A growing number of consumers tend to products based on plant materials for medical reasons or as a lifetime choice, therefore plant milk variants have gained growing interest. The dehydrated product in particular is advantageous with regard to an increase shelf life and a reduced transport weight.
To date, plant-based milk powders show unfavorable reconstitution properties due to extensive lump formation. The lump formation is correlated with the powder bulk structure as well as the viscosifying and swelling properties of the plant ingredients.Achieving good instant properties requires targeted structuring of the plant-based milk powder. A promising approach is the formation of agglomerates such that primary particles are fixed together to form larger, porous secondary particles. The created open structures enhance the dissolving of the particles and also the flowability of the powder is improved by agglomeration.
In order to reach a favored structure, the impact factors on the agglomerate formation has to be understood. Therefore, the relations of the structure to the material properties and process conditions need to be analyzed. The experimental and numerical results in single-particle investigations need to be transferred to the fluidized bed process with numerous particles and interactions between them.
Special focus is also set on the supra-molecular structure of the components. Depending on the viscosity and consequently on moisture as well as temperature, food substances tend to sinter. Sintering is a process in which atoms or molecules close the gap between two particle neighbors. This often occur during agglomerating powder particles containing amorphous components.
Nestlé Research Center, Lausanne, Switzerland