%0 Book Section %1 statphys23_0743 %A Kobayashi, N. %A Kohyama, K. %A Sasaki, Y. %A Matsushita, M. %B Abstract Book of the XXIII IUPAP International Conference on Statistical Physics %C Genova, Italy %D 2007 %E Pietronero, Luciano %E Loreto, Vittorio %E Zapperi, Stefano %K distribution dynamic fragmentation human lognormal mastication scaling sequential statphys23 topic-4 %T Statistical Laws for Food Fragmentation by Human Mastication %U http://st23.statphys23.org/webservices/abstract/preview_pop.php?ID_PAPER=743 %X Mastication is the first process in eating behavior. This process is a very complex set of subprocesses including the size reduction of food and the lubrication of food particles. In general, a major problem of the oral process observation analysis is lack of visualization of what goes on. This fact indicates that by investigating the food states before and after eating experimentally and numerically, we can understand some of principal features of mastication processes and propose some phenomenological models. From physical viewpoints, mastication is regarded as an example of a far-from-equilibrium phenomenon without any theory based on first principles. We believe that it is important to study macroscopic patterns to understand dynamics of mastication. We investigated, therefore, the mechanism of food fragmentation by human mastication through macroscopic pattern formation. As the first approximation, mastication is regarded as the sequential fragmentation in the oral cavity. Therefore, we have investigated the fragment-size distribution produced by human mastication. We report that a single lognormal distribution well fits the entire region for masticated food fragments for several chewing strokes (N. Kobayashi, K. Kohyama, Y. Sasaki and M. Matsushita, J. Phys. Soc. Jpn. 75, 083001 (2006)). As the number of chewing strokes increased, the fragment-size distribution changed from the lognormal distribution to a double-size-group structure, i.e., the smaller group fitted to the lognormal distribution, whereas the larger group represented the power-law behavior. The excellent data fitting by the lognormal and power-law distributions implied that two functions of mastication, a sequential fragmentation with cascade and randomness, and a lower threshold for fragment size affect the size distribution of masticated food fragments. Next, we investigate the scaling property of the shape of food fragments (N. Kobayashi, K. Kohyama, Y. Sasaki and M. Matsushita, J. Phys. Soc. Jpn. 76, 044002 (2007)). Mastication experiments showed that most fragments have more or less isotropic shapes which are independent of the number of chewing strokes, whereas larger fragments than a crossover size have complicated shapes. Since the crossover size had the structure which was dependent on the number of chewing strokes, we have tried to propose dynamic scaling hypothesis analogous to the case of growing self-affine interface. It was found that the dynamic scaling yields fairly accurate values of the scaling exponents. Our results will provide a new observation and insight of not only sequential fragmentation but also construction for physiological measurement. This work was supported by the Program for Promotion of Basic Research Activities for Innovative Biosciences (PROBRAIN).

@incollection{statphys23_0743, abstract = {Mastication is the first process in eating behavior. This process is a very complex set of subprocesses including the size reduction of food and the lubrication of food particles. In general, a major problem of the oral process observation analysis is lack of visualization of what goes on. This fact indicates that by investigating the food states before and after eating experimentally and numerically, we can understand some of principal features of mastication processes and propose some phenomenological models. From physical viewpoints, mastication is regarded as an example of a far-from-equilibrium phenomenon without any theory based on first principles. We believe that it is important to study macroscopic patterns to understand dynamics of mastication. We investigated, therefore, the mechanism of food fragmentation by human mastication through macroscopic pattern formation. As the first approximation, mastication is regarded as the sequential fragmentation in the oral cavity. Therefore, we have investigated the fragment-size distribution produced by human mastication. We report that a single lognormal distribution well fits the entire region for masticated food fragments for several chewing strokes (N. Kobayashi, K. Kohyama, Y. Sasaki and M. Matsushita, J. Phys. Soc. Jpn. 75, 083001 (2006)). As the number of chewing strokes increased, the fragment-size distribution changed from the lognormal distribution to a double-size-group structure, i.e., the smaller group fitted to the lognormal distribution, whereas the larger group represented the power-law behavior. The excellent data fitting by the lognormal and power-law distributions implied that two functions of mastication, a sequential fragmentation with cascade and randomness, and a lower threshold for fragment size affect the size distribution of masticated food fragments. Next, we investigate the scaling property of the shape of food fragments (N. Kobayashi, K. Kohyama, Y. Sasaki and M. Matsushita, J. Phys. Soc. Jpn. 76, 044002 (2007)). Mastication experiments showed that most fragments have more or less isotropic shapes which are independent of the number of chewing strokes, whereas larger fragments than a crossover size have complicated shapes. Since the crossover size had the structure which was dependent on the number of chewing strokes, we have tried to propose dynamic scaling hypothesis analogous to the case of growing self-affine interface. It was found that the dynamic scaling yields fairly accurate values of the scaling exponents. Our results will provide a new observation and insight of not only sequential fragmentation but also construction for physiological measurement. This work was supported by the Program for Promotion of Basic Research Activities for Innovative Biosciences (PROBRAIN).}, added-at = {2007-06-20T10:16:09.000+0200}, address = {Genova, Italy}, author = {Kobayashi, N. and Kohyama, K. and Sasaki, Y. and Matsushita, M.}, biburl = {https://www.bibsonomy.org/bibtex/204b2203da06f8c12ca57907688830abb/statphys23}, booktitle = {Abstract Book of the XXIII IUPAP International Conference on Statistical Physics}, editor = {Pietronero, Luciano and Loreto, Vittorio and Zapperi, Stefano}, interhash = {d6218b49c6785581a8adddce2f89a79e}, intrahash = {04b2203da06f8c12ca57907688830abb}, keywords = {distribution dynamic fragmentation human lognormal mastication scaling sequential statphys23 topic-4}, month = {9-13 July}, timestamp = {2007-06-20T10:16:28.000+0200}, title = {Statistical Laws for Food Fragmentation by Human Mastication}, url = {http://st23.statphys23.org/webservices/abstract/preview_pop.php?ID_PAPER=743}, year = 2007 }