Fats and waxes in microencapsulation of food ingredients

Abstract

Microencapsulation is a broad area of research with applications in drug delivery, cosmetics, and prepared foods. It is a process in which a substance (solid, liquid, or gas) is incorporated into a matrix, generally in the form of fine particles. The particles can exist as a suspension in the liquid media (emulsions) or in a dry form. Microencapsulation allows the protection of sensitive ingredients, the controlled release of food and pharmaceutical actives, the miscibility of substances with food matrices, and the transformation of liquids into more manageable solid forms. Depending on the desired encapsulated product architecture, several techniques include emulsification, spray-drying, spray-cooling/chilling, freeze-drying, fluidized bed coating, centrifugal extrusion, centrifugal suspension separation, coacervation, and liposomal entrapment have been utilized and are discussed in details elsewhere in this book. In food, one or more materials from the following categories can be used as carriers: carbohydrates, proteins, gums, fats and waxes. Material selection is dictated by the encapsulation techniques, the active ingredient, the release mechanism, the properties of the carrier material itself, and the application scenarios. Since the properties of the carrier material are of vital importance, a holistic understanding of their fundamental properties is necessary. In this chapter, we will focus on fats and waxes as carriers. Fats and waxes are often chosen because of their melt properties and moisture barrier properties. These are essential in both microcapsule fabrication and release mechanisms. This chapter will discuss the impact of chemical structure of fats and waxes on their physical characteristics such as crystallization, melting, and chemical barrier properties. We will also discuss applications of microencapsulated products where fats and waxes are employed as carriers.