Optimization of the Crosslinking Reaction Conditions of Gum Arabic with Sodium Trimetaphosphate (STMP).

Abstract

Gum Arabic (GA) have wide applications in the food, textile and pharmaceutical industries. However, some of its physico-chemical attributes like high water solubility and hydrophilicity limits its applications. In this study, sodium trimetaphosphate (STMP) was used as a crosslinker in modifying the properties of GA. Experimental design was carried out using Response Surface Methodology (RSM) via Minitab 19 software by adopting temperature, STMP concentration, pH and duration as input parameters while viscosity and water absorption were investigated as responses. The optimum conditions to obtain maximum viscosity (4.22 cP) were found to be 9% STMP concentration, pH of 11, 30°C temperature and duration of 4 hr. Also, to have minimum water absorption (18.38%), the optimum conditions required were 6% STMP concentration, pH of 11, temperature of 20°C and 4 hr duration. The coefficient of determination (R 2) value for viscosity and water absorption were 0.96 and 0.76 respectively. The analysis of variance (ANOVA) shows that STMP concentration had the most significant effect on viscosity with a contribution of 83.04%, while pH had the greatest influence on water absorption with a percentage impact of 36.33%. The ANOVA results presented an error of 0.87% and 4.28% for viscosity and water absorption respectively, indicating that the experiment was carried out with minimal noise effects. The effects of these factors on the properties of gum Arabic are significant since their p-values (0.001 for viscosity and 0.006 for water absorption) are less than 0.05. Crosslinking with STMP improved the properties of GA, with the potential for broadening its applications.