Caking Process and Microstructural Changes of Wall Materials Used in Spray-Drying Process

Abstract

The caking of food powders is an unwanted and very common problemthat occurs during processing, handling, and storage. The particles of amorphouspowders may progressively be deformed until they stick to each other, and eventually form agglomerates. This phenomenon is affected bymicrostructure and hygroscopicity; however, other facts are reported as decisivelike stress, humidity, and temperature for caking mechanism and caking kinetics. The caking phenomenon reduces the product qualityand functionality, rehydration, dispersibility, and the shelf life and increases deterioration of organoleptic quality and the formation of lumps and agglomerates. Microscopy techniques have been applied to analyze powdermicrostructure, identifying useful factors to describe changes observed duringprocessing and storage.The aim of this work was to propose a correlation of caking with the glass transition temperature of different wall materials and the powder microstructure.