Cassava starch (Manihot esculenta Crantz) esterified with stearic acid

Resumo

The objective of this study was to esterification cassava starch with stearic acid, to obtain starches with emulsifying properties, stabilizing and encapsulant of oleic acid. The cassava starch was treated with stearic acid in an alkaline medium (pH 8.0, 9.0, 11.0 and 13.0) and catalyzed by microwave radiation, to obtain the saturated ester starch. The percentage of esterification and degree of substitution (DS), the swelling power and solubility, the apparent viscosity of gels, emulsifying activity and the stability of the emulsions prepared with the modified starches were determined. The use of modified starch in the encapsulation of oleic acid and salad dressings was assessed. The pH of the reaction influences the content and esterification in the GS, only sample evaluated at pH 13.0 showed no percentage esterification. The modification reduced apparent viscosity, the swelling power and the solubility of the granules. Esterification at pH 8.0, 9.0 and 11.0 increased the emulsifying stability and encapsulation efficiency of the starches. Could not find correlation between encapsulation efficiency and the hydrophobicity of the starches. The application of modified starch in sauces like mayonnaise for salads did not show favorable results since the emulsion formed was not stabilized. The emulsion stability was compromised due to low viscosity of the starches after modification