Plum Brandy Research Articles

Preliminary Investigation of Fruit Mash Inoculation with Pure Yeast Cultures: A Case of Volatile Profile of Industrial-Scale Plum Distillates.

This study investigates the effect of pure yeast culture fermentation versus spontaneous fermentation on the volatile compound profile of industrially produced plum brandy. Using traditional distillation methods, the evolution of key volatile compounds is monitored at seven different moments during the distillation process. By integrating advanced analytical techniques such as GC-MS and sensory evaluation, significant differences in the composition of the distillates are highlighted, particularly in terms of ethyl esters and higher alcohols which are key to the sensory properties of the final product. Distillates produced with the addition of pure cultures gave higher concentrations of esters than those obtained by wild fermentation. The results of our industrial research show that the most critical step is to limit the storage of the input raw material, thereby reducing the subsequent risk of producing higher concentrations of 1-propanol. Furthermore, our results indicate that the heart of the distillate can only be removed up to an ethanol content of approximately 450 g/L and that the removal of additional ethanol results in only a 10% increase in the total volume of the distillate, which in turn results in an increase in boiler heating costs of approximately 30%.

Differences in Volatile Profiles and Sensory Characteristics in Plum Spirits on a Production Scale

The specific sensory properties attributed to distillates from different plum varieties are intricately linked to aromatic substances, fruit quality, and technology employed during production. This study compares four plum brandies, each made from a renowned plum variety: Presenta, Valjevka, Čačanská lepotica, and Čačanská rodná on a production scale. Analytical and sensory profiles were assessed using GC-FID, an available analytical method advantageous for monitoring industrial fruit distillate production. Between 71 and 85 analytes were detected in the distillates, with the Presenta plum distillate containing the highest number of substances. Statistically significant differences in analyte concentration between plum varieties (p < 0.05) were observed for 11 analytes. The comparison of analytical profiles and sensory evaluation revealed that a high concentration of 1-propanol, despite its negative sensory perception, significantly impacts the overall perception of a distillate, contrasting with substances like acetaldehyde and propyl acetate, which have positive sensory evaluations but lesser significance in content. Our work identified key compounds and procedures that can be used as benchmarks for production of plum brandy with positive sensory evaluation. These findings demonstrate the broad application potential of GC-FID in fruit distillate production as an independent tool for aromatic profile assessment and quality control.

THE PLUM BRANDY FROM OAȘ LAND SYMBOL OF IDENTITY AND OF LOCAL SPECIFICITY

The plum brandy from Oaș Land is an identitary, specific element, deeply rooted into geographical romanian realities. With its origins long lost in past time, the craft and art of obtaining the plum brandy are nowadays in danger to be lost against the background of socio-economic changes specific to globalization. In this context, the purpose of the present study is to highlight and briefly describe a traditional occupation (plum tree cultivation and obtaining plum brandy) that has endured and survived over time. The obtained results highlighted the main aspects regarding the culture of plums and the craft of obtaining traditional style plum brandy, in Gherța Mică Commune, Romania.

BRANDING OF THE DESTINATION OF PODGORINA THROUGH THE ROUTE OF “RAKIJA ŠLJIVOVICA”, A UNESCO HERITAGE ROUTE

Plum brandy is one of the most recognizable symbols of Republic of Serbia. Production of plum brandy is recently on the UNESCO list and can be a very significant factor in the process of promoting the destination from the aspect of tourism. Looking at the current situation, through positive examples of practice and a review of the theoretical framework, the collection of statistical data obtained on the basis of previous research, it was observed that the destination of Podgorina has numerous predispositions for branding. The aim of this paper is to point out the importance of the formation of “The Rakija Šljivovica Route”, where the production of plum brandies would be a significant component of the branding process of the destination. In this way, permanent migration from rural to urban areas would be slowed down, the rich cultural heritage of this region, agriculture and traditional occupations would be revived.

