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Searching for natural alternatives to synthetic fermentation activators has led to the study of bee pollen as a natural alcoholic fermentation activator. This study evaluated the potential of different bee pollen extracts (0.25 g/L) as activators in a Palomino Fino grape must. By analysing the composition of each extract, it was possible to identify the specific bee pollen fractions with the highest efficacy for activating alcoholic fermentation. Four extracts were obtained through sequential extraction using various organic solvents of increasing polarity (hexane, acetone, ethanol, and water), and their compositions were characterised. The effect of each extract was evaluated by monitoring the viable yeast populations and fermentation kinetics throughout the alcoholic fermentation process, along with the physicochemical and colour characterisation of the white wines obtained. The bee pollen fraction extracted with hexane, which was rich in long-chain fatty acids, significantly increased the maximum yeast populations and improved the fermentation kinetics. However, the extracts rich in polyphenolic compounds exhibited slower fermentation rates. Based on the obtained results, the lipid fraction of bee pollen extracted with hexane may be responsible for its ability to activate alcoholic fermentation. [ABSTRACT FROM AUTHOR]

Searching for natural alternatives to synthetic fermentation activators has led to the study of bee pollen as a natural alcoholic fermentation activator. This study evaluated the potential of different bee pollen extracts (0.25 g/L) as activators in a Palomino Fino grape must. By analysing the composition of each extract, it was possible to identify the specific bee pollen fractions with the highest efficacy for activating alcoholic fermentation. Four extracts were obtained through sequential extraction using various organic solvents of increasing polarity (hexane, acetone, ethanol, and water), and their compositions were characterised. The effect of each extract was evaluated by monitoring the viable yeast populations and fermentation kinetics throughout the alcoholic fermentation process, along with the physicochemical and colour characterisation of the white wines obtained. The bee pollen fraction extracted with hexane, which was rich in long-chain fatty acids, significantly increased the maximum yeast populations and improved the fermentation kinetics. However, the extracts rich in polyphenolic compounds exhibited slower fermentation rates. Based on the obtained results, the lipid fraction of bee pollen extracted with hexane may be responsible for its ability to activate alcoholic fermentation.

This article deals with the analysis of the condensates which are formed from fermentation gases during the fermentation of grape must. The experiment was divided into two parts. In the first part, the evolution of the individual volatiles was monitored throughout the whole fermentation process of the Riesling variety. In the second part, the condensates from three different grape varieties (Riesling, Merlot, Sauvignon blanc) were investigated and the total content of the selected volatile substances was measured at the end of the fermentation. Attention was focused on the measurements using a GC-MS (gas chromatography-mass spectrometry) for the volatile substances: isoamyl alcohol, isobutyl alcohol, 1-propanol, ethyl acetate, ethyl hexanoate, ethyl octanoate, ethyl decanoate, acetaldehyde, acetic acid, and acetoin. In addition, changes in the alcohol content of the condensate, with respect to the fermentation phase, were analysed. From the results of part 1, the quantity of the substances under investigation produced during fermentation was determined. The highest concentration of flavour compounds was during the fourth and fifth days of fermentation. The most dominant substance was isoamyl alcohol with a concentration of 1267 mg−1.The results of part 2 led to a comparison of the overall profile of volatiles between the varieties. The results showed that the condensates have both a high content of volatile substances and of alcohol. It was also shown that the Sauvignon blanc variant had the highest number of volatile compounds in the representation. The Merlot and Riesling variants were very similar. This product has an exceptionally high potential for further use in the wine or food industry. [ABSTRACT FROM AUTHOR]

The autochthonous, i.e. local, red wine variety Prokupac is one of the most important varieties in Serbia. In the past, this variety was the leading one in the largest number of wine-growing areas of our country. The Prokupac variety is currently the most represented in the Tri Morave wine-growing region (Central Serbia), while the largest number of vineyards with this variety are located in the Župa wine-growing subregion. Due to its importance as an old and traditional variety, certain researches of this variety have been initiated in recent years in wine-growing areas where Prokupac is traditionally grown. Certain scientific activities were initiated to isolate different genotypes with improved production and use value, all with the aim of clonal selection of this variety. In this paper, some characteristics and quality parameters of the more promising Prokupac genotypes that were isolated in the Župa wine-growing subregion in the Aleksandrovac municipality are presented. More extensive research was carried out on grapes from the harvest of 2019, 2020 and 2021 with 16 selected genotypes, namely eight genotypes from the Latkovac locality and eight genotypes from the Drenča locality. In addition to laboratory analyses of sugar, acid and pH content in the grape must, the theoretical alcohol content was also calculated. Furthermore, spectrophotometric methods were used to determine colour intensity A-420, colour intensity A-520, colour intensity A-620 and total colour intensity, as well as colour tonality. The analyses showed that certain main quality parameters from the research are within the value limits as in earlier research, but that the acid content is generally more optimal for red wine varieties compared to the research of that parameter carried out in the earlier period in other wine-growing areas (Fruška Gora and Čegar wine-growing subregions). Moreover, in our research, the sugar content of the grape is higher than the established values of that parameter in the grape must from the Čegar wine-growing subregion.

In this study, the effectiveness of a selected strain of Metschnikowia pulcherrima (MP1) was compared to that of sulphur dioxide for preventing white grape must from browning. Sulphur dioxide was found to drastically reduce oxygen consumption rate, protect hydroxycinnamic acids against oxidation and prevent grape must from browning, even in the presence of laccase. By contrast, supplementation with the selected strain of Metschnikowia pulcherrima (MP1) drastically increased oxygen consumption rate, thus reducing the amount of oxygen available for polyphenol oxidases. In the absence of laccase, this resulted in a decrease in browning and a certain degree of protection of the hydroxycinnamic acids, but in the presence of laccase it was not effective enough. Consequently, the selected strain of Metschnikowia pulcherrima (MP1) can be considered an interesting alternative to sulphur dioxide for preventing browning in white grape must, but only in conditions of healthy grapes.

