Cereal Chem. 70:137-144   |  VIEW ARTICLE

Preparation and Pasting Properties of Wheat and Corn Starch Phosphates.

S. Lim and P. A. Seib. Copyright 1993 by the American Association of Cereal Chemists, Inc. 

Wheat and corn starches were phosphorylated in a semidry state at 130 C with 5% (based on dry starch) sodium tripolyphosphate (STPP) and/or 2% sodium trimetaphosphate (STMP). All phosphorylation reactions were done using 5% sodium sulfate and adjusting the initial reaction pH by adding aqueous sodium hydroxide or hydrochloric acid to the prereaction slurries. As reaction pH was increased from 6 to 11, the degree of phosphorylation decreased 40-50% with STPP, whereas it increased 100% with STMP. At an initial reaction pH of 10 with STPP, a wheat starch phosphate was obtained with 0.22% P (including 0.05% P from phospholipids), and its pasting properties showed optimum thickening power with shear stability when cooked at 95 C. The best corn starch phosphate, judging from its paste properties, was obtained at an initial pH of 11 with STPP and contained 0.16% P (including 0.02% from lipid). When corn or wheat starch was heated with a mixture of 5% STPP and 2% STMP, the best product when pasted at 95 C was obtained at the initial reaction pH of 9.5. Paste clarity of the phosphorylated starches indicated that cross-linking accelerated rapidly above pH 8 with STMP but above pH 10 with STPP.