Fracture properties of foods: Experimental considerations and applications to mastication

Foods are broken down during oral processing, which for solid foods often involves fracture. The aim of this article is to review previous research applying fracture mechanics to mastication, the effect of selected physiological variables on the fracture of foods in the mouth, and certain experimental methods that can be used to quantify the fracture properties of foods relevant to mastication. Fracture mechanics defines food properties that influence mastication, such as fracture stress, fracture strain, and toughness. Additionally, fracture mechanics provides a quantitative way to interpret the effect of physiological variables that influence the fracture of foods in the mouth, for example saliva, temperature change, and variations in strain rates applied by the teeth for different types of food. Previous research has determined displacement and stress-limited indices to link fundamental fracture properties of foods to their behavior during mastication. There are several experimental methods to measure the fracture properties of foods, which include compression, wedge, puncture, and tensile tests. Finally, there are opportunities for future studies to establish structure—property—oral processing relationships, which could inform the design of novel processes and products.