Introduction

Summary

To the biologist, especially the zoologist, the mechanical properties of food are treated rather vaguely: from an early age one is taught that carnivorous mammals have special teeth for coping with meat, but the properties of the meat which is being coped with are left variously as vague, assumed or obvious. The real answer is not only that the mechanical properties of meat are very subtle and difficult to measure, but that they are variably dependent upon a range of factors, few of which are properly understood (Purslow, this volume). Problems can be taken to a finer degree of resolution: within the range of animals which eat other animals it is possible to differentiate between the dentition of those which are specialised to eat hard-bodied insects (e.g. beetles) and those which can eat soft-bodied insects (e.g. caterpillars). Recent work (J.F.V. Vincent and S. Strait, unpublished results) suggests that the differences in dentition in these two types of animal (which may be closely related bats, or primitive primates) are based on the fracture mechanics of the food items – beetles are brittle and can be crushed; caterpillars are more ductile and have to be cut.

Food scientists are aware of some of these subtle differences in the mechanical properties of food and their implications. Much current research in industry and academia is directed at understanding the mechanics of food and the ways in which the mechanical properties of a wider variety of starting materials can be brought into the relatively narrow area of mechanical competence of the mouth. This can be illustrated by considering man's early efforts in food science.