DIRECT SENSITIVITY ANALYSIS OF A WHITE WINE ALCOHOLIC FERMENTATION PROCESS

Process engineering became, recently in historical terms, an extension of food engineering principles to other fields of manufacturing as the food biotechnology and beverage industry is. This article proposes a non-linear mathematical model that makes possible the simulation of the batch alcoholic fermentation of white wine. The model was developed on the basis of zone modelling principle, considering the physiological states of the yeast cells. The nonlinear mathematical model led to a good qualitative and quantitative description of the alcoholic fermentation process. The model was implemented as a Matlab S-function and the results were compared with experimental data. Further on, the mathematical model was used for the investigation of the dynamic behaviour of a batch fermentation process through direct sensitivity analysis method (DSA). The DSA of dynamic model allowed the calculus of the matrix of the sensitivity functions in order to determine the influence of the small deviations of initial state and parameters from their nominal values on the state trajectory and system output over the time.