Abstract As a continuation of our previous work, which concerned the binding of aldehydes to bisulfite and cysteine, this article presents more results on the applicability of 4-vinylpyridine addition to beer prior to analysis aiming at release of aldehydes from these preformed bound states, thus making them quantifiable with the headspace solid-phase microextraction method combined with gas chromatography-mass spectrometry. This article also presents the first results on spiking beer samples with cysteine prior to forced-aging, pointing to the important role of cysteine in beer flavor stability. Both the levels in free and bound aldehydes show a relatively large degree of variation among different beers, but also between marker aldehydes. For some aldehydes (e.g., hexanal), the bound amount was shown to increase rather strongly upon forced beer aging, whereas for others (e.g., 2-methylpropanal), large amounts appeared to already be present in a bound state in the fresh samples. Spiking beer samples with cysteine prior to aging significantly lowered the aldehyde levels compared with nonspiked samples. Flavor stability of the cysteine-spiked beers was thereby greatly improved through aldehyde-cysteine adduct formation. It was further hypothesized that, in addition to efficient binding of aldehydes, cysteine also inhibits the formation of furfural during beer aging from Maillard reaction intermediates.

中文翻译：

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探索 4-乙烯基吡啶在啤酒中的醛释放和半胱氨酸添加对啤酒结合醛库的影响

摘要 作为我们之前关于醛与亚硫酸氢盐和半胱氨酸结合的工作的延续，本文在分析之前提供了更多关于将 4-乙烯基吡啶添加到啤酒中的适用性的结果，旨在从这些预先形成的结合状态中释放醛，因此使用顶空固相微萃取方法结合气相色谱-质谱法对它们进行量化。本文还介绍了在强制老化之前用半胱氨酸添加啤酒样品的第一个结果，指出半胱氨酸在啤酒风味稳定性中的重要作用。游离醛和结合醛的水平在不同啤酒之间以及标记醛之间都显示出相对较大程度的变化。对于某些醛（例如己醛），在强制啤酒老化后，结合量显示出相当强的增加，而对于其他（例如，2-甲基丙醛），新鲜样品中似乎已经存在大量结合状态。与未加标的样品相比，在老化前加入半胱氨酸的啤酒样品显着降低了醛含量。通过形成醛-半胱氨酸加合物，半胱氨酸加标啤酒的风味稳定性因此得到极大改善。进一步假设，除了醛的有效结合外，半胱氨酸还抑制啤酒老化过程中由美拉德反应中间体形成的糠醛。与未加标的样品相比，在老化前加入半胱氨酸的啤酒样品显着降低了醛含量。通过形成醛-半胱氨酸加合物，半胱氨酸加标啤酒的风味稳定性因此得到极大改善。进一步假设，除了醛的有效结合外，半胱氨酸还抑制啤酒老化过程中由美拉德反应中间体形成的糠醛。与未加标的样品相比，在老化前加入半胱氨酸的啤酒样品显着降低了醛含量。通过形成醛-半胱氨酸加合物，半胱氨酸加标啤酒的风味稳定性因此得到极大改善。进一步假设，除了醛的有效结合外，半胱氨酸还抑制啤酒老化过程中由美拉德反应中间体形成的糠醛。