Abstract The current article is concerned with the instability of 2-methylbutyl isobutyrate (2-MBIB) throughout beer storage. 2-MBIB is the primary ester of hops and HS-SPME-GC-MS/MS analysis of 135 commercial ales confirmed that 2-MBIB is also one of most abundant hop-derived volatiles in ale. To investigate 2-MBIB stability during beer aging, eleven domestic ales with initial 2-MBIB levels ranging from 10 − 311 µg/L were analyzed across freshly packaged, naturally and forced aged beer. Upon storage, 2-MBIB concentrations in all ales decreased remarkably. After 24 weeks at 20 °C the tested ales lost 80% of their initial 2-MBIB concentration on average. At 4 °C, which is considered an ideal beer storage temperature, the average reduction was still 60%. Overall, the lowest 2-MBIB reduction was found in pasteurized ales, indicating that 2-MBIB decrease is driven by chemical and enzymatic reactions. The losses of 2-MBIB appear to be a significant contributor to the chemical instability of hoppy ales.

中文翻译：

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啤酒花衍生的 2-甲基异丁酸丁酯在商业巴氏杀菌和未经巴氏杀菌的麦芽酒陈酿过程中的不稳定性

摘要 本文关注的是 2-甲基丁基异丁酸酯 (2-MBIB) 在啤酒储存过程中的不稳定性。2-MBIB 是啤酒花的主要酯，对 135 种商业啤酒的 HS-SPME-GC-MS/MS 分析证实，2-MBIB 也是啤酒中最丰富的啤酒花衍生挥发物之一。为了研究啤酒老化过程中 2-MBIB 的稳定性，对 11 种初始 2-MBIB 水平范围为 10 - 311 µg/L 的国产麦芽酒进行了分析，这些啤酒包括新鲜包装的、自然老化的和强制老化的啤酒。储存后，所有麦芽酒中的 2-MBIB 浓度显着降低。在 20 °C 下 24 周后，测试的麦芽酒平均损失了其初始 2-MBIB 浓度的 80%。在被认为是理想啤酒储存温度的 4 °C 下，平均减少量仍为 60%。总体而言，在巴氏杀菌麦芽酒中发现了最低的 2-MBIB 减少，表明 2-MBIB 的减少是由化学和酶促反应驱动的。2-MBIB 的损失似乎是啤酒花啤酒化学不稳定性的重要原因。