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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.

Carob liqueur is an alcoholic drink (minimum 15% v/v of ethanol and 100 g/L of sugar) typical for the Mediterranean countries. In the current work, carob macerate produced by maceration of carob pods in hydroalcoholic base at different maceration conditions was characterized for the first time based on its aroma compounds/profile, physicochemical parameters, and chromatic characteristics. The results confirm the migration process of bioactive compounds, aroma compounds, and sugars flowing from the carob pod to the hydroalcoholic base. Changes in ethanol concentration modify the physical properties of the solvent and influence the phenolic and aroma compounds extraction, color, and acidity of the obtained samples. The higher content of phenolic compounds was determinate in the samples obtained in the darkness. The amounts of phenols were in the range of some red fruit liqueurs or walnut liqueurs, and sugars (mostly sucrose) ranging between 96 and 107 g/L. Twenty‐six (out of total 94) aroma compounds were detected in all samples, of which 17 esters, 3 alcohols, 4 ketones, and 2 acids. Low molecular weight ethyl esters, ethyl hexanoate, ethyl 2‐methyl propanoate, ethyl octanoate, ethyl benzoate, ethyl butanoate, and ethyl cinnamate, were the most abundant. Carob pod maceration in 50% v/v hydroalcoholic base (1:5 solid to liquid ratio) in darkness at room temperature during 8 weeks can be recommended as optimal maceration conditions for production of the aromatic carob macerate with functional properties., The results confirm migration process such as: bioactive compounds, aroma compounds, and sugars flows from the carob pod to the alcoholic base. Changes in ethanol concentration modify the physical properties of the solvent and influence the phenolic and aroma compounds extraction, colour, and acidity of the obtained samples. The higher content of phenolic compounds was determinate in the samples obtained in the darkness. The amounts of phenols were in the range of some red fruit liqueurs or walnut liqueurs.

During the ageing period wine spirits are changing their color, chemical composition and sensory characteristics. These changes should be simply monitored. The aim of this study was to develop partial least squares regression (PLS) models for higher alcohols and phenols in wine spirits as well as to show the feasibility of the NIR spectroscopy combined with chemometric tools to distinguish wine spirits and brandies with different ageing degree. To get the reference values, the usual methods for the analysis of spirits drinks were used. Ethanol, esters, acids, methanol and higher alcohols were studied. Wine spirits and brandies phenol composition was determined by liquid chromatography. Principal component analysis (PCA) was used to classify the wine spirits and brandies according to their phenolic and higher alcohols composition. Moreover, the Partial least squares regression (PLS regression) was used to calibrate and predict expected contents of higher alcohols and phenols in the wine spirits. Success of the classification of samples by ageing based on individual alcohols was 93.8 %, while success of the classification based on individual phenols raised to 100 %. This efficiency of the prediction was evaluated by use of linear discriminator analysis (LDA).

Spirits have proliferated and become an indispensable part of most gastronomic cultures around the world. The production and consumption of fruit brandies, especially plum and grape brandies as well as pear and apple brandies, have a long tradition in the countries of Southeast Europe. The aim of this study was to evaluate 47 fruit brandies produced in small distilleries and industrial plants from five countries. The content of the most common volatile compounds (methanol, higher alcohols and fatty acid esters) and the sensory quality of the fruit brandies were analysed. Principal component analysis (PCA) was performed using the concentrations of the main volatile compounds in the spirit samples and sensory evaluation to identify similarities or differences between the spirit samples based on distillery size. The methanol concentration in all samples was below the EU legal limit. Methanol concentration was highest in Williams pear spirits and lowest in grape pomace spirits. The PCA sample distribution confirms the good quality of samples from both small distilleries (SD) and industrial plants (IP), with some exceptions - samples with identified defects produced in some small distilleries. The results of the sensory evaluation show high sensory quality of fruit spirits from this part of Europe., Alkoholna pića su postala neizostavni dio većine gastronomskih kultura širom svijeta. Proizvodnja i potrošnja voćnih rakija, posebno rakija od šljiva i grožđa, kao i rakija od krušaka i jabuka, imaju dugu tradiciju u zemljama jugoistočne Europe. Cilj ovog istraživanja bio je procijeniti 47 voćnih rakija proizvedenih u malim destilerijama i industrijskim pogonima iz pet zemalja. Analiziran je sadržaj najčešćih hlapljivih spojeva (viši alkoholi, esteri masnih kiselina i metanol) te senzorna kvaliteta voćnih rakija. Kako bi se utvrdile sličnosti ili razlike između uzoraka alkoholnih pića na temelju veličine destilerije provedena je analiza glavnih komponenata (PCA) korištenjem koncentracija glavnih hlapljivih spojeva u uzorcima alkoholnih pića te senzorna procjena. Koncentracija metanola u svim uzorcima bila je ispod zakonske granice EU-a. Koncentracija metanola bila je najviša u rakijama od kruške Williams, a najniža u rakijama od grožđa. Distribucija uzoraka PCA potvrđuje dobru kvalitetu uzoraka iz malih destilerija (SD) i iz industrijskih postrojenja (IP), uz neke iznimke pojedinih uzoraka s utvrđenim nedostacima proizvedenih u nekim malim destilerijama. Rezultati senzorne evaluacije pokazuju visoku senzornu kvalitetu voćnih alkoholnih pića iz ovog dijela Europe.

