To fine tune the production of phenolic aromas in beer, a pulsed electric field (PEF) was applied to beer wort, which was enriched with flax seeds. The choice of flax seeds as a source of FA is based on its high content of ferulic precursors and their intrinsic nutritional value. PEF was applied to ground flax seeds, with and without beta glycosidase. Fermentation was carried out with Saccharomyces and non-Saccharomyces yeast strains. Moreover, 4-vinylguaiacol (4-VG), a flavor highly active derived from volatile phenol, was produced by decarboxylation of ferulic acid (FA), or its precursor and flavor-inactive (4-hydroxy-3-methoxycinnamic acid). All yeast strains could metabolize FA into 4-VG, using the pure compound in the synthetic medium or in flax seeds, with the best quantity produced by Saccharomyces cerevisiae as a precursor. The method yields 4-VG production efficiencies up to 120% (mgL−1). Experimental treatment conditions were conducted with E= 1 kV/cm, total time treatment 15 min (peak time ti = 1 μs, pause time tp = 1 ms, Total pulses 9003). Treatment efficacy is independent of the fermentation yeast.

中文翻译：

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啤酒天然酚类香气的原位产生：应用于富含麦汁的亚麻籽的脉冲电场

为了微调啤酒中酚类香气的产生，将脉冲电场 (PEF) 应用于富含亚麻籽的啤酒麦芽汁。选择亚麻籽作为 FA 的来源是基于其高含量的阿魏酸前体及其内在营养价值。PEF 应用于磨碎的亚麻籽，有和没有 β 糖苷酶。用酵母属和非酵母属酵母菌株进行发酵。此外，4-乙烯基愈创木酚 (4-VG)，一种源自挥发性酚的高活性风味物质，是通过阿魏酸 (FA) 或其前体和风味非活性 (4-羟基-3-甲氧基肉桂酸) 的脱羧作用产生的。所有酵母菌株都可以将 FA 代谢为 4-VG，使用合成培养基或亚麻种子中的纯化合物，以酿酒酵母作为前体产生的最佳量。该方法产生高达 120% (mgL-1) 的 4-VG 生产效率。实验处理条件采用 E = 1 kV/cm，总时间处理 15 分钟（峰值时间 ti = 1 μs，暂停时间 tp = 1 ms，总脉冲数 9003）。处理功效与发酵酵母无关。