Quantification of Maillard Reaction Products in Doce de Leite

The Maillard reaction (MR), a temperature-dependent reaction, affects the sensory and nutritional properties of Doce de leite. While 5-hydroxymethylfurfural (HMF) is commonly used as a marker to indicate thermal exposure, its use alone does not capture the full complexity of MR. This study investigated a set of additional Maillard reaction products (MRPs) including furosine, N-carboxymethyl-lysine (CML), pyrraline, 2-furfural, 2-furylmethyl ketone, 2-methylfurfural, and the heat-induced cross-linking marker lysinoalanine (LAL)– in 11 different Brazilian commercial Doce de leite samples. The findings demonstrate that a single MRP is insufficient for characterizing the Maillard reaction progress in Doce de leite. To address this limitation, we propose a “Maillard Reaction Stage Index” (MRSI), which integrates both early and advanced MRPs to consider the formation and consumption of MRPs in subsequent reactions. Thus, this provides a more accurate picture of the progress of MR in Doce de leite.