Modificação do amido de mandioca com mistura de anidrido-acético e ácidos orgânicos

Abstract

The native starches do not support extreme conditions, such as strong mechanical agitation or acidic pH and naturally retrogrades. Given that, the chemical modifications are made so that the starch is able to withstand these conditions. The objective of this work was to modify the native cassava starch with mixtures of acetic anhydride and organic acids (citric, malic and tartaric acid) and then evaluate its properties such as anionic characteristics, paste formation temperature, viscosity of the gels, clarity and turbidity of the paste and its spectra in Fourier transform infrared (FTIR). Methylene blue dye microscopical analysis indicated modification of the starch. The paste formation temperature indicated that the starch modified with a mixture of acetic anhydride and citric acid (EAC) presented low paste formation temperature. The apparent viscosity when in acidic medium suggests intercrossing between the modified starch and the organic acids, while its clarity and turbidity report low tendency to downgrading, associated to the starch esterification. FTIR analysis made it possible to observe a peak in 1740 cm-1 region that suggests the starches have been esterified. It is concluded that all the organic acids were able to esterify the native cassava starch.