Mechanism for formation of the lightstruck flavor in beer revealed by time-resolved electron paramagnetic resonance

Chemistry - A European Journal

Volumn 7, Issue 21, 2001, Pages 4553-4561

  Burns, Colin S ^a   Heyerick, Arne ^b   De Keukeleire, Denis ^b   Forbes, Malcolm D E ^a  

^a University of North Carolina at Chapel Hill   (United States)

^b GHENT UNIVERSITY   (Belgium)

Author keywords

Beer; EPR spectroscopy; Isohumulones; Photolysis

Indexed keywords

COMPUTER SIMULATION; ENERGY TRANSFER; FLAVORS; FREE RADICALS; PHOTODEGRADATION; PHOTOLYSIS;

LIGHTSTRUCK FLAVORS;

PARAMAGNETIC RESONANCE;

CYCLOHEXANE; FLAVORING AGENT; FREE RADICAL; TOLUENE;

ARTICLE; BEER; COMPUTER SIMULATION; CROSS LINKING; ELECTRON SPIN RESONANCE; ENERGY TRANSFER; LIGHT ABSORPTION; METHODOLOGY; PHOTODEGRADATION; PHOTOLYSIS; POLARIZATION;

BEER; ELECTRON SPIN RESONANCE SPECTROSCOPY; FLAVORING AGENTS;

EID: 0035813808     PISSN: 09476539     EISSN: None     Source Type: Journal    
DOI: 10.1002/1521-3765(20011105)7:21<4553::aid-chem4553>3.0.co;2-0     Document Type: Article

References (35)

1. D. De Keukeleire, Spectrum 1991, 4, 1.
2. C. Linter, Lehrbuch der Bierbrauerei 1875, 343.
3. M. Uchida, S. Suga, N. Ono, J. Am. Soc. Brew. Chem. 1996, 54, 205.
4. L. Andersen-Mogens, H. Skibsted-Leif, J. Agric. Food Chem. 1998, 46, 1272.
5. Y. Kuroiwa, N. Hashimoto, Proc. Am. Soc. Brew. Chem. 1961, 28.
6. F. Gunst, M. Verzele, J. Inst. Brew. 1978, 84, 291.
7. C. Andres-Lacueva, F. Mattivi, D. Tonon, J. Chromatogr. A 1976, 823, 355.
8. G. M. A. Blondeel, D. De Keukeleire, M. Verzele, J. Chem. Soc. Perkin Trans. 1 1987, 2715.
9. P. J. Wagner, G. S. Hammond, Adv. Photochem. 1968, 5, 21.
10. M. Salzmann, Y. P. Tsentalovich, H. J. Fischer, Chem. Soc. Perkin Trans. 2 1994, 2119.
11. H. Goldstein, S. Rader, A. A. Murakami, J. Am. Soc. Brew. Chem. 1993, 51, 70.
12. A. J. Irwin, L. Bordeleau, R. L. Barker, J. Am. Soc. Brew. Chem. 1993, 51, 1.
13. M. Meilgaard, G. V. Civill, B. T. Carr, Sensory Evaluation Techniques, CRC, Boca Raton, Florida (USA), 1999, p. 127.
14. K. A. McLauchlan, D. G. Stevens, Acc. Chem. Res. 1988, 21, 54.
15. K. M. Salikhov, Y. N. Molin, R. Z. Sagdeev, A. L. Buchachenko, Spin Polarization and Magnetic Effects in Radical Reactions, Elsevier, Amsterdam (The Netherlands), 1984.
16. In the present day hop-processing industry, the iso-α-acids, which are naturally formed during wort boiling, are prepared from hop extracts by using liquid or supercritical carbon dioxide. The α-acids contained in the extract are isomerized under alkaline conditions following separation from other material (see M. Verzele, D. De Keukeleire, Chemistry and Analysis of Hop and Beer Bitter Acids, Elsevier, Amsterdam (The Netherlands), 1991, pp. 88-126). This so-called "advanced hop product" based on iso-α-acids is widely used in the brewing industry to dose exactly the desired beer bitterness either during wort boiling, after fermentation, or just prior to bottling.
17. J. L. Benitez, A. Forster, D. De Keukeleire, M. Moir, F. R. Sharpe, L. C. Verhagen, K. T. Westwood, Hops and Hop Products, Getränke-Verlag Hans Carl, Nürnberg (Germany), 1997, pp. 25-50.
18. H. A. Thornton, J. Kulandai, M. Bond, M. P. Jontef, D. B. Hawthorne, T. E. Kavanagh, J. Inst. Brew. 1993, 99, 473-477.
19. Tetrahydroiso-α-acids are prepared from pure iso-α-acids (see ref. [16]) by catalytic hydrogenation. The high interest in this type of advanced hop product resides in its pronounced bitterness (almost twice as bitter as the iso-α-acids) and its propensity to stabilize beer foam. It is furthermore claimed that the tetrahydroiso-α-acids resist light-induced decomposition.
20. The dihydroiso-α-acids are obtained by sodium borohydride reduction of pure iso-α-acids (see ref. [16]) and, as light-stable bittering agents, they are increasingly used in breweries worldwide to make "lightproof" beers.
21. M. D. E. Forbes, Photochem. Photobiol. 1997, 65, 73.
22. J. K. Vollenweider, H. Paul, Int. J. Chem. Kinet. 1986, 18, 791.
23. P. J. Krusic, P. Meakin, B. E. Smart, J. Am. Chem. Soc. 1974, 96, 1402.
24. B. C. Gilbert, R. G. G. Holmes, R. O. C. Norman, J. Chem. Res. 1977, 1.
25. R. J. Wilson, J. Chem. Soc. B 1968, 84.
26. K. A. McLauchlan in Advanced EPR: Applications in Biology and Biochemistry (Ed.: A. J. Hoff), Elsevier, New York (USA), 1989, p. 350 ff.
27. J. K. S. Wan, M. C. Depew, Res. Chem. Intermed. 1992, 18, 227.
28. K. Tominaga, S. Yamauchi, N. Hirota, J. Phys. Chem. 1990, 94, 4425.
29. S. Yamauchi, N. Hirota, J. Higuchi, J. Phys. Chem. 1988, 92, 2129.
30. K. Akiyama, S. Tero-Kubota, T. Ikoma, Y. Ikegami, J. Am. Chem. Soc. 1994, 116, 5324.
31. K. Akiyama, S. Tero-Kubota, Mol. Phys. 1994, 83, 1091.
32. The EEEAAA phase (E = emission, A = enhanced absorption) of the frozen triplet of 11a-c is consistent with a structure that gives emissive TM; for example, the same pattern is observed in the randomly-oriented frozen triplet TREPR spectrum of benzophenone: see H. Murai, T. Imamura, K. Obi, Chem. Phys. Lett. 1982, 87, 295.
33. C. Blättler, F. Jent, H. Paul, Chem. Phys. Lett. 1990, 166, 375.
34. S. L. Murov, Handbook of Photochemistry, Marcel Dekker, New York (USA), 1973.
35. G. L. Closs, M. D Johnson, J. R. Miller, P. Piotrowiak, J. Am. Chem. Soc. 1989, 111, 3751.