Kinetic Analysis of the Volatile Compounds Production: a study of the Impact of Nitrogen Addition and Anisothermal Temperature During Alcoholic Fermentation

Temperature management and nitrogen addition during fermentation are two key drivers to optimize the production of fermentative aromas. Temperature has both physical and biological impacts on liquid accumulation of volatile compounds whereas nitrogen addition directly activates the synthesis of certain aromas, especially acetate esters. The objective of this work was to study the cross impact of anisothermal temperature profiles and nitrogen additions on the fermentative aromas production. For this purpose, eight anisothermal profiles were designed and tested in combination with nitrogen addition during the stationary phase. The concentration of fermentative aromas of different chemical families was measured at the end of fermentation while the kinetics of esters production were monitored throughout the fermentation. The results were compiled and analyzed using GAM modeling. The main results of this study showed an important cross impact between the two factors on fermentation and aroma kinetics. Moreover, the precise monitoring of the ester production gave a more precise vision of the impact of temperature management on their synthesis. For example, GAM modeling showed that profiles including a temperature decrease during the stationary phase allowed both a higher synthesis of esters and a better preservation in the liquid phase. Another interesting point was the possibility to develop fermentation managements making it possible the de-correlation between the production of ethyl hexanoate and octanoate whereas these two compounds were generally correlated in previous works.