啤酒酒花颗粒异构化研究

Research on the Isomerization of Hop Pellets

啤酒苦味的主要来源是α-酸,在麦汁煮沸过程中α-酸会转变成苦味更强、溶解性能更好的异α-酸。以单因素和响应面试验设计为基础,啤酒花颗粒为原料,反应温度/压力、酒花添加量、缓冲液pH值和催化剂使用量为因素,研究探讨对α-酸异构化的影响。结果表明,当实际温度为116℃,酒花添加量2 g,pH值11,催化剂添加量3%时,异α-酸转化率最高,达到116.03%。在实际生产过程中,α-酸的异构化率并不是很高,若在麦汁煮沸过程中加入预异构化的异α-酸会使酒花制品利用率提高。

α-acids,the main source of beer bitterness,are isomerized into iso-α-acids in wort boiling process.Iso-α-acids are much bitter and easily-dissolved than α-acids.On the basis of single factor test and response surface experiments,hop pellets used as raw materials,the effects of reaction temperature and pressure,the addition level of hop,buffering solution pH,and the use level of MgCl2 on α-acids isomerization were in-vestigated.The results indicated that the highest isomerization rate of α-acids into iso-α-acids could be achieved（the yield of iso-α-acids were 116.03 %） as the actual reaction tempreture was at 116 ℃,the addition level of hop was 2 g/150 mL,buffering solution pH was 11,and the use level was MgCl2 3 %.However,the yield of iso-α-acids was not so high in practice.The addition of preisomerized iso-α-acids during wort boil-ing could enhance the use rate of hop.