The effects of amino acids on removal of acrylamide in a model reaction system

Abstract

Ten (10) amino acids (asparagine, aspartic acid, cysteine, glycine, glutamic acid, glutamine, methionine, 
leucine, tyrosine and lysine) were used to test their effect on elimination of acrylamide, when co-heating 
of 10 mol of acrylamide respectively with 0.1 mmol of amino acids at 160C for 15 min, acrylamide was 
eliminated from 7.4% (asparagine) to 94.4% (cysteine) at natural pH, and 11.4% (glutamic acid) to 94.8% 
(cysteine) at pH 7.0. It was found that cysteine, glysine and lysine showed much higher reactivity with 
acrylamide than the other seven amino acids. When the molar ratios of amino acid to acrylamide were 
increased to 60:1 for cysteine and glycine, and 80:1 for lysine, acrylamide in the reaction system was 
almost eliminated. The elimination efficiencies of the three amino acids for acrylamide were enhanced 
by addition of glucose. Liquid chromatography/time-of-flight mass spectroscopy showed that cysteine, 
glycine, and lysine adducted with two molecules of acrylamide, while the other amino acids except for 
glutamic acid (no adduct compounds were found) just adducted with one mole of acrylamide. This 
finding may partly explain why cysteine, glycine and lysine showed high capacity to reduce acrylamide 
content in high-temperature processing food.