结晶麦芽的制备工艺优化及其品质分析

Optimization of preparation process and quality analysis of crystal malt

结晶麦芽作为重要的特种麦芽,可以赋予啤酒多样的风味和独特的口感。选取不同发芽时间的绿麦芽为原料,比较糖化后还原糖和游离氨基氢含量的变化,确定用于制备结晶麦芽的绿麦芽,优化绿麦芽的预糖化与焙焦工艺,制备结晶麦芽,并分析其常规理化指标与风味特征。结果表明,选择发芽84h的绿麦芽为原料,调节预糖化水的pH为3.36,蛋白质休止温度杓60℃,糖化温度为71.1℃,预糖化结束的绿麦芽游离氨基氦与还原糖含量分别达到142.4mg·L^-1与26.2g·L^-1。由此制备的结晶麦芽结晶率98%,且麦芽内部结晶均匀,风味物质含量达到1265μg·L^-1,比普通商品结晶麦芽提高了98.3%,主要风味物质为醛类。本研究为国产优质结晶麦芽的规模化生产奠定了基础。

Crystal malt,one of the most important specialty malts,confers a variety of flavors and unique taste on beer.After saccharification with green malts that produced with different germination time,the variations of reducing sugar and free amino nitrogen contents in malt were compared,to determine the which gennination time is fit for producing green malt that can used to prepare crystal malt.The pre-saccharification and roasting process of green malt were optimized at the same time.Its regular physical and chemical indicators and flavor characteristics were also analyzed.The results showed that the optimized condition for producing green malt was:germination time was 84 h,the pH of the pre-saccharification water was 3.36,the protein resting temperature was 60℃,the saccharification temperature was 71.1℃.With the optimized condition,the contents of free amino nitrogen and reducing sugar of green malt at the end of pre-saccharification reached to 142.4 mg·L^-1 and 26.2 g·L^-1 respectively.At the same time,the crystallization rate was 98%,and the malt was crystallized evenly.Furthermore,the content of flavor substances reached to 1265 g·L^-1,which was 98.3%higher than that of commercial crystal malt.The main flavor substances were detected to be aldehydes.This study laid a foundation for the large-scale production of high-quality crystal malt in China.