Process Proteomics of Beer Reveals a Dynamic Proteome with Extensive Modifications

Modern beer production is a complex industrial process. However, some of its biochemical details remain unclear. Using mass spectrometry proteomics, we have performed a global untargeted analysis of the proteins present across time during nanoscale beer production. Samples included sweet wort produced by a high temperature infusion mash, hopped wort, and bright beer. This analysis identified over 200 unique proteins from barley and yeast, emphasizing the complexity of the process and product. We then used data independent SWATH-MS to quantitatively compare the relative abundance of these proteins throughout the process. This identified large and significant changes in the proteome at each process step. These changes described enrichment of proteins by their biophysical properties, and identified the appearance of dominant yeast proteins during fermentation. Altered levels of malt modification also quantitatively changed the proteomes throughout the process. Detailed inspection of the proteomic data revealed that many proteins were modified by protease digestion, glycation, or oxidation during the processing steps. This work demonstrates the opportunities offered by modern mass spectrometry proteomics in understanding the ancient process of beer production.现代啤酒生产是一项复杂的工业制程，但其部分生化细节仍有待进一步阐明。本研究借助质谱蛋白质组学（mass spectrometry proteomics）技术，对纳升级啤酒生产过程中不同时间点的总蛋白质开展了全局非靶向分析。所采集的样本涵盖采用高温浸渍糖化法制备的甜麦芽汁、加酒花麦芽汁以及成熟清啤酒。本次分析从大麦与酵母中鉴定出200余种独特蛋白质，凸显了该制程与最终产品的复杂性。随后，我们使用数据独立采集SWATH-MS（data independent SWATH-MS）技术，对全制程中这些蛋白质的相对丰度进行了定量比较，揭示了各制程步骤中蛋白质组发生的显著且大幅变化。这些变化体现了蛋白质依据其生物物理特性的富集规律，并鉴定出发酵过程中优势酵母蛋白质的出现。麦芽修饰程度的改变同样会在全制程中定量改变蛋白质组。对蛋白质组数据的详细解析显示，诸多蛋白质在制程各步骤中会经历蛋白酶解、糖基化或氧化修饰。本研究证实了现代质谱蛋白质组学技术在解析啤酒生产这一古老制程方面的巨大应用潜力。