Organoleptic Properties Of Wine Research Articles

Potential Use of Torulaspora delbrueckii As a New Source of Mannoproteins of Oenological Interest.

In this work, three MP extracts obtained from Torulaspora delbrueckii were added to red wine, and the changes in phenolic composition, color, and astringency were evaluated by HPLC-DAD-ESI-MS, tristimulus colorimetry, and sensory analysis, respectively. The MP extracts modified wine phenolic composition differently depending on the type of MP. Moreover, two MP extracts were able to reduce wine astringency. The fact that the MP-treated wines showed an increased flavanol content suggests the formation of MP-flavanol aggregates that remain in solution. Furthermore, the formation of these aggregates may hinder the interaction of flavanols with salivary proteins in the mouth. The effect of these MPs might be associated with their larger size, which could influence their ability to bind flavanols and salivary proteins. However, one of the astringent-modulating MPs also produced a loss of color, highlighting the importance of assessing the overall impact of MPs on the organoleptic properties of wine.

Yeast mannoproteins: Organoleptic modulating functions, mechanisms, and product development trends in winemaking

AbstractMannoproteins (MPs) originate from yeast cells and can play important roles in maintaining wine stability and modulating wine organoleptic properties. Due to their natural presence in wines, MP products are allowed to be used as enological additives in wine industry. To guarantee an appropriate application of these products during winemaking, it is necessary for both researchers and winemakers to understand the mechanisms of MPs as multifunctional organoleptic modulators. This review has introduced the current state of knowledge of the researches focus on the application of different MP products in red wines and also the interactions between MPs and wine sensory active components (polyphenols, aroma compounds) in model wine solutions. We have summarized the possible mechanisms of MPs that affect the color, astringency, and aroma of red wines and the relationship between the physicochemical characteristics and functionalities of MPs. Besides, development trends of MP products are also discussed. It seems that yeast biomass, especially those from non‐Saccharomyces yeasts show good potential in producing large quantities of MPs, an appropriate combination of yeast cultivation and preservation methods with extraction and purification techniques may obtain MPs of ideal production, purity, and functionality in an industrial scale, which should be put more efforts by both scientists and manufacturers in the future.

Sulphate Uptake Plays a Major Role in the Production of Sulphur Dioxide by Yeast Cells during Oenological Fermentations

Sulphur dioxide (SO2) is mostly used as an antioxidant additive in winemaking, but excessive levels may be harmful to both wine quality and consumers health. During fermentation, yeast Saccharomyces cerevisiae contributes significantly to final SO2 levels, and low-producing strains become especially interesting for the wine industry. Recent evidence implicating the impairment of sulphate transport in the SO2 decrease prompted us to further investigate the sulphate/sulphite metabolic connection in multiple winery yeast strains. Here, we inactivated by CRISPR/Cas9 the high-affinity sulphate permeases (Sul1p and Sul2p) in four strains normally used in winemaking, selected by their different abilities to produce SO2. Mutant strains were then used to perform fermentation assays in different types of natural must, and the final levels of SO2 and other secondary metabolites, crucial for wine organoleptic properties, were further determined for all fermentation products. Overall, data demonstrated the double ΔSUL1/ΔSUL2 inactivation in winery strains significantly decreases the levels of SO2 produced by mutant cells, without however altering both yeast fermentative properties and the ability to release relevant metabolites. Since similar effects were observed in diverse must types for strains with different features, the data strongly support that sulphate assimilation is the determining factor in SO2 production during oenological fermentations.

Isolation, Characterization, and Compositional Analysis of Polysaccharides from Pinot Noir Wines: An Exploratory Study

