Properties of cassava starch--dicarboxylic acid complexes
1999
John, J.K. | Raja, K.C.M.
Cassava (Manihot esculenta Crantz) starch prepared from fresh roots of M4 cultivar was complexed with oxalic, malonic and succinic acids. The products were examined for their physicochemical, structural and enzyme digestibility properties. The results were compared to that of untreated starch sample. The properties looked into were swelling, solubility, intrinsic viscosity, viscosity, amylose (blue value), free reducing sugar, pH and carboxyl content. Enzyme digestibility pattern was examined with respect to alpha-and beta-amylases. Crystallinity of the sample was checked by means of X-ray diffractometry, and their IR spectra were taken and compared. Pronounced increase in aqueous and DMSO solubility was noticed in the case of starch-oxalic acid and starch malonic acid complexes. These samples, also showed relatively higher carboxyl content and their pH turned to acidic range. pH value was lowest (2.4) in the case of starch-oxalic acid complex. Amylose content was also found to be the lowest in these samples. Among the three starch-acid complexes, starch-succinic acid complex showed relatively less change in these properties. alpha-amylase digestibility pattern of both untreated and experimental samples revealed highest resistance to enzyme digestibility by starch-succinic acid complex. However, this resistance could not be observed with respect to beta-amylase. Both X-ray diffraction pattern and IR spectra of all the starch samples were generally similar.
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