On five separate occasions, eight volunteers were asked to consume five edible gels with known texture and flavour properties. The electrical activity of their temporal and masseter muscles was recorded using electromyography (EMG). The electrode voltages were sampled at a rate of 1 kHz, starting when each volunteer began to masticate, and terminating when the volunteer indicated that the gel's flavour could no longer be perceived. Data from the mastication phase (first 20 s) were Fourier transformed to give a power spectrum in the frequency domain. Upon visual examination, the low frequency (< 10 Hz) region was found to contain spectral features that differ between volunteers, and the differences were generally consistent between sessions. Principal component analysis (PCA) supported this finding, by showing some clustering of the scores from different volunteers. However, when PCA was applied to the whole of the frequency range, the clustering became much more pronounced, indicating that higher frequencies also contribute to the distinction between volunteers. Clusters of readings from each volunteer were almost entirely separated using internally cross-validated canonical variate analysis (CVA), showing that each individual demonstrated characteristic and consistent mastication behaviour. Finally, a statistically significant association was found between the integrated power spectrum and the concentration of flavour compound in the gels; however, a similar relationship was discovered to exist between the flavour and the texture, as determined by cutting and compression. Hence, it was not possible to determine conclusively whether flavour alone has an effect on mastication characteristics.
|Journal of Texture Studies
|Published - May 2002