Vesna M. Vučurović

Fermentation Characteristics and Aromatic Profile of Plum Wines Produced with Indigenous Microbiota and Pure Cultures of Selected Yeast

The aim of this study was to assess and compare fermentation characteristics and aromatic profile of plum wines produced with indigenous microbiota and pure cultures of different selected yeast. Experiments were carried out with plum (Prunus domestica L.) varieties of different fruit ripening times (Čačanska rana, Čačanska lepotica, and Požegača). Wine fermentations were conducted by the activity of indigenous microbiota, commercially available Saccharomyces cerevisiae and Saccharomyces bayanus yeast strains and joint activity of Schizosaccharomyces pombe and S. cerevisiae (sequential inoculation). Statistically significant differences in fermentative characteristics and the content of certain volatile compounds were observed as a result of metabolic activity of various indigenous and/or selected yeasts during fermentation of plum pomace. Minimal duration of fermentation (4 to 5 d) and fastest ethanol production rate (from 12.3 to 15.5 g/L/d) were the characteristics of the studied S. cerevisiae strains. Isobutanol, 3-methyl-1-butanol, 1-heptanol, and 1-octanol were the most prevalent higher alcohols in the tested plum wine samples. The predominant ester in plum wines was ethyl acetate, ethyl lactate, amyl acetate, isoamyl acetate, and ethyl palmitate, esters responsible for the floral and fruity olfactory tones, were also present in large amounts. Also, the use of S. cerevisiae strains resulted in the production of plum wines with better sensory characteristics than ones produced with other investigated yeasts. Obtained results are significant since there is limited data on the compounds responsible for the unique flavor of plum wine, as well as on the impact of different yeast starter cultures application on the overall quality of fruit wines.

Aromatic compounds of brandies produced from three apricot varieties cultured in Serbia

This study investigated the effect of certain apricot varieties cultured in Serbia on the quality of produced brandies, primarily in terms of the content and relationships of aromatic substances. In this study, fruits of three apricot varieties (NS 6, NS rodna and Ambrozija) were used for production of brandies. Primary fruit processing and distillation were carried out in a distillery of industrial capacity. High differences in the quantity of 14 identified aromatic components of the distillates produced from three apricot varieties were recorded. Ethyl decanoate was present in all three distillates in significantly larger amounts compared to other esters. Ethyl isobutyrate was found in a small amount (0.32 mg/L) in the distillate produced from Ambrozija variety, while in the distillates from other varieties this compound was not detected. The distillates produced from varieties NS6 and NS rodna contained significantly higher amounts of ethyl lactate (12.50 to 13.46 mg/L) compared to the distillate from Ambrozija variety (8.87 mg/L). The content of linalool determined in NS6 distillate was three times higher (22.12 mg/L) in comparison to the distillate from Ambrozija (7.31 mg/L).

The influence of table salt, white sugar and complex bakery additive on the fermentative activity of Saccharomyces cerevisiae

This study determined the influence of the addition of commercial bakery improver (0.1-0.9 %), table salt (1-7 %), and white sugar (1-9 %) into dough on fermentative activity (FA) of yeast, and consequently CO2 production, to improve dough handling and quality of wheat bread by using an optimized additive combination. The FA of yeast cells was evaluated using fermentograph SJA device. The addition of white sugar in the amount of 1-4 % and complex additive in the amount 0.1-0.5 % enhances FA of yeast. Further increase of the amount of these two compounds decreases the FA. The addition of table salt in the amount of 1-7 % negatively affected the FA. The optimal amounts of complex additive, table salt and white sugar, obtained by response surface methodology (RSM) using Design Expert software, which provided maximum FA of 1171.31 ml CO2/gdm/2h were the following: 0.41, 1.0 and 3.91 % based on flour weight, respectively.