GELATINIZATION OF HYPOCHLORITE OXIDIZED MAIZE STARCH IN AQUEOUS-SOLUTIONS

The effect of concentration of sodium hydroxide on the gelatinization of hypochlorite oxidized maize starches was thoroughly investigated. I t was found that oxidation of starch increases its affinity towards ge latinization with alkali solutions at room temperature. Clear gelatini zed starch could be obtained immediately at a concentration of sodium hydroxide of 1% on using hypochlorite oxidized starches irrespective o f their degree of oxidation. While in case of native maize starch clea r gelatinized paste was obtained at a concentration of 4% or more. The rheological properties of the alkali gelatinized starches were determ ined after 2 h of preparation and after storing of their pastes for 4 days. Hypochlorite oxidation of starch changes its rheological charact eristics from non-Newtonian thixotropic to non-Newtonian pseudoplastic . The suitability of one g/l active chlorine oxidized maize starches g elatinized at 25 degrees C, under the influence of different concentra tions of sodium hydroxide, either alone or in admixture with sodium al ginate as thickeners in printing pastes of vat dyes was thoroughly inv estigated.