Lead (II) Ions Strongly Inhibit the Maillard Reaction in a Glucose–Lysine Model System: Implications for Flour Safety

Background: The Maillard reaction is responsible for color and flavor development in baked goods and has been proposed as a potential mechanism for heavy metal sequestration due to the chelating capacity of melanoidins. Therefore, this study aimed to investigate the influence of lead (II) ions on the Maillard reaction under simulated bread-making conditions. Methods: A glucose–lysine model system (pH 6.5) was heated and maintained at 100 °C for 60 minutes in the presence or absence of 0.5 mg/L Pb2+. Browning development was monitored by measuring absorbance at 450 nm. Data were analyzed statistically using two-way analysis of variance (ANOVA) followed by Tukey’s post hoc test. Results: Lead ions significantly inhibited browning intensity at all time points, reducing absorbance by 66–76% relative to controls (p < 0.01). Time-dependent browning was observed only in control samples, whereas Pb2+-treated systems showed no significant progression. Conclusion: Pb2+ strongly suppresses the Maillard reaction, likely by sequestering lysine or masking reactive carbonyl groups, thereby preventing early-stage Schiff base formation. Although partial metal binding may occur, the substantial loss of sensory attributes limits the feasibility of Maillard-based lead decontamination in flour systems.