One of the problems that most seriously affects oenology today is enzymatic browning, especially when grapes are infected by grey rot. We studied the capacity of glutathione (GSH) and a specific inactivated dry yeast rich in glutathione (IDY-GSH) to protect white grape must from browning compared to that of sulphur dioxide (SO2). The results indicate that SO2 drastically reduces the oxygen consumption rate (by around 72%), protects hydroxycinnamic acids from oxidation and prevents grape must against browning even in the presence of laccase. Specifically, the presence of SO2 reduced the colour's blue–yellow component (b*) by around 91% in control conditions and around 76% in the presence of laccase. GSH, pure or in the form of IDY-GSH, also reduces the oxygen consumption rate (by 23% and 36%, respectively) but to a lesser extent than SO2. GSH also favours the formation of grape reaction product (GRP) from hydroxycinnamic acids and effectively protects grape must against browning in healthy grape conditions. Specifically, the presence of GSH reduced b* by around 81% in control conditions. Nevertheless, in the presence of laccase, it was not effective enough, reducing b* by around 39% in the case of pure GSH and 24% in the case of IDY-GSH. Therefore, both forms of GSH can be considered as interesting alternative tools to SO2 for preventing browning in white grape must, but only when the grapes are healthy. [ABSTRACT FROM AUTHOR]

BackgroundThe geographic and temporal distributions of bacterial and fungal populations are poorly understood within the same wine grape cultivar. In this work, we describe the microbial composition from 'Pinot noir' must with respect to vintage, growing region, climate, and must chemistry across the states of California and Oregon, USA.Materials and methodsWe sampled 'Pinot noir' clone 667 clusters from 15 vineyards existing in a latitudinal gradient spanning nearly 1,200 km in California and Oregon for two vintages (2016 and 2017). Regions included five American Viticultural Areas (AVA). In order from southern California to Oregon, these AVAs were Santa Barbara, Monterey, Sonoma, Mendocino, and Willamette Valley. Uninoculated grape musts were subjected to 16S rRNA gene and ITS-1 amplicon sequencing to assess composition of microbial communities. We also measured grape maturity metrics. Finally, to describe regions by precipitation and growing degree days, we queried the Parameter-elevation Regressions on Independent Slopes Model (PRISM) spatial climate dataset.ResultsMost of the dominant bacterial taxa in must samples were in the family Enterobacteriaceae, notably the lactic acid bacteria or the acetic acid bacteria groups, but some, like the betaproteobacterial genus Massilia, belonged to groups not commonly found in grape musts. Fungal communities were dominated by Hanseniaspora uvarum (Saccharomycetaceae). We detected relationships between covariates (e.g., vintage, precipitation during the growing season, pH, titratable acidity, and total soluble solids) and bacterial genera Gluconobacter and Tatumella in the family Enterobacteraceae, Sphingomonas (Sphingomonodaceae), Lactobacillus (Lactobacillaceae), and Massilia (Oxalobacteraceae), as well as fungal genera in Hanseniaspora, Kazachstania, Lachancea, Torulaspora in the family Saccharomycetaceae, as well as Alternaria (Pleosporaceae), Erysiphe (Erysiphaceae), and Udeniomyces (Cystofilobasidiaceae). Fungal community distances were significantly correlated with geographic distances, but this was not observed for bacterial communities. Climate varied across regions and vintages, with growing season precipitation ranging from 11 mm to 285 mm and growing degree days ranging from 1,245 to 1,846.DiscussionWe determined that (1) bacterial beta diversity is structured by growing season precipitation, (2) fungal beta diversity reflects growing season precipitation and growing degree days, and (3) microbial differential abundances of specific genera vary with vintage, growing season precipitation, and fruit maturity metrics. Further, the correlation between fungal community dissimilarities and geographic distance suggests dispersal limitation and the vineyard as a source for abundant fungal taxa. Contrasting this observation, the lack of correlation between bacterial community dissimilarity and geographic distance suggests that environmental filtering is shaping these communities.

Despite the increasing number of publications on non-conventional yeasts (NCYs), many areas in this field remain poorly understood, making the examination of these strains important for determining their potential in wine fermentations. The amino acid metabolic pathways involved, particularly the catabolic Ehrlich pathway but also anabolic pathways such as the leucine biosynthesis pathway, are crucial for producing high-value aroma compounds that contribute to the final flavour of wine. We examined the potential use of Saccharomycopsis fermentans in wine fermentations. We selected mutant strains resistant to the toxic compound trifluoro-leucine (TFL), verified mutations in the SfLEU4 gene, and characterized the ability of the resulting strains to contribute to fermentation bouquets. Resistance to TFL relieves feedback inhibition in the leucine biosynthesis pathway and resulted in increased leucine biosynthesis. Concomitantly, the S. fermentans TFL-resistant mutants generated increased amounts of isoamyl alcohol and isovalerate during wine fermentation. Selection of TFL-resistant strains thus provides a generally applicable strategy for the improvement in NCYs and their utilization in co-fermentation processes for different grape must varieties. [ABSTRACT FROM AUTHOR]

BACKGROUND: The profitable production of gluconic acid (GA), an organic acid extensively used in the food and beverages industries, relies on the use of cheap and available substrates with high sugar content. The high oxygen demand for the microbial conversion of glucose to GA is still a bottleneck of industrial production in conventional stirred‐tank reactors. Therefore, in this study, for the first time, the effect of increased air pressure up to 4 bar on GA production and sugar consumption in batch and step‐wise fed‐batch cultures in sugarcane molasses (ScM) and grape must (GM) medium was studied. RESULTS: ScM and GM, by‐products of the agro‐food industry, proved to be adequate feedstocks to replace pure glucose in GA batch production by Aspergillus niger MUM 92.13. A threefold improvement in GA productivity was obtained in batch experiments carried out at 4 bar with ScM and GM compared to those at 1 bar. Furthermore, the addition of two pulses of ScM, under pressurized conditions, increased the GA production, reaching a final concentration of 140 g L−1. CONCLUSION: This work proved that the use of total air pressure up to 4 bar is an effective approach to enhance GA productivity using ScM and GM as substrates in batch and step‐wise fed‐batch cultures. Also, this study provides a novel strategy for developing a biotechnological bioprocess for GA production by A. niger from low‐cost and sugar‐rich by‐products performed in pressurized stirred tank reactors. © 2023 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

