Cereal Chem 40:31 - 37.  |  VIEW ARTICLE

Location and Possible Role of Esterified Phosphorus in Starch Fractions.

M. W. Radomski and M. D. Smith. Copyright 1963 by the American Association of Cereal Chemists, Inc. 

Phosphorus determinations were made on various amylose and amylopectin fractions by a modified Fiske- Subbarow technique. Results were reproducible to +/- 2.5%. A positive correlation was found between the beta-amylase limits and the phosphorus content of seven potato amylose samples. Hydrolysis of amylose with beta-amylase resulted in a concentration of phosphorus in the beta-limit dextrin. The phosphate groups appear to be responsible for the incomplete hydrolysis of amylose by enzymes. A decreasing gradient of phosphorus content existed between the amylopectin (0.165%), the intermediate (0.083%), and the amylose (0.008%) fractions of potato starch. Beta- or alpha-amylolysis of waxy corn starch resulted in a concentration of its phosphorus in the limit dextrins, indicating the presence of chemically bound phosphorus. The results also suggest an association between the esterified phosphorus and the branch points which would explain the distribution of phosphorus in starch fractions.