基于电导率的酒精发酵过程在线监测

为了探讨电导率在酒精发酵过程在线监测的适用性，对酒精发酵过程中电导率与还原糖、酒精度、pH值的变化规律以及氯化钙和硫酸铵2种盐类对电导率的影响进行了研究。结果表明：电导率与还原糖和酒精度之间存在着一定的逻辑关系，即在电导率下降阶段，电导率随着还原糖的降低而下降，随着酒精度的增加而上升。利用电导率的测量值间接地反映还原糖和酒精度的变化；同时，电导率达到最低点时，酒精度和还原糖均符合酒精发酵终点的参数指标，可以据此确定酒精发酵的终点。pH值与电导率之间存在着一定的线性关系（发酵60 h前变化规律相同）；氯化钙和硫酸铵2种盐类在一定范围内对电导率的变化不产生影响。因此，试验成果可用于酒精发酵过程的在线监测和发酵终点的判定。

Online monitoring alcoholic fermentation based on electrical conductivity

To test the applicability of electrical conductivity for on-line monitoring alcohol fermentation process. The relationships between conductivity changes and reducing sugar contents, alcohol contents, or pH values were studied respectively. And the impacts of calcium chloride and ammonium sulfate on conductivity during alcoholic fermentation process were further explored. The results showed that there were certain logical relationships between conductivity changes and reducing sugar or alcohol contents respectively. That is, during the decrease stage of electrical conductivity, the electrical conductivity decreased with the decrease of reducing sugar, while increased with the increase of alcohol contents. The results indicated that conductivity could be used to reflect the contents of reducing sugar and alcohol indirectly. Meanwhile, the contents of alcohol and reducing sugar were in line with the parameters of the end of alcoholic fermentation when the conductivity reached its lowest point, then the end of alcoholic fermentation could be determined. There was a certain linear relationship between pH value and conductivity (the variation of pH value and conductivity were the same 60 h before fermentation.). The variation of conductivity could not be affected by calcium chloride and ammonium sulfate within a certain range. Therefore the conductivity could be applied in the on-line monitoring alcoholic fermentation progress and determining the end point of fermentation.