University of California, Davis, Department of Food Science and Technology Davis, California, USA.
University of California, Davis, Department of Food Science and Technology Davis, California, USA.
Food Microbiol. 2023 Sep;114:104298. doi: 10.1016/j.fm.2023.104298. Epub 2023 May 10.
Hop creep continues to present an unresolved issue for the brewing industry, specifically stemming from those hops added to beer during fermentation. Hops have been found to contain four dextrin-degrading enzymes: alpha amylase, beta amylase, limit dextrinase, and an amyloglucosidase. One recent hypothesis predicts that these dextrin-degrading enzymes could originate from microbes rather than the hop plant itself.
This review begins by describing how hops are processed and used in the brewing industry. It will then discuss hop creep's origins with a new beer style, antimicrobial factors from hops and resistance mechanisms that bacteria use to counter them, and finally microbial communities that inhabit hops, focusing on whether they can produce the starch degrading enzymes which drive hop creep. After initial identification, microbes with possible links to hop creep were then run through several databases to search the genomes (if available) and for those specific enzymes.
Several bacteria and fungi contain alpha amylase as well as unspecified glycosyl hydrolases, but only one contains beta amylase. Finally, this paper closes with a short summary of how abundant these organisms typically are in other flowers.
啤酒花变质问题一直是酿造行业尚未解决的难题，主要源于发酵过程中添加的啤酒花。研究发现，啤酒花中含有四种分解糊精的酶：α-淀粉酶、β-淀粉酶、极限糊精酶和淀粉葡糖苷酶。最近有一种假说预测，这些分解糊精的酶可能来自微生物，而不是啤酒花本身。
本文首先描述了啤酒花在酿造行业中的加工和使用方式。然后讨论了啤酒花变质的起源，包括新的啤酒风格、啤酒花中的抗菌因子和细菌用来对抗它们的耐药机制，最后还讨论了栖息在啤酒花中的微生物群落，重点关注它们是否能产生导致啤酒花变质的淀粉降解酶。在初步鉴定后，具有潜在关联的微生物随后被输入到几个数据库中，以搜索它们的基因组（如果有的话）和特定的酶。
有几种细菌和真菌含有α-淀粉酶和未指定的糖苷水解酶，但只有一种含有β-淀粉酶。最后，本文简要总结了这些微生物在其他花卉中的丰度。
