啤酒酿造过程中麦芽香气变化规律的研究

Study on the change law of malt aroma during beer brewing

采用顶空固相微萃取-气相色谱质联用技术跟踪测定啤酒酿造过程中16种麦芽香气组分的含量变化,通过对三种不同类型产品Pilsener、Weissbier、Lager进行原料、糖化过程关键位点、发酵过程关键位点、成品进行麦芽香气含量测定及差异性分析。结果表明,Pilsner混合配比麦芽香气突出,麦芽香气组分总含量分别高于Weissbier和Lager麦芽33.6%、61.0%。在酿造过程阶段,三种不同类型产品的甲基吡嗪类在酿造阶段变化趋势不明显,最终成品甲基吡嗪类含量略低于发酵初始含量,2-乙酰吡啶与吡嗪类麦芽香气变化趋势相似。麦芽酚、2-乙酰吡咯在煮沸阶段呈现明显增长趋势,菠萝酮在糖化位点含量最高,在煮沸位点出现损失,含量呈现下降趋势。三种不同类型产品的3-甲基丁醛在糖化阶段出现大量损失,损失率达98.3%~99.5%,在发酵初期有小幅度上涨,在发酵的第3天~第4天出现下降,下降至发酵初期的1/8~1/4,在后酵期含量平稳,成品含量为12.80~14.80μg/L。相比其它两个产品类型,Pilsener原料麦芽中2-乙酰吡略含量最高,最终到成品啤酒损失率达79.8%。虽然三种不同啤酒类型产品麦芽香气经过复杂的酿造过程大量损失,但在最终Pilsener成品酒中麦芽香气总含量仍高于其它两个品种。

The content changes of 16 malt aroma components in beer brewing process were tracked and determined by headspace solid-phase microextraction gas chromatographymass spectrometry.The malt aroma content and difference analysis were carried out on three different beer types:Pilsen,white beer and lager.The results showed that the malt with Pilsen mixture had outstanding aroma,and the total content of components was 33.6%and 61.0%higher than that of white beer and lager malt,respectively.In the brewing process stage,the change trend of methyl pyrazines of three different beer types is not obvious in the brewing stage,the content of methyl pyrazines in the final product is slightly lower than the initial fermentation content,and the change trend of 2-acetylpyridine and pyrazine malt aroma is similar.Maltol and 2-acetylpyrrole showed an obvious increase trend in the boiling stage,the content of bromelone was the highest at the saccharification site,lost at the boiling site,and the content showed a downward trend.3-Methylbutyraldehyde of three different types of beer products lost a lot in the saccharification stage,with a loss rate of 98.3%~99.5%.It increased slightly in the initial stage of fermentation,decreased from the third day to the fourth day of fermentation,and decreased to 1/8~1/4 in the initial stage of fermentation.In the post fermentation stage,the content was stable,and the content of finished products was 12.80~14.80μg/L.Although the malt aroma of three different beer types was lost a lot through the complex brewing process,the total aroma content in the final Pilsen product was still higher than that of the other two varieties.Compared with the other two product types,the content of 2-acetylpyrrole in Pilsen raw malt is the highest,and the loss rate of finished beer is 79.8%.