Food structure and its food oral processing

Topic 1. Influence of protein on oral coatings of oil in water emulsions.

Oral coatings are residues remaining on oral surfaces after the consumption of foods and beverages. Oral coatings have long been hypothesized to significantly influence the perception of taste and mouthfeel attributes. However, a mechanism describing the formation of oral coatings is not known. There is only very little information available on the composition and structure of oral coatings despite its influence on sensory perception.
In recent years we have been using in vivo fluorescence to further study the deposition and clearance of oral coatings, mainly focusing on lipid deposition.
Aim
The aim of this subproject is to determine the role of protein in the formation of the coating using oil in water emulsions as a beverage model, and a large group of subjects to account for well-known inter-individual differences. The relationship between removal of oral coating due to salivation which differs between subjects is determined and linked to taste perception.

Approach

A first approach will be to request subjects to drink a model sample with a food grade dye, and measure the fluorescence on the tongue after spitting the sample. The relation between the fluorescence intensity and the amount of protein on the tongue will be drawn by using different amounts of the oil in water emulsions spread over well-defined pieces of pig’s tongue. The different points of concentrations/fluorescent intensity will be used for a calibration curve.

For more information please contact Sara Camacho.

Topic 2. Designing food structures to understand texture perception.

Sensory attributes of food that are perceived at late stages of oral processing depend on food properties and on physiology of eating. These attributes are important for consumer appreciation of foods and the mechanisms of their perception are not well known. Creaminess is generally perceived at the end of mastication of solid foods and is an attribute valued by consumers. In order to understand this complex attribute, structure and properties of food have to be controlled effectively. Model food systems such as gelled foods can be designed to obtain a desired structure and to investigate the effect of a single parameter on the perception of creaminess.
Objective

The objective of this thesis project is to design gelled structures with controlled properties in order to investigate further the mechanisms of creaminess perception.

Approach

Formulation of gel recipes, characterization of gels (rheology, dry matter, melting) for a BSc + sensory test (TDS or progressive profiling) and test on spit-out gels (e.g. Texture Profile Analysis) for MSc.

For more information please contact Marine Devezeaux-de Lavergne.