In Croatia, as part of the Mediterranean region where carob is grown, only carob liquor is produced, mostly as a domestic product. In contrast, pure spirit production by alcoholic fermentation and distillation of carob is very rare and the compounds responsible for the characteristic bouquet of carob spirit are unknown. Therefore, the aim of this study was to evaluate the potential of carob as a raw material (source of sugars, nutrients and yeast inhibitors) for the production of carob spirit using commercial yeast strains. Moreover, a preliminary characterization of the volatiles in the obtained distillates was considered. Fermentations were carried out in carob mash with or without added nutrients by five Saccharomyces cerevisiae strains at three different temperatures (20°C, 30°C and room temperature). The obtained wine was subjected to fractional distillation in a copper still to produce carob spirit with an alcohol content of 40 % vol. Analysis of sugars and fermentation products was performed by high performance liquid chromatography. Gas chromatography and gas chromatography coupled with MS detection was used to analyse the volatile components of the carob wine and brandy. Carob flour and S. cerevisiae strains can be efficiently used for the fermentation process to produce carob wine with ethanol content ranging from 46.4 to 50.5 gL-1 and corresponding yield coefficients ranging from 0.45 to 0.49 gg-1. More than ninety compounds detected in carob spirit, namely ethyl 2-methyl butanoate, ethyl 2-methyl propanoate, ethyl cinnamate, ethyl hexanoate, beta-ionone, ethyl butanoate and ethyl octanoate, contribute significantly to the fruity and floral bouquet of carob spirit. Thus, by using the tested yeast strains, a novel brandy rich in volatiles can be obtained. Carob brandy can be 82 an additional product in the carob processing chain and new potential, especially for small carob growers.

Yeasts have an important role in the biotechnological production of ethanol, as well as in the production of fermented food and beverages. Mycotoxins, secondary metabolites of molds, can contaminate a large number of foods due to their ubiquity and therefore present great risk to human health. Other than their toxicological effects on humans, mycotoxins can have negative effects on various properties of yeasts and consequently limit their use in industry. Therefore, the aim of this work was to determine the effects of aflatoxin B1 (AFB1), ochratoxin A (OTA) and zearalenone (ZEA) on metabolic activity and biomass growth of selected yeasts S. cerevisiae, S. uvarum, C. utilis and K. marxianus. The presence of fermentation products was determined with high-performance liquid chromatography after 24h of incubation. In the early stage, all mycotoxin-exposed yeasts had lower metabolic activity as well as biomass growth when compared to control. However, concentrations of metabolic products and biomass reached the control levels by the end of the process, with the exception of C. utilis exposed to zearalenone (ZEA). Adaptive response to exposed mycotoxins suggests that certain yeasts could be used to control mycotoxin concentrations in the production of fermented food and beverages.

U radu je ispitan učinak aflatoksina B1, okratoksina A i zearalenona na morfologiju, parametre rasta i metaboličku aktivnost kvasaca Saccharomyces cerevisiae, Saccharomyces uvarum, Candida utilis i Kluyveromyces marxianus. Rezultati pokazuju da su tri mikotoksina utjecala na morfologiju svih kvasaca, prvenstveno na promjer stanica, ali ne i na njihov konačni broj. Fourierova transformacija infracrvene spektroskopije pokazala je da su membrane kvasaca vezale mikotoksine, naročito C. utilis. Kod većine kvasaca, osim kvasca S. uvarum izloženog okratoksinu A i zearaenonu, došlo je do denaturacije staničnih membrana. U ranoj su fazi fermentacije svi kvasci izloženi mikotoksinima imali nižu metaboličku aktivnost i sporiji rast biomase u usporedbi s kontrolom, no koncentracije produkata fermentacije i biomase dosegnule su razinu kontrolnih uzoraka do završetka fermentacije, osim u slučaju C. utilis izloženog 20 µg/mL zearalenona. Adaptivni odgovor mikotoksina upućuje na zaključak da se određeni kvasci mogu koristiti za kontrolu koncentracije mikotoksina u proizvodnji fermentirane hrane i pića., In this paper the effect of aflatoxin B1, ochratoxin A and zearalenon on morphology, growth parameters and metabolic activity of yeasts Saccharomyces cerevisiae, Saccharomyces uvarum, Candida utilis and Kluyveromyces marxianus was determined. The results showed that the three mycotoxins affected the morphology of all these yeasts, primarily the cell diameter, but not their final cell count. Fourier transform infrared spectroscopy showed that the yeast membranes bound the mycotoxins, C. utilis in particular. The cell membranes of most yeasts underwent denaturation, except S. uvarum exposed to ochratoxin A and zearalenone. In the early stage of fermentation, all mycotoxin-exposed yeasts had lower metabolic activity and biomass growth than controls, but fermentation products and biomass concentrations reached the control levels by the end of the fermentation, except for C. utilis exposed to 20 μg/mL of zearalenone. The adaptive response to mycotoxins suggests that certain yeasts could be used to control mycotoxin concentrations in the production of fermented food and beverages.

