“Chemical Modification of Yam [Dioscorea sp.] Starches and their Potential Use in Pharmaceutical Formulations"

Alexia Harvey 

Globally, corn starch is one of the most widely applied industrial starches. There is a high demand of the crop by the fast growing ethanol industry, hence its continuous increasing cost over the last couple years. Being expensive and the most utilised starch in Jamaica, the importation cost is the highest of all imported
starches (US$862,206 in 2010). It is therefore imperative that alternative starches be sought locally, from cheaper indigenous crops. 

UWI yam research group conducted research to identify industrially applicable non-traditional starches. Armed with the knowledge that native starches possess inherent limitations, the research focussed on improving yam starch functionality with acetylation and oxidation, from three Jamaican yam varieties,
including the popular Round Leaf yellow yam. This was in an effort to apply them as additives in solid dosage formulations such as tablets, capsules and granules. The findings indicated that tablets, conforming to Pharmacopeia standards, can be produced by applying the yam starch analogues as direct compression binders (which are responsible for aiding in the consolidation of solid dosage forms such
as granules and tablets via the most preferred method of tablet production). Such formulations include some of those of active pharmaceutical ingredients that are of low compressibility, for example metronidazole. The yam starch analogues also proved to be comparable, and in many cases superior, to Pharmacopeia grade corn starch (both untreated and treated) thus making them suitable candidates for
use in the pharmaceutical industry. Their potential utilisation in this industry will result in significant reductions in production time and costs which in turn will result in a reduced cost to the consumer. The applications of the starches, however, are not limited to this function, or industry. 

With yam starches being alternatives to traditional starches, it is expected that if applied, they will contribute to a significant reduction in the Jamaican economic net loss for starch. The BSJ/UWI Starch conference reported US$998,O00 for importation as against US$8,200 for exportation of starch in 2010) The application of yam starches could also significantly reduce the annual post-harvest loss of yams
(approximately 400/o) caused by the tuber's vulnerability to microbial contamination when wounded, since starch has a significantly longer shelf life than the tuber. Collaborations between UWI, local farmers and industry experts has the potential to make industrial utilisation of yam starch in Jamaica a reality. Consideration should also be given to funding training programmes to equip potential employees with the knowledge needed to drive this effort. 

Dr Alexia Harvey is a graduate of the Faculty of Science and Technology. Graduating with High Commendation, her research interests include formulating, producing and analysing nutraceuticals/ pharmaceuticals with plant extracts /plant bioactives; plant tissue culture; and powder technology.