Chemoenzymatic Synthesis of Aroma Active 5,6-Dihydro- and Tetrahydropyrazines from Aliphatic Acyloins Produced by Baker's Yeast

• Published in: Journal of agricultural and food chemistry Vol. 51; no. 10; pp. 3103 - 3107
• Main Authors: Kurniadi, Toshinari, Rhlid, Rachid Bel, Fay, Laurent-Bernard, Juillerat, Marcel-Alexandre, Berger, Ralf Günter
• Format: Journal Article
• Language: English
• Published: WASHINGTON American Chemical Society 07.05.2003; Amer Chemical Soc
• Subjects: acids; Agriculture; Agriculture, Multidisciplinary; air; aldehydes; Aldehydes - metabolism; Aroma and flavouring agent industries; bakers yeast; Bioconversions. Hemisynthesis; Biological and medical sciences; Biotechnology; biotransformation; breads; Carboxylic Acids - metabolism; Catalysis; Chemistry; Chemistry, Applied; Fatty Alcohols - metabolism; Food industries; Food Science & Technology; Fundamental and applied biological sciences. Psychology; Gas Chromatography-Mass Spectrometry; Life Sciences & Biomedicine; Methods. Procedures. Technologies; Odorants - analysis; odors; Physical Sciences; Pyrazines - metabolism; Saccharomyces cerevisiae; Saccharomyces cerevisiae - metabolism; Science & Technology; flavor; baker's yeast; carboligation; pyrazine derivatives; PYRAZINES; acyloins; Chemical reaction; Biotransformation; Pyrazine derivatives; Baker yeast; Flavor; Odor
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/jf0261809

Twenty-five acyloins were generated by biotransformation of aliphatic aldehydes and 2-ketocarboxylic acids using whole cells of baker's yeast as catalyst. Six of these acyloins were synthesized and tentatively characterized for the first time. Subsequent chemical reaction with 1,2-propanediamine under mild conditions resulted in the formation of thirteen 5,6-dihydropyrazines and six tetrahydropyrazines. Their odor qualities were evaluated, and their odor thresholds were estimated. Among these pyrazine derivatives, 2-ethyl-3,5-dimethyl-5,6-dihydropyrazine (roasted, nutty, 0.002 ng/L air), 2,3-diethyl-5-methyl-5,6-dihydropyrazine (roasted, 0.004 ng/L air), and 2-ethyl-3,5-dimethyltetrahydropyrazine (bread crustlike, 1.9 ng/L air) were the most intensive-smelling aroma active compounds. Keywords: Pyrazine derivatives; acyloins; baker's yeast; carboligation; flavor