In this study, we focused on acoustic emission (AE) as a method for quantitative evaluation of fermentation. Since bubbling in the culture medium and detachment of the medium during fermentation are considered to be phenomena similar to corrosion, AE could be expected to be detected. Therefore, we conducted AE measurements using ECS during fermentation of yeast in sucrose solution, fermentation of yeast during sake brewing, and fermentation of sawdust in a hot bath facility, and investigated the possibility of evaluation of fermentation process using electret sensor (ECS). AE was detected during the fermentation of yeast. The peak frequency of AE detected during yeast fermentation was widely distributed. Cumulative number of AE, however, showed a strong correlation with the decrease in sugar content during fermentation, indicating the possibility of quantitative evaluation of the fermentation state by AE measurement if a time lag is considered. In the measurement of AE from the fermentation of sake malt, a large amount of AE was detected from the lower part of the tank immediately after brewing, and the number of AE gradually increased in the upper part of the tank. These AE measurements suggested that even in top fermentation, the initial fermentation may occur in the lower part of the tank. In the fermentation and warm bath facility, AE during fermentation could be detected even in powdered media. Although the durability of the ECS needs to be improved under high temperature and high humidity conditions, it is expected to be able to monitor the fermentation process better than temperature measurements.

中文翻译：

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使用驻极体传感器检测发酵过程中的声发射

在本研究中，我们重点关注声发射（AE）作为定量评估发酵的方法。由于发酵过程中培养基中的鼓泡和培养基的脱离被认为是类似于腐蚀的现象，因此可以预期检测到AE。因此，我们在蔗糖溶液中酵母发酵、清酒酿造过程中酵母发酵以及热水浴设施中锯末发酵期间使用ECS进行了AE测量，并研究了使用驻极体传感器（ECS）评估发酵过程的可能性。酵母发酵过程中检测到AE。酵母发酵过程中检测到的AE峰值频率分布广泛。然而，AE 的累积数量与发酵过程中糖含量的降低有很强的相关性，表明如果考虑时滞，通过AE测量定量评估发酵状态的可能性。在清酒麦芽发酵的AE测量中，在酿造后立即从罐的下部检测到大量AE，并且在罐的上部AE的数量逐渐增加。这些AE测量表明，即使在顶部发酵中，初始发酵也可能发生在罐的下部。在发酵和温浴设施中，即使在粉末培养基中也可以检测到发酵过程中的AE。尽管ECS在高温和高湿条件下的耐用性需要提高，但预计它能够比温度测量更好地监测发酵过程。