Abstract The purpose of this research was to understand and evaluate the effect of high temperature treatment of wort at varying time periods (30, 45, 60, 90, and 120 min) on wort fermentability. The effect of trub was also analyzed. Small-scale fermentations were conducted using a malt (malted from AC Metcalfe) free of premature yeast flocculation tendencies and a standard SMA yeast strain. The turbidity and apparent extract were measured at specific time intervals. The decline in extract was modeled with the ASBC Yeast-14 logistic equation predicting a sigmoidal curve. Turbidity measurements were modeled with a “tilted Gaussian” fit. Heat-treating the wort (at 100 or 121.1 °C) resulted in a significant decline in ADF (p < 0.05). As denoted by the midpoint of the fermentation, all fermentation runs, with and without trub, at lower wort boil durations fermented faster than longer or higher wort-boiling treatments. The decline in wort fermentability was highest upon treatment at wort temperature and pressure levels of 121.1 °C and 3.0 atm. The amount of trub and the wort color formed after each heat treatment showed a gradual increase with heating duration. Free amino nitrogen levels of wort declined significantly with respect to both increase in wort boiling temperature and time intervals (p < 0.001).

中文翻译：

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麦汁煮沸时间和麦汁对发酵性的影响

摘要 本研究的目的是了解和评估不同时间段（30、45、60、90 和 120 分钟）对麦芽汁进行高温处理对麦芽汁发酵能力的影响。还分析了 trub 的影响。使用无过早酵母絮凝倾向的麦芽（来自 AC Metcalfe 的麦芽）和标准 SMA 酵母菌株进行小规模发酵。在特定时间间隔测量浊度和表观提取物。提取物的下降用预测 S 形曲线的 ASBC Yeast-14 逻辑方程建模。浊度测量采用“倾斜高斯”拟合建模。对麦芽汁进行热处理（在 100 或 121.1 °C 下）导致 ADF 显着下降（p < 0.05）。正如发酵的中点所表示的，所有发酵都在进行，无论有没有 trub，在较低的麦芽汁煮沸时间下，发酵速度比较长或较高的麦芽汁煮沸处理更快。在 121.1 °C 和 3.0 atm 的麦芽汁温度和压力水平下处理时，麦芽汁发酵能力的下降幅度最大。每次热处理后形成的残渣量和麦芽汁颜色随着加热时间的增加而逐渐增加。麦芽汁的游离氨基氮水平随着麦芽汁煮沸温度和时间间隔的增加而显着下降（p < 0.001）。