3‐Chloro‐1,2‐propanediol Derived Amino Acids in Protein Hydrolysates

Abstract

ABSTRACT Glycerol monochlorohydrin, (3‐chloro‐1,2‐propanediol), which occurs in chemical hydrolysates of proteins, reacted with amino acids in model aqueous solutions to form the corresponding glycerylamino acids, i.e. N‐(2,3‐dihydroxypropyl)‐amino acids. N‐(2,3‐dihydroxy‐propyl)‐derivatives of 15 amino acids were prepared and analyzed by gas chromatography and gas chromatography‐mass spectrometry. No N‐(2,3‐dihydroxypropyl)‐amino acid was detected in a freshly produced commercial soybean hydrolysate. Amounts up to ∼1 mg‐kg ‐1 of N‐(2,3‐dihyproxypropyl)‐serine and ‐threonine were found in a stored hydrolysate. Higher amounts of N‐(2,3‐dihydroxypropyl)‐amino acids (up to about 10 mg‐kg ‐1 ) were found in the alkaline treated and with 3‐chloro‐1,2‐propanediol fortified hydrolysate. N‐(2,3‐dihydroxypropyl)‐amino acids represent a new class of amino acids not previously reported in foodstuffs.