The Loss of Added Lysine During the Baking of a Soft Bread with an Exceptionally High Content of Reducing Sugar

Abstract

Abstract— An estimation was made of the loss of supplementary L‐lysine HCl that occurs during the baking of a soft bread containing a very high content of syrup. Rats and bacteria served as test systems. The nitrogen efficiency ratios of young albino rats given bread diets to which L‐lysine HCl was added before or after baking indicated that approximately 30 % of the L‐lysine HCl added before baking was inactivated or destroyed. Extraction of the supplementary L‐lysine HCl with cold dilute acid or alkali followed by microbiological determination of the lysine gave values of the order of 25 % for the loss of lysine during baking.It was found that the protein value of the type of bread studied was in itself poor, probably due to inactivation of the protein‐bound lysine caused by reactions with the reducing sugar.Liver fat content and three different liver transaminase activities were also measured. No pathological changes were indicated.