It has been reported that polysaccharides in wine can interact with tannins and other wine components and modify the sensory properties of the wine. Unfortunately, the contribution of polysaccharides to wine quality is poorly understood, mainly due to their complicated structure and varied composition. In addition, the composition and molecular structure of polysaccharides in different wines can vary greatly. In this study, the polysaccharides were isolated from pinot noir wine, then separated into high-molecular-weight (PNWP-H) and low-molecular-weight (PNWP-L) fractions using membrane-based ultrafiltration. Each polysaccharide fraction was further studied using size exclusion chromatography, UV-Vis, FT-IR, matrix-assisted laser desorption/ionization-high-resolution mass spectrometry, and gas chromatography-mass spectrometry (GC-MS). The results showed that PNWP-L and PNWP-H had different chemical properties and compositions. The FT-IR analysis showed that PNWPs were acidic polysaccharides with α- and β-type glycosidic linkages. PNWP-L and PNWP-H had different α- and β-type glycosidic linkage structures. FT-IR showed stronger antisymmetric and symmetric stretching vibrations of carboxylate anions of uronic acids in PNWP-L, suggesting more uronic acid in PNWP-L. The size exclusion chromatography results showed that over 72% of the PNWP-H fraction had molecular sizes from 25 kDa to 670 kDa. Only a small percentage of smaller molecular polysaccharides was found in the PNWP-H fraction. In comparison, all of the polysaccharides in the PNWP-L fraction were below 25 KDa, with a majority distributed approximately 6 kDa (95.1%). GC-MS sugar composition analysis showed that PNWP-L was mainly composed of galacturonic acid, rhamnose, galactose, and arabinose, while PNWP-H was mainly composed of mannose, arabinose, and galactose. The molecular size distribution and sugar composition analysis suggested that the PNWP-L primarily consisted of rhamnogalacturonans and polysaccharides rich in arabinose and galactose (PRAG). In comparison, PNWP-H were mostly mannoproteins and polysaccharides rich in arabinose and galactose (PRAG). Further research is needed to understand the impacts of these fractions on wine organoleptic properties.

Effects of Blending on Phenolic, Colour, Antioxidant and Aroma Components of Cabernet Sauvignon Wine from Xinjiang (China).

High-quality wines in industrial winemaking frequently require a professional winemaker to make adjustments according to the wine of single-batch fermentation. Blending can improve the chemical composition and certain organoleptic properties of wine, promote copigmentation, and increase the complexity of the wine body and aroma. In this study, high-performance liquid chromatography (HPLC) and headspace solid-phase microextraction with gas chromatography coupled to tandem mass spectrometry (HS-SPME-GC-MS/MS) were used to study the effects of adding 20% of Merlot, Marselan, Syrah and Pinot Noir and different blending methods on the nutritional, taste, color and aroma components of Cabernet Sauvignon wine. The results showed that the highest total phenols and flavonoids, the greatest content of antioxidant characteristics, the optimal color according to the parameter of T, red% and blue% and the most abundant aroma were observed both in CGM (grape blending Cabernet Sauvignon and Merlot) and CGS (grape blending Cabernet Sauvignon and Marselan), thus indicating the higher quality and complexity of these wines. In addition, the co-grapes treatment afforded more color and hue value than co-wines, which indicates co-grapes had more stable and more varied colors than co-wines. Our findings provide theoretical support for improving wine quality and craftsmanship.

Recombinant Thaumatin-Like Protein (rTLP) and Chitinase (rCHI) from Vitis vinifera as Models for Wine Haze Formation.

Cross-linking net aggregates of thermolabile thaumatin-like proteins (TLPs) and chitinases (CHIs) are the primary source of haze in white wines. Although bentonite fining is still routinely used in winemaking, alternative methods to selectively remove haze proteins without affecting wine organoleptic properties are needed. The availability of pure TLPs and CHIs would facilitate the research for the identification of such technological advances. Therefore, we proposed the usage of recombinant TLP (rTLP) and CHI (rCHI), expressed by Komagataella phaffii, as haze-protein models, since they showed similar characteristics (aggregation potential, melting point, functionality, glycosylation levels and bentonite adsorption) to the native-haze proteins from Vitis vinifera. Hence, rTLP and rCHI can be applied to study haze formation mechanisms on a molecular level and to explore alternative fining methods by screening proteolytic enzymes and ideal adsorptive resins.

Species-Dependent Metabolic Response to Lipid Mixtures in Wine Yeasts.

