Continuous process for phosphorylating starch

摘要

Starch is phosphorylated by a virtually pollution-free, continuous process whereby an aqueous reagent solution of a tripolyphosphate, orthophosphate or pyrophosphate salt or a mixture thereof is sprayed onto a moist starch cake on a rotary vacuum filter in an amount sufficient to achieve efficient impregnation of the starch cake without losing significant levels of salt to the effluent. In a preferred embodiment, the reagent solution contains alkali metal tripolyphosphate salt and is obtained by diluting a concentrated solution thereof. The thus-impregnated starch is subsequently dried and heat-reacted by known procedures to produce an orthophosphate starch monoester.