Revealing how maltodextrin-containing droplets dry using optical coherence tomography.

Properties of powders produced from drying solute-containing droplets arise from the dynamic redistribution of solute during drying. While insights on the dynamic redistribution are instrumental for the rational design of powders and for the optimized operation of equipment such as spray dryers, experimental techniques that allow measuring the spatio-temporal concentration of solute in drying droplets are scarce. In this work, we explore and demonstrate the use of optical coherence tomography (OCT) to measure the spatio-temporal concentration of solute in drying droplets and the development of a solidifying shell at the liquid-air interface, using aqueous droplets of maltodextrin as a model system.

Analysis and modeling of enhanced green fluorescent protein diffusivity in whey protein gels.

During gastric digestion, hydrolysis of proteins by pepsin contributes largely to the breakdown of protein-rich food. We hypothesized that the effect of pepsin is limited by its diffusivity, which is co-determined by the food structure and the local pH in the food during digestion. To investigate the principle mechanism of enzyme diffusion in food matrices, we used enhanced green fluorescent protein (EGFP) as probe to study the diffusivity of proteins in whey protein isolate gels, using fluorescence correlation spectroscopy (FCS).