Compaction of food powders: The influence of material properties and process parameters on product structure, strength, and dissolution
Aug. 10, 2017, midnight
W. Robert Mitchell
Remove from favorites
Add to favorites
Throughout the pressure agglomeration of food powders, achieving control over final product properties remains challenging due to the intricate behaviors of the materials involved. This study aims to enhance the understanding of how the quality of a compact is influenced by the material characteristics of raw materials and the applied process conditions. An amorphous powder was subjected to compaction under diverse conditions to explore the impact of material properties (water activity and molecular weight) and process parameters (pressure and dwell time) on tablet porosity, tensile strength, and dissolution time.
As pressure increased, porosity decreased, and strength rose, attributed to the formation of bridges between particles at their contact points. In cases where the glass transition temperature (Tg) was low (resulting from moisture-induced plasticization or extensive enzyme hydrolysis) and compaction pressure was high, the powder's temperature exceeded its Tg. This caused temporary local glass transition within the powder bed, facilitating enhanced deformation and microsintering between particles. Consequently, stronger interparticle bridges and increased overall tablet crushing strength were observed, with a more pronounced effect for longer dwell times.
Tablets dissolved more rapidly at higher water temperatures but exhibited slower dissolution at higher compaction pressures. This phenomenon might be attributed to a shift in dissolution regimes (erosion vs. disintegration). Higher molecular weight led to slower dissolution due to reduced liquid penetration, influenced by wetting, viscosity-building, and pore collapsing effects. The findings of this study could contribute to optimizing processing parameters, resulting in improved product properties, particularly enhanced mechanical strength and reconstitution performance.