A comprehensive characterization of volatile profiles of plum brandies using gas chromatography coupled to high resolution mass spectrometry

Alike in case of other spirits, specific sensory properties of plum brandies, which are associated with aromatic compounds pattern, depend not only on a fruit quality but also on technology used for raw material processing. In this study, novel approach based on the non-target screening of (semi)volatile compounds by gas chromatography coupled to high-resolution mass spectrometry (GC–HRMS) was employed. The potential of this approach to distinguish plum brandies of different origin was investigated. To involve as many compounds as possible for assessment, three different sample handling strategies prior to instrumental analysis were tested: (i) no pre-treatment direct sample injection, (ii) liquid-liquid extraction by ethyl acetate, (iii) extraction of volatiles by head-space solid-phase microextraction (HS-SPME). The latter approach was selected for obtaining GC–HRMS volatiles fingerprints of a unique set of 41 plum brandy samples produced by the distilleries from Czech Republic and from Bulgaria. Multivariate statistical data analysis enabled construction of chemometric models for unbiased authentication of plum brandies, moreover, distinguishing between premium plum brandies and other ones from the Czech Republic was achieved. In addition, volatile compounds such as p-cymene, methyl eugenol and furfural were identified among the most significant ‘markers’ responsible for reliable classification of the samples.

Aqua vitae – Notes on Geographies of Alcohol Production and Consumption in the Ottoman Balkans

The paper addresses the beginning of brandy distillation in the Ottoman Balkan, the transfer of technology, commerce and taxation, as well as patterns of consumption. Those patterns include rules of alcohol production, distribution and use according to religion, class and gender, i.e. restrictions and their transgressions. Linguistic, documentary and narrative sources are deployed in building a multifaceted picture. Production of various spirits, foremost plum brandy in the Ottoman Balkans, and the usage of alcohol drinks could be viewed as an area where private and public, official and clandestine, permitted and forbidden mixed and coexisted, and influenced Ottoman political and religious system.

Production of superior quality plum brandy in small domestic distilleries in Serbia

Production of superior quality plum brandy in small domestic distilleries in Serbia

GC-FID-MS Based Metabolomics to Access Plum Brandy Quality.

Plum brandy (Slivovitz (en); Šljivovica(sr)) is an alcoholic beverage that is increasingly consumed all over the world. Its quality assessment has become of great importance. In our study, the main volatiles and aroma compounds of 108 non-aged plum brandies originating from three plum cultivars, and fermented using different conditions, were investigated. The chemical profiles obtained after two-step GC-FID-MS analysis were subjected to multivariate data analysis to reveal the peculiarity in different cultivars and fermentation process. Correlation of plum brandy chemical composition with its sensory characteristics obtained by expert commission was also performed. The utilization of PCA and OPLS-DA multivariate analysis methods on GC-FID-MS, enabled discrimination of brandy samples based on differences in plum varieties, pH of plum mash, and addition of selected yeast or enzymes during fermentation. The correlation of brandy GC-FID-MS profiles with their sensory properties was achieved by OPLS multivariate analysis. Proposed workflow confirmed the potential of GC-FID-MS in combination with multivariate data analysis that can be applied to assess the plum brandy quality.

Impact of plum processing on the quality and oxidative stability of cold-pressed kernel oil

Plum kernels of the “Čačanska rodna” variety, by-products from plum brandy production, were collected before and after fermentation and distillation, and used for cold-pressed oil production. Fatty acid and tocopherol contents were determined by capillary GC and HPLC, while the oxidation stability of the resulting cold-pressed oils was tested by the Rancimat method. The results showed that oleic fatty acid was dominant in the oil samples with a content of 56.6 to 61.8%, regardless of the plum kernels’ origin. The fermentation and distillation processes had a pronounced effect on the tocopherol content and oxidative stability of the resulting kernel oils. Tocopherol contents were 61.8 mg·100g-1, 87.4 mg·100g-1, 79.6 mg·100g-1 of oil, while the induction periods were 38.7, 44.4 and 33.6 hours for samples before fermentation, after fermentation and distillation, respectively. Based on the results, it could be concluded that the fermentation process increased the content of tocopherols in kernel oil whereas the high temperature during the distillation process adversely affected the tocopherol content and oxidative stability of the obtained kernel oil.

