Exploration of the synergistic inhibition of 4-methylimidazole and 5-hydroxymethylfurfural in caramel colors by amino acid combinations and potential mechanisms

The current study examined the impact of different amino acids and heating durations on the levels of 4-MI and 5-HMF in caramel colors. At the 30-min mark, the 3:1 mass ratio (with a 0.2% addition) of the Cys-Pro combination inhibited 4-MI and 5-HMF by 20.33% and 18.39%, respectively. At 60 and 90 min, the 1:3 mass ratio (with a 1% addition) of the Cys-Pro combination yielded inhibition rates of 31.33% and 8.64% for 4-MI and 31.75% and 22.52% for 5-HMF within the caramel colors. The Cys-Pro mass ratios of 1:1, 1:3, and 3:1 demonstrated peak inhibition rates of 81.63%, 86.28%, and 86.57% against MGO, respectively. The most effective inhibition against 3-DG was achieved with a 30-min heating duration and a 1:3 mass ratio (with a 1% addition) of the Cys-Pro combination, resulting in a 14.21% inhibition rate. Notably, in a model system, cysteine also exhibited significant inhibitory effects against MGO. Additionally, ESR measurements revealed that amino acid combinations can effectively eliminate the free radicals generated during the caramelization process.