Effect of different types of phosphorylating reagent on the synthesis of modified tapioca starch

Abstract

Tapioca starch is isolated from the root of cassava (Manihot esculenta) plant and currently ranked second among commercial starch produced worldwide. Tapioca starch has very low residual impurities, bland flavor, and superior gel properties. Native tapioca starch has been widely used for daily food preparation. Chemical modifications of native starch structure, however, is often needed before starch can be utilized for industrial applications. In this research, a preliminary study on the use of different types of phosphorylating reagents (Sodium Tripolyphosphate/STPP, Sodium Trimetaphosphate/STMP, and mixture of both reagents) on the synthesis of modified tapioca starch was performed. Phosphorylation of tapioca starch was performed at a temperature of 130 °C, initial suspension pH of 9, and an intake of STPP of 5 %-w/w and/or STMP of 2 %-w/w based on dry starch. The experimental result shows that modified starch products with Degree of Substitution (DS) of 0.0084-0.0132 (correlated to P-content of 0.169-0.258 %-w/w) were obtained. The use of both STPP and STMP phosphorylating reagents gives starch products with increased solubility. Phosphorylation with all types of reagent also increases water and oil absorption capacity as well as paste clarity of tapioca starch. The result suggests that STPP and STMP are potential phosphorylating agents for modified tapioca starch preparation.