Fermentation is a crucial process in the production of alcoholic beverages such as spirits, which produces a number of volatile compounds due to the metabolic activities of yeast. These volatile compounds, together with the volatile components of the raw materials and the volatile compounds produced during the distillation and aging process, play a crucial role in determining the final flavor and aroma of spirits. In this manuscript, we provide a comprehensive overview of yeast fermentation and the volatile compounds produced during alcoholic fermentation. We will establish a link between the microbiome and volatile compounds during alcoholic fermentation and describe the various factors that influence volatile compound production, including yeast strain, temperature, pH, and nutrient availability. We will also discuss the effects of these volatile compounds on the sensory properties of spirits and describe the major aroma compounds in these alcoholic beverages.

This study was conducted with the aim of developing fruit spirits by utilizing old (autochthonous) apple and pear cultivars that can be attractive to both consumers and producers. Consumers of spirits could enjoy the unique flavor, and producers could gain an opportunity for brand development. In total, eight old apple cultivars (Sarija, Žuja, Samoniklica, Prijedorska zelenika, Bobovec, Masnjača, Lijepocvjetka, and Šarenika) and three pear cultivars (Budaljača, Krakača, and Kalićanka) from Bosnia and Herzegovina were used for the spirits production and for characterizing the flavor of distillates. Golden Delicious was used as a representative of commercial apple cultivar. The aroma profile was conducted through the identification of minor volatile organic compounds (VOCs) and the sensory perception of spirits. Analysis of the VOCs was performed by gas chromatography mass spectroscopy (GC/MS) techniques after enrichment via solid-phase microextraction (SPME). Sensory evaluation was performed by 12 trained panelists. Overall, 35 minor volatile compounds were found in spirits: 13 esters, 7 alcohols, 6 acids, 5 terpenes, and 4 aldehydes. Significant differences were detected in the distribution and quantity of the VOCs, which were fruit cultivar-dependent. Spirits made from Šarenika apple cultivar showed the largest amount of all acids, especially short- and medium-chain fatty acids; however, this richness was not correlated with pleasant sensory attributes. Spirits obtained from Prijedorska zelenika and Masnjača apple cultivars had the best sensory attributes. Budeljača and Krakača pears are promising cultivars as flavoring in spirits production.

Harvest timing is a critical factor in viticulture, as it directly influences grape composition and, consequently, wine quality. This study evaluated the effects of harvest timing on the physical and chemical traits of two widely cultivated grape varieties from the Trebinje vineyard area, Bosnia and Herzegovina. Basic chemical parameters (total soluble solids, pH, titratable acidity) were measured alongside cluster and berry traits, including length, width, and weight of clusters; the number and weight of berries; the skin and flesh weight of 100 berries; and the number and weigh of seeds. Early-harvested grapes showed greater cluster weight but lower total soluble solids, higher titratable acidity, and lower pH compared to later harvests in both cultivars. Changes in cluster and berry traits were more pronounced in ‘Vranac’, where berry weight, skin and flesh mass increased significantly at later harvests, however, in ‘Žilavka’ only the seed weight was notably affected. Across all harvests period, ‘Žilavka’ consistently exhibited higher total soluble solids and lower pH values than ‘Vranac’, indicating a strong varietal effect on grape quality. These findings highlight that delaying harvest within the recommended window can enhance grape composition, while varietal differences determine the extent of morphological and chemical changes during ripening.

Five free volatile monoterpenes (linalool, α-terpineol, citronellol, nerol, and geraniol; FVmT) in free-run musts obtained from differently macerated crushed grapes of white cv. Zilavka in two consecutive vintages (2011 and 2012) were quantified with HS-SPME-GCMS. Unexpectedly high concentrations of the analyzed FVmT were found in free-run musts of Zilavka whose grapes and wine have not been previously described as monoterpene potent. The most abundant were linalool, α-terpineol and geraniol, with tens μg/L of nerol. Citronellol was detactable, but its low concentration was quantified in free-run must of only one experimental trial. Remarkably higher concentrations of the analyzed FVmT were found in the free-run musts obtained in 2012, after extremely hot and dry summer months and an early harvest. Increasing maceration temperatures from 6°C, through 12°C, to 20°C during the 20 hour tretatment resulted in increased extractions of FVmT. However, only increases in nerol concentrations were statistically significant with increases in the applied maceration temperatures in both years. The calculated odor activity values (OAV) for linalool, α-terpineol, and geraniol were relatively high (1.6 to 8). The obtained results indicated monoterpenic potentials of Zilavka. These could be an invitation to its wine producers to consider technological modifications directed to extraction of FVmT and possible monoterpene profiling of Zilavka wines.

The aim of this study was to analyse the effects of harvest timing on the total phenolic and flavonoid contents, in addition to the total antioxidant capacity in the berries of 'Žilavka' and 'Vranac' varieties grown in the Trebinje vineyard area. Grape samples for both varieties were collected at three distinct points during their ripening. The chosen harvest dates were set 10 days apart, and the optimal date for grape harvesting was determined by assessing the sugar content and titratable acidity present in the grapes. Total phenolics, total flavonoids and total antioxidant activity of grape samples were determined by the Folin-Ciocalteu method, aluminium chloride method, and ferric reducing antioxidant power assay, respectively. The total phenolic and flavonoid contents, along with the total antioxidant capacity in the 'Vranac' grape, increased from the first to the second harvest date, but a decline was noted at the third harvest. 'Žilavka' grape exhibited an increase in total phenolic and flavonoid contents, as well as total antioxidant capacity from the first to the second harvest date, with no decrease recorded by the third harvest. As expected, the red grape variety 'Vranac' contained higher levels of phenolics and flavonoids than the light-skinned grape variety 'Žilavka' .