Application of fracture mechanics to the texture of food

The fracture mechanics of food is a rational and useful branch of materials science which can yield information of more general interest. The critical stress intensity factor, K-IC, is a valid replacement for the organoleptic (sensory) assessment of "hardness" or "crunchiness" in fruit and vegetables and suggests that crack initiation and propagation in these foods is controlled by factors similar to those found in engineering materials. The work to fracture, W-f of such materials is from 1 to 500 J m(-2). By contrast "crispness", an attribute of foods with low water content and W-f of around 1 J m(-2) is a distinct and separate parameter whose understanding requires knowledge of the fracture behaviour of glassy cellular materials and the deconvolution of the sensory cues, while chewing, of sound and muscular proprioception. (C) 2004 Elsevier Ltd. All rights reserved.