Le blocage de la lysine par la réaction de Maillard. II. Propriétés chimiques des dérivés N‐(désoxy‐1‐D‐fructosyl‐1) et N‐(désoxy‐1‐D‐lactulosyl‐1) de la lysine

Lysine is often inactivated by ‘Maillard‐type’ reactions in food proteins; the values obtained for it by different methods cannot be compared because the chemical behaviour of inactivated lysine is unknown. In this paper, the behaviour of an important form of inactivated lysine, namely its 1‐deoxyketosyl derivatives, during acid hydrolysis as well as on the different assays for available lysine (F‐DNB, TNBS, pipsylchloride and guanidination) is studied. The relative proportions of regenerated lysine and of formed furosine and pyridosine are established as a function of the conditions of hydrolysis. The validity of the methods used to estimate available lysine from its 1‐deoxyketosyl derivatives is discussed.