Muscat of Alexandria is one of the most aromatic grape cultivars, with a characteristic floral and fruity aroma, producing popular appellation of origin wines. The winemaking process is a critical factor contributing to the quality of the final product, so the aim of this work was to study metabolomic changes during the fermentation of grape musts at the industrial level from 11 tanks, 2 vintages, and 3 wineries of Limnos Island. A Headspace Solid-Phase Microextraction (HS-SPME) and a liquid injection with Trimethylsilyl (TMS) derivatization Gas Chromatography-Mass Spectrometry (GC-MS) methods were applied for the profiling of the main volatile and non-volatile polar metabolites originating from grapes or produced during winemaking, resulting in the identification of 109 and 69 metabolites, respectively. Multivariate statistical analysis models revealed the differentiation between the four examined time points during fermentation, and the most statistically significant metabolites were investigated by biomarker assessment, while their trends were presented with boxplots. Whilst the majority of compounds (ethyl esters, alcohols, acids, aldehydes, sugar alcohols) showed an upward trend, fermentable sugars, amino acids, and C6-compounds were decreased. Terpenes presented stable behavior, with the exception of terpenols, which were increased at the beginning and were then decreased after the 5th day of fermentation. [ABSTRACT FROM AUTHOR]

Sulfur dioxide is the most used additive today for preventing browning in grape musts and wines. However, since wine consumers are increasingly interested in healthier wines, the wine industry is keen to reduce its use. Some promising alternatives to sulfur dioxide have been proposed in recent years, including glutathione, both pure and in the form of inactivated yeasts, and Metschnikowia pulcherrima used as a bioprotective agent. Some information exists about the protective effect against oxidation of glutathione but there is very few about the use of bioprotection for that purpose. Supplementation with glutathione, regardless of the commercial form, reduced oxygen consumption and browning intensity when laccase was not present in the grape juice. Metschnikowia pulcherrima also reduced browning intensity in the absence of laccase but increased the total oxygen consumption. However, in the presence of laccase, glutathione and Metschnikowia pulcherrima were not effective enough to adequately prevent the grape juice from browning. Glutathione, both pure and in the form of inactivated yeasts, and Metschnikowia pulcherrima are interesting tools for protecting grape must against browning, and thus reducing the use of sulfur dioxide. [ABSTRACT FROM AUTHOR]

This article deals with the analysis of the condensates which are formed from fermentation gases during the fermentation of grape must. The experiment was divided into two parts. In the first part, the evolution of the individual volatiles was monitored throughout the whole fermentation process of the Riesling variety. In the second part, the condensates from three different grape varieties (Riesling, Merlot, Sauvignon blanc) were investigated and the total content of the selected volatile substances was measured at the end of the fermentation. Attention was focused on the measurements using a GC-MS (gas chromatography-mass spectrometry) for the volatile substances: isoamyl alcohol, isobutyl alcohol, 1-propanol, ethyl acetate, ethyl hexanoate, ethyl octanoate, ethyl decanoate, acetaldehyde, acetic acid, and acetoin. In addition, changes in the alcohol content of the condensate, with respect to the fermentation phase, were analysed. From the results of part 1, the quantity of the substances under investigation produced during fermentation was determined. The highest concentration of flavour compounds was during the fourth and fifth days of fermentation. The most dominant substance was isoamyl alcohol with a concentration of 1267 mg−1.The results of part 2 led to a comparison of the overall profile of volatiles between the varieties. The results showed that the condensates have both a high content of volatile substances and of alcohol. It was also shown that the Sauvignon blanc variant had the highest number of volatile compounds in the representation. The Merlot and Riesling variants were very similar. This product has an exceptionally high potential for further use in the wine or food industry.

Myo-inositol polyalcohol is a characteristic component of natural and concentrated grape musts (CMs), and Regulation (EU) no. 1308/2013 prescribes its presence as a marker of the authenticity of rectified concentrated must (RCM). Other polyalcohols besides myo-inositol, such as scyllo-inositol or minor sugars, could be considered authenticity markers, but an extensive search in the literature yielded no exhaustively investigated study of their concentration variability in genuine products. The aim of this study was to create an extensive national data bank of minor carbohydrates profiles and investigate the impact of the geographical origin and the different vintages on the concentration of these compounds; to this end, 450 authentic Italian grape musts of different varieties were sampled and analyzed during the harvest season in 2019, 2020, and 2021. The grape musts from the Italian wine-growing areas CII and CIIIb had myo- and scyllo-inositol contents always higher than 756 and 39 mg/kg of sugar, respectively. Conversely, also considering other mono- and disaccharides, sucrose, sorbitol, lactose, maltose, and isomaltose showed contents always lower than 534, 1207, 390, 2222, and 1639 mg/kg of sugar, respectively. The general applicability to the CM and RCM of the proposed authenticity thresholds, established in the must, was demonstrated by studying the influence of must concentration on the myo- and scyllo-inositol content. Inter-laboratory comparison experiments were also conducted to harmonize and characterize laboratory methods and validate the analytical dataset. Based on the obtained results, the text of the EU legislation (Reg. (EU) 1308/2013), which defines the characteristics of the must and the CRM product, should be revised. [ABSTRACT FROM AUTHOR]

The aim of the paper was to determine the potential of using grape must and unconventional yeasts in the beer production process. Samples were fermented using non-Saccharomyces yeasts (Dekkera bruxellensis 3429, Wickerhamomyces anomalus MG971261, Kluyveromyces lactis MG971263), and Saccharomyces cerevisiae Safale US-05 was used as a control. Grape must was pasteurized and, together with wort, volumetrically introduced into fermentation flasks for fermentation. Mass changes taking place during the process were analyzed. Real extract, alcohol content, free amino nitrogen (FAN) content, titratable acidity, color, and sugar profile were determined in obtained beers. The obtained results have proven that the tested non-Saccharomyces yeasts can adapt to fermentation conditions, just like S. cerevisiae Safale US-05, and can be used to produce beer-wine hybrid alcoholic beverages. The yeast K. lactis MG971263 produced a greater amount of alcohol in beers compared to other yeast strains. There were no significant differences in the color of the obtained beers and in the degree of FAN utilization during the fermentation process. The unconventional yeasts used are capable of producing beers without and with the addition of grape must with parameters similar to beers obtained using S. cerevisiae Safale US-05. [ABSTRACT FROM AUTHOR]

Italian grape ale (IGA) beers have been categorized by the Beer Judge Certification Program as a sub-category of fruit beers in which grape, or grape must, is added during the brewing process to provide additional characteristics to the final beer. In the present work, IGA beers have been produced with must and pomace of the Malvasia di Candia Aromatica (MaCA) grape variety, which were added before fermentation at two different percentages (10% and 20%). The (poly)phenolic profile of IGA beers have been characterized with HPLC-MS/MS and compared to a golden ale control beer (produced in the same conditions without the addition of grape-derived ingredients). A series of sub-samples have been collected to monitor the (poly)phenol profile at time 0 and during the different phases of the fermentation process (1, 3, 5, 7 30, 65 days). Results demonstrated how the addition of pomace allowed to significantly enrich (p < 0.05) final beers in total (poly)phenols detected by MS, while must addition did not influence that amount if compared to the control sample. However, a PCA cluster analysis identified strong similarities among IGA beers and differentiated them to control beer samples. This study underlined how the addition of must and pomace from the MaCA grape variety improved the (poly)phenolic profile of beer from both a qualitative and quantitative point of view. [ABSTRACT FROM AUTHOR]

