A large number of volatile compounds are formed during the baking of foods by reactions such as caramelization and Maillard reactions. Elucidating the reaction mechanisms may be useful to predict and control food quality. Ten reaction volatile markers were extracted during baking of solid model cakes implemented with known amounts of precursors (glucose with or without leucine) and then quantified by Thermal desorption-Gas chromatography-Mass spectrometry. The kinetic data showed that the level of air convection in the oven had no significant influence on the reaction rates. In contrast, increasing baking temperatures had a nonlinear accelerating impact on the generation of newly formed volatile compounds with a bell-shaped kinetic curve found for most of the markers at 200 degrees C. The presence of leucine triggered the activation of the Maillard and Strecker routes with a specific and very rapid formation of 3-Methylbutanal and pyrazines. A dynamic model was developed, combining evaporation flow rate and kinetic formation and consumption of reaction markers. It can be used to describe, for two furanic compounds of different volatilities, the vapor concentrations in the oven from the concentrations measured in the model cakes.

The substitution of animal proteins with plant-based ones to fit environmental and economic demands is a challenge in gel applications. This study examined the thermal elation of mixtures of pea protein isolate (PPI) and egg white proteins (EWPs) at different PPI/EWP weight ratios (100/0, 75/25, 50/50, 25/75, 0/100) at pH 7.5 and 9.0. Viscoelastic and texture properties of the composite gels, along with the microstructure and molecular interactions involved in the gel network, were investigated. Except for PPI-EWP 100/0 at pH 9.0, all systems gelled with increasing gel hardness, springiness, and cohesiveness when EWP content increased. This was explained by the microstructure of the gels, wherein the presence of PPI enhanced the formation of aggregates embedded in the EWP network, thus loosening it. The rheological properties of the mixed gels were primarily influenced by the EWP network, involving disulfide bonds. However, upon the addition of PPI, hydrogen bonds and hydrophobic interactions predominated and the structure of the gel became more sensitive to pH as electrostatic repulsions interfered. Adjusting the ratio of PPI/EWP allows the production of gels with varying textures, and suggests the possibility of partially substituting egg white with pea proteins in food gel formulation.

Dairy powders are mainly produced by droplet spray drying, an articulated process that enables the manufacture of high added-value goods with a long shelf life and well-preserved functional properties. Despite the recent advances, a full understanding of the mechanisms occurring at the droplet scale in drying towers and, consequently, of the impact of process parameters and processed fluid characteristics on the powder properties is far from being achieved. In the wake of previous studies based on a laboratory scale approach, in this work, we provided a global picture of the drying in droplets of dairy protein mixes, i.e., whey proteins and casein micelles, which represent crucial dairy powder ingredients. Using profile visualization and optical microscopy, we explored the shape evolution in droplets with a range of protein contents and compositions typical of commercial powder production. The observation favored the evaluation of the specific role of each protein on the evaporation dynamics, and led to the construction of a phase diagram predictive of the dry droplet shape starting from the characteristics of the initial protein dispersions. Our outcomes represent a further step shedding light on the paradigm linking the physics of drying at the microscale and the nutritional properties of complex dairy powders.