Lipids are essential energy storage compounds and are the core structural elements of all biological membranes. During wine alcoholic fermentation, the ability of yeasts to adjust the lipid composition of the plasma membrane partly determines their ability to cope with various fermentation-related stresses, including elevated levels of ethanol and the presence of weak acids. In addition, the lipid composition of grape juice also impacts the production of many wine-relevant aromatic compounds. Several studies have evaluated the impact of lipids and of their metabolism on fermentation performance and aroma production in the dominant wine yeast Saccharomyces cerevisiae, but limited information is available on other yeast species. Thus, the aim of this study was to evaluate the influence of specific fatty acid and sterol mixtures on various non-Saccharomyces yeast fermentation rates and the production of primary fermentation metabolites. The data show that the response to different lipid mixtures is species-dependent. For Metschnikowia pulcherrima, a slight increase in carbon dioxide production was observed in media enriched with unsaturated fatty acids whereas Kluyveromyces marxianus fermented significantly better in synthetic media containing a higher concentration of polyunsaturated fatty acids than monounsaturated fatty acids. Torulaspora delbrueckii fermentation rate increased in media supplemented with lipids present at an equimolar concentration. The data indicate that these different responses may be linked to variations in the lipid profile of these yeasts and divergent metabolic activities, in particular the regulation of acetyl-CoA metabolism. Finally, the results suggest that the yeast metabolic footprint and ultimately the wine organoleptic properties could be optimized via species-specific lipid adjustments.

Sensory characterisation of Cognac eaux-de-vie aged in barrels subjected to different toasting processes

Toasting is a key step in the barrel-making process. It plays an important role in the breakdown of oak wood compounds and thus influences the chemical composition and organoleptic properties of wines and brandies. However, the effect of toasting on distilled spirit quality has not yet been extensively studied. The objective of this study was therefore to study the impact of toasting on cognac eaux-de-vie by characterising the eaux-de-vie sensorially after 12 months of ageing. Eight eaux-de-vie aged in barrels with 8 different toasts were studied. The 8 toasts represented 4 different temperatures (low, medium, medium plus and high) and two toasting lengths for each temperature (one so-called “normal” and the other “slow”). Sensory analysis was carried out on these eaux-de-vie through several tests. First, a sorting test showed the differences between the samples and then training was carried out on previously chosen descriptors in order to build a sensory profile and perform a ranking test. The study was realised for two alcohol levels: 60 % (v/v), which is the alcohol level of eaux-de-vie in barrels, and 40 % (v/v), which is the alcohol level of a commercial cognac. This approach demonstrated that barrel toasting generally leads to significant sensorial differences in eaux-de-vie during ageing. These differences are greater between a lightly and a highly toasted barrel. This study is a first step in the characterisation of cognac eaux-de-vie aged in barrels made with different toasts.

The effect of growth rate on the production and vitality of non-Saccharomyces wine yeast in aerobic fed-batch culture.

Non-Saccharomyces wine yeasts are of increasing importance due to their influence on the organoleptic properties of wine and thus the factors influencing the biomass production of these yeasts, as starter cultures, are of commercial value. Therefore, the effects of growth rates on the biomass yield (Yx/s) and fermentation performance of non-Saccharomyces yeasts at bench and pilot scale were examined. The fermentative performance and (Yx/s) were optimised, in aerobic fed-batch cultivations, to produce commercial wine seed cultures of Lachancea thermotolerans Y1240, Issatchenkia orientalis Y1161 and Metschnikowia pulcherrima Y1337. Saccharomyces cerevisiae (Lalvin EC1118) was used as a benchmark. A Crabtree positive response was shown by L. thermotolerans in a molasses-based industrial medium, at growth rates exceeding 0.21h-1 (µcrit), resulting in a Yx/s of 0.76g/g at 0.21h-1 (46% of µmax) in the aerobic bioreactor-grown fed-batch culture at bench scale. At pilot scale and 0.133h-1 (36% of µmax), this yeast exhibited ethanol concentrations reaching 10.61g/l, as a possible result of substrate gradients. Crabtree negative responses were observed for I. orientalis and M. pulcherrima resulting in Yx/s of 0.83g/g and 0.68g/g, respectively, below 32% of µmax. The Yx/s of M. pulcherrima, I. orientalis and L. thermotolerans was maximised at growth rates between 0.10 and 0.12h-1 and the fermentative capacity of these yeasts was maximised at these lower growth rates.

Unique volatile chemical profiles produced by indigenous and commercial strains of <i>Saccharomyces uvarum</i> and <i>Saccharomyces cerevisiae</i> during laboratory-scale Chardonnay fermentations

