Particle de-agglomeration with an in-line rotor-stator mixer at different solids loadings and viscosities

Enhancing the Techno-Functional Properties of Lentil Protein Isolate Dispersions Using In-Line High-Shear Rotor-Stator Mixing

In response to global challenges such as climate change and food insecurity, plant proteins have gained interest. Among these, lentils have emerged as a promising source of proteins due to their good nutritional profile and sustainability considerations. However, their widespread use in food products has been impeded by limited solubility. This study aimed to investigate the potential of high-shear mixing, a resource-efficient technique, to enhance lentil protein solubility and its functional properties. Red lentil protein isolate powders were rehydrated and subjected to a semi-continuous in-line high-shear treatment at 10,200 rpm for a timespan ranging from 0 to 15 min. The results highlighted a significant (p < 0.05) increase in solubility from 46.87 to 68.42% after 15 min of shearing and a reduction in particle size as a result of the intense shearing and disruption provided by the rotor and forced passage through the perforations of the stator. The volume-weighted mean diameter decreased from 5.13 to 1.72 µm after 15 min of shearing, also highlighted by the confocal micrographs which confirmed the breakdown of larger particles into smaller and more uniform particles. Rheological analysis indicated consistent Newtonian behaviour across all dispersions, with apparent viscosities ranging from 1.69 to 1.78 mPa.s. Surface hydrophobicity increased significantly (p < 0.05), from 830 to 1245, indicating exposure of otherwise buried hydrophobic groups. Furthermore, colloidal stability of the dispersion was improved, with separation rates decreasing from 71.23 to 24.16%·h-1. The significant enhancements in solubility, particle size reduction, and colloidal stability, highlight the potential of in-line high-shear mixing in improving the functional properties of lentil protein isolates for formulating sustainable food products with enhanced techno-functional properties.

Ultrasonic-assisted de-agglomeration and power draw characterization of silica nanoparticles

Breakage of nanoparticle cluster require high-intensity devices for stable and uniform distribution of aggregates. The ultra-sonication process is a high energy-intensive technique that produces cavitation effect to break the aggregates. In the present study, ultra-sonication is used for the de-agglomeration of fumed silica nanoparticles in low to high viscosity liquids. Water- and glycerol-based dispersion has been investigated at different solid loadings (up to 10 wt% for water-based dispersion and 5 wt% in glycerol-based dispersion) and viscosity of continuous phase (1-100 mPa.s). Breakup mechanism and kinetics have been studied at optimized operating conditions and no significant effect is found at different solid loadings on breakup mechanism. Particle size measurements are reported and found that volume of fine generation increased with an increase in sonication time. Further, it is observed that the stability of dispersion in the liquid is very high even at high concentration of solid used. Larger agglomerates are found at high viscosity of continuous phase and a lag is also observed for 100 mPa.s glycerol solution even at low solid loading (1 wt%). From, rheological characterizations it is found that the behavior of dispersed solution changed with time, temperature and solid loading. Erosion is found to be the breakup mechanism and further, validated with scattering light characterization. Furthermore, power draw increased with an increase in the viscosity of continuous phase, however, no significant effect of solid loading is observed. It is also observed that process is more energy-efficient at higher solid loading as the volume of fine produced is more as compared to low solid loading. Therefore, it can be concluded that the stable and uniform dispersion of nanoparticles can be achieved using an ultra-sonication device at high solid loading in viscous liquids.