A SPIRIT IN THE SERVICE OF THE NATION

The thesis of the article is that slivovitz or plum brandy (slivovka in Slovene) played an important role in the reproduction of Yugoslav banal nationalism. It reminded Yugoslavs on a daily basis that they were members of a particular national community. The article is based on an analysis of texts containing the word slivovka that appeared in Delo, Slovenia’s newspaper of record, in the period 1959–91 and Delo’s predecessors Slovenski poročevalec and Ljudska pravica in the period 1945–59.

Authentification of fruit spirits using HS-SPME/GC-FID and OPLS methods

This research provides an accurate description of the origin for fruit spirits. In total, 63 samples of various kinds of fruit spirits (especially from apples, pears, plums, apricots and mirabelle) were analysed using headspace-solid phase microextraction and gas chromatography with flame-ionization detector. Obtained volatile profiles were treated and analysed by multivariate regression with a reduction of dimensionality-orthogonal projections to latent structure for the classification of fruit spirits according to their fruit of origin. Basic result of statistical analysis was the differentiation of spirits to groups with respect to fruit kind. Tested kinds of fruit spirits were strictly separated from each other. The selection was achieved with a specificity of 1.000 and a sensitivity of 1.000 for each kind of spirit. The statistical model was verified by an external validation. Hierarchical cluster analysis (calculation of distances by Ward’s method) showed a similarity of volatile profiles of pome fruit spirits (apple and pear brandies) and stone fruit spirits (especially mirabelle and plum brandies).

Determination of Ethanol in Alcoholic Drinks: Flow Injection Analysis with Amperometric Detection Versus Portable Raman Spectrometer

AbstractA flow injection analysis with integrated amperometric alcohol dehydrogenase biosensor and a handheld Mira‐DS Raman spectrometer have been compared for the determination of ethanol in different samples of alcoholic drinks. The biosensor was constructed from the commercial screen‐printed carbon electrode as amperometric transducer and covered by a thin layer comprising alcohol dehydrogenase, reduced single‐layer graphene oxide, rhodium(IV) dioxide, and glutaraldehyde. Both assemblies were tested on analysis of plum brandy, white rum, vodka, white and red wines, strong dark beer, and non‐alcoholic beer. The two principally different analytical methods were critically compared and some limitations found, especially in case of analysis of red wine and beers. Finally, some future improvements of both analytical tools under test outlined.

Sample matrix influence on microdrop hold-up in single drop microextraction

Abstract Single drop microextraction has become a widespread liquid/liquid microextraction technique owing to its simplicity, high preconcentration factor and low consumption of organic solvents in the extraction due to direct introduction of the very low volume of extract into the analytical system. Crucial features ensuring excellent repeatability of single drop microextraction include: solvent volume, solvent type, sample agitation, salts addition, and pH. The influence of sample quality on the microdrop volume and agitation type was studied. Effect of the sample matrix, such as water, acid content samples (orange juice), sample containing alcohol (plum brandy) and protein content sample (milk), on the microdrop hold-up was also investigated. For water analysis, several organic solvents such as chloroform, dichloromethane, tetrachloromethane, tetrachloroethane and chlorobenzene were tested; last three mentioned were suitable for SDME experiments. For milk samples analysis, chlorobenzene microdrop was found to be optimal; advantage of salt addition has been reported. For orange samples, 1:10 dilution was suggested with stable microdrop volumes (toluene) of up to 6 µL for lower stirring rates (100 rpm and 250 rpm). For alcohol-content samples, the change of alcohol percentage of real-life samples had to be considered. A strong influence of the matrix quality on the microdrop stability has been proven.

