Early Maillard reaction derivatives of lysine include N-
(1-deoxy-D-fructosyl) lysine and N- (1-deoxy-D-lactulosyl)
lysine (Finot and Mauron, 1972). These compounds
are deaminated only by intestinal microflora and thus are
not available to mammals and birds (Bleyl et al., 1980).
Because destruction of lysine is often 5 to 15 times greater
than that occurring with other amino acids (e.g., methionine,
cystine, tryptophan, leucine), changes in its bioavailability
indicate both the occurrence and intensity of the
Maillard reaction (Adrian, 1967).
Destruction of lysine is accomplished in two ways.
First, lysine is bound to sugars forming early-Maillard reaction
products. Although at this stage lysine is still detectable
in chemical assays, it is no longer bioavailable