The use of barley malt infected with microorganisms can induce premature yeast flocculation (PYF) during fermentation. To understand this further, it is necessary to determine the role of microbial enzymes influencing PYF. In this study, the induction of PYF by two arabinoxylanases from Bacillus subtilis (A and B) and one from Aspergillus brasiliensis (F) was investigated. The results showed that all three arabinoxylanases could induce premature yeast flocculation. Husk from PYF negative (PYF‐) malt pre‐treated with arabinoxylanases could induce severe PYF. An increase in enzyme activity resulted in an increase in of PYF. Bound ferulic acid – an important component inducing PYF – increased significantly in the 40% (v/v) ethanol precipitate of wort. However, the ratio of ferulic acid/arabinoxylan in the 40% ethanol precipitate decreased with an increase in arabinoxylanase F, but increased with arabinoxylanases A and B. The addition of the three arabinoxylanases at the beginning of the PYF‐ mashing process showed that the arabinoxylanases A and B could induce PYF with greater intensity than arabinoxylanase F. It can be inferred that the bacterial arabinoxylanases produced more PYF factors than from Aspergillus brasiliensis. The results of this study may provide new insights for further research and focus on the role of bacteria in PYF. © 2020 The Institute of Brewing & Distilling

中文翻译：

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微生物阿拉伯木聚糖酶对过早酵母絮凝的影响

在感染过程中，使用感染了微生物的大麦麦芽可以诱导酵母过早絮凝（PYF）。为了进一步了解这一点，有必要确定微生物酶影响PYF的作用。在这项研究中，枯草芽孢杆菌（A和B）中的两种阿拉伯木聚糖酶和巴西曲霉中的 一种对PYF的诱导（F）被调查。结果表明，所有三种阿拉伯木聚糖酶均可诱导酵母过早絮凝。阿拉伯糖木聚糖酶预处理的PYF阴性（PYF-）麦芽中的果壳可能诱导严重的PYF。酶活性的增加导致PYF的增加。结合的阿魏酸（一种诱导PYF的重要成分）在麦芽汁的40％（v / v）乙醇沉淀物中显着增加。但是，40％乙醇沉淀物中阿魏酸/阿拉伯木聚糖的比率随阿拉伯木聚糖酶F的增加而降低，但随着阿拉伯木聚糖酶A和B的增加而增加。在PYF糖化过程开始时添加了三种阿拉伯木聚糖酶表明，阿拉伯木聚糖酶A和B诱导PYF的强度高于阿拉伯木聚糖酶F。巴西曲霉。这项研究的结果可能会为进一步的研究提供新的见解，并着重于细菌在PYF中的作用。©2020酿酒与蒸馏研究所