EFFECTS OF SAMPLE SIZE AND PRIOR MASTICATION ON TEXTURE JUDGMENTS

Two experiments were conducted. In the first, 25 untrained subjects judged the hardness and chewiness of three different food samples following either 0, 60, 120, or 180 s of adaptive chewing on an experimental gum compound. No effect of the adaptive chewing was found, in spite of observable and self-reported masticatory fatigue induced by the experimental procedures. These data fail to support the prevalent use of procedural limits on the number and temporal spacing of samples in sensory texture studies. In the second experiment, six groups of subjects (n = 107) judged the hardness and chewiness of two series of food samples that varied in physical size (volume). The groups differed in the degree to which cues about the true size differences were made available. Results showed both hardness and chewiness judgments to increase as a function of sample size, independently of subject awareness of the size differences. These data support the use of procedural controls on sample size, but fail to provide evidence of a size constancy phenomenon. A rheological explanation is proposed to account for the observed sensory effect.