New approaches to the kinetic study of alcoholic fermentation by chromatographic techniques.

The kinetics of the fermentation process has gained increasing interest, not only in the scientific community, but in the industrial world as well. Information concerning the improvement of batch fermentation performance may potentially be valuable for the designing of scale-up processes. Intensive studies have been conducted with the use of various chromatographic techniques, such as conventional gas chromatography, reversed-flow gas chromatography (RFGC), high-performance liquid chromatography, field-flow fractionation and others. In the present study, specific focus is placed on the employment of RFGC, a method that can successfully be applied for the determination of physicochemical quantities, such as reaction rate constants and activation energies, at each phase of the alcoholic fermentation. In contrast to conventional chromatographic techniques, RFGC can lead to substantial information referring to the evaluation of fermentation kinetics at any time of the process. Moreover, gravitational field-flow fractionation, a sub-technique of field-flow fractionation, presents the ability to monitor the proliferation of Saccharomyces cerevisiae cells through their elution profiles that can be related to the different cell growth stages. The combination of the two techniques can provide important information for kinetic study and the distinction of the growth phases of yeast cell proliferation during alcoholic fermentations conducted under different environmental conditions.