Brewing using enzyme rich ‘green’ (germinated, but not kilned) malt has the potential to unlock considerable energy savings in the malting and brewing chain. This paper examines the major quality issues associated with green malt, by monitoring lipoxygenase (LOX) activity and S‐methyl methionine (SMM) levels through a micromalting cycle both with and without rootlets after 48 h of germination. The data suggest that rootlets are a major concern when brewing with green malt and that their influence on wort and beer quality needs to be further investigated. Lipoxygenase activity and nonenal potential were measured following treatment under varying conditions of pH, temperature and pre‐treatment. Results indicated that lipoxygenase activity can be controlled to a substantial degree by manipulating these limiting factors, while preserving diastatic enzyme activity. Green malt worts were then prepared from (i) whole green malt immediately post‐germination; (ii) heat treated green malt (65°C x 1 h); (iii) re‐steeped green malt and (iv) endosperm‐rich extracts of green malt after the husk and rootlets had been removed; using laboratory mashing with a ‘LOX‐hostile’ mash schedule. Data were compared with mashing of kilned pale malt made from the same green malt, as a reference point. Based on the present data, re‐steeping of green malt in combination with a LOX hostile mashing environment (63°C, pH 5.2) could help to control LOX activity and the trans‐2‐nonenal potential of green malt. The resultant brewing process would need to be optimised to deal with the elevated SMM levels in green malt worts. © 2020 The Authors. Journal of the Institute of Brewing published by John Wiley & Sons Ltd on behalf of The Institute of Brewing & Distilling

中文翻译：

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克服绿色（非窑）麦芽酿造的技术障碍：可行性研究

使用富含酶的“绿色”（发芽但未煮熟）麦芽进行酿造，有可能在麦芽和酿造链中释放出可观的能量节省。本文通过发芽48小时后有或没有小根的微芽周期监测脂氧合酶（LOX）活性和S-甲基蛋氨酸（SMM）的水平，研究了与绿色麦芽有关的主要质量问题。数据表明，在用绿色麦芽酿造时，小根是一个主要问题，需要进一步研究其对麦芽汁和啤酒质量的影响。在不同的pH，温度和预处理条件下处理后，测量脂氧合酶活性和正清电位。结果表明，通过控制这些限制因素，脂氧合酶活性可以得到很大程度的控制，同时保持透析酶的活性。然后从（i）刚发芽后的整个绿色麦芽制备绿色麦芽麦芽汁；（ii）热处理过的生麦芽（65°C x 1小时）；（iii）除去果壳和小根后，重新浸入绿色麦芽和（iv）富含胚乳的绿色麦芽提取物；使用带有“ LOX敌对”混搭时间表的实验室混搭。将数据与以相同绿色麦芽制成的煮熟的浅麦芽糖化液作为参考点进行比较。根据目前的数据，再将绿色麦芽与LOX敌对的捣碎环境（63°C，pH 5.2）结合使用，可以帮助控制LOX活性和绿色麦芽的跨2非壬醛潜力。最终的酿造过程将需要进行优化，以应对生麦芽汁中SMM含量升高的问题。©2020作者。