Continually increasing global temperature could severely affect grape berry metabolite accumulation and ultimately wine polyphenol concentration and color intensity. To explore the effect of late shoot pruning on grape berry and wine metabolite composition, field trials were carried out on Vitis vinifera cv. Malbec and cv. Syrah grafted on 110 Richter rootstock. Fifty-one metabolites were detected and unequivocally annotated employing UPLC-MS based metabolite profiling. Integrating the data using hierarchical clustering showed a significant effect of late pruning treatments on must and wine metabolites. Syrah metabolite profiles were characterized by a general trend of higher metabolite content in the late shoot pruning treatments, while Malbec profiles did not show a consistent trend. In summary, late shoot pruning exerts a significant effect, though varietal specific, on must and wine quality-related metabolites, possibly related to enhanced photosynthetic efficiency, which should be taken into consideration when planning mitigating strategies in warm climates. [ABSTRACT FROM AUTHOR]

Ćupter is Herzegovinian candy made of must and flour/semolina. Much research about the incorporation of brewers' spent grains into the human diet has been published. The purpose of this study was to partially replace semolina (Samples 1 and 2) and flour (Samples 3 and 4) with brewers' spent grains originating from industrial (Samples 1 and 4) and craft breweries (Samples 2 and 3) and study nutritive, chemical, and preference properties of the product. In this research, the authors aimed to find application of this already proven functional ingredient in ćupter production. Values for pH were higher for all samples compared to the traditional recipe. Samples produced with flour had higher values of water activity (0.86 ± 0.01) and moisture (41.82 ± 1.68 and 41.11 ± 1.41). Ash content increased with BSG addition, but between samples, there were no significant differences. Collected data showed significant differences in fat levels. Higher protein content was measured for Samples 4 (6.60 ± 0.17) and 1 (6.13 ± 0.07). The highest total sugar content was measured for Sample 1. The general appearance for all samples was "moderately like". Nutritive value was improved with the addition of BSG, but recipes and drying should be modified to improve consumer acceptance. [ABSTRACT FROM AUTHOR]

Enzymatic browning caused by polyphenol oxidases, tyrosinase and laccase, continues to be one of the main problems in winemaking. Therefore, wineries are very interested in studying the mechanisms of browning and procedures for decreasing the use sulphur dioxide. This research proposes a model to study tyrosinase activity from grape must using different substrates: one monophenol (p -hydroxybenzoic acid), two diphenols (caftaric acid and (−)-epicatechin) and one triphenol (gallic acid). The kinetic constants of tyrosinase, Vmax and K M , indicate that caftaric acid is the best substrate for tyrosinase, followed in decreasing order by (−)-epicatechin, gallic acid and p -hydroxybenzoic acid. This last acid does not appear to be susceptible to browning by the action of grape must tyrosinase. The influence of pH, temperature and ethanol on grape must tyrosinase were also determined and the results indicate that tyrosinase Vmax increases when pH and temperature are higher and that the presence of ethanol reduces it. • A method to study the grape must tyrosinase activity is proposed. • This method has been proved with caftaric, gallic and p-hydroxycinnamic acids and (−)-epicatechin. • The kinetic constants, Vmax and KM, of grape tyrosinase have been determined for different substrates. • Caftaric acid is the best substrate for grape tyrosinase of all those studied • The influence of pH, temperature and ethanol on the kinetic constants have been studied [ABSTRACT FROM AUTHOR]

One of the problems that most seriously affects oenology today is enzymatic browning, especially when grapes are infected by grey rot. We studied the capacity of glutathione (GSH) and a specific inactivated dry yeast rich in glutathione (IDY-GSH) to protect white grape must from browning compared to that of sulphur dioxide (SO2). The results indicate that SO2 drastically reduces the oxygen consumption rate (by around 72%), protects hydroxycinnamic acids from oxidation and prevents grape must against browning even in the presence of laccase. Specifically, the presence of SO2 reduced the colour’s blue–yellow component (b*) by around 91% in control conditions and around 76% in the presence of laccase. GSH, pure or in the form of IDY-GSH, also reduces the oxygen consumption rate (by 23% and 36%, respectively) but to a lesser extent than SO2. GSH also favours the formation of grape reaction product (GRP) from hydroxycinnamic acids and effectively protects grape must against browning in healthy grape conditions. Specifically, the presence of GSH reduced b* by around 81% in control conditions. Nevertheless, in the presence of laccase, it was not effective enough, reducing b* by around 39% in the case of pure GSH and 24% in the case of IDY-GSH. Therefore, both forms of GSH can be considered as interesting alternative tools to SO2 for preventing browning in white grape must, but only when the grapes are healthy.

Continually increasing global temperature could severely affect grape berry metabolite accumulation and ultimately wine polyphenol concentration and color intensity. To explore the effect of late shoot pruning on grape berry and wine metabolite composition, field trials were carried out on Vitis vinifera cv. Malbec and cv. Syrah grafted on 110 Richter rootstock. Fifty-one metabolites were detected and unequivocally annotated employing UPLC-MS based metabolite profiling. Integrating the data using hierarchical clustering showed a significant effect of late pruning treatments on must and wine metabolites. Syrah metabolite profiles were characterized by a general trend of higher metabolite content in the late shoot pruning treatments, while Malbec profiles did not show a consistent trend. In summary, late shoot pruning exerts a significant effect, though varietal specific, on must and wine quality-related metabolites, possibly related to enhanced photosynthetic efficiency, which should be taken into consideration when planning mitigating strategies in warm climates.

