Novel Taste-Enhancing 4-Amino-2-methyl-5-heteroalkypyrimidines Formed from Thiamine by Maillard-Type Reactions

Abstract

Increasing the thiamine concentration in a respective process flavor yields a product with a significant higher kokumi activity. S-plot analysis of the mass spectrometric data revealed beside thiamine itself, 4-methyl-5-thiazoleethanol, (S)-((4-amino-2-methylpyrimidin-5-yl)­methyl)-l-cysteine, N-((4-amino-2-methylpyrimidin-5-yl)­methyl)­formamide, 3-(((4-amino-2-methylpyrimidin-5-yl)­methyl)­thio)-5-hydroxypentan-2-one, and 2-methyl-5-(((2-methylfuran-3-yl)­thio)­methyl)­pyrimidin-4-amine as marker molecules for a process flavor with higher thiamine concentration. Sensory-based targeted isolation revealed that (S)-((4-amino-2-methylpyrimidin-5-yl)­methyl)-l-cysteine, 3-(((4-amino-2-methylpyrimidin-5-yl)­methyl)­thio)-5-hydroxypentan-2-one, and 2-methyl-5-(((2-methylfuran-3-yl)­thio)­methyl)­pyrimidin-4-amine showed an influence on the kokumi taste activity with taste threshold concentrations between 35 and 120 μmol/L. An adapted mass spectrometric-based carbon module labeling experiment as well as quantitative studies clearly demonstrated thiamine as the only precursor and an intermolecular formation pathway for the compounds (S)-(((4-amino-2-methylpyrimidin-5-yl)­methyl)­thio)-5-hydroxypentan-2-one and 2-methyl-5-(((2-methylfuran-3-yl)­thio)­methyl)­pyrimidin-4-amine. On the basis of the knowledge that several thiamine derivatives showed taste-modulating activity, selected thiamine-based binary model reactions and synthesis were carried out. This resulted in the isolation of further thiamine-derived taste modulators like (S)-((4-amino-2-methylpyrimidin-5-yl)­methyl)-l-cysteinylglycine, (S)-3-((((4-amino-2-methylpyrimidin-5-yl)­methyl)­thio)­methyl)­piperazine-2,5-dione, 3-(((4-amino-2-methylpyrimidin-5-yl)­methyl)­thio)­pentan-2-one, 5-(((furan-2-ylmethyl)­thio)­methyl)-2-methylpyrimidin-4-amine, and (4-amino-2-methylpyrimidin-5-yl)­methanethiol, 2-methyl-5-((methylthio)­methyl)­pyrimidin-4-amine with taste thresholds ranging from 35 to 880 μmol/L.

Quantitative Proton NMR Spectroscopy for Basic Taste Recombinant Reconstitution Using the Taste Recombinant Database

“…The differences between the artificial flavor and the BTR could be explained by a lack of N -acetylated amino acids, such as N -acetylalanine, S -((4-amino-2-methylpyrimidin-5-yl)­methyl)- l -cysteine and 4-amino-2-methyl-5-heteroalkypyrimidines formed from thiamine via Maillard-type reactions, in the recombinant. These compounds have shown taste-modulating effects related to umami and kokumi enhancement. , …”

“…These compounds have shown taste-modulating effects related to umami and kokumi enhancement. 19,41 Shrimp. Cooked shrimp were processed analogously to the literature.…”

Quantitative Determination of Thiamine-Derived Taste Enhancers in Aqueous Model Systems, Natural Deep Eutectic Solvents, and Thermally Processed Foods

“…6 Recently, several new kokumi-enhancing compounds (3−11; Figure 1) derived from thiamine (1; Figure 1) have been identified. 1,2 All of these thiamine-based kokumi-active compounds have in common that the thiazole moiety (2; Figure 1) of thiamine is substituted by a sulfur compound, such as cysteine (in compound 3) or 2-methyl-3-furanthiol (MFT, in compound 5). 2 These compounds have been isolated from aqueous model reaction systems.…”

“…2 These compounds have been isolated from aqueous model reaction systems. 1,2 Recently, Kranz et. al showed that it is possible to increase the formation rate of several Maillard-derived taste modulators in a new reaction system, the natural deep eutectic solvents (NADES).…”

Conversion of 5-Hydroxymethylfurfural into 6-(Hydroxymethyl)pyridin-3-ol: A Pathway for the Formation of Pyridin-3-ols in Honey and Model Systems

“…Maillard reaction is a major route for the formation of aromas as a consequence of food processing. − The compounds responsible for these aromas have a great diversity of structures. Thus, the formation of aldehydes, alcohols, thiols, sulfides, acids, lactones, and a large variety of heterocyclic compounds has been described .…”