Cereal Chem 49:566 - 571.  |  VIEW ARTICLE
Determination of Tryptophan in Cereals.

J. M. Howe, Y. Yamamura, and H. E. Clark. Copyright 1972 by the American Association of Cereal Chemists, Inc. 

A method for the analysis of tryptophan in cereals is described which employs NaOH solution containing histidine to hydrolyze the sample in an O-ring joint tube under N2. For cereal products an 8-hr. hydrolysis was found optimum. Interfering substances are removed by an ion-exchange column. Tryptophan is measured colorimetrically by p-dimethylaminobenzaldehyde. Results are in good agreement with mean values reported in the literature and are generally higher than those obtained by enzymatic hydrolysis.