The topic of microbial interactions is of notable relevance in oenology, being connected with their impact on microbial biodiversity and wine quality. The interactions among different couples of microorganisms, in particular yeasts and lactic acid bacteria representative of the must/wine microbial consortium, have been tested in this study. This interaction's screening has been implemented by means of plate assays, using culture medium, grape juice, and wine agar as substrates. Different antagonistic phenomena have been detected, belonging to the following interaction categories: yeast-yeast, yeast-bacteria, bacteria-yeast, and bacteria-bacteria. In general, the inhibitory activity has been observed in all three media agar used as substrates, resulting in more frequent on culture medium, followed by grape juice and, finally, wine. Specifically, the work is one of the first reports demonstrating the reciprocal interactions between non-Saccharomyces yeasts (NSY) and malolactic bacteria. The findings shed new light on the co-inoculation of the yeast starter culture with malolactic bacteria, as well as the biocontrol potential of Lactic Acid Bacteria (LAB) strains. Highlighted microbial interactions are relevant for the management of alcoholic fermentation, malolactic fermentation, and the development of distinctive aroma profiles, control of spoilage yeasts, and the selection of tailored mixed starter cultures. In addition, the plate assay method could be a fast, cheap, and suitable method to exclude negative interactions among Saccharomyces spp., NSY, and malolactic bacteria during trials from regional spontaneous fermentations with the aim to select tailored mixed starter cultures. [ABSTRACT FROM AUTHOR]

The influence of vintage, geographical location and farming system on yeast populations was evaluated in grape musts from Galicia (NW Spain) in three consecutive years. Grape samples were taken in organic and conventional vineyards from four Denominations of Origin (DOs) during the 2013, 2014 and 2015 vintages. Cultivable yeast populations were characterised at the quantitative and qualitative level. The general results show the existence of significant differences for yeast counts in musts among vintages and DOs, but not between farming systems. Given the geographical location of the grapes, the influence of vintage was significant in all DOs; however, the farming system only had a significant impact on viable yeasts in Rías Baixas, although the number of yeasts tended to be higher in organic samples than in conventional ones in most cases. Species richness was location dependent, with Rías Baixas and Ribeira Sacra showing the highest values. In addition, the type of yeasts varied between Denominations of Origin. From a total of 39 different yeast species identified, Metschnikowia spp., Hanseniaspora uvarum and Aureobasidium spp. were the prevailing species. These major yeasts were found to be widely distributed. However, species such as Issatchenkia terricola, Starmerella bacillaris and different species of Candida, Pichia and Zygosaccharomyces genera were mainly found in Rías Baixas and Ribeira Sacra DOs. In contrast, Lachancea thermotolerans was isolated in Monterrei and Ribeiro DOs only. Accordingly, the ANOSIM and PERMANOVA analyses evidenced significant differences in species richness among different DOs and, to a lesser extent, among vintages, but not between farming systems.

Despite the increasing number of publications on non-conventional yeasts (NCYs), many areas in this field remain poorly understood, making the examination of these strains important for determining their potential in wine fermentations. The amino acid metabolic pathways involved, particularly the catabolic Ehrlich pathway but also anabolic pathways such as the leucine biosynthesis pathway, are crucial for producing high-value aroma compounds that contribute to the final flavour of wine. We examined the potential use of Saccharomycopsis fermentans in wine fermentations. We selected mutant strains resistant to the toxic compound trifluoro-leucine (TFL), verified mutations in the SfLEU4 gene, and characterized the ability of the resulting strains to contribute to fermentation bouquets. Resistance to TFL relieves feedback inhibition in the leucine biosynthesis pathway and resulted in increased leucine biosynthesis. Concomitantly, the S. fermentans TFL-resistant mutants generated increased amounts of isoamyl alcohol and isovalerate during wine fermentation. Selection of TFL-resistant strains thus provides a generally applicable strategy for the improvement in NCYs and their utilization in co-fermentation processes for different grape must varieties.

Glycosides represent a large source of potential flavor in grape must. Commercial preparations enzymes with glycosidase activity are commonly employed to enhance wine aroma. In this study, we conducted an evaluation of twelve commercial enzymes to assess their effectiveness in releasing volatile compounds from their conjugated forms in a white grape must under laboratory conditions by solid-liquid extraction (SPE) and gas chromatography–mass spectrometry (GC–MS). In this laboratory-level experiment, regardless of the enzymes used, the total concentration of volatile compounds was not statistically affected by the treatments. While the total concentration of volatile compounds remained largely unchanged, four specific volatile groups were significantly affected by the enzyme treatments: acids, alcohols, C 13 -norisoprenoids, and terpenes. The results also revealed a significant effect of commercial enzymes on individual compounds, which led to a notable increase in the concentration of twenty-one aroma compounds, mainly terpenes. Rapidase Revelation Aroma and Enozym Extra Aroma emerged as the most powerful ones on the must's volatile composition with important ability to release higher concentrations of essential varietal aroma compounds, particularly terpenes and C 13 -norisoprenoids. • Glycosides represent a large source of potential flavor in grape must. • The effectiveness of 12 commercial enzymes in releasing volatile compounds was study. • Significant effect of commercial enzymes on individual compounds was observed. • Terpenes concentration was mainly increased by effect of commercial enzymes. • Rapidase Revelation Aroma and Enozym Extra Aroma were the most powerful enzymes. [ABSTRACT FROM AUTHOR]

Muscat of Alexandria is one of the most aromatic grape cultivars, with a characteristic floral and fruity aroma, producing popular appellation of origin wines. The winemaking process is a critical factor contributing to the quality of the final product, so the aim of this work was to study metabolomic changes during the fermentation of grape musts at the industrial level from 11 tanks, 2 vintages, and 3 wineries of Limnos Island. A Headspace Solid-Phase Microextraction (HS-SPME) and a liquid injection with Trimethylsilyl (TMS) derivatization Gas Chromatography-Mass Spectrometry (GC-MS) methods were applied for the profiling of the main volatile and non-volatile polar metabolites originating from grapes or produced during winemaking, resulting in the identification of 109 and 69 metabolites, respectively. Multivariate statistical analysis models revealed the differentiation between the four examined time points during fermentation, and the most statistically significant metabolites were investigated by biomarker assessment, while their trends were presented with boxplots. Whilst the majority of compounds (ethyl esters, alcohols, acids, aldehydes, sugar alcohols) showed an upward trend, fermentable sugars, amino acids, and C6-compounds were decreased. Terpenes presented stable behavior, with the exception of terpenols, which were increased at the beginning and were then decreased after the 5th day of fermentation.

