Effects of Preservative Agents on Cassava Starch Adhesives

This research seeks to explain the effects of various preservative agents on starch adhesives. Adhesives were produced from cassava starch by gelatinizing with sodium hydroxide and heat. Modifications and addition of preservative agents to these adhesives were done in order to obtain a suitable working consistency and also to prolong their shelf life. Starch adhesives formed by gelatinizing with sodium hydroxide possesses good working properties, but requires mild alkalinity (pH 9.60). The stability of the final adhesives produced was also found to be dependent on the pH. At pH 9.60, the percentage decrease of viscosity after 18 days was 69.6%, while at pH 3.2, it was 98.85%. The shelf life was also controlled by adding various preservative agents to the adhesives pastes. The preservative agents added were formaldehyde, benzoate and butraldehyde. The addition of 2g of these preservative agents per 100g adhesives reduced the percentage decrease of viscosity by as much as 40% compared to that when preservative agents were not added.