Understanding and optimising binding mechanisms to enhance process sustainability within food granulation

Granulation is a well-established size enlargement process in which small particles agglomerate to form larger structures called granules. Enhancing sustainability within granulation is a key focus for the food industry, particularly when processing amorphous powders. These powders are sensitive to moisture and heat due to their Glass Transition Temperature, making controlled agglomeration difficult and often leading to material waste.
Despite its significance, the sustainability of competing granulation technologies remains underexplored. This study addresses this gap by screening the sustainability of four major granulators based on material, energy, and time efficiency. The findings highlight the energy efficiency of dry granulation due to the elimination of the drying step and the high material efficiency of wet granulation, attributed to its cyclic bonding mechanism.
Among the screened technologies, the High Shear Granulator emerged as a strong candidate for further development. A novel regime map was constructed using the parameters ‘Temperature – Glass Transition Temperature’ and ‘Liquid/Solid Ratio divided by a viscosity based constant’ to define an optimal operating region where controlled agglomeration can occur, minimizing caking and material waste.
High Shear Granulation was also used to create layered granule microstructures. Compared to standard granules with randomly distributed components, these layered granules demonstrated greater resistance to humidity-induced caking, colour change, and shrinkage during storage.
Additionally, this study evaluated Dry Twin Screw Granulation for the agglomeration of amorphous food powders. This led to the development of the first-ever regime map for the process, which captured key operational behaviours including granulation, barrel blocking, and extrusion. Dry Twin Screw Granulation exhibited strong potential based on sustainability metrics, positioning it as a viable future alternative to the more established techniques.
Ultimately, this study takes a multifaceted approach to advancing sustainable granulation by identifying key factors contributing to efficiency, process optimisation to minimize material waste, and developing next-generation granulation technologies.