Adhesion of Food on Surfaces: Theory, Measurements, and Main Trends to Reduce It Prior to Industrial Drying

Adhesion is characterized by the force of attraction between a material and a surface. This phenomenon occurs in several processes (such as baking, chocolate or powder production, bacterial adhesion to industrial plants), causing product losses and contamination. In this sense, parameters as surface energy and food composition play an essential role in adhesion study, being an essential field of understanding to optimize processes. This review approaches the adhesion fundamentals and their relation to food composition and surface properties. Moreover, it describes the tests usually applied to measure the adhesion of food on surfaces. Besides, this work shows that, regarding the literature, it is difficult to differentiate the adhesive from the cohesive forces. Food adhesion in different dryers and alternatives to reduce the problem are discussed, considering that the deposition of dried material on supports and dryer walls causes low yields and operational and handling problems.