The wine market has always faced the problem of fraud, including the addition of exogenous sugar solutions to grape musts to increase the final alcohol content. Since in some countries the practice of chaptalization is prohibited (except by adding concentrated must) it is necessary to broaden the analytical techniques that allow the identification of this type of fraud. The aim of this study was to define an NMR-based sugar profile of genuine grape must to set concentration limits for each sugar as parameters of authenticity. Glucose, fructose, together with eleven minor sugars were quantified in 82 genuine Italian grape musts, developing an analytical procedure based on highly selective chemical shift filters followed by TOCSY. Alongside the characteristic myo - and scyllo -inositol, significant contents of mannose, galactose, and trehalose were also found. Otherwise, maltose, rhamnose, arabinose, sucrose and lactose are present in lower concentrations and show great concentration variability. • The sugar profile of grape must was defined by NMR. • The concentration natural limits of minor sugars are defined as parameter of authenticity of grape must. • Myo -, scyllo -inositol, galactose, mannose and trehalose: the most representative sugars of grape must. [ABSTRACT FROM AUTHOR]

Myo-inositol polyalcohol is a characteristic component of natural and concentrated grape musts (CMs), and Regulation (EU) no. 1308/2013 prescribes its presence as a marker of the authenticity of rectified concentrated must (RCM). Other polyalcohols besides myo-inositol, such as scyllo-inositol or minor sugars, could be considered authenticity markers, but an extensive search in the literature yielded no exhaustively investigated study of their concentration variability in genuine products. The aim of this study was to create an extensive national data bank of minor carbohydrates profiles and investigate the impact of the geographical origin and the different vintages on the concentration of these compounds; to this end, 450 authentic Italian grape musts of different varieties were sampled and analyzed during the harvest season in 2019, 2020, and 2021. The grape musts from the Italian wine-growing areas CII and CIIIb had myo- and scyllo-inositol contents always higher than 756 and 39 mg/kg of sugar, respectively. Conversely, also considering other mono- and disaccharides, sucrose, sorbitol, lactose, maltose, and isomaltose showed contents always lower than 534, 1207, 390, 2222, and 1639 mg/kg of sugar, respectively. The general applicability to the CM and RCM of the proposed authenticity thresholds, established in the must, was demonstrated by studying the influence of must concentration on the myo- and scyllo-inositol content. Inter-laboratory comparison experiments were also conducted to harmonize and characterize laboratory methods and validate the analytical dataset. Based on the obtained results, the text of the EU legislation (Reg. (EU) 1308/2013), which defines the characteristics of the must and the CRM product, should be revised.

Italian grape ale (IGA) beers have been categorized by the Beer Judge Certification Program as a sub-category of fruit beers in which grape, or grape must, is added during the brewing process to provide additional characteristics to the final beer. In the present work, IGA beers have been produced with must and pomace of the Malvasia di Candia Aromatica (MaCA) grape variety, which were added before fermentation at two different percentages (10% and 20%). The (poly)phenolic profile of IGA beers have been characterized with HPLC-MS/MS and compared to a golden ale control beer (produced in the same conditions without the addition of grape-derived ingredients). A series of sub-samples have been collected to monitor the (poly)phenol profile at time 0 and during the different phases of the fermentation process (1, 3, 5, 7 30, 65 days). Results demonstrated how the addition of pomace allowed to significantly enrich (p < 0.05) final beers in total (poly)phenols detected by MS, while must addition did not influence that amount if compared to the control sample. However, a PCA cluster analysis identified strong similarities among IGA beers and differentiated them to control beer samples. This study underlined how the addition of must and pomace from the MaCA grape variety improved the (poly)phenolic profile of beer from both a qualitative and quantitative point of view.

Ćupter is Herzegovinian candy made of must and flour/semolina. Much research about the incorporation of brewers’ spent grains into the human diet has been published. The purpose of this study was to partially replace semolina (Samples 1 and 2) and flour (Samples 3 and 4) with brewers’ spent grains originating from industrial (Samples 1 and 4) and craft breweries (Samples 2 and 3) and study nutritive, chemical, and preference properties of the product. In this research, the authors aimed to find application of this already proven functional ingredient in ćupter production. Values for pH were higher for all samples compared to the traditional recipe. Samples produced with flour had higher values of water activity (0.86 ± 0.01) and moisture (41.82 ± 1.68 and 41.11 ± 1.41). Ash content increased with BSG addition, but between samples, there were no significant differences. Collected data showed significant differences in fat levels. Higher protein content was measured for Samples 4 (6.60 ± 0.17) and 1 (6.13 ± 0.07). The highest total sugar content was measured for Sample 1. The general appearance for all samples was “moderately like”. Nutritive value was improved with the addition of BSG, but recipes and drying should be modified to improve consumer acceptance.

The topic of microbial interactions is of notable relevance in oenology, being connected with their impact on microbial biodiversity and wine quality. The interactions among different couples of microorganisms, in particular yeasts and lactic acid bacteria representative of the must/wine microbial consortium, have been tested in this study. This interaction’s screening has been implemented by means of plate assays, using culture medium, grape juice, and wine agar as substrates. Different antagonistic phenomena have been detected, belonging to the following interaction categories: yeast-yeast, yeast-bacteria, bacteria-yeast, and bacteria-bacteria. In general, the inhibitory activity has been observed in all three media agar used as substrates, resulting in more frequent on culture medium, followed by grape juice and, finally, wine. Specifically, the work is one of the first reports demonstrating the reciprocal interactions between non-Saccharomyces yeasts (NSY) and malolactic bacteria. The findings shed new light on the co-inoculation of the yeast starter culture with malolactic bacteria, as well as the biocontrol potential of Lactic Acid Bacteria (LAB) strains. Highlighted microbial interactions are relevant for the management of alcoholic fermentation, malolactic fermentation, and the development of distinctive aroma profiles, control of spoilage yeasts, and the selection of tailored mixed starter cultures. In addition, the plate assay method could be a fast, cheap, and suitable method to exclude negative interactions among Saccharomyces spp., NSY, and malolactic bacteria during trials from regional spontaneous fermentations with the aim to select tailored mixed starter cultures.