Each wine growing region hosts unique communities of indigenous yeast species, which may enter fermentation and contribute to the final flavour profile of wines. One of these species, Saccharomyces uvarum, is typically described as a cryotolerant yeast that produces relatively high levels of glycerol and rose-scented volatile compounds as compared with Saccharomyces cerevisiae, the main yeast in winemaking. Comparisons of fermentative and chemical properties between S. uvarum and S. cerevisiae at the species level are relatively common; however, a paucity of information has been collected on the potential variability present among S. uvarum strains. The objective of this study was to compare the fermentation kinetics and production of volatile compounds between indigenous and commercial Saccharomyces strains at different temperatures. We compared laboratory-scale fermentation of Chardonnay juice at 15 °C and 25 °C for 11 Saccharomyces yeast strains (six indigenous S. uvarum, one commercial S. uvarum, one indigenous S. cerevisiae and three commercial S. cerevisiae). Fermentation kinetics and the production of volatile compounds known to affect the organoleptic properties of wine were determined. The indigenous S. uvarum strains showed comparable kinetics to commercially sourced strains at both temperatures. Volatile compound production among the strains was more variable at 15 °C and resulted in unique chemical profiles at 15 °C as compared with 25 °C. Indigenous S. uvarum strains produced relatively high levels of 2-phenylethyl acetate and 2-phenylethanol, whereas these compounds were found at much lower levels in fermentations conducted by commercial strains of both S. cerevisiae and S. uvarum. Production of glycerol by indigenous S. uvarum strains did not differ from commercial strains in this study. Our findings demonstrate that indigenous strains of S. uvarum show functional variation among themselves. However, when compared with commercial S. cerevisiae and S. uvarum strains, they have comparable fermentation kinetics but unique volatile compound profiles, especially at low fermentation temperatures.

Impact of High-Power Ultrasound for Barrel Regeneration on the Extraction of Wood Volatile and Non-Volatile Compounds

High-power ultrasound (HPU) is an innovative cleaning method used in wineries for oak barrel sanitation and regeneration. The process is associated with hot water (HPUhw) to ensure microbial stabilization and has been proved to be highly effective in recent years. This study thus examines the impact of different cleaning treatments on the subsequent extraction of wood compounds in wine and their impact on organoleptic properties. Red wines aging in barrels treated (HPUhw and steam) in different years (1, 2, and 3 years) were examined during the first 12 months for chemical exchange from wood to wine. Specific analyses were realized on ellagitannins, the physicochemical composition, and oak wood volatile compounds. Only a small increase in some wood volatile compounds occurred in the case of HPUhw, including furfural, 5-methylfurfural, trans-whisky lactone, vanillin, and syringaldehyde. The sensory analysis carried out by a panel of experts showed that the impact on the organoleptic properties of wines is similar with both processes (HPUhw and steam). However, since HPUhw treatment requires lower energy for the same efficiency, it could be an interesting alternative to steam treatment, given the promising prior microbial results.

Assessment of the influence of foliar treatment on productivity and phenolic maturity of grapes

An urgent task of today for grape growers is to find effective ways to achieve the compliance of conditional parameters to phenolic ripeness of grapes while maintaining high cropping capacity. In this study the influence of foliar treatment of grapes with nitrogen-containing preparations "Siamino Pro 500" on productivity and phenolic maturity of ‘Cabernet-Sauvignon’ grape variety was investigated. Studies were carried out during 2018-2019. Grape maturity degree was assessed by the Glories method, based on the determining of the total and extractable anthocyanin potential of grapes. It was shown that, as a result of the experimental scheme of processing, the cropping capacity increased by 10- 14%, as well as the bunch weight - by 13 - 16%. Use of the preparation contributed to the onset of technical maturity of grapes at the earlier period compared to the control. The content of anthocyanins extracted from the skins was 49- 56%. Experimental grape samples were characterized by a higher content of titratable acids (by 1.4 and 1.2 g/l) and a lower sugar accumulation (by 9 and 16 g/l). Positive influence of the experimental scheme of processing on organoleptic properties of wines was observed.

Influence of simulated grape crushing process on phenolic compounds extraction, astringency and color of Cabernet Sauvignon model wine

Phenolic compounds extracted from grapes play a decisive role on organoleptic properties of wine, especially wine astringency and color. In this study, the skins and seeds of Cabernet Sauvignon grape were implemented 4 physical treatments (tearing, shearing, rubbing and squeezing) to simulate mechanical damage caused by crusher or de-stemmer in the process of industrial wine production. Equivalent weight of treated grape skins (14.79%) or seeds (6.11%) separated from grapes were added into pre-prepared synthetic wine to simulate the maceration for 14 days to obtain the model wines. Polyphenolic components, astringency and color index as well as sensory evaluation of model wines were then analyzed. The results indicated that 4 physical treatments led to an increase of the mean degree of polymerization and percentage of galloylation of proanthocyanidin in model wines. A significant increase of b* value of model wine by the rubbing or squeezing treatment on both skins and seeds was detected, despite of no significant difference of total anthocyanin in skin model wines. The physical treated skins and seeds gave model wine a more effective capacity in precipitating proteins, indicating a stronger astringency potential, among which the rub treatment strengthened the most of astringency perceptions.

