Insight Into Consumers’ Assessments of Biscuit Texture Based on Mastication Analysis – Hardness Versus Crunchiness

Nineteen ordinary consumers assessed the hardness, crunchiness and crumbliness of a series of biscuits exhibiting texture differences. Chewing patterns were obtained from all of the subjects eating the same samples by simultaneous recording of masticatory muscle activity and jaw movement. There was a strongly significant inverse correlation between hardness and crumbliness and weaker but significant correlations between hardness and crunchiness (positive) and between crunchiness and crumbliness (negative). The hardness/crumbliness dimension was well represented by several instrumental measures of the mechanical properties of the samples and by several descriptors assessed by a trained sensory panel. Crunchiness gave ambiguous relationships with these objective measures. Chewing data indicated an increase in masticatory muscle effort between the first 5 chews and the next 5 chews with a subsequent decline in effort to the end of the chewing sequence. This was associated with a transfer of effort from a principally compressive force during the initial chews, to a mixture of compressive (fracture) force and grinding (shear) force during later chews. Mastication of the harder and crunchier samples required more total chewing effort. Principal component analysis demonstrated a relationship between sensory hardness (and conversely, crumbliness) and the chewing effort during the first 5 chews, and between crunchiness and the chewing effort during the subsequent 5 chews. This study indicates the importance of the temporal changes occurring in the sample during mastication to perception of textural characteristics.