氮肥运筹对大麦啤酒混浊性状的影响

啤酒混浊是一个严重的品质问题,它显著缩短啤酒的贮藏与货架时间。为给生产低混浊啤酒大麦提供科学依据,本研究选用混浊特性不同的4个大麦品种,设置不同的氮肥用量与施用时期,探讨氮肥运筹对啤酒混浊性状的影响。结果发现,供试大麦品种之间和氮肥施用时期之间混浊性状差异极显著;澳大利亚大麦品种Franklin和Yerong的酒精冷混浊值(ACHD)显著低于国产大麦品种浙大9号和花30。Franklin的混浊敏感蛋白最低,花30次之,浙大9号和Yerong的混浊敏感蛋白含量较高。增施抽穗期氮肥,显著提高大麦的混浊度。不同氮肥用量之间,混浊敏感蛋白HAP1和HAP3差异极显著,但酒精冷混浊值和HAP2无显著差异;品种与氮肥用量及施用时期之间的互作效应对部分混浊性状表现显著。因此,为生产低混浊的啤酒大麦,生产上首先应考虑选用低混浊品种,并在氮肥施用上适当减少穗肥用量。

Effect of Nitrogen Application Amount and Timing on Haze Characters of Beer in Barley

In bright beers,haze formation is a serious quality problem,limiting beer storage and shelf life. Barley is mainly used as raw material for beer brewing,and its quality largely affects the values of the final product beer. In this study,the influence of nitrogen fertilizer amounts and timings on beer haze parameters was investigated using 4 barley varieties differing in haze characters. The results showed that haze characters differed greatly among barley varieties and timings of nitrogen application. The alcohol chill haze degree (ACHD) of cultivars Franklin and Yerong were significant lower than cultivars Hua 30 and Zheda 9,and the haze active protein level became lower as in the order of Franklin,Hua 30,Zheda 9 and Yerong. Higher ratio of nitrogen fertilizer application at heading stage would increase haze formation in beer. A significant difference among N fertilizer amounts was observed in HAP1 and HAP3,but not in ACHD and HAP2. Haze formation would be enhanced when more N fertilizer was applied at booting stage. So it is important to reduce N fertilizer application at heading stage in addition to use of the varieties with low haze protein contents,in order to reduce haze formation in beer for improving malt quality.