Inactivation of Amino Acids by Autoclaving

Abstract

After autoclaving soybean protein and soybean protein plus sucrose for 4 hrs. at 15 lbs. pressure, bioassays were made of the amino acid constituents. None of the amino acids was destroyed in the soybean protein, but over 40% of the lysine and arginine were inactivated in protein plus sucrose, apparently by reaction of the free amino groups with sucrose; smaller fractions of cystine, histidine, and aspartic acid were inactivated. Free amino acids added to the soybean protein before autoclaving were from 2% (methionine) to 22% (aspartic acid) destroyed, with sucrose added over 45% of all free amino acids except cystine was destroyed. Amino acids are inactivated either by destruction, or forming enzyme-resistant linkages.