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.

The purpose of this investigation was to determinate effects of distillation cuts on the distributions of higher alcohols (1-propanol, 2-methyl-1-propanol, 3-methyl-1-butanol, 2-methyl-1-butanol, 1-butanol, 2-butanol, 1-hexanol and 1-pentanol) and esters (ethyl acetate, isopentyl acetate + ethyl lactate, isobutyl acetate, ethyl propionate and ethyl butyrate) in plum brandy. The volatiles were determined by gas chromatography–flame ionization detection. The three most popular plum varieties used in plum brandy (Sljivovica) production, Stanley, Pozegaca and Bilska rana (Buhler), were distilled using a traditional distilling pot and fraction distillation. Three distillation cuts were considered. After separating the head fraction, in the amount of 1.7% of the distilling pot volume, heart fractions were cut at 40, 45 and 50% (v/v) ethanol and tail fractions, analogous to the heart fraction, were collected up to 10% (v/v) ethanol. The ratio of the content of 2-methyl-1-propanol and 3-methyl-1-butanol was 1:1 in the plum brandy produced from Stanley and Pozegaca and the ratio was 2:1 in the plum brandy produced from Bilska rana. This ratio can be used as a ‘mark’ of variety recognition in plum brandy production. The main differences in the heart fraction were accounted for by the content of the higher alcohols and esters for the distilling cut at 40 and 50% (v/v) ethanol. Copyright © 2013 The Institute of Brewing & Distilling.

During the distillation of the fermented fruit mash or juice, ethanol and water are the carriers of a huge number of the other volatile aroma compounds. Unique and distinctive flavour of the final spirits depends on their quantity and quality. Fruit spirits have higher concentration of almost all types of volatile compounds with comparing to other types of distilled spirits. The art of distillation run is to obtain the best balance between congeners present. Two different types of distillation equipment are used for the production of fruit spirits: copper Charentais alembic and batch distillation columns. Although both distillation methods are based on the same theoretical principles, a different quantity of the flavour compounds of the final spirits is produced by using different distillation equipment. The main difference was shown in different distributions of the methanol, n-propanol, higher alcohols and fatty acid esters. Distillation methods need to be adjusted for each fruit spirits regardless to distillation equipment employed because fermented mash of different fruit varieties has a different requirement for distilling. Alembic stills yield better aroma and more characteristic fruit distillates but are slow and require more labour. Column still cleans the distillate giving a decent aroma and higher concentration of alcohol.

Traditional pear cultivars are increasingly in demand by consumers because of their excellent taste, the possibility of use in sustainable food production systems, convenience as raw materials for obtaining products of high nutritional quality, and perceived health benefits. In this study, individual sugars, organic acids, and polyphenols in the fruits of nine traditional and one commercial pear cultivar during two growing seasons were determined by HPLC. A significant influence of cultivars, growing years, and their interaction on the content of analyzed primary and secondary metabolites was determined. The commercial pear cultivar ‘Président Drouard’ and traditional cultivars ‘Dolokrahan’, ‘Budaljača’, and ‘Krakača’ had a lower content of all analyzed sugars. Overall, traditional pear cultivars had higher total polyphenols in the peel and pulp than ‘Président Drouard’, with the exception ‘Takiša’ and ‘Ahmetova’. High polyphenol content detected in ‘Budaljača’, ‘Dolokrahan’, and ‘Krakača’ shows the utilization value of traditional pear germplasm. The obtained data can serve as practical supporting data for the use of traditional pears in the neutraceutical, pharmaceutical, and food industries.

The chemical variability of bilberry (Vaccinium myrtillus L.), wild strawberry (Fragaria vesca L.), cornelian cherry (Cornus mas L.) and rosehip (Rosa canina L.) based on the content of individual and total sugars and organic acids in fruit was investigated. The fruits were picked in fully ripened condition within the period from 2014 to 2015 from different locations. The fresh fruits were analyzed with the high performance liquid chromatography (HPLC) technique for the purpose of identifying and quantifying the content of glucose, fructose and sucrose, as well as malic, citric, fumaric and shikimic acids. However, the content of individual sugars and organic acids differed by locations as well as by growing year within the same wild fruit species. The differences between wild fruit species as well as among different locations are presented by principal component analysis (PCA). Based on results obtained, rosehip fruits with higher sugars and organic acids ratio (S/A) are suitable for production of “pekmez” and drying, while genotypes of cornelian cherry, wild strawberry and bilberry with lower S/A are recommended for production of juices and gelatin products. The research results show that specific environmental conditions may influence significantly the content of analyzed parameters, as is the case with cornelian cherry and rosehip. Considering that the food industry is searching for new products, the wild fruit species analyzed represent a promising source of ingredients for the development of beverages and foods with functional properties as well as for supplements and nutraceuticals.

Pomological characteristics and consumer acceptability of four scab-resistant apple cultivars (‘Topaz’, ‘Florina’, ‘Goldstar’ and ‘Golden Orange’) and standard commercial cultivar ‘Golden Delicious’ were investigated. Consumer acceptability consisted of rating fruit samples on Likert scales measuring appearance, flavour, size, sweetness, acidity, crispiness, juiciness, skin texture and general impression. Consumers better evaluated the cultivar ‘Topaz’ sensory characteristics of flavour, juiciness, taste and general impression than other evaluated scab-resistant apple cultivars and the cultivar ‘Golden Delicious’. ‘Golden Delicious’ got good grades for appearance, size and sweetness. ‘Topaz’ also had the best pomological characteristic related to measured fruit firmness, contents of soluble solids and organic acids. It can be concluded that only the cultivar ‘Topaz’ among the scab-resistant apple cultivars achieved a good consumer assessment.