Instrumental and sensory evaluation of crispness: I—In friable foods

Using the Constant Loading Rate Texture Testing instrument it was possible to extract from the deformation/time and force/time curves together with the sound emitted from the samples during the test, those variables included in both the definition of crispness and the assumption that in the case of friable foods crispness may be regarded as ‘compressive brittleness’.Significant correlations (P<0·01) were obtained between sensory crispness and the instrumental variables: equivalent sound level L_eq (r = 0·701), ratio of work done during fracture to total work W_F/W_T (r = 0·878) and fracture or collapse rate (r = 0·570).A poor correlation between sensory crispness and both sensory hardness (r = 0·398) and instrumental fracture force (r = 0·018) indicates that a hard friable food material is not necessarily a crisp one, whereas the highly significant correlation between sensory crispness and both sensory sound intensity (r = 0·908) and instrumental L_eq (r = 0·701) indicates the importance of sound in the sensory and instrumental evaluations.The results of regression analysis showed a number of almost equally well fitting equations with the ratio W_F/W_T and L_eq as the dominant variables in predicting sensory crispness in friable foods.