Autophagic Proteome in Two Saccharomyces cerevisiae Strains During Second Fermentation for Sparkling Wine Elaboration.

A correlation between autophagy and autolysis has been proposed in order to accelerate the acquisition of wine organoleptic properties during sparkling wine elaboration. In this context, a proteomic analysis was carried out in two industrial Saccharomyces cerevisiae strains (P29, conventional sparkling wine strain and G1, implicated in sherry wine elaboration) with the aim of studying the autophagy-related proteome and comparing the effect of CO2 overpressure during sparkling wine elaboration. In general, a detrimental effect of pressure and second fermentation development on autophagy-related proteome was observed in both strains, although it was more pronounced in flor yeast strain G1. Proteins mainly involved in autophagy regulation and autophagosome formation in flor yeast G1, and those required for vesicle nucleation and expansion in P29 strain, highlighted in sealed bottle. Proteins Sec2 and Sec18 were detected 3-fold under pressure conditions in P29 and G1 strains, respectively. Moreover, ‘fingerprinting’ obtained from multivariate data analysis established differences in autophagy-related proteome between strains and conditions. Further research is needed to achieve more solid conclusions and design strategies to promote autophagy for an accelerated autolysis, thus reducing cost and time production, as well as acquisition of good organoleptic properties.

Effect of endogenous CO2 overpressure on the yeast “stressome” during the “prise de mousse” of sparkling wine

Sparkling wines elaboration by the “Champenoise” method involves a second fermentation of a base wine in hermetically sealed bottles and a subsequent aging period. The whole process is known as “prise de mousse”. The endogenous CO2 pressure produced during the second fermentation by the yeast Saccharomyces cerevisiae could modify the sub-proteome involved in the response to different stresses, or “stressome”, and cell viability thus affecting the wine organoleptic properties. This study focuses on the stressome evolution along the prise de mousse under CO2 overpressure conditions in an industrial S. cerevisiae strain. The results reveal an important effect of endogenous CO2 overpressure on the stress sub-proteome, cell viability and metabolites such as glycerol, reducing sugars and ethanol. Whereas the content of glycerol biosynthesis-related proteins increased in sealed bottle, those involved in the response to toxic metabolites like ROS, ethanol, acetaldehyde and acetic acid, decreased in content. Proteomic profile obtained in this study may be used to select suitable wine yeast strains for sparkling wine elaboration and improve their stress tolerance.

Unravelling the scientific research on grape and wine phenolic compounds: a bibliometric study

The antioxidant nature and the significant role played by phenolic compounds in wine organoleptic properties place these molecules in the core of a significant amount of viticulture and oenology research. Despite the large amount of grape and wine phenolic research, the understanding of the phenolic chemistry and its role played on wine quality still remains inconclusive. Bibliometric studies are a valuable tool to provide a critical evaluation of the research status of a specified topic. The evaluation of quantitative methods is used to process measurable outcomes of research activity from articles published in scientific journals and included in databases. The main aim of this study was thus to provide a bibliometric approach on phenolic compounds with an exclusive focus on grape and wine phenolics from a strictly winegrowing and winemaking perspective. To evaluate the scientific structure in phenolic compounds a bibliometric search using the Web of Science Core Collection platform from Clarivate Analytics was evaluated. The critical evaluation of the results showed a significant effort made towards the understanding of the organoleptic role played by phenolic compounds. Despite a considerable amount of research currently available, it is foreseen that the research efforts will move towards a more complete interpretation of the astringency and bitterness phenomena. Furthermore, it can also be speculated that future research topics will point towards the comprehension of wine flavour compounds in which phenolic substances are also expected to play a crucial role.

