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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, amylose (blue value), free reducing sugars, pH and carboxyl content. Enzyme digestibility pattern was examined with respect to α - and β -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. α -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 β -amylase. Both X-ray diffraction pattern and IR spectra of all the starch samples were generally similar.

Cassava and maize starches were subjected to lintnerization under identical experimental conditions using 2·0 m hydrochloric acid. The filtrate and residual starch samples were separated at 5-day intervals up to 35 days. There were considerable changes in amylose content, viscosity, and cold water solubility values. Despite the α- and β-amylase susceptibility patterns being quite distinct, there were less perceptible changes between cassava and maize. X-ray diffractograms of lintnerized samples showed greater crystalline peaks than native samples.