Abstract:

The change of electrical conductivity, an initial increase followed by a decrease, during alcoholic fermentation
of saccharified corn starch was observed in our previous work. This study further examined the effects of 4 main ions,
reducing sugar, alcohol, cell concentration and pH on the variability of this parameter during the fermentation process. The
results showed that all the above factors affected the change of electrical conductivity with alcohol concentration being the
most important determinant. The decline of electrical conductivity was mainly due to the continuous increase of alcohol
concentration in the fermented liquid. When alcohol concentration reached a plateau, electrical conductivity tended to
increase as a result of a reduction in pH. Therefore, alcohol concentration had a direct impact on the change of electrical
conductivity during the fermentation process. It is feasible to directly reflect the change of alcohol concentration by the
change of electrical conductivity through the established mathematical model. The results could be applied for on-line
monitoring alcoholic fermentation process and determining the end point of fermentation.

Key words: alcoholic fermentation, electrical conductivity, alcohol concentration, reduced sugar concentration