Rehydratation
The impact of cohesion on rehydration.
A case where Powder cohesion controls rehydration
Background
In the food industry, powder rehydration is a critical process influencing both product quality and consumer perception. Many powdered ingredients such as milk, cocoa, protein blends, and instant soups are expected to rehydrate quickly and uniformly when mixed with water. However, the rehydration behavior depends strongly on chemical and cohesive properties of the powder. Traditional cohesion measurements based on shear cell testing often fail to capture subtle differences in powder flow and aggregation behavior during wetting. PowderCraft has developed a novel cohesion characterization method based on column rupture, offering a more direct and sensitive measurement of interparticle forces.
Objective
PowderCraft has investigated the relationship between powder cohesion and rehydration time for various food powders, and to compare the predictive capability of PowderCraft’s column rupture cohesion measurements with traditional shear-based cohesion data.
Materials
Methods
Shear Cell Test: The Shear Cohesion was obtained from standard ring shear tests procedures. The shear test measures the shear stress needed to obtain powder bed failure as a function of applied normal stress.
PowderCraft Column Rupture Test: Each powder was packed into a vertical column at a given porosity and subjected to controlled rupture measurements (PowderCraft Protocol). The cohesion is given in Pa.
Rehydration Time Measurement: A fixed mass of each powder (10 g) was added to 200 mL of water at 25 °C under stirring (1500 RPM). The rehydration time (tᵣ) is calculated using conductivity measurements. One advantage of this technique was the ability to follow the powder rehydration during time in high concentration of powder (user condition), in comparison with laser diffraction technique.
Results
*Cohesion was evaluated at aw=0.30 (T=20°C)
Discussion
A strong correlation was observed between the PowderCraft Cohesion and the rehydration time, confirming that powders with higher cohesion tend to rehydrate more slowly. Traditional shear-based cohesion data showed no meaningful correlation, highlighting that shear tests are not sensitive to the adhesive forces governing wetting and breakup in this range of cohesion.
Conclusion
PowderCraft’s column rupture method provides a sensitive and reliable indicator of powder cohesion directly linked to functional performance such as rehydration. This approach enables food manufacturers to predict and optimize rehydration behavior, differentiate powders with similar flow properties but distinct wetting behaviors, and accelerate product development and quality control.
Prêts à mieux comprendre vos poudres ?
Nous prendrons le temps de comprendre votre environnement et vos problèmes avant de vous proposer la solution la plus adaptée à vos besoins.