Zbog bolje učinkovitosti i sigurnosti potreba za enantiomerno čistim kiralnim spojevima u stalnom je porastu, pogotovo u farmaceutskoj industriji. Da bi se te potrebe zadovoljile potrebne su nove, učinkovitije i jeftinije ali i ekološki prihvatljive metode njihove priprave. U skladu s tim veliku je pažnju privukla biokataliza gdje se kao biokatalizatori koriste mikroorganizmi ili enzimi izolirani iz njih. Posljednjih godina znanstvena zajednica se okrenula istraživanju upotrebe svježeg, netaknutog biljnog materijala kao biokatalizatora. Upotreba biljnog materijala ne zahtijeva dodatak skupih kofaktora budući da se različiti enzimski sustavi i potrebni kofaktori, te njihov regeneracijski sustav već nalaze u biljnom tkivu. Ovisno o upotrijebljenoj biljci (voću, povrću, začinima), pojedini enantiomeri se mogu dobiti u visokom prinosu i s visokim enantiomernim viškom, što je kritični faktor za razvoj biološki aktivnih spojeva i njihovu bioaktivnost. U ovom radu dan je pregled istraživanja potencijalne upotrebe različitih biljnih vrsta i njihovih dijelova kao biokatalizatora u stereoselektivnim transformacijama pogodnih spojeva s ciljem dobivanja novih enentiomerno čistih spojeva. Primjena biljnih biokatalitičkih sustava u skladu je s principima zelene kemije i predstavlja značajnu alternativu sintetskim kemijskim postupcima.

Poljoprivreda, šumarstvo i prehrambena industrija izvori su velike količine lignocelulozne biomase, koja može poslužiti kao lako dostupna i jeftina obnovljiva sirovina za dobivanje različitih bioproizvoda. Jedan od takvih proizvoda je i bioetanol. Ovaj rad daje pregled bakterija koje se koriste i/ili istražuju za proizvodnju bioetanola iz lignoceluloznih sirovina. U navedenim istraživanjima proizvodnje bioetanola pomoću bakterija primijenjuju se različiti pristupi kako bi se povećala ekološka i ekonomska efikasnost procesa. Pored uobičajenih bioprocesa, koji se provode u više faza i uz pomoć monokulture, razvijaju se i visokointegrirani (konsolidirani) bioprocesi uz primjenu mikrobnih kokultura., Agriculture, forestry and food industry are sources of large quantities of lignocellulosic biomass, which can be used as an easily accessible and cheap renewable raw material for production of different bioproducts. One of these bioproducts is also bioethanol. This paper provides an overview of bacteria used and/or investigated for bioethanol production from lignocellulose-containing feedstocks. In the research of bioethanol production using bacteria, various approaches are applied in order to increase ecological and economic efficiency of bioprocess. In addition to conventional multi-stage bioprocesses that are carried out using monoculture, highly integrated (consolidated) bioprocesses and applications of microbial cocultures are also in developing stage.

In this paper the effect of aflatoxin B1, ochratoxin A and zearalenon on morphology, growth parameters and metabolic activity of yeasts Saccharomyces cerevisiae, Saccharomyces uvarum, Candida utilis and Kluyveromyces marxianus was determined. The results showed that the three mycotoxins affected the morphology of all these yeasts, primarily the cell diameter, but not their final cell count. Fourier transform infrared spectroscopy showed that the yeast membranes bound the mycotoxins, C. utilis in particular. The cell membranes of most yeasts underwent denaturation, except S. uvarum exposed to ochratoxin A and zearalenone. In the early stage of fermentation, all mycotoxin-exposed yeasts had lower metabolic activity and biomass growth than controls, but fermentation products and biomass concentrations reached the control levels by the end of the fermentation, except for C. utilis exposed to 20 μg/mL of zearalenone. The adaptive response to mycotoxins suggests that certain yeasts could be used to control mycotoxin concentrations in the production of fermented food and beverages.

Organic farming preserves biodiversity and organic products can be the source of many microbial species. The species diversity in organically grown wheat, spelt and rye was investigated in order to find strains suitable for sourdough fermentation. Colonies representing various morphological appearances were isolated and catalase-negative colonies were identified by mass spectrometer Microflex LT ™ MALDI-TOF. The fermentation products (lactic, acetic, formic and phenyllactic acid) were determined by high performance liquid chromatography, while the antifungal activity was determined using an overlay agar method. Wheat flours showed less microbial biodiversity than the rye and spelt flours. The most common genera in the tested flour were Lactobacillus, Pediococcus and Enterococcus. Isolated Lactobacillus farciminis, Pediococcus pentosaceus, Leuconostoc citreum and Lactobacillus brevis showed the best acidification activity. Lactobacillus brevis, Pediococcus pentosaceus, Weissella cibaria and Lactobacillus farciminis showed significant antifungal activity against A. niger 357 and Penicillium sp. 505. The prefermented medium of Lactobacillus farciminis were characterized by high content of lactic and phenyllactic acid.