Original scientific paper                                                                                                                                            DOI: 10.17508/CJFST.2022.14.2.02

The influence of fermentation activity and ester producing capacity of yeast strains on the chemical composition and organoleptic characteristics of Gamza wines

https://orcid.org/0000-0002-8156-0530Tatyana Yoncheva1*, Hristo Spasov2, https://orcid.org/0000-0003-4661-0421Georgi Kostov2

1Institute of Viticulture and Enology, Department of Vine Selection, Enology and Chemistry, 1 “Kala tepe” str., 5800 Pleven, Bulgaria
2University of Food Technologies, Department of Wine and Beer Technology, 26 “Maritsa” blvd., 4002 Plovdiv, Bulgaria

Article history:
Received: August 13, 2021
Accepted: November 22, 2021
The influence of the two technological parameters, temperature (20 °C, 24 °C, 28 °C) and the inoculum amount of the yeast culture (2%, 3%, 4%) on the duration of the alcoholic fermentation and the ester-producing capacity of the Badachoni and the 24-6 strains of Saccharomyces cerevisiae species was studied. The yeast exhibited high fermentation activity. The intensity with which it initiated the process and the time for its completion was in correlation with the studied factors. The strains showed the best activity at 28 °C/4%. Neural networks were applied and mathematical models were derived, properly describing the fermentation process and the change in the total amount of esters in the course of the process, depending on the technological conditions. The rate in the dynamic of the esters during the process was monitored in 4 stages – onset, rapid fermentation, quiet fermentation, and after malolactic fermentation. The maximum quantity of esters was synthesized in the middle of the process. During alcoholic fermentation, the esters followed a tendency to increase with decreasing the temperature, increasing the amount of yeast culture and the time of the process. The Badachoni and the 24-6 strains demonstrated the highest ester-producing capacity under the temperature of 20 °C and with the 4% inoculum of the yeast culture. The Badachoni strain quantitatively produced more esters than the 24-6 strain. No strict correlation was found between the amount of esters and the organoleptic properties of the wines. The sample containing the most esters had the highest tasting score only in the variants of the 24-6 strain.
Saccharomyces cerevisiae
alcoholic fermentation
neural networks