Design of microbial consortia for the fermentation of pea-protein-enriched emulsions.

In order to encourage Western populations to increase their consumption of vegetables, we suggest turning legumes into novel, healthy foods by applying an old, previously widespread method of food preservation: fermentation. In the present study, a total of 55 strains from different microbial species (isolated from cheese or plants) were investigated for their ability to: (i) grow on a emulsion containing 100% pea proteins and no carbohydrates or on a 50:50 pea:milk protein emulsion containing lactose, (ii) increase aroma quality and reduce sensory off-flavors; and (iii) compete against endogenous micro organisms. The presence of carbohydrates in the mixed pea:milk emulsion markedly influenced the fermentation by strongly reducing the pH through lactic fermentation, whereas the absence of carbohydrates in the pea emulsion promoted alkaline or neutral fermentation.

An experimental model to investigate the biomechanical determinants of pharyngeal mucosa coating during swallowing.

The development of innovative experimental approaches is necessary to gain insights in the complex biomechanics of swallowing. In particular, unraveling the mechanisms of formation of the thin film of bolus coating the pharyngeal mucosa after the ingestion of liquid or semi-liquid food products is an important challenge, with implication in dysphagia treatment and sensory perceptions. The aim here is to propose an original experimental model of swallowing (i) to simulate the peristaltic motions driving the bolus from the oral cavity to the esophagus, (ii) to mimic and vary complex physiological variables of the pharyngeal mucosa (lubrication, deformability and velocity) and (iii) to measure the thickness and the composition of the coatings resulting from bolus flow.

The important role of salivary α-amylase in the gastric digestion of wheat bread starch.

The role of salivary α-amylase (HSA) in starch digestion is often overlooked in favour of that of pancreatic α-amylase due to the short duration of the oral phase. Although it is generally accepted that the amylase of salivary origin can continue to be active in the stomach, studies ascertaining its contribution are lacking. This study aimed to address this issue by coupling in vitro oral processing with an in vitro dynamic system that mimicked different postprandial gastric pH reduction kinetics observed in vivo following a snack- or lunch-type meal.

Exploring the breakdown of dairy protein gels during in vitro gastric digestion using time-lapse synchrotron deep-UV fluorescence microscopy.

A novel time-lapse synchrotron deep-UV microscopy methodology was developed that made use of the natural tryptophan fluorescence of proteins. It enabled the monitoring in situ of the microstructural changes of protein gels during simulated gastric digestion. Two dairy gels with an identical composition, but differing by the coagulation mode, were submitted to static in vitro gastric digestion.

Effect of Bread Crumb and Crust Structure on the in Vivo Release of Volatiles and the Dynamics of Aroma Perception.

This study examined the effects of bread crumb and crust structure on volatile release and aroma perception during oral processing. French baguettes with different crumb structures were procured from a supermarket or local bakeries (n = 6) or produced in the laboratory via par baking (n = 3). Eight study participants consumed crumb-only and crumb-and-crust samples, and the resulting volatile release was measured in vivo using proton transfer reaction-mass spectrometry.

Gaining deeper insight into aroma perception: An integrative study of the oral processing of breads with different structures.

The objective of this study was to investigate for the first time the influence of bread structure, volatile compounds, and oral processing on aroma perception. 3 types of French baguette were created using the same raw ingredients but different bread-making processes; they consequently varied in their crumb and crust structures. We characterized the initial volatile profiles of two bread structural subtypes-namely bread crumb and bread crumb with crust-using proton transfer reaction-mass spectrometry (PTR-MS) headspace analysis.

Chewing bread: impact on alpha-amylase secretion and oral digestion.

During chewing, saliva helps in preparing the food bolus by agglomerating the formed particles, and it initiates enzymatic food breakdown. However, limited information is actually available on the adaptation of saliva composition during the oral processing of complex foods, especially for foods that are sensitive to salivary enzymes. We addressed this question in the context of starch-based products and salivary alpha-amylase.

Respective impact of bread structure and oral processing on dynamic texture perceptions through statistical multiblock analysis.

Texture perception is a multidimensional and dynamic phenomenon resulting from both the initial structure of food and its breakdown during oral processing. The aim of this study is to identify the respective contribution of food and bolus properties to temporal changes in texture perceptions during bread consumption. For this purpose, the perception dynamics of three French baguettes with dif\ferent structures were assessed through Temporal Dominance of Sensations and Progressive Profiling.

Kinetics of bread crumb hydration as related to porous microstructure.

During oral processing and throughout the digestion process, hydration mechanisms have a key influence on the functional properties of food. This is the case with bread, for which hydration may affect the kinetics of starch hydrolysis as well as taste, aroma and texture perceptions. In this context, the aim of the present study is to understand how crumb porous micro-architecture impacts hydration kinetics.

Breakdown pathways during oral processing of different breads: impact of crumb and crust structures.

Oral processing during bread consumption is a key process related to the dynamics of texture perceptions, sensory stimuli release and starch digestion. The aim of this study was to determine the respective contribution of bread properties (composition and structure of crumb and crust) and of the oral physiology of subjects to the breakdown pathways in the mouth. The properties of the in vivo bread bolus obtained from eight healthy subjects were studied at three key points in time during their oral processing.

Mechanistic model to understand in vivo salt release and perception during the consumption of dairy gels.

The objective of this study was to develop a model to simulate salt release during eating. Salt release kinetics during eating was 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.

Cellulase and protease preparations can extract pectins from various plant byproducts.

The use of protease and cellulase preparations to extract pectins from plant byproducts (chicory, cauliflower) was investigated. Different enzymatic preparations were characterized by their activities toward proteins, cellulose, and pectins. These preparations were then tested regarding pectin extraction, and extraction conditions (nature and concentration of enzyme, incubation time) were optimized.

Jamming and gelation of dense beta-casein micelle suspensions.

The rheology of dense suspensions of beta-casein micelles is investigated at pH 6. For a given temperature, the viscosity increases dramatically at a critical concentration (Cc) of about 100 g/L due to jamming of the micelles. For a given concentration close to and above Cc, the viscosity of dense suspensions decreases strongly with increasing temperature because Cc increases.

Dynamic mechanical properties of suspensions of micellar casein particles.

Small micellar casein particles, so-called submicelles, were obtained by removing colloidal calcium phosphate from native casein by adding sodium polyphosphate. Aqueous submicelle suspensions were characterized using light scattering and rheology as a function of concentration and temperature. The casein submicelles behave like soft spheres that jam at a critical concentration (C(c)) of about 100 g L(-1).

Aggregation and gelation of micellar casein particles.

Micellar casein particles (submicelles) are formed by removing calcium phosphate from native casein. The submicelles aggregate and eventually form a gel with a rate that increases strongly with increasing temperature and casein concentration. At low casein concentrations the gel is very weak and collapses under its own weight so that a precipitate is formed.