Degradation of the Coffee Flavor Compound Furfuryl Mercaptan in Model Fenton-type Reaction Systems
详细信息 查看全文
- 作者：Imre Blank ; Ederlinda C. Pascual ; Sté ; phanie Devaud ; Laurent B. Fay ; Richard H. Stadler ; Chahan Yeretzian ; and Bernard A. Goodman
- 刊名：Journal of Agricultural and Food Chemistry
- 出版年：2002
- 出版时间：April 10, 2002
- 年：2002
- 卷：50
- 期：8
- 页码：2356 - 2364
- 全文大小：126K
- 年卷期：v.50,no.8(April 10, 2002)
- ISSN：1520-5118
文摘
The stability of the coffee flavor compound furfuryl mercaptan has been investigated in aqueoussolutions under Fenton-type reaction conditions. The impact of hydrogen peroxide, iron, ascorbicacid, and ethylenediaminetetraacetic acid was studied in various combinations of reagents andtemperature. Furfuryl mercaptan reacts readily under Fenton-type reaction conditions, leading to upto 90% degradation within 1 h at 37 
C. The losses were lower when one or more of the reagentswas omitted or the temperature decreased to 22 C. Volatile reaction products identified were mainlydimers of furfuryl mercaptan, difurfuryl disulfide being the major compound. In addition, a large numberof nonvolatile compounds was observed with molecular masses in the range of 92-510 Da. Theformation of hydroxyl and carbon-centered radicals was indicated by electron paramagnetic resonancespectra using 
-(4-pyridyl-1-oxide)-N-tert-butylnitrone or 5-(diethoxyphosphoryl)-5-methyl-1-pyrroline-N-oxide as spin traps. Whereas 
OH was generated by Fenton-type reactions, the C-centered radicalis probably a secondary product of the reaction of OH with various organic molecules, the reactionwith furfuryl mercaptan appearing to be the most important. No evidence for S-centered radicals wasseen in the spin-trapping experiments, but a sulfur-containing radical was detected when measurements were made at 77 K in the absence of spin traps.Keywords: Coffee; furfuryl mercaptan; thiols; Fenton chemistry; mass spectrometry; electronparamagnetic resonance spectroscopy
C. The losses were lower when one or more of the reagentswas omitted or the temperature decreased to 22 C. Volatile reaction products identified were mainlydimers of furfuryl mercaptan, difurfuryl disulfide being the major compound. In addition, a large numberof nonvolatile compounds was observed with molecular masses in the range of 92-510 Da. Theformation of hydroxyl and carbon-centered radicals was indicated by electron paramagnetic resonancespectra using -(4-pyridyl-1-oxide)-N-tert-butylnitrone or 5-(diethoxyphosphoryl)-5-methyl-1-pyrroline-N-oxide as spin traps. Whereas OH was generated by Fenton-type reactions, the C-centered radicalis probably a secondary product of the reaction of OH with various organic molecules, the reactionwith furfuryl mercaptan appearing to be the most important. No evidence for S-centered radicals wasseen in the spin-trapping experiments, but a sulfur-containing radical was detected when measurements were made at 77 K in the absence of spin traps.Keywords: Coffee; furfuryl mercaptan; thiols; Fenton chemistry; mass spectrometry; electronparamagnetic resonance spectroscopy