Adhesion of liquid food to packaging surfaces: Mechanisms, test methods, influencing factors and anti-adhesion methods

The adhesion of liquid food to packaging surfaces is an unsolved problem in the food industry. The theoretical backgrounds that are provided in this article are based on an adequate understanding of the mechanisms of adhesion between liquid food and packaging materials. Various mechanisms of liquid food adhesion are reviewed, such as mechanical interlocking, thermodynamic adsorption, diffusion, and electrostatic adsorption. The available tests and calculation methods are summarized and discussed, but there is no universal test standard. Basing on several available liquid food adhesion cases, it was found that liquid food adhesion results from multiple factors, such as rheological properties, surface tension, philicity, and roughness. Finally, we summarize some of the anti-adhesion methods developed in related fields, including surface coating technologies, surface structure design, and ecologically friendly approaches. It is important to produce re-entrant geometric structures combined with low surface energy compounds in the design of anti-adhesion packaging. In addition, for food applications, more attention should be paid to ecologically friendly materials. Comprehensive and systematic examination of these aspects would be conducive to the development of anti-adhesion materials for food packaging. (C) 2018 Elsevier Ltd. All rights reserved.