. 2007. Visualization of flavor release in the spray-dried particle by confocal laser scanning microscopy. Proceedings of the 5th Asia-Pacific Drying Conference, Hong Kong, China, pp. 317-322. 

Chow et al. [22] used spray drying to prepare nanosize hydroxyapatite (HA) particles. They used a nozzle to spray the acidic calcium phosphate solutiou aud an electrostatic precipitator to collect nanosize powder. Their high-resolution transmission electron microscopy (TEM) showed that the particles, some of which were only 5 nm in size, exhibited... 

Butyl acrylate-methyl methacrylate copolymer latices with a core-shell structure were prepared by a sequential emulsion polymerisation technique. SEM and transmission electron microscopy studies undertaken on the polymer dispersions, powders obtained by spray drying and latices prepared by redispersing the powders in water revealed the influence of polymerisation parameters on the micromorphology of the starting latices, and correlations between the dimensional and micromorphological characteristics of the starting latices, the powders and the redispersed latices. 8 refs. 

FIGURE 2.9 Scanning electron microscopy microphotograph of glutinous rice starch. (Reprinted from Colloids and Surfaces B Biointerfaces, 78, Laovachirasuwan et al., The physicochemical properties of a spray dried glutinous rice starch hiopolymer, 30-35. Copyright 2010, with permission from Elsevier.)... 

CFD) to improve and optimize the drying system. In the present chapter, the morphology of spray-dried particles is examined as a function of the outlet air temperature and additives, such as surfactants and proteins. Scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) are used for the investigation of the outside and inside morphology of the spray-dried particles. 

In the last decade confocal laser scanning microscopy (CLSM) was shown to be a helpful tool for various further tasks of microparticle characterization (Lamprecht et al., 2000a, b, c). It minimizes the light scattered from out-of-focus structures, and permits the identification of several compounds through use of different fluorescence labels. Therefore, CLSM can be applied as a non-destructive visualization technique for microparticles. Moreover, CLSM allows visualization and characterization of structures not only on the surface, but also inside the particles, provided the carrier matrices are sufficiently transparent and can be fluorescently labeled by collecting several coplanar cross-sections, a three-dimensional reconstruction of the inspected objects is possible. Figure 6.13 shows the application of CLSM to investigatation of the cross-sectional structures of spray-dried powders of maltodextrin (MD) with a dextrose equivalent value of DE = 2 and 20. Florescein sodium salt was dissolved in the feed solution as a fluorescent probe of the carrier... 

Figures 6.12-6.15 show example electron microscopy images of foamed and non-foamed detergent and maltodextrin powders for different drying temperatures. In these images, a significant difference can be observed in the structure of foamed and non-foamed spray-dried products, with foaming leading to an increase in particle diameter and the formation of a porous shell. Under certain drying...

The surface morphology of spray-dried emulsions was analysed by scanning electron microscopy (Hitachi S4800, Hitachi High-Technologies Corporation, Tokyo, Japan) at 3 kV and ambient temperature. Powder samples were deposited on aluminium SEM stubs coated with double-sided adhesive carbon tabs (Leit adhesive carbon tabs) and sputter coated with a layer of 6-7 nm thickness of gold. Fibrils were also characterised using atomic force microscopy (NanoWizard 3, JPK Instruments AG, BerUn, Deutschland) in cooperation with the Institute for Material Science, Kiel University. For details refer to Serfert et al. [56]. 

Size exclusion chromatography Scanning electron microscopy Spray-freeze-drying Time... 

The M3YSZ samples sintered at 1550°C were characterized by SEM. Microscopy of polished surfaces revealed very little porosity present but showed the present of large (10 to 50 pm) ball-like agglomerates (see Fig. 2a). EDS revealed that the balls were zirconia-rich. It was discovered that the Tosoh 3YSZ zirconia powders are spray-dried which creates ball-like agglomerates of up to 55... 

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