Microencapsulation is a technology that physically wraps sensitive ingredients in a protective matrix. This may be required for several reasons, such as: 1) to contain aromatic compounds that can be rapidly evaporated or aromas that may be lost during storage, 2) to avoid undesirable interactions between the matrix and the aromas, 3) to minimize interactions between volatile compounds (flavor/flavor), 4) to protect substances against oxidative reactions, 5) to control and prolong the release of probiotics, drugs and/or flavor. Materials that have been microencapsulated include: enzymes, probiotics and microorganisms, acids, bases, oils, vitamins, antioxidants, salts, gases, pharmacologically active peptides and amino acids, flavorings and colorings. Several materials have been employed as microencapsulants, such as: gums (carrageenan, alginate and gum arabic), carbohydrates (starch, maltodextrin, β-cyclodextrin and chitosan), celluloses (cellulose acetate phthalate) and proteins (gelatin and dairy protein isolates). In this chapter we discuss some of the variables, such as the concentrations of the reactants used, that affect the formation of microencapsulation materials.