A comprehensive
quantitative characterization of Maillard reaction
products was carried out for conventional (CON) and lactose-hydrolyzed
(LH) ultrahigh temperature (UHT) milk during storage at 20, 30, and
40 °C for 1 year. The accumulation of 3-deoxyglucosone (3-DG)
and 3-deoxygalactosone (3-DGal) in LH-UHT milk ranged from 20-fold
(at 20 °C) to 44-fold (at 40 °C) higher than that in CON-UHT
milk. High temperature storage (40 °C) significantly accelerated
the accumulation of 3-DG, 3-DGal, and 5-hydroxymethyl furfural but
not the majority of the analyzed advanced glycation endproducts (AGEs).
The concentrations of major AGEs including N-ε-carboxymethyllysine
(CML), N-ε-carboxyethyllysine (CEL), methylglyoxal-hydroimidazolone
isomers (MG-H1/H3), glyoxal-hydroimidazolone isomers (G-H1/H3), and
G-H2 detected in CON milk during storage were in the range 12–700,
1–14, 8–45, 4–13, and 1–30 μM, respectively,
while they were 30–570, 2–88, 17–150, 9–20,
and 5–34 μM, respectively, in LH milk. Pyrraline, S-(carboxymethyl)cysteine (CMC), and glyoxal-lysine dimer
were detected in lower levels, while MG-H2, methylglyoxal-lysine dimer,
argpyrimidine, glyoxal-lysine-amide, glycolic acid-lysine-amide, and
pentosidine were not detected in any of the milk samples. This work
demonstrates for the first time that five of the analyzed AGEs (CML,
CEL, MG-H1/H3, G-H1/H3, and G-H2) could be selected as markers for
evaluation of the extent of the Maillard reaction in UHT milk. These
results contribute to a better understanding of how Maillard reactions
progress during storage of UHT milk and can be used to develop strategies
to inhibit Maillard reactions in LH milk.