Recovery of ethanol during the maceration of green walnuts in the production of ratafia

Identifier:  TFG:8068

Handle: https://hdl.handle.net/20.500.11797/TFG8068

Authors:  Campos Sánchez, Joan Marc

Abstract:
One of the problems in the production of ratafia, which many producing companies face, is the loss of ethanol during the maceration stage of the botanical ingredients. This leads to a significant decrease in efficiency and profitability for the industry. However, there are no studies regarding the recovery of this lost ethanol or on techniques and/or methods to prevent or reduce this effect. In order to evaluate the total recovery of ethanol during the production of ratafia and its impact on the final product quality, this study aimed to investigate the effect of conducting water macerations following the main hydroalcoholic maceration of green walnuts. To achieve this, different experimental conditions (ethanol concentration, walnut dosage) were defined for obtaining the green walnut extract. Regarding ethanol concentration, three variables were proposed (40 % v/v, 60 % v/v and 90 % v/v) and two variables for the walnut dosage (15 % w/v and 30 % w/v). Subsequently, two consecutive 15-day water washes were carried out, recovering each macerate separately. All macerates were subjected to physical analysis to determine their alcohol content. Finally, four ratafias were prepared with the same final composition, with or without the addition of the wash waters, to demonstrate their impact in a triangular organoleptic tasting. In all cases, more than 96 % of the initial absolute alcohol was recovered, demonstrating the viability of this method. However, no clear differences were observed between the different experimental conditions, except for the higher initial ethanol loss during alcoholic maceration when the walnut dosage was higher (30 % w/v). From a sensory point of view, it was statistically demonstrated that there are no significant differences between adding or not adding the two water macerates. Therefore, this study has shown quite promising results, demonstrating that it is possible to recover the lost ethanol by performing water macerations of green walnuts and that their addition does not negatively affect the organoleptic qualities of the final product. However, further studies on other analytical parameters (colour, aroma, etc.) and other ethanol recovery methods are necessary to compare them, as well as to study the effect of other extraction conditions and improvements for their optimization.