An engineering method to evaluate the crisp texture of fruit and vegetables

Precise measurements of the deformation and fracture behaviour of food can be difficult because of problems associated with the produce, for example, sample preparation, gripping, size and geometry. The aim of this study was to characterise fruits and vegetables in terms of fracture properties using an established engineering test method and geometry, the Single-Edge Notch ed Bend (SENB). The SENB geometry was found to be readily applicable to cri sp food produce such as carrots, celery, and apples, which exhibit linear e lastic behaviour up to fracture. Fracture toughness and fracture energies w ere found to be in the range 10-50 kPa m(1/2) and 40-400 J m(-2), respectiv ely. The structure of these materials was confirmed, using confocal microsc opy, and related to the observed fracture behaviour. Cell size and intercel lular spaces influenced the values of fracture toughness and fracture energ y.