Monitoring Alcoholic Fermentation of Red Wine by Electrochemical Biosensors

Amperometric biosensors for the determination of glucose, fructose, ethanol, and glycerol were used to monitor alcoholic fermentation during red wine production in industrial-scale plants. Platinum-based probes, covered with appropriate enzyme membranes, were assembled in electrochemical flow-injection analysis systems. Before use, the biosensors were validated in must and wine samples by spectrophotometric procedures. The biosensors were applied during alcoholic fermentation in three wineries that used different red winemaking techniques. Results are reported and compared. Glucose, fructose, ethanol, and glycerol content varied with different kinetics corresponding to three characteristic phases: an early phase with no detectable variation of the analytes, an intermediate phase characterized by rapid sugar use, and a late phase with little variation of the concentration levels. In particular, glucose was consumed more rapidly than fructose, confirming that the former is the preferential sugar source for Saccharomyces cerevisiae. Experimental data demonstrated that the biosensors are useful tools for the close monitoring of alcoholic fermentation during industrial mass production of wine.