Material properties and compaction characteristics of natural and pregelatinized forms of four starches

Material properties and compaction characteristics of natural and pregelatinized forms of white trifoliate (T.) yam, yellow trifoliate (T.) yam, rice and official corn starches were studied. Physico-chemical properties and viscosity profiles of the starches were evaluated. Pregelatinized starches exhibited lower viscosity values than natural starches in the viscoamylography. The pregelatinized starches showed more densification than natural starches during compression and also had lower mean yield pressure, Py. The ranking of Py for the starches was; corn < white T. yam < yellow T. yam < rice. The values of Pk, an inverse measure of plasticity, were, however, lower for the natural starches with the ranking for the starches being white T. yam < yellow T. yam < corn < rice. Tablets produced from pregelatinized starches had lower values of tensile strength (T) and brittleness (BFI) than those made from natural starches. The ranking of T for the starches was generally white T. yam > corn > yellow T. yam > rice. The rankings of the BFI for the natural and pregelatinized starches were corn < yellow T. yam < white T. yam < rice; and corn < white T. yam < yellow T. yam < rice, respectively.The material properties of the starches appear to show some limited correlation with their tablet properties. The experimental starches showed similar properties to official corn starch in many cases and could serve as suitable alternatives for particular purposes.