Malolactic fermentation (MLF) is a desirable biotransformation in red and some high-acidity white wines. This process involves the decarboxylation of l -malic acid into l -lactic acid by lactic acid bacteria (LAB). Among them, Oenococcus oeni and Lactiplantibacillus plantarum are the most common, being the last usually used as starter to perform MLF in wine. Compared with O. oeni , L. plantarum is less tolerant to wine conditions such as pH and ethanol; thus, it is preferable to inoculate it in must. The current literature has not yet addressed the impact of some parameters on the inoculation of this bacterium in grape must. Therefore, the aim of this work was to characterize the effect of the inoculum concentration, pH and ethanol tolerance, as well as the inoculation strategy, on the MLF performance of L. plantarum in grape must. We observed that a population < 108 CFU/mL could compromise MLF performance. Additionally, L. plantarum was able to survive at low pH values, such as 2.50, but in the presence of ethanol or a fermenting yeast, it could tolerate pH values in the range of 3.00–3.25. Finally, coinoculation or sequential inoculation with S. cerevisiae allows for the completion of MLF before the end of alcoholic fermentation. • The optimal inoculation rate of L. plantarum was 108 CFU/mL. • L. plantarum is suitable for improving the performance of MLF in red grape must during AF. • Both coinoculation and sequential inoculation allow MLF to occur at moderate pH values. • A low pH (<3.00) can compromise the performance of the MLF during AF. • L. plantarum inoculation in must can increase the acetaldehyde concentration in wine. [ABSTRACT FROM AUTHOR]

Starmerella bacillaris (synonym Candida zemplinina) is a non-Saccharomyces yeast species, frequently found in enological ecosystems. Peculiar aspects of the genetics and metabolism of this yeast species, as well as potential industrial applications of isolated indigenous S. bacillaris strains worldwide, have recently been explored. In this review, we summarize relevant observations from studies conducted on standard laboratory and indigenous isolated S. bacillaris strains. [ABSTRACT FROM AUTHOR]

Background. The geographic and temporal distributions of bacterial and fungal populations are poorly understood within the same wine grape cultivar. In this work, we describe the microbial composition from 'Pinot noir' must with respect to vintage, growing region, climate, and must chemistry across the states of California and Oregon, USA. Materials and Methods. We sampled 'Pinot noir' clone 667 clusters from 15 vineyards existing in a latitudinal gradient spanning nearly 1,200 km in California and Oregon for two vintages (2016 and 2017). Regions included five American Viticultural Areas (AVA). In order from southern California to Oregon, these AVAs were Santa Barbara, Monterey, Sonoma, Mendocino, and Willamette Valley. Uninoculated grape musts were subjected to 16S rRNA gene and ITS-1 amplicon sequencing to assess composition of microbial communities. We also measured grape maturity metrics. Finally, to describe regions by precipitation and growing degree days, we queried the Parameterelevation Regressions on Independent Slopes Model (PRISM) spatial climate dataset. Results. Most of the dominant bacterial taxa in must samples were in the family Enterobacteriaceae, notably the lactic acid bacteria or the acetic acid bacteria groups, but some, like the betaproteobacterial genus Massilia, belonged to groups not commonly found in grape musts. Fungal communities were dominated by Hanseniaspora uvarum (Saccharomycetaceae). We detected relationships between covariates (e.g., vintage, precipitation during the growing season, pH, titratable acidity, and total soluble solids) and bacterial genera Gluconobacter and Tatumella in the family Enterobacteraceae, Sphingomonas (Sphingomonodaceae), Lactobacillus (Lactobacillaceae), and Massilia (Oxalobacteraceae), as well as fungal genera in Hanseniaspora, Kazachstania, Lachancea, Torulaspora in the family Saccharomycetaceae, as well as Alternaria (Pleosporaceae), Erysiphe (Erysiphaceae), and Udeniomyces (Cystofilobasidiaceae). Fungal community distances were significantly correlated with geographic distances, but this was not observed for bacterial communities. Climate varied across regions and vintages, with growing season precipitation ranging from 11mmto 285mmand growing degree days ranging from 1,245 to 1,846. Discussion. We determined that (1) bacterial beta diversity is structured by growing season precipitation, (2) fungal beta diversity reflects growing season precipitation and growing degree days, and (3) microbial differential abundances of specific genera vary with vintage, growing season precipitation, and fruit maturity metrics. Further, the correlation between fungal community dissimilarities and geographic distance suggests dispersal limitation and the vineyard as a source for abundant fungal taxa. Contrasting this observation, the lack of correlation between bacterial community dissimilarity and geographic distance suggests that environmental filtering is shaping these communities. [ABSTRACT FROM AUTHOR]

Ultra-high pressure homogenization (UHPH) is a high pressure technique in which a fluid is pressurized by pumping at higher than 200 MPa and instantaneously depressurized at atmospheric pressure across a special valve. The full process takes

In the modern world, one of the most important is the problem of food safety. Ensuring the safety and quality of food raw materials and food products is one of the main tasks of modern human society that determine the health of the population and the preservation of its gene pool. Throughout the world, there is a deterioration in the quality of food products, associated primarily with the active introduction of various chemical compounds into agriculture in order to increase production volumes. Along with organic and mineral fertilizers, pesticides that are used to control weeds, pathogens and pests are widely used to increase productivity. Pesticides accumulate in agricultural products and have a negative impact on human health. The negative role of pesticides in food production technological processes, for example, in winemaking, pesticides negatively affect the fermentation activity and the physiological state of yeast, has also been established. The article presents the results of studies of the effect of organochlorine pesticides on biochemical transformations in the process of obtaining grape materials. [ABSTRACT FROM AUTHOR]

Yeasts are unicellular fungi that harbour a large biodiversity of thousands of species, of which particularly ascomycetous yeasts are instrumental to human food and beverage production. There is already a large body of evidence showing that insects play an important role for yeast ecology, for their dispersal to newhabitats and for breeding and overwintering opportunities. Here,we sought to investigate a potential role of the terrestrial snails Cepaea hortensis and C. nemoralis, which in Europe are often found in associationwith human settlements and gardens, in yeast ecology. Surprisingly, even in a relatively limited culture-dependent sampling size of over 150 isolates,we found a variety of yeast genera, including species frequently isolated from grape must such as Hanseniaspora,Metschnikowia,Meyerozyma and Pichia in snail excrements. We typed the isolates using standard ITS-PCR-sequencing, sequenced the genomes of three non-conventional yeasts H. uvarum,Meyerozyma guilliermondii and P. kudriavzevii and characterized the fermentation performance of these three strains in grape must highlighting their potential to contribute to novel beverage fermentations. Aggravatingly, however,we also retrieved several human fungal pathogen isolates from snail excrements belonging to the Candida clade, namely Ca. glabrata and Ca. lusitaniae. Overall, our results indicate that diverse yeasts can utilise snails as taxis for dispersal. This courier service may be largely non-selective and thus depend on the diet available to the snails. [ABSTRACT FROM AUTHOR]

