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

International audienceAfter 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 a 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 flavour 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 flavour 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

A lubrication analysis of pharyngeal peristalsis: application to flavour release.

International audienceAfter eating a liquid or a semi-liquid food product, a thin film responsible for the dynamic profile of aroma release coats the pharyngeal mucosa. The aim of this article was to analyse the fluid mechanics of pharyngeal peristalsis and to develop a simple biomechanical model in order to understand the role of saliva and food bolus viscosity on the coating of pharyngeal mucosa. We began by analysing the physiology and the biomechanics of swallowing in order to determine relevant model assumptions. This analysis of the literature clarified the types of mechanical solicitations applied on the food bolus. Moreover, we showed that the pharyngeal peristalsis in the most occluded region is equivalent to a forward roll coating process, the originality of which is lubrication by a film of saliva. A model based on the lubrication theory for Newtonian liquids was developed in dimensionless form. The parametric study showed the strong influence of relative saliva thickness on the food bolus coating. A specific experimental device was designed that confirms the model predictions. Two sets of conditions that depend on the relative thickness of saliva were distinguished. The first is characterised by a relatively thin film of saliva: food bolus viscosity has a strong impact on mucosa coating. These phenomena are well represented by the model developed here. The second is obtained when the saliva film is relatively thick: hydrodynamic mixing with saliva, interdiffusion or instabilities may govern mucosa coating. Finally, these results were extrapolated to determine the influence of food bolus viscosity on the dynamic profile of flavour release according to physiological parameters

Scale-down emulsion homogenization: Conditions to mimic pilot homogenizer depending on the emulsifier

The standard tool for emulsification during formulation trials is a homogenizer, which unfortunately requires toomuch raw material and is time consuming. A lab-scale process using a rotor-stator shearing step followed byultrasound treatment was designed, both with lecithin and whey protein, for emulsification as efficient as inpilot-plant trials. Ranges for the lab-scale process were defined (rotor-stator: 5 min, 5000–10000 rpm; sonicationtime: 2–10 min). Process conditions were identified to obtain both emulsions with the same structure at lab andpilot scales: for lecithin, respectively shearing at 10000 rpm/10 min sonication and high pressure for both pilotstages. However, due to protein denaturation, some conditions differed for whey proteins: shearing at 5000 rpminstead of 10000 rpm (all the other parameters being unchanged). Finally, recommendations concerning theposition of the ultrasound probe and temperature control are provided to insure good reproducibility

Structurer l'aliment pour mieux piloter sa déconstruction dans le tube digestif et optimiser la biodisponibilité des nutriments.

Dans un contexte réglementaire contraint et une demande sociale et sociétale en pleine évolution, une refonte complète de l’ouvrage « Aliments fonctionnels » voit le jour. Grâce à la contribution de plus d’une cinquantaine d’experts aux compétences complémentaires, « Aliments fonctionnels » s’enrichit d’approches nouvelles en lien avec la durabilité des systèmes alimentaires.Ainsi cet ouvrage fournit de multiples pistes de réflexion et de nombreux axes de recherche pour l’innovation alimentaire.Aux chapitres des précédentes éditions entièrement réactualisés, s’ajoutent des volets illustrant les comportements, les inégalités sociales, la compréhension des messages, l’acceptabilité des innovations et les enjeux de la durabilité.Ce livre présente donc des questions nouvelles en lien avec la sécurité alimentaire du consommateur et les perspectives d’évolution de la démographie mondiale.« Aliments fonctionnels » s’adresse aux ingénieurs en R&D agroalimentaire, aux professionnels de la nutrition et de l’alimentation, de la santé, aux spécialistes du marketing, de l’innovation et de la communication et à tous les acteurs de la sécurité alimentaire.Les dernières décennies ont vu une augmentation spectaculaire, à l’échelle internationale,des pathologies liées à l’aliment et à l’alimentation. Le surpoids et ses conséquences tellesque les maladies cardiovasculaires ou le diabète de type 2 touchent environ 1,5 milliard d’adultes dans le monde et la plupart des prévisions prévoient que ce chiffre atteindra 3 milliards d’individus à l’horizon 2030. On estime à près de 3 millions le nombre de personnes décédant chaque année du fait de leur surpoids ou de leur obésité. En France, 6,5 millions de personnes sont considérées comme obèses. La proportion des personnes obèses est ainsi passée de 8,5 % à 14,5 % entre 1997 et 2009. L’augmentation de la prévalence est observée dans toutes les tranches d’âge de la population, y compris chez les séniors, avec une exacerbation chez les femmes (15,1 %) par rapport aux hommes (13,9 %). L’augmentation de l’obésité est majoritairement liée à (1) une plus grande consommationd’aliments très caloriques riches en graisses et (2) un manque croissant d’activité physique en raison de la nature de plus en plus sédentaire de nombreuses formes de travail, de l’évolution des modes de transport et de l’urbanisation. Malgré de multiples campagnes de sensibilisation, force est de constater qu’il est difficile de contraindre les personnes en surpoids à accroître leur activité physique. Une des solutions possibles serait donc de proposer au consommateur une offre alimentaire moins calorique, tout en présentant lesmêmes propriétés de rassasiement et de satiété

