Secagem em leito de espuma (foam-mat drying) aplicada em alimentos: uma revisão

Abstract

Drying is one of the most used unit operations for food preservation. Several products of commercial importance undergo this process, such as coffee, powdered milk, grains, flours, dehydrated fruits, and others. However, the heat dehydration process can cause losses in various product´s sensory quality and nutritional value. Due to this, several kinds of drying processes (and process combinations) are carried out to minimize some of these losses in food. In this aspect, foam-mat drying is shown to be an advantageous alternative to other methods, as it efficiently maintains some sensory characteristics of the product. This method consists of producing a stable foam of the food to be dried with the use of foaming agents. This foam is spread on a surface and dried by the proper method, can be by convective drying, by microwave, by lyophilization and even by spray dryer. Finally, the product is ground to obtain powdered food. Thus, this work aims is to carry out a literature review on foam-mat drying, highlighting the products that are dried by this technique, the main drying methods used in foam drying, the foaming agents that are used, and list the advantages and disadvantages of using this method. In short, it can be concluded with the accomplishment of this study, that this method is more applied for the drying of fruits; the main foaming and stabilizing agents used for foam formation are: egg albumin, Emustab, maltodextrin and liga neutra; and the most used method for drying foam is convective drying.