Plum fruits maturity indices and quality of plum brandy

Plum fruits maturity indices and quality of plum brandy

Classification of plum brandies based on phenol and anisole compounds using HPLC

This research work was carried out to investigate the content of phenol and anisole compounds of plum brandies using HPLC–diode array detection–fluorescence detection. The phenols and anisoles monitored as minor components in plum brandies can be considered as markers of origin of 30 plum varieties (Prunus domestica L.). Phenols and anisoles were separated with an HPLC gradient system of acetonitrile–water and detected using a DAD at 260 and 280 nm, and fluorescence detector at wavelengths of 280 nm and 320 nm, for excitation and emission, respectively. Two phenols (eugenol, 4-ethylphenol) and three anisoles (4-vinylanisole, 4-allylanisole, 4-propenylanisole) were observed and quantified in plum brandies with different origins. Moreover, quantitative profiles of the eugenol, 4-vinylanisole and 4-ethylphenol showed high diversity between summer and autumn plum brandy samples. The heterogeneity between the different plum brandies was also assessed using principal component analysis and linear discrimination analysis of samples according to harvest time or origins.

Effect of filtration on elimination of turbidity and changes in volatile compounds concentrations in plum distillates

The purpose of this study was to investigate the effect of alcoholic strength by volume (ASV) and storage conditions on turbidity in plum brandies. Different types of filter sheet were also tested for their effects on turbidity, as well as on the chemical composition and organoleptic characteristics of the distillates. The raw materials used were two plum distillates with initial ASVs of 76.77% v/v and 81.92% v/v. The distillates were diluted to alcohol contents of 37.5%, 40% and 50% v/v and stored under various conditions for 64 days. Filtration was performed using two depth filter sheets, with nominal retention rates of 0.40–0.48 μm and 0.80 μm, or with an activated carbon-based filter sheet. The lowest turbidity was observed in samples stored at ambient temperature with an ASV of 50% v/v. Reducing the alcohol content and storage temperature caused turbidity to increase. Samples prepared from distillate with an initial alcohol content of 76.77% v/v were characterized by significantly higher turbidity than those produced from spirit with an initial ASV of 81.92% v/v. Lowering the storage temperature resulted in a larger decrease in the concentration of volatile compounds after filtration. Use of an activated carbon filter sheet caused the greatest decrease in the majority of volatiles. Use of a filter sheet with a nominal retention rate of 0.80 μm led to the greatest improvement in the organoleptics of the tested plum distillates.

Volatile fingerprinting of the plum brandies produced from different fruit varieties.

Nowadays, fingerprinting of food became one of the most perspective analytical tools to resolve a problem of food quality and authentication, especially in difficult cases like differentiation of fruit varieties. In this work, plum brandies distillated by the same technology from 25 plum cultivars were distinguished by comprehensive two-dimensional gas chromatographic analysis and sensory evaluation. The number of identified compounds in studied samples varied between 91 and 195 depending on the plum variety. Enriched volatile organic compounds (VOC) profile was identified for the samples received from "Chrudimer", "Cacak Fruitful" and "Hanita" plum varieties, whereas in the case of "Gabrovská", "Presenta", Elena" and "President" plum varieties, the VOC profile was significantly reduced. From qualitative point of view, the particular plum brandies showed differences in the presence of unsaturated fusel alcohols (e.g. 3-methyl-3-buten-1-ol, trans-3-hexenol), unsaturated aldehydes (2-butenal, 2-nonenal), monoterpene derivatives (e.g. linalool acetate, geraniol acetate) and lactones, which were mainly detected at the trace level.