Mechanistic Model To Understand in Vivo Salt Release and Perception during the Consumption of Dairy Gels

International audienceThe objective of this study was to develop a model to simulate salt release during eating. Salt release kinetics during eating were measured for four model dairy products with different dynamic salty perceptions. A simple in vivo model of salt release was developed to differentiate between the contribution of the individual and of the product to salt release. The most difficult model parameter to determine or predict is the evolution of the contact area between the product and the saliva. Fitting the model to the experimental data allowed us to show that the subject's masticatory performance and product structure determined the contact area between the product and the saliva generated by mastication. Finally, the role of release dynamics on sensory time-intensity profiles is discussed

Ultra-processed foods: how functional is the NOVA system?

BACKGROUND: In the NOVA classification system, descriptive criteria are used to assign foods to one of four groups based on processing-related criteria. Although NOVA is widely used, its robustness and functionality remain largely unexplored. We determined whether this system leads to consistent food assignments by users. METHODS: French food and nutrition specialists completed an online survey in which they assigned foods to NOVA groups. The survey comprised two lists: one with 120 marketed food products with ingredient information and one with 111 generic food items without ingredient information. We quantified assignment consistency among evaluators using Fleiss' κ (range: 0-1, where 1 = 100% agreement). Hierarchical clustering on principal components identified clusters of foods with similar distributions of NOVA assignments. RESULTS: Fleiss' κ was 0.32 and 0.34 for the marketed foods (n = 159 evaluators) and generic foods (n = 177 evaluators), respectively. There were three clusters within the marketed foods: one contained 90 foods largely assigned to NOVA4 (91% of assignments), while the two others displayed greater assignment heterogeneity. There were four clusters within the generic foods: three clusters contained foods mostly assigned to a single NOVA group (69-79% of assignments), and the fourth cluster comprised 28 foods whose assignments were more evenly distributed across the four NOVA groups. CONCLUSIONS: Although assignments were more consistent for some foods than others, overall consistency among evaluators was low, even when ingredient information was available. These results suggest current NOVA criteria do not allow for robust and functional food assignments

Classer les aliments selon leur niveau de transformation -Quels sont les différents systèmes et leurs limites ?

International audienceThe proportion of processed foods in diets of many countries increased over the past decades. Processed foods meet the expectations and needs of contemporary lifestyles, and contribute to a large extent to covering nutritional needs. However, numerous epidemiological studies have identified links between the consumption of so-called ‘‘ultra’’ or ‘‘highly’’ processed foods and health. These studies are based on food classification systems according to their level of processing. This article gives an overview of the literature on the different classification systems, as well as their limitations. Nine classifications are discussed and compared. Although some of them are described with more precise rules, none of these classifications is based on a real algorithm, nor does it propose an ‘‘official’’ classification that users could use as a ‘‘gold standard’’. This observation partly explains the lack of robustness of these classifications. Furthermore, there is no consensus on what factors determine the level of food processing, showing the need for interdisciplinary work in order to propose a robust and universal classification system for foods according to their level of processing.La part des aliments transformés dans les régimes alimentaires n’a cessé de croître ces dernières décennies. Ils répondent aux attentes et besoins des modes de vie contemporains, et couvrent une grande part les besoins nutritionnels. Toutefois, de nombreuses études épidémiologiques ont pu identifier des liens entre la consommation d’aliments dits « ultra » ou « très » transformés et la santé. Ces études s’appuient sur des systèmes de classement des aliments selon leur niveau de transformation. Cet article s’appuie sur une analyse de la littérature et vise à présenter les différents systèmes de classement, ainsi que les limites de ces derniers. Neuf classifications sont discutées et comparées. Si certaines sont décrites avec des règles plus précises, aucune de ces classifications ne s’appuie sur un réel algorithme et ne propose pas non plus de classement "officiel" que les utilisateurs pourraient utiliser comme "gold standard", expliquant pour partie le manque de robustesse de ces classifications. Par ailleurs, aucun consensus ne semble se dégager sur les facteurs déterminant le niveau de transformation d’un aliment, montrant le besoin d’un travail interdisciplinaire afin de proposer un système de classification robuste et universel des aliments selon leur niveau de transformatio

Interactions texture-flaveur (TPA+TPV)

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