Methods to characterize the structure of food powders - a review.

Food powders can exist in amorphous, crystalline or mixed structure depending on the order of molecular arrangement in the powder particle matrices. In food production, the structure of powders has a greatly effect on their stability, functionality, and applicability. The undesirable structure of powders can be accidentally formed during production. Therefore, characterization of powder structure as well as quantification of amorphous-crystalline proportions presenting in the powders are essential to control the quality of products during storage and further processing. For these purposes, many analytical techniques with large differences in the degree of selectivity and sensitivity have been developed. In this review, differences in the structure of food powders are described with a focus being placed on applications of amorphous powders. Essentially, applicability of common analytical techniques including X-ray, microscopic, vapor adsorption, thermal, and spectroscopic approaches for quantitative and qualitative structural characterization of food powders is also discussed.