Real time monitoring of alcoholic fermentation with low-cost amperometric biosensors.

Screen-printed glucose, ethanol and fructose biosensors, coupled with portable instrumentation, and their application to monitor micro-alcoholic fermentations (micro-ALFs) in red wine is described. For the fabrication of glucose and ethanol biosensors, graphite screen-printed sensors modified with Prussian Blue were coupled with oxidase enzymes while for the fructose biosensor, a bare screen-printed sensor was coated with fructose dehydrogenase and phenazine methansulphate was used as electrochemical mediator. The working range, reproducibility of probe fabrication and biosensor stability were all evaluated. After a recovery study, performed analysing fortified must-wine samples, the biosensors were employed to monitor micro-ALFs induced by the inoculation of two different strains of Saccharomyces cerevisiae. During the red micro-ALFs, samples of must-wine were collected and analysed by use of both biosensors and spectrophotometric kits. The data obtained demonstrated that a biosensor-based system could represent a useful tool to assist winemakers during wine production.