Packing and Cohesive Properties of Some Locally Extracted Starches

Abstract

Purpose: The packing and cohesive properties of locally developed cassava, potato and yam starches have been characterised using the maximum volume reduction due to packing as expressed by the Kawakita constant a, and the angle of internal flow, θ, respectively. Methodology: The starches were characterized for their particle size, shape and particle size distribution using optical microscopy. Tapping experiments were used to quantify the packing and cohesive properties of the starches. The volume reduction ability was estimated using the Kawakita equation. Results: The shape factor of the starches provided a proportionality constant between the particle size and surface area. The rank order of the particle size and shape factor of the starches was yam>potato>cassava. The ranking of maximum volume reduction, a, for the starches was potato > cassava > yam while the ranking for the angle of internal flow,θ, an index of cohesiveness, was cassava > potato > yam. The values of these parameters depended on the physical properties of the starches. Conclusion: The results obtained indicate that the physical properties of the particles affect the packing and cohesive properties of the starches, and are important in predicting the behaviour of the starches during handling and use in pharmaceutical preparations. These properties need to be closely controlled in pre-formulation studies.