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

Abstract

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. Two sets of conditions were distinguished. The first one was obtained when the saliva film is thin, in which case food bolus viscosity has a strong impact on mucosa coating and on flavor release. More importantly, we demonstrated the existence of a second set of conditions. It was obtained when the saliva film is thick and the food bolus coating the mucosa is very diluted by saliva during the swallowing process and the impact of its viscosity on flavor release is weak. This last phenomenon explains physically in vivo observations for Newtonian food products found in the literature. Moreover, in this case, the predicted thickness of the mix of food bolus with saliva coating the mucosa is approximately of 20 μm; value in agreement with orders of magnitude found in the literature.

Fabrication of Artificial Food Bolus for Evaluation of Swallowing

“…This is probably because participants recognized this bolus as sol phase. Previous studies revealed that solution or sol type foods indicate less than 20 kPa in Young’s modulus [30]. Altogether, it was confirmed that the fabricated artificial food bolus reflects one's normal swallowing.…”

Combined effect of cheese characteristics and food oral processing on in vivo aroma release

“…Tactile and mouthfeel sensations occur after swallowing which reflect sensory properties of food coatings . This coating depends both on product characteristics and physiological parameters such as salivary flow, and could explain differences in aroma release curves . Until now no experimental study has been conducted on in vivo aroma release from real foods during the whole consumption process, from the beginning of mastication to the end of mouth cleaning, while considering the effect of saliva.…”

Combined influence of streaming potential and substrate compliance on load capacity of a planar slider bearing

“…[2][3][4]6 Such deformable substrates are particularly relevant from a biological perspective, and there have been a number of rigorous studies in recent years to fundamentally understand the mechanics of these scenarios. [7][8][9][10][11][12] The concerned interaction between the lubricating fluid and its confining boundaries may, in addition, be complicated by the transport of ionic species within the flow medium because of electro-chemical-hydrodynamic interactions. The resultant interactions between the compliant surface and electrostatic transport in the lubricating fluid are by no means straightforward and are yet to be addressed in a comprehensive manner by the research community.…”