- Generation of thiols by biotransformation of cysteine-aldehyde conjugates with baker's yeast
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Baker's yeast was shown to catalyze the transformation of cysteine-furfural conjugate into 2-furfurylthiol. The biotransformation's yield and kinetics were influenced by the reaction parameters such as pH, incubation mode (aerobic and anaerobic), and substrate concentration. 2-Furfurylthiol was obtained in an optimal 37% yield when cysteine-furfural conjugate at a 20 mM concentration was anaerobically incubated with whole cell baker's yeast at pH 8.0 and 30 °C. Similarly to 2-furfurylthiol, 5-methyl-2-furfurylthiol (11%), benzylthiol (8%), 2-thiophenemethanethiol (22%), 3-methyl-2-thiophenemethanethiol (3%), and 2-pyrrolemethanethiol (6%) were obtained from the corresponding cysteine-aldehyde conjugates by incubation with baker's yeast. This work indicates the versatile bioconversion capacity of baker's yeast for the generation of thiols from cysteine-aldehyde conjugates. Thanks to its food-grade character, baker's yeast provides a biochemical tool to produce thiols, which can be used as flavorings in foods and beverages.
- Huynh-Ba, Tuong,Matthey-Doret, Walter,Fay, Laurent B.,Rhlid, Rachid Bel
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p. 3629 - 3635
(2007/10/03)
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- Mercaptomethylation of aromatics
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Mercaptomethylarenes 2a - f were prepared in moderate yields by facile mercaptomethylation consisting of the metalation of the corresponding aromatics 1a - f with magnesium or butyllithium / magnesium bromide diethyl etherate, followed by the addition of O-propyl chlorothioformate, and the reduction with lithium aluminum hydride or sodium borohydride.
- Nakamura, Tohru,Matsumoto, Mutsuyoshi
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p. 201 - 210
(2007/10/03)
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- Evaluation of the Key Odorants in a Thermally Treated Solution of Ribose and Cysteine by Aroma Extract Dilution Techniques
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Application of the aroma extract dilution analysis on a solvent extract isolated from a thermally treated solution (145 deg C; 20 min) of cysteine/ribose led to the identification of 2-furfurylthiol, 3-mercapto-2-pentanone, 2-methyl-3-furanthiol, 5-acetyl-2,3-dihydro-1,4-thiazine, 3-mercapto-2-butanone, and bis(2-methyl-3-furyl) disulfide showing the highest flavor dilution factors among the 29 odor-active volatiles.HRGC/olfactometry of decreasing headspace volumes established especially 2-furfurylthiol and 2-methyl-3-furanthiol as important odorants and revealed 2-thenyl mercaptan and ethyl mercaptan as further key contributors to the overall roasty, meatlike, sulfury odor of the model mixture. 5-acetyl-2,3-dihydro-1,4-thiazine, identified for the first time among the volatiles of Maillard model reactions or foods, exhibited an intense roasty, popcorn-like odor at the low odor threshold of 0.06 ng/L of air, which was of the same order of magnitude as those reported in the literature for the roasty-smelling odorants 2-acetyl-1-pyrroline and 2-acetyl-2-thiazoline.Keywords: Aroma extract dilution analysis; nonenzymatic browning; Maillard reaction; ribose; cysteine; flavor; 5-acetyl-2,3-dihydro-1,4-thiazine
- Hofmann, Thomas,Schieberle, Peter
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p. 2187 - 2194
(2007/10/02)
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- Substituted dibenzoxazepine compounds, pharmaceutical compositions and methods for treating pain
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The present invention provides substituted dibenzoxazepine compounds of Formula I: STR1 which are useful as analgesic agents for the treatment of pain, pharmaceutical compositions comprising a therapeutically-effective amount of a compound of Formula I in combination with a pharmaceutically-acceptable carrier, and a method for eliminating or ameliorating pain in an animal comprising administering a therapeutically-effective amount of a compound of Formula I to the animal.
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- Rotational Conformers of Furan and Thiophene Thioaldehyde Anion Radicals
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The radical anions of the four isomeric furan and thiophene thioaldehydes have been obtained by photolysis, in an alkaline medium, of the corresponding thiols in the presence of di-tert-butyl peroxide.The same reaction also yields the four corresponding aldehyde radical anions, starting from the appropriate alcohols.The ESR spectra show that in most cases the two rotational conformers (E and Z) are present at the equilibrium.By means of appropriate methyl-substituted derivatives it has been possible to assign the structure of the two conformers.In the case of the 2-furan and 2-thiophene aldehyde anion radicals it has been found that the conformational preference is the same as that exhibited by the corresponding molecules.
- Borghi, R.,Cremonini, M. A.,Lunazzi, L.,Placucci, G.,Macciantelli, D.
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p. 6337 - 6341
(2007/10/02)
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