Mixed culture fermentation using Torulaspora delbrueckii and Saccharomyces cerevisiae with direct and indirect contact: impact of anaerobic growth factors

The role of the initial concentration of anaerobic growth factors (AGF) on interactions between Torulaspora delbrueckii and Saccharomyces cerevisiae was investigated in strict anaerobiosis. Experiments were performed in a synthetic grape must medium in a membrane bioreactor, a special tool designed for studying direct and indirect interactions between microorganisms. In pure culture fermentations, increased AGF concentration had no impact on S. cerevisiae behaviour, whereas it induced an extension of T. delbrueckii latency. Surprisingly, T. delbrueckii used only 75 to 80% of the consumed sugar to produce biomass, glycerol and ethanol. Physical separation influenced the population dynamics of co-fermentations. S.cerevisiae dominated the co-cultures having a single dose of AGF as its presence indirectly induced a decrease in numbers of living T. delbrueckii cells and physical contact with T. delbrueckii stimulated S.cerevisiae growth. Increasing the AGF initial concentration completely upset this domination: S. cerevisiae growth was not stimulated and T. delbrueckii living cells did not decrease. Yeasts incorporate exogenous AGFs, which probably impact their response to competing yeasts. The increase in AGF might have induced changes in the lipid composition of the T. delbrueckii membrane, which would hinder its interaction with S. cerevisiae antimicrobial peptides. The initial concentration of anaerobic growth factors influenced co-culture fermentation population dynamics tremendously, thus highlighting a new way to monitor population evolution and eventually wine organoleptic properties.

Non-canonical regulation of glutathione and trehalose biosynthesis characterizes non-Saccharomyces wine yeasts with poor performance in active dry yeast production.

Several yeast species, belonging to Saccharomyces and non-Saccharomyces genera, play fundamental roles during spontaneous must grape fermentation, and recent studies have shown that mixed fermentations, co-inoculated with S. cerevisiae and non-Saccharomyces strains, can improve wine organoleptic properties. During active dry yeast (ADY) production, antioxidant systems play an essential role in yeast survival and vitality as both biomass propagation and dehydration cause cellular oxidative stress and negatively affect technological performance. Mechanisms for adaptation and resistance to desiccation have been described for S. cerevisiae, but no data are available on the physiology and oxidative stress response of non-Saccharomyces wine yeasts and their potential impact on ADY production. In this study we analyzed the oxidative stress response in several non-Saccharomyces yeast species by measuring the activity of reactive oxygen species (ROS) scavenging enzymes, e.g., catalase and glutathione reductase, accumulation of protective metabolites, e.g., trehalose and reduced glutathione (GSH), and lipid and protein oxidation levels. Our data suggest that non-canonical regulation of glutathione and trehalose biosynthesis could cause poor fermentative performance after ADY production, as it corroborates the corrective effect of antioxidant treatments, during biomass propagation, with both pure chemicals and food-grade argan oil.

Methyl jasmonate: effect on proanthocyanidin content in Monastrell and Tempranillo grapes and wines

Proanthocyanidins or “condensed tannins” play an important role in the organoleptic properties of wines, and their levels in both grapes and wines can be achieved by several means. One such way is based on the use of elicitors, agrochemicals which were originally designed to improve resistance to plant pathogens, but whose action mechanism has also been found to increase polyphenol levels. Among these chemical elicitors, jasmonic acid and, especially, its methyl ester, methyl jasmonate (MeJ), can increase the production of secondary metabolites such as anthocyanins, flavonoids, phenolic acids, and other antioxidant molecules, enhancing the fruit quality and post-harvest life, as well as increasing their health-related properties. The objective of this study was to determine whether the application during two consecutive years of MeJ to Monastrell and Tempranillo varieties at the veraison period had any effect on the accumulation of proanthocyanidins and subsequently on their extractability into wine. The results obtained indicated that treatments increased the grape proanthocyanidin content only in one of the years but for both varieties tested, as well as their levels in the corresponding wines.

Linking microbial community on grapes from two Portuguese wine regions to the biogenic amines production in musts

Grapevine-associated microbiota influences wine organoleptic properties. Spoilage due to undesired microorganisms and biogenic amines (BAs) presence are two main constrains that must be seriously considered. In wine, BAs can originate from the grape berries or can be produced during fermentation, ageing or storage. This work aimed to understand if the high BAs levels observed in musts can have its origin in the microbial community present on grapes. The following methodologies were done: bacterial and fungal grapes communities' isolation, BAs quantification in grapes and musts and molecular amplification of the genes related to BAs production. For comparative purposes, microbial communities from grapes and musts from Douro (low BAs levels in musts) and Alentejo (high BAs levels in musts) were used. Higher number and diversity of bacteria were observed in Alentejo grapes comparatively to Douro ones. Filamentous fