文摘
Recently, it was reported that furfuryl ethyl ether is an important flavor compound indicative of beerstorage and aging conditions. A study of the reaction mechanism indicates that furfuryl ethyl ether ismost likely formed by protonation of furfuryl alcohol or furfuryl acetate followed by SN2-substitution ofthe leaving group by the nucleophilic ethanol. For the reaction in beer, a pseudo-first-order reactionkinetics was derived. A close correlation was found between the values predicted by the kinetic modeland the actual furfuryl ethyl ether concentration evolution during storage of beer. Furthermore, 10commercial beers of different types, aged during 4 years in natural conditions, were analyzed, andit was found that the furfuryl ethyl ether flavor threshold was largely exceeded in each type of beer.In these natural aging conditions, lower pH, darker color, and higher alcohol content were factorsthat enhanced furfuryl ethyl ether formation. On the other hand, sulfite clearly reduced furfuryl ethylether formation. All results show that the furfuryl ethyl ether concentration is an excellent time-temperature integrator for beer storage.Keywords: Furfuryl ethyl ether; flavor; beer; aging; staling; furanic ethers; kinetics