Engineering aspects of confectionery coatings in baked products

Abstract

Confectionery coatings are popular for industrial and home applications because they enhance the food aspect, giving texture, gloss, color, and sweet flavor. There is a need to give special attention to the application of this type of coatings in processed foods like baked goods, such as cookies, donuts, cakes, muffins, pastries, etc. An adequate formulation of confectionery coatings is an important variable in the manufacture process, because their composition (especially moisture, fat, and sugar contents) can influence the quality of the final product. In this way, modifications in the lipid profile and the carbohydrate content in the formulations can generate technological problems relating to variations in the drying times, migration of water inside the baked food, and changes in the water sorption properties of the coated product. The response of coated foods to storage conditions will determine their shelf life. Coatings have the potential to protect the core food, but variations in the external temperature and humidity can influence the moisture content and/or water activity of the coating. The film thickness is affected by different coating techniques as well as the rheological behavior of the film-forming fluid. Since the rheological properties influence the film characteristics (thickness, leveling capacity, homogeneity), both measurement and evaluation of these properties are necessary for optimal operation and processing design. In addition, the mathematical modeling of the film formation and deposition during coating processes, taking into account rigorous mass and momentum balances, can be useful to control and predict the thickness and homogeneity of the film. This information can readily satisfy the quality requirements of the final product and decrease the common trial-and-error procedures. For this reason, the present chapter will focus on the analysis of some engineering aspects (formulation, drying and sorption phenomena, rheology, and mathematical modeling of film formation and deposition) of confectionery coatings applied in baked products.