Structure formation spray drying

By achieving random dispersion of the Kaolin in the sodium silicate solution prior to formation of the silica-alumina gel, it was possible to disperse the clay crystals. They condensed somewhat perpendicular to each other and were bound together by silica-alumina gel. I therefore speculated that spray drying, during which the gel system contracts, might create a dual structure. An analogy would be a house built of cards (Kaolin), cemented together with silica-alumina gel. 

The internal structure of the resulting polymeric microspheres depends on the solubility of the peptide/protein in the polymer before being spray dried leading to the formation of reservoir- or matrix-type products (see Figure 1). When the initial dispersion is solution, the final product obtained following spray drying is matrix or monolithic type, that is, polymer particles with a dissolved or dispersed nature of the active ingredient (defined as microspheres). Conversely, when the initial... 

SD is a unique drying process since it involves both particle formation and drying. From a micro-structural viewpoint, the formation of spray-dried powders involves the droplet formation from a liquid state followed by a solidification operation driven by solvent evaporation, as schematically represented in Fignre 32.5. 

The key implication of denaturation of protein is the disruption and possible destruction of both the secondary and tertiary structures of proteins. If a protein is denatured during powder formation while spray drying, the resultant spray-dried powders may not dissolve and lose their therapeutic effectiveness as well as other functionalities such as gelling and emulsification. The denaturation of protein negatively impacts the properties of consumer products when they are used as ingredients. 

Freeze spray drying is applied to substances with otherwise very sticky surfaces, as in the food industry, or to enable the formation of very porous structures with excellent... 

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...

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