Introduction

Those who research in food texture have long known that the first bite is a critical element of the feeding process. It is probable that many sensory decisions about the nature of the food mechanical properties that control particle fracture are made at this point (Bourne, 2002; Vincent et al., 2002). At least this is likely to be true for homogeneous foods that do not change much in texture as they are chewed (but is much less valid for industrially processed foods that melt or dissolve in the mouth). This “fact” appears to be recognized culturally, and is often imbued with social importance, such as when someone is expected or encouraged to express his or her appreciation of a dish at a social occasion immediately after “trying” something by biting into it (Visser, 1991). Taste is, of course, involved in such assessments, but texture nearly always has a role too.

Despite this interest, the first bite has not been the subject of much mechanical investigation. What happens when humans bite into food particles with their incisors? Is there simply flow of the food particle as the upper and/or lower teeth ease their way through it so as to eventually contact? It might be felt that the name “incision” implies that this is what happens. However, is fracture of the food particle involved?