采用基于顶空固相微萃取-气相色谱质谱技术(HS-SPME/GC-MS)建立的啤酒中酒花物质的检测方法,跟踪了啤酒酿造过程中源自酒花的5种萜烯醇类香气化合物的变化规律,初步为啤酒厂酒花配方及工艺调整奠定了理论基础。通过对糖化过程中不同酒花配方、不同煮沸方式及酒花添加工艺对冷麦汁中萜烯醇类化合物含量影响的研究,发现冷麦汁中的萜烯醇类化合物主要受最后一次添加酒花的添加量和添加时机影响,最后一次酒花在煮终回旋前添加较煮终前10 min添加,更利于萜烯醇类化合物在冷麦汁中的保留,这与国外的late-hopping工艺相一致;与煮终前10 min最后一次添加相比,在煮终回旋前最后一次添加酒花能使冷麦汁中里那醇含量提高209.4%,α-萜品醇为91.2%,香叶醇为31.4%,橙花醇175.0%。通过研究发酵过程中萜烯醇类化合物的变化规律,发现5种萜烯在发酵过程中呈上升趋势,且它们之间可能被酵母相互转化。

A method developed by our lab based on gas chromatography–mass spectrometry(GC/MS) coupled with headspace solid-phase micro-extraction was used to track the content changes of 5 terpenols derived from hops,aiming at finding out their dynamic changes during the fermentation of commercial beer.Firstly,the influence of different hop formulations,boiling system and hopping regimes were evaluated during the mash process.The results showed that the terpenols in the cold wort were mainly attributed to the last addition of hops.Compared to the traditional boiling system,the use of Stromboli system was conductive to the remaining of terpenols in the cold wort.In the case of last hop addition,it was suggested that adding hops at the end of boiling was of great meanings for the remaining terpenols in the cold wort,where the linalool content in experiment C was 209.4% higher than experiment A,while α-terpineol was 91.2%,geraniol was 31.4% and nerol was 175.0%.Secondly,the content change of 5 terpenols in the fermentation process were tracked,and it was observed that the content of terpenols in beer were higher than those in cold wort,which can be explained by an occurrence of glycosidically bound flavor precursor and a glucoside hydrolase activity secreted from our lager yeast.Citronellol was almost absent in the cold wort but sharply increased during the first 3days,corresponding to the fast decrease of geraniol,which indicated that geraniol can be converted into citronellol in the first 3 days.