THE CHEMICAL DETERMINATION OF TRYPTOPHAN IN FOODS AND MIXED DIETS.

Abstract A description is given of a colorimetric method for the determination of tryptophan in foods and mixed diets. The method is based on enzymic hydrolysis of the material, extraction of the hydrolyzed protein with a mixture of diluted potassium hydroxide and carbon tetrachloride, and spectrophotometric determination of tryptophan after the addition of p -dimethylaminobenzaldehyde to an aliquot of the extract.