Mechanical properties of foods responsible for resisting food breakdown in the human mouth (original) (raw)
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The Influence of Initial Breakage on Size Reduction during Habitual Chewing of a Solid Test Food
Archives of Oral Biology, 2020
Food comminution during chewing is due to intra-oral particle selection and subsequent breakage. Under conditions of habitual chewing and a nearly complete selection, the influence of initial breakage on particle size reduction was studied in trials with a first chewing cycle (N = 1) from a sequence of randomized trials with various cycle numbers. Furthermore, relationships were examined between degree of fragmentation from breakage (r-fr), molar maximal bite force (MBF) and chewing efficiency (the number of cycles needed to half the initial particle size, N(1/2-Xo)). Design: Thirty-one subjects with a natural dentition chewed samples of 2 half-cubes (9.6 × 9.6x4.8 mm) of Optosil®, using sequences with 1-7 cycles, in 2-10 randomized trials; 10 trials with one cycle. Particle size distributions by underweight, characterized by median particle size, X 50 , were obtained using sieving. N(1/2-Xo) was derived from the log(X 50)-log(N) relationship. and r-fr from the cumulative distribution of underweight fractions of damaged particles for N = 1. MBF was determined on both sides of the jaw using a force transducer and averaged. Conclusions: A strong, decreasing regression occurred in X 50 at N = 1 with r-fr (R 2 = 0.934, p < 0.001). The decreasing regression of N(1/2-Xo) with r-fr was moderately strong (R 2 = 0.454; p < 0.001). Thus, initial size reduction is strongly determined by breakage and overall reduction partly, when chewing small amounts of particles. N(1/2-Xo) vs. MBF and r-fr vs. MBF were weakly related (R 2 ≤0.124, p = 0.052-0.127). The lack of a pronounced relationship between r-fr and MBF suggests that either MBF is not relevant but supra-threshold force, or that another factor, occlusion, may influence breakage.
The role of mechanical properties of brittle airy foods on the masticatory performance
Journal of Food Engineering, 2010
This work investigates the mastication of two samples of typical cereal food products previously characterised by different sensory, textural and mechanical properties, by two complementary approaches. Electromyographic records and image analysis of chewed food particles first confirm the importance of the brittle behaviour of the products on human mastication. For both products, the fragmentation is followed by a significant agglomeration after less than 10 chewing cycles, both phenomena being correlated to the force magnitude and its evolution. Then, artificial mastication is undertaken to shed more light on the capability of the chewing simulator to discriminate both products under dry mastication conditions. The results depict a qualitative agreement with human mastication and texture properties.
Force-deformation properties of artificial and natural foods for testing chewing efficiency
The Journal of Prosthetic Dentistry, 1992
The force-deformation characteristics of two artificial test foods (Optosil and Optocal) for measurements of food comminution during mastication were investigated in a bite simulator and compared with those of carrots and peanuts. The influence of cusp geometry was evaluated by use of a flat plate and three cusp forms. The forces at the yield point were lower for Optocal than for Optosil artificial test food. The forces needed for Optocal overlapped those needed for carrots and peanuts. The natural foods showed more variation in the force and percentage of deformation at the yield point than the artificial foods. The artificial foods reflected the differences in cusp form better than did the natural foods. The use of artificial foods fulfills a need for standardization and warrants consideration in studies ofmastication.(J
Methods for analysing the breakdown of food in human mastication
1983
4 method is described for measuring the rate at which carrot particles are broken down in chewing. In IO subjects, this rate declined progressively throughout mastication. This was analysed in terms ofi two variables: (a) the intra-oral selection of particles for fracture, (b) the size distribution of fractured pieces of those particles. When intra-oral selection was measured by different methods, it depended mainly upon particle size. The selection of small particles might depend on the number of chews taken after I.he food was placed in the mouth. The size distribution of fractured pieces was obtained from one chew on three different particle sizes. These distributions were partially described by two different equations whose characteristics suggest that carrot particles are subjected to only one breakage per chew and that the number of fragments formed per breakage is small. It is suggested that the cusps present on the post-canines were important in determining this breakage pattern, and that the dependence of selection on particle size was primarily responsible for the decline in the rate of breakdown with increasing numbers of chews.
