Process for phosphorylating starch in alkali metal tripolyphosphate salts
AssigneeNational Starch and Chemical Corporation
InventorsOtto B. Wurzburg, Wadym Jarowenko, Roger W. Rubens, Jayant K. Patel
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Abstract
Starch is phosphorylated by an improved pollution-free process which involves forming a reagent solution of an alkali metal tripolyphosphate salt in water having 20- 36% by weight of the salt dissolved therein, forming a starch cake containing no more than 45% by weight moisture, adding 2 - 30% by weight of the tripolyphosphate salt reagent solution to the starch cake, and drying and heat-reacting the thus-impregnated starch. In this process more efficient impregnation of the starch is achieved. The impregnation is preferably effected in a centrifuge.
Claims10
An improved process for phosphorylating starch comprising the steps of:
- (a) forming a reagent solution of an alkali metal tripolyphosphate salt which comprises water, 20-36% by weight of said salt, and an amount of a water-soluble acid having a pK.sub.a less than 4.7 sufficient to obtain a solution pH of 2.8-5.0;
- (b) forming a starch cake having no more than 45% by weight moisture;
- (c) adding 2-30% by weight of said reagent solution to said starch cake to achieve efficient impregnation of the cake;
- (d) drying the thus-impregnated starch;
- and
- (e) heat-reacting the dried starch to obtain an orthophosphate starch monoester.
A reagent solution of alkali metal tripolyphosphate salt which comprises water, 20-36% by weight of said salt, and an amount of a water-soluble acid having a pK.sub.a less than 4.7 sufficient to obtain a solution pH of 2.8-5.0.
A process for preparing a reagent solution of alkali metal tripolyphosphate salt which comprises mixing, at a temperature no greater than 40.degree. C., an alkali metal tripolyphosphate salt, water and a water-soluble acid having a pK.sub.a less than 4.7 to obtain a reagent solution having a pH of 2.8-5.0 and having 20-36% by weight of said tripolyphosphate salt dissolved therein.
Dependencies are inferred from the claim text.