BOLUS MOISTURE CONTENT OF SOLID FOODS DURING MASTICATION (original) (raw)

The relationship between chewing activity and food bolus properties obtained from different meat textures

Food Quality and Preference, 2002

During chewing, a meat sample is mashed under compression and shear bite forces whilst saliva is incorporated. The resulting mixture is shaped into a cohesive bolus by agglomeration of small particles to trigger a swallow. This study aims to investigate the relationship between meat structure before chewing and texture after various chewing durations, according to the subject's chewing behavior. Twenty-five young adults participated. Electromyography activity (EMG) was recorded from surface electrodes on the elevator muscles during mastication of cold beef (5 g). Two different meat textures were obtained by varying aging and cooking temperature. Subjects were asked to chew and then to spit out the bolus either after a constant chewing duration (7 s) or when the bolus was ready to be swallowed. Boluses were then weighed to determine saliva incorporation. Cutting tests were applied to measure maximum shear force and to assess bolus structure homogeneity. From EMG recordings, temporal and amplitude parameters were analyzed. The mechanical shear force was maximal for meat before chewing and decreased for the bolus with the lengthening of the chewing duration. Significant texture differences were found for samples before chewing and for two types of bolus but differences were larger for the bolus after 7 s chewing than for the bolus when ready to be swallowed. The amount of saliva incorporated into the bolus increased with both chewing muscular activity and chewing duration. Finally, the more chewing cycles before swallowing, the more comminuted the meat bolus (lower shear force) and the more saliva was incorporated in it. These results fit with one of the major roles of the saliva, that is, to provide cohesion between particles [Nature 391 (1998) 329] and with the intra-oral management of meat during chewing as analyzed by videofluorography [Arch. Oral Biol. 47 (2002) 267].

Consequences of Individual Chewing Strategies on Bolus Rheological Properties at the Swallowing Threshold

Journal of Texture Studies, 2012

The chewing process transforms food into bolus for a safe swallow. It is known that humans adapt their chewing behavior to food product characteristics. This study aimed at identifying individual chewing strategies of healthy consumers and determining the respective consequences on bolus properties. For that purpose, the chewing activity of 50 subjects was recorded during consumption of five model cheeses. Boluses were collected at the swallowing threshold for rheological analyses. We found that 30% of subjects showed only slight adaptation of chewing activity to product characteristics and thus produced boluses with different rheological properties. Among the 70% of subjects who adapted their chewing behavior, 57% adapted their behavior via chewing time and 40% adapted their behavior via chewing time and muscular contraction amplitude. Among the bolus rheological parameters, only consistency was not influenced by chewing strategies. Hence, it seemed to be a determinant factor of the swallowing threshold for these products.

Particle size distribution in the food bolus after mastication of natural foods

Food Quality and Preference, 2007

The main goal of mastication is to prepare a food bolus suitable for deglutition. The bolus preparation consists in food breakdown and processing during which oral sensations are generated. This study was performed to examine the particle size distribution in the bolus formed by chewing 10 natural foods. Ten young subjects with normal dentition were asked to chew the food and to expectorate the bolus just before swallowing, while masticatory parameters were recorded. The particle size distribution of each bolus was evaluated by wet sieving. The number of cycles, sequence duration and masticatory frequency varied among subjects and foods. The particle size distributions differed among foods but were similar among subjects. The median particle size d 50 gave a range from 0.82 to 3.04 mm allowing a food classification based on the state of the bolus. The d 50 value reflected the fracturability and may be useful to describe food behaviour in the mouth during bolus preparation.

Relationships between saliva and food bolus properties from model dairy products

Food Hydrocolloids, 2011

During food consumption, complex oral processing occurs to transform the food into a bolus, ready to be swallowed. The objective of this study was to relate food, saliva and bolus properties, by using model dairy products, to better understand the role of saliva in bolus formation. Un-stimulated and stimulated saliva was collected from 5 subjects and biochemical and enzymatic properties were measured. Food bolus was then obtained from 8 different dairy products, varying in composition and ranging from liquid to gelled samples. The rate of saliva incorporation, pH, spreading ability and bolus rheological properties were determined. Some correlations seemed to exist between lysozyme activity and bolus properties. Subject and food product had a significant effect on almost all bolus properties. The rheology of bolus was highly correlated with food product texture. Even though preliminary, this approach could be used to better understand stimulus release and perception during food consumption.

Particle Size Distribution of Food Boluses after Mastication of Six Natural Foods

Journal of Dental Research, 2004

There is a large variability between and among individuals in the physiology of mastication, but it is not known whether this produces a similar variability in the particle sizes of food boluses at the end of the chewing process. Food boluses obtained just before swallowing were analyzed in ten subjects (aged 36.7 ± 9.5 yrs) with normal dentition. Food samples of 3 nuts (peanut, almond, pistachio) and 3 vegetables (cauliflower, radish, and carrot) were chewed and expectorated after self-estimated complete mastication. Measurements with sieving and laser diffraction methods indicated that particles were much larger in vegetables than in nuts. Particle size distributions were similar among nuts and among vegetables. Surprisingly, no inter-individual variability was observed in the particle distributions for the 6 foods, although several sequence variables differed markedly. A need for a bolus to be prepared with a precisely determined texture before it can be swallowed may explain the...

A biomechanical model of swallowing for understanding the influence of saliva and food bolus viscosity on flavor release

Journal of Theoretical Biology, 2011

After swallowing a liquid or a semi-liquid food product, a thin film responsible for the dynamic profile of aroma release coats the pharyngeal mucosa. The objective of the present article was to understand and quantify physical mechanisms explaining pharyngeal mucosa coating. An elastohydrodynamic model of swallowing was developed for Newtonian liquids that focused on the most occluded region of the pharyngeal peristaltic wave. The model took lubrication by saliva film and mucosa deformability into account. Food bolus flow rate and generated load were predicted as functions of three dimensionless variables: the dimensionless saliva flow rate, the viscosity ratio between saliva and the food bolus, and the elasticity number. Considering physiological conditions, the results were applied to predict aroma release kinetics.

Understanding the Link between Bolus Properties and Perceived Texture

Journal of Texture Studies, 2013

The relationships between food structure, texture perception and bolus properties during bolus formation are poorly understood. This preliminary single-subject study on three biscuit recipes investigated the links between bolus macrostructure, perceived texture (using temporal dominance of sensations), and mechanical and rheological properties (using back extrusion and consecutive double compression) throughout mastication. The fracture properties of the biscuits dominated textural perception in the early stages of mastication. As mastication progressed, a sensory transition from dry to sticky was accompanied by an increase in "cohesiveness" and decreases in the consistency coefficient, peak force and "adhesiveness." At the point of swallow, the boluses were shear thinning pastes and sticky dominated perception. Consistency coefficient and "cohesiveness" indicated different swallowing thresholds for the different recipes. This study found back extrusion to be a suitable method for characterizing biscuit bolus rheology in the later stages of mastication as it is unaffected by bolus dimensions. PRACTICAL APPLICATIONS Mastication of a solid food involves the breakdown of the food and reassembly with saliva into a deformable bolus that can be swallowed safely. The relationships between the perceived texture and structural, mechanical and rheological properties throughout mastication are not well understood. An understanding of these relationships could aid in the design of foods that can be swallowed safely by the elderly or those with dysphagia, or foods that follow a desired oral processing path and thus have a desired texture profile or flavor release. produced (Hutchings and Lillford 1988; Szczesniak 2002; Bourne 2004). Several studies have investigated bolus properties such as particle size distribution, saliva content and rheological properties at the point of swallow (