Techniques for internal and surface structure characterisation of food powders

Food powders represent a great portion of food products, ranging from raw materials and ingredients such as flours and spices, to processed products like instant coffee or powdered milk. Food powders differ in composition, microstructure, particle size, chemical and physical characteristics, and therefore functionality and application. In food production, the structural properties of powders have a great effect on their stability, functionality and applicability. Furthermore, the undesirable structure of powders (e.g., collapsing and caking) can be accidentally formed during production and storage. Therefore, the characterization of food powder structure and properties is important for controlling the product quality during processing, storage and further applications. To this end, many analytical techniques with wide variations in the degree of selectivity and sensitivity have been developed. In this chapter, we provide an overview of the principles, as well as the reported studies of different analytical techniques that have been used to study the constituents of food powders and their important properties, such as thermal properties, porosity, particle size and charge, water sorption and morphology.