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。该文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氮含量的变化,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84 h的绿麦芽为原料,调节预糖化水的pH值为3.36,蛋白质休止温度为60℃,糖化温度为71.1℃,预糖化结束的绿麦芽游离氨基氮与还原糖含量分别达到142.4 mg/L与26.2 g/L。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,比普通商品结晶麦芽提高了98.3%,主要风味物质为醛类。该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, contribute to flavor variety and unique taste in beer. Through saccharification of green malts with different germination time followed by analysis of reducing sugar and free amino nitrogen, the optimal time for green malt germination was determined. Pre-saccharification and roasting process of green malt were optimized according to the physicochemical indexes and flavor characteristics. The results showed the optimized condition for producing crystal malt to be: germination time 84 h, pH of the pre-saccharification water 3.36, protein resting temperature 60 ℃ and saccharification temperature 71.1 ℃. Under this condition, the contents of free amino nitrogen and reducing sugar at the end of pre-saccharification reached 142.4 mg/L and 26.2 g/L, respectively. With the inner part of the malt evenly crystallized, the crystallization rate reached 98%. Furthermore, the content of flavor substances, most significantly aldehydes, reached 1 265 μg/L, which was 98.3% higher than that of common commercial crystal malt. This study laid a foundation for large-scale production of high-quality crystal malt.