Anatomical, functional, physiological and behavioural aspects of the development of mastication in early childhood

Mastication efficiency is defined as the efficiency of crushing food between the teeth and manipulating the resulting particles to form a swallowable food bolus. It is dependent on the orofacial anatomical features of the subject, the coordination of these anatomical features and the consistency of the food used during testing. Different measures have been used to indirectly quantify mastication efficiency as a function of children's age such as observations, food bolus characterisation, muscle activity measurement and jaw movement tracking. In the present review, we aim to describe the changes in the oral physiology (e.g. bone and muscle structure, teeth and soft tissues) of children and how these changes are associated with mastication abilities. We also review previous work on the effect of food consistency on children's mastication abilities and on their level of texture acceptance. The lack of reference foods and differences in testing methodologies across different studies do not allow us to draw conclusions about (1) the age at which mastication efficiency reaches maturity and (2) the effect of food consistency on the establishment of mature mastication efficiency. The effect of food consistency on the development of children's mastication efficiency has not been tested widely. However, both human and animal studies have reported the effect of food consistency on orofacial development, suggesting that a diet with harder textures enhances bone and muscle growth, which could indirectly lead to better mastication efficiency. Finally, it was also reported that (1) children are more likely to accept textures that they are able to manipulate and (2) early exposure to a range of textures facilitates the acceptance of foods of various textures later on. Recommending products well adapted to children's mastication during weaning could facilitate their acceptance of new textures and support the development of healthy eating habit

Oral processing and matrix composition affect aroma release and particle size distribution after consumption of coffee-creamer emulsions.

International audienceContext and objectives: In humans, the main events that contribute to in-mouth emulsion breakdown are shear forces due to tongue movements and action of saliva. To date, most of the studies on the field were conducted on model emulsions and little is known about creamer emulsion and in particular hot coffee/creamer emulsions. In this context, the objective of the present work is to better understand how human oral physiology may govern the in-mouth breakdown of coffee-creamer beverages with consequence of food bolus structure and aroma release and to focus on saliva role and composition in particular. Methodology: The work was conducted on 7 coffee-creamer matrices differing by the amount of salt, fat and texturing agents. In vivo aroma release, mouth coating and bolus structure and moistening were followed on 12 subjects with highly variable saliva composition. Eight aroma compounds (butanone, 2-methylfuran, 3-methylbutanal, furfural, pyridine, acetoin, 2,3-pentanedione, diacetyl) were followed in vivo and online by PTR-ToF-MS. Matrix coating was evaluated thanks to fluorimetric methodology. Particle size distribution (PSD) of the food bolus was evaluated with laser granulometry. Saliva properties (viscosity, composition) and oral volume were also measured in each panellist. Statistic was performed through multivariate and anova analysis. Results: In vivo aroma release was mostly explained by oral physiology, the most influenced aroma being diacetyl, 2,3-pentanedione & 3-methylbutanal. Aroma persistence is mainly linked to oral volume, salivary flux and composition (proteolysis). Aroma release depends also on coating: the higher the coating, the higher the aroma release and conversely for aroma persistence. Mouth coating depends on oil droplet flocculation in the bolus, bolus moistening, salivary flux and oral volume: the higher these parameters, the higher the coating. At last, bolus structure (PSD) is matrix dependant and not subject dependant except for 1 matrix differing by its texturing agent. To conclude in vivo aroma release after consumption of coffee-creamer matrices is mainly influenced by the subjects and in particular salivary composition while food bolus structures is principally driven by the product formulation. These results can help to formulate coffee creamer matrices better adapted to oral physiology and thus to consumer liking

Changing Wheat Bran Structural Properties by Extrusion-Cooking on a Pilot and Industrial Scale: A Comparative Study

Extrusion-cooking can be used to change the techno–functional and nutrition-related properties of wheat bran. In this study, pilot-scale (BC21) and industrial-scale (BC45) twin-screw extrusion-cooking using different types of extrusion (single-pass, double-pass and acid extrusion-cooking) and process parameters (temperature, moisture) were compared for their impact on wheat bran. When applying the same process settings, the higher strong water-binding capacity, extract viscosity and extractability displayed by bran extruded using the industrial set-up reflected a more considerable wheat bran structure degradation compared to pilot-scale extrusion-cooking. This was attributed to the overall higher specific mechanical energy (SME), pressure and product temperature that were reached inside the industrial extruder. When changing the type of extrusion-cooking from single-pass to double-pass and acid extrusion-cooking, wheat bran physicochemical characteristics evolved in the same direction, irrespective of extruder scale. The differences in bran characteristics were, however, smaller on industrial-scale. Results show that the differentiating power of the latter can be increased by decreasing the moisture content and increasing product temperature, beyond what is possible in the pilot-scale extruder. This was confirmed by using a BC72 industrial-scale extruder at low moisture content. In conclusion, the extruder scale mainly determines the SME that can be reached and determines the potential to modify wheat bran

Role of Physical Bolus Properties as Sensory Inputs in the Trigger of Swallowing

International audienceBackground: Swallowing is triggered when a food bolus being prepared by mastication has reached a defined state. However, although this view is consensual and well supported, the physical properties of the swallowable bolus have been under-researched. We tested the hypothesis that measuring bolus physical changes during the masticatory sequence to deglutition would reveal the bolus properties potentially involved in swallowing initiation. Methods: Twenty normo-dentate young adults were instructed to chew portions of cereal and spit out the boluses at different times in the masticatory sequence. The mechanical properties of the collected boluses were measured by a texture profile analysis test currently used in food science. The median particle size of the boluses was evaluated by sieving. In a simultaneous sensory study, twenty-five other subjects expressed their perception of bolus texture dominating at any mastication time. Findings: Several physical changes appeared in the food bolus as it was formed during mastication: (1) in rheological terms, bolus hardness rapidly decreased as the masticatory sequence progressed, (2) by contrast, adhesiveness, springiness and cohesiveness regularly increased until the time of swallowing, (3) median particle size, indicating the bolus particle size distribution, decreased mostly during the first third of the masticatory sequence, (4) except for hardness, the rheological changes still appeared in the boluses collected just before swallowing, and (5) physical changes occurred, with sensory stickiness being described by the subjects as a dominant perception of the bolus at the end of mastication. Conclusions: Although these physical and sensory changes progressed in the course of mastication, those observed just before swallowing seem to be involved in swallowing initiation. They can be considered as strong candidates for sensory inputs from the bolus that are probably crucially involved in the triggering of swallowing, since they appeared in boluses prepared in various mastication strategies by different subjects

Sequential analysis of bolus characteristics.

<p>Changes observed during the progress of masticatory sequence in mechanical hardness (A), adhesiveness (B), cohesiveness (C) and springiness (D) calculated on data obtained from TPA performed at 65% deformation, associated changes in proportions of subjects perceiving hardness (E) stickiness (F) and dryness (G) as being dominant in the bolus, and bolus median particle size (H). Bars represent slopes calculated between values from two consecutives boluses.</p