摘要
In the beverage fermentation industry, especially at the craft or micro level, there is a movement to incorporate as many local ingredients as possible to both capture terroir and stimulate local economies. In the case of craft beer, this has traditionally only encompassed locally sourced barley, hops, and other agricultural adjuncts. The identification and use of novel yeasts in brewing lags behind. We sought to bridge this gap by bio-prospecting for wild yeasts, with a focus on the American Midwest. We isolated 284 different strains from 54 species of yeast and have begun to determine their fermentation characteristics. During this work, we found several isolates of five species that produce lactic acid and ethanol during wort fermentation: Hanseniaspora vineae, Lachancea fermentati, Lachancea thermotolerans, Schizosaccharomyces japonicus, and Wickerhamomyces anomalus. Tested representatives of these species yielded excellent attenuation, lactic acid production, and sensory characteristics, positioning them as viable alternatives to lactic acid bacteria (LAB) for the production of sour beers. Indeed, we suggest a new LAB-free paradigm for sour beer production that we term “primary souring” because the lactic acid production and resultant pH decrease occurs during primary fermentation, as opposed to kettle souring or souring via mixed culture fermentation.
摘要译文
在饮料发酵行业，特别是在工艺或微观层面，有一项运动将尽可能多的当地原料纳入捕获土壤和刺激当地经济。在精酿啤酒的情况下，传统上这只包括当地采购的大麦，啤酒花和其他农业附属品。酿造中新型酵母的识别和使用滞后。我们试图通过对野生酵母进行生物勘探来弥补这一差距，重点放在美国中西部地区。我们从54种酵母中分离出284种不同的菌株，并开始确定其发酵特性。在这项工作中，我们发现了麦汁发酵过程中产生乳酸和乙醇的五种物种的几种分离物：汉逊酵母葡萄球菌（Hanseniaspora vineae），发酵乳球菌（Lachancea fermentati），耐热乳酸酵母菌（Lachancea thermotolerans）（Schizosaccharomyces japonicus）和Wickerhamomyces anomalus。这些物种的经过检测的代表产生了极好的衰减，乳酸生产和感官特征，将其定位为生产酸味啤酒的乳酸菌（LAB）的可行替代品。确实，我们建议一种新的不含LAB的酸性啤酒生产模式，我们称之为“主要酸性”，因为在初始发酵过程中会产生乳酸生成和pH降低，而不是通过混合培养发酵的水壶酸味或酸味。
KaraOsburn[a];JustinAmaral[b];Sara R.Metcalf[a];David M.Nickens[a];Cody M.Rogers[a];ChristopherSausen[a];RobertCaputo[c];JustinMiller[c];HongdeLi[d];Jason M.Tennessen[d];Matthew L.Bochman[a][c];. Primary souring: A novel bacteria-free method for sour beer production[J]. Food Microbiology, 2018,70: 76-84