On the use of the fluorescence, ultraviolet–visible and near infrared spectroscopy with chemometrics for the discrimination between plum brandies of different varietal origins

This paper investigates the use of synchronous fluorescence, UV−Vis and near infrared (NIR) spectroscopy coupled with chemometric methods to discriminate samples of high-quality plum brandies (Slivovica) of different varietal origins (Prunus domestica L.). Synchronous fluorescence spectra (SFS) for wavelength differences in the range of 70–100nm, NIR spectra in the wavenumber range of 4000–7500cm−1 and UV−Vis spectra in the wavelength interval of 220–320nm were compared. The best discrimination models were created by linear discriminant analysis based on principal component analysis applied to SFS recorded with wavelength difference either 80nm or 100nm, allowing the classification of plum brandy according to harvest time as early (summer) and late (autumn) plum varieties; the total correct classifications were 96% and 100% for the calibration and prediction steps, respectively.

The effect of distillation conditions and alcohol content in ‘heart’ fractions on the concentration of aroma volatiles and undesirable compounds in plum brandies

This study investigates the effect of double- or single-stage distillation and different alcohol content in ‘hearts’ (middle fractions) on the distribution of aroma volatiles and undesirable compounds (methanol, hydrocyanic acid, ethyl carbamate) during distillation of plum brandies. Irrespective of the distillation method used, the first fractions (‘heads’) included mainly aliphatic aldehydes, acetals and esters as well as higher alcohols (1-propanol, 2-methyl-1-propanol, 1-butanol, 2-methyl-1-butanol and 3-methyl-1-butanol). Furfural, 1-hexanol, benzyl alcohol, 2-phenylethanol and ethyl carbamate occurred in relatively high concentrations in the ‘tail’ fractions. Increasing the concentration of alcohol in the heart fractions from 70 to 90% v/v resulted in a gradual decrease in the concentration of all detected volatile compounds. Compared with single-stage distillation, double distillation produced heart fractions with lower concentration of acetaldehyde and benzaldehyde and with higher contents of furfural and esters, such as isobutyl acetate and isoamyl acetate. There was a statistically significant increase in the amounts of methanol and ethyl carbamate obtained from double distillation compared with similar fractions derived from the single-stage process. However, in all fractions these compounds occurred in concentrations much lower than the limits specified by EU regulations. The heart fraction from the double-stage process with 83% v/v alcohol content received the best scores for aroma and flavour. Copyright © 2017 The Institute of Brewing & Distilling

Influence of yeast on the yield of fermentation and volatile profile of ‘Węgierka Zwykła’ plum distillates

The character of plum brandies depends on a unique aroma profile of the plum and the microbiota present on the surface of the fruits, as well as yeast used for fermentation. In this study, an evaluation of the effect of microorganisms applied for the fermentation of Węgierka Zwykła var. plum mashes and processing temperature (18 °C, 30 °C) on its efficiency and volatile profile, as well as taste and flavour of distillates obtained was performed. An estimation of the odour activity values (OAVs) of the volatile compounds was also conducted. Regardless of whether the fermentation was carried out using Saccharomyces bayanus wine yeast or by native microflora present on plums as well as raisins, the efficiency of this process was high and ranged between 91.7 and 96.7% of the theoretical efficiency. Especially rich in esters (among others ethyl acetate and isoamyl acetate) was the distillate derived after fermentation with the microflora of plums and raisins, at 18 °C. An evaluation of the individual aromatic effect of chemical compounds present in tested distillates, in terms of their OAVs, revealed that the highest OAVs were reached with isovaleraldehyde. Other compounds that showed aroma values >1 and possibly had an effect on the overall aroma of tested plum distillates were the following: hexanal, benzaldehyde, ethyl acetate, isoamyl acetate, ethyl benzoate, ethyl hexanoate, 1-propanol, 2-methyl-1-butanol, 3-methyl-1-butanol and 1-hexanol. The performed sensory ranking showed that the best rated distillate was the one obtained after fermentation with the indigenous microflora of plums and raisins, at 18 °C. Copyright © 2016 The Institute of Brewing & Distilling