The food industry is one of the most regulated industries in the world, as the mishandling of food products can have detrimental side effects. To achieve desired product performance and safety, a series of analytical measurements must be performed from research and development down to production, on raw materials as well as final product.
Stability, dissolution and reaction rate, texture, mouth feel, spreadability, flavor are key parameters to ensure product quality and consistency. Let us focus on dissolution, and on the reasons why this property of food materials is so important to characterize.
Dissolution: how is it influenced by material properties?
Dissolution of a solid in water depends upon the collisions that occur between the solvent molecules and the solid particles. Increasing the frequency of those collisions and/or the energy of those collisions will speed up the dissolution rate. For instance, dissolving sugar in water will be achieved quicker if the water is heated or stirred: upon heating the water molecules acquire kinetic energy and undergo faster motion, increasing the collisions with the sugar particles increasing dissolution process. Stirring allows fresh solvent molecules to continually be in contact with the sugar particles. If not stirred, water becomes saturated with dissolved sugar molecules, right at the surface of the solute meaning that it is more difficult for additional sugar to dissolve.
Particle size is another key parameter to optimize/control dissolution process. Keeping sugar as an example, the same amount of granulated sugar will dissolve faster than a sugar cube. The rate at which sugar particles dissolves depends upon the size of the sugar particles. Dissolving is a surface phenomenon since it depends on solvent molecules colliding with the outer surface of the solute (sugar here). When a higher surface area is exposed to water molecules, the solid particles dissolve faster.
The figure below illustrates the relation between particle size and surface Area
In Alfatestlab we are experts in particle characterization: upon request of a food producer we have measured the particle size distribution of different quality of sugar and have correlated it to the dissolution rate.
The sugar dissolution test Performing showed that 45 Microns particle size presents the fastest dissolution rate as expected from the particle size distribution.
Particle shape is also a key parameter influencing the dissolution process. In Alfatestlab we are equipped to measure more than 20 morphological parameters of your particulate material. To study dissolution profile, convexity is the most important shape parameter. Convexity represents the edge roughness of a particle, lower the convexity is, higher is the particle surface and therefore faster is dissolution. The example below shows 2 types of particulate samples to be dissolved in water. The sample having the lower convexity (green curve) shows faster dissolution profile.
Feel free to contact us to discuss the right analytical technique to characterize the key parameters influencing the dissolution of your samples!