AN IMPROVED METHOD FOR THE DETERMINATION OF TRYPTOPHANE IN FOODS / 营养学报

ABSTRACT

An improved method was described for the determination of tryptophane in foods (maize, rice, millet, wheat, soybean, milk powder substitute, fish protein concentrate and casein) hydrolyed by cyanide-activated papain. The color-deyeloping agent was a mixture of equal volume of 30N sulfuric acid and glacial acetic acid containing 2% acetic anhydride and 27mg% FeC13.6H2O, and its intensity was measured with spectrophotometer at absoption maximum 545nm. The sensitivity was 0.2?g of tryptophane per ml of tested solution through 1cm length. The recovery was found to be between 96-104%. By comparing noncyanide and cyanide-activated papain for analysis of varieties of maize the mean tryptophane values were 50.1 mg% and 68.7mg% respectively, and the difference was very significant (p