In the wine and in the grape must, there is a complex microbial ecosystem that harbours a great diversity of yeast species, amongst other, non-Saccharomyces yeasts (Issatchenkia orientalis, Metschnikowia pulcherrima, Torulaspora delbrueckii, Candida zemplinina and Hanseniaspora spp.). The paper aimed to develop a molecular method for quantifying Hanseniospora populations during the winemaking process. Specific primers and SYBR Green probe have been used for real-time qPCR method and dilutions from a reference strain of Hanseniospara uvarum, it also hs been used for the calibration curve. After the method was developed, it was used to study different samples of grape must and wine, following a natural or controlled fermentation with commercial yeast strains. This study is necessary, useful and shows the relevance of qPCR for studying non-Saccharomyces yeasts in the complex ecosystem of grape must and wine. [ABSTRACT FROM AUTHOR]

Four terroirs where cv. Malvasia Istriana is grown under equal viticultural practices and climatic conditions, but on different soil types, were studied. Grape juice samples were taken during ripening at three grapevine growth stages (S35 – berries begin to colour and enlarge; S36 – berries with intermediate Brix values; and S38 – berries harvest ripe). Malvasia Istriana grape juice showed a specific free amino acids profile during all three grapevine growth stages, where arginine was the most abundant free amino acid, followed by alanine, threonine, tyrosine, aspartic acid, serine, histidine and glutamic acid. Leucine was the least abundant free amino acid on all studied terroirs at all grapevine growth stages. Total free amino acids decreased at S38, compared to both S35 and S36, on all terroirs, except Fiorini terroir where total free amino acids concentration at S38 was significantly lower compared to S36, but significantly higher compared to S35. [ABSTRACT FROM AUTHOR]

Knowledge of the concentration of mineral elements from winemaking products, particularly from the final product is important because of their influence on wine quality. Some metal ions such as iron and copper can induce haze formation and changes in the sensory proprieties of wine. The presence of heavy metals in wine is due to different factors including vineyard soil, agricultural practices (the use of fertilizers and pesticides), and can be at the same time a result of environmental pollution. In addition, the acidity of wine and grape must (freshly pressed grape juice) can dissolve Cr, Cu, Ni, and Zn from winemaking equipment like pumps and taps. As wine is the most widely consumed alcoholic beverage, analytical control of mineral elements content is required during the whole process of wine production, from the grapes used to the final product. In this study the content of micro- and macroelements in grape pomace, yeast sediment, grape must and wine was determined by inductively coupled plasma-mass spectrometry (ICP-MS). Samples of winemaking products originating from five grape varieties were analyzed in four forms in order to determine to what measure the values varied the PCA (Principal component analysis). The obtained results using PCA highlighted major differences in the content in trace elements between samples.

Starmerella bacillaris (synonym Candida zemplinina) is a non-Saccharomyces yeast species, frequently found in enological ecosystems. Peculiar aspects of the genetics and metabolism of this yeast species, as well as potential industrial applications of isolated indigenous S. bacillaris strains worldwide, have recently been explored. In this review, we summarize relevant observations from studies conducted on standard laboratory and indigenous isolated S. bacillaris strains.

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Highlights • FT-NIR technique can be used to evaluate calcium content in must and wine. • To overcome the wine matrix effect, samples should be pre-treated before AAS analysis. • Dry ashing mineralisation is an adequate sample pre-treatment procedure. • Calcium content in wine is well correlated with calcium content in grape must. Abstract Calcium content in sparkling wines may not exceed 80 mg/L due to the risk of aggregation with alginate capsules. The high calcium content usually found in wine and must emphasizes the need to develop alternative and appropriate techniques faster and cleaner than atomic absorption spectrometry (AAS). To obtain a robust model to predict calcium content, FT-NIR spectroscopy was used in 98 base white wine samples and 60 must samples from an Alentejo winery. The reference method for calcium determination was AAS technique, with a dry ashing sample procedure, as a prior treatment. Results confirmed the ability of FT-NIR as an alternative technique to AAS, to predict calcium content in grape must and base wine. Advance knowledge of the calcium content in the grape must will help avoid obtaining a mixture of musts with a high calcium content in the same container. [ABSTRACT FROM AUTHOR]

Yeasts are unicellular fungi that harbour a large biodiversity of thousands of species, of which particularly ascomycetous yeasts are instrumental to human food and beverage production. There is already a large body of evidence showing that insects play an important role for yeast ecology, for their dispersal to new habitats and for breeding and overwintering opportunities. Here, we sought to investigate a potential role of the terrestrial snails Cepaea hortensis and C. nemoralis, which in Europe are often found in association with human settlements and gardens, in yeast ecology. Surprisingly, even in a relatively limited culture-dependent sampling size of over 150 isolates, we found a variety of yeast genera, including species frequently isolated from grape must such as Hanseniaspora, Metschnikowia, Meyerozyma and Pichia in snail excrements. We typed the isolates using standard ITS-PCR-sequencing, sequenced the genomes of three non-conventional yeasts H. uvarum, Meyerozyma guilliermondii and P. kudriavzevii and characterized the fermentation performance of these three strains in grape must highlighting their potential to contribute to novel beverage fermentations. Aggravatingly, however, we also retrieved several human fungal pathogen isolates from snail excrements belonging to the Candida clade, namely Ca. glabrata and Ca. lusitaniae. Overall, our results indicate that diverse yeasts can utilise snails as taxis for dispersal. This courier service may be largely non-selective and thus depend on the diet available to the snails.

Autochthonous microorganisms are an important source of the distinctive metabolites that influence the chemical profile of wine. However, little is known about the diversity of fungal communities associated with grape musts, even though they are the source of local yeast strains with potential capacities to become starters during fermentation. By using internal transcribed spacer (ITS) amplicon sequencing, we identified the taxonomic structure of the yeast community in unfermented and fermented musts of a typical Vitis vinifera L. var. Sauvignon blanc from the Central Valley of Chile throughout two consecutive seasons of production. Unsurprisingly, Saccharomyces represented the most abundant fungal genus in unfermented and fermented musts, mainly due to the contribution of S. uvarum (42.7%) and S. cerevisiae (80%). Unfermented musts were highly variable between seasons and showed higher values of fungal diversity than fermented musts. Since microbial physiological characterization is primarily achieved in culture, we isolated nine species belonging to six genera of fungi from the unfermented must samples. All isolates were characterized for their potential capacities to be used as new starters in wine. Remarkably, only Metschnikowia pulcherrima could co-exist with a commercial Saccharomyces cerevisiae strain under fermentative conditions, representing a feasible candidate strain for wine production.