Foods
This study assessed the usefulness of the miniature Kramer shear cell to determine relevant instrumental parameters of solid foods and bolus counterparts, examining their relationships with oral processing behaviors to obtain greater knowledge about the texture perception process. Six solid foods with different textural properties were tested. Bolus mechanical properties were also determined by means of cone penetration tests and rheological measurements, and their particle size distributions by sieving. Oral processing behavior (chewing time, number of chews, chewing rate, eating rate) and food saliva uptake (SU) of a young volunteer and a panel of 39 untrained participants were analyzed. The Kramer mechanical properties were very suitable for detecting different levels of food and bolus textural hardness and fracturability and the associated degrees of fragmentation achieved during mastication. Chewing time and number of chews were highly correlated with Kramer food and bolus mech...
Fragmentation of a Viscoelastic Food by Human Mastication
Journal of the Physical Society of Japan, 2010
Fragment-size distributions have been studied experimentally in masticated viscoelastic food (fish sausage). The mastication experiment in seven subjects was examined. We classified the obtained results into two groups, namely, a single lognormal distribution group and a lognormal distribution with exponential tail group. The facts suggest that the individual variability might affect the fragmentation pattern when the food sample has a much more complicated physical property. In particular, the latter result (lognormal distribution with exponential tail) indicates that the fragmentation pattern by human mastication for fish sausage is different from the fragmentation pattern for raw carrot shown in our previous study. 11) The excellent data fitting by the lognormal distribution with exponential tail implies that the fragmentation process has a size-segregation-structure between large and small parts. In order to explain this structure, we propose a mastication model for fish sausage based on stochastic processes.
Fundamental Fracture Properties Associated with Sensory Hardness of Brittle Solid Foods
Journal of Texture Studies, 2012
A series of biscuit-like model foods that vary primarily in hardness, while keeping other sensory attributes less variable, was developed and used to investigate the relationship between fundamental fracture properties and the sensory perception of hardness of brittle solid foods. Fifteen biscuit samples were evaluated by both a trained sensory panel and three instrumental tests (three-point bending test, singleedge notched bend test and modified texture profile analysis), and their relationships were determined by simple linear regression analysis. Correlations revealed that the perceived hardness during biting or chewing is fracture related, and it is directly related to the amount of stress required to initiate and propagate a crack in a material (i.e., fracture stress [s] and critical stress intensity factor [KIC], respectively). The fracturing of these hard and brittle biscuits appeared to be associated with the release of energy as sound, and thus, the perceived hardness and crunchiness were indistinguishable.
2012
Color-and form-labeled particles of Optosil (version 1980, a silicone rubber, Bayer, Leverkusen, Germany) have been used previously to quantify the underlying processes of food comminution, i.e., selection and breakage, in subjects with normal dentitions. The aim of this present study was to develop a weakened Optosil that is suitable for the study of selection and breakage in subjects with impaired chewing ability. Half cubes (4.8 ¥ 9.6 ¥ 9.6 mm) were subjected to load tests to determine the force, deformation and work at particle fracture for periods of up to 6 months. Methods of modifying Optosil were (1) heat-treating the base material to produce "Optosoft"; (2) mixing the base of Optosil or Optosoft with a nonprescribed catalyst (Verone, Davis Schott Lander & Davis Ltd, Herts, England) to produce "Optoweak" or "Optosoft-weak" and (3) heating half cubes that were preweakened. A weakened and stable test food that is suitable for labeling and reuse has been obtained by colordyeing the Optosoft base and using Verone ("dyed-Optosoft-weak"). PRACTICAL APPLICATIONS Every chewing cycle begins with selection, in which food particles have a chance to be placed between the teeth in such a way that they are at least damaged, if not broken, by the subsequent breakage process. Bite force is reduced in certain patients, e.g., patients with neuromuscular diseases, following orthognathic surgery and in full denture wearers, and the action of the tongue and cheeks differs when compared with healthy individuals. Both factors are important in selection and breakage. The artificial test food Optosil has a large fracture force so that it is difficult to chew for subjects with an impaired chewing ability. This problem has been solved by developing a weaker test food, i.e., "dyed-Optosoft-weak." This test food allows the study of selection and breakage in general with color-and form-labeled particles and to determine the effect of medication, orthognathic surgery or oral implants on these processes. bs_bs_banner A journal to advance the fundamental understanding of food texture and sensory perception