Control of the sugar/ethanol conversion rate during moderate pulsed electric field-assisted fermentation of a Hanseniaspora sp. strain to produce low-alcohol cider

The effect of moderate pulsed electric fields (PEF) on Hanseniaspora sp. fermentations in apple juice was examined. The treatments were applied prior to or during the fermentation using a field strength of 285 V/em. A significant increase (p < 0.05) in the biomass growth was observed during all the treatments along with a significant decrease (p < 0.05) in the ethanol yield. The optimal impact of PEF on ethanol reduction by 1.6% (v, v) was obtained during the treatment of the pre-culture for 6 h. The greatest rate was observed for the treatment during the first 12 h of the fermentation. During this fermentation performed at 28 degrees C under agitation at 250 rpm, the time to reach the stationary phase was reduced by 10 h, and the maximum biomass growth rate was ten-fold higher than that of the control. In addition, the sensitivity of Hanseniaspora sp. yeast to PEF treatment was more pronounced during the lag phase rather than the log phase in term of shortening the fermentation time, and reducing the ethanol content. The results obtained here demonstrated the promising efficiency of stimulated yeast by PEF in reducing the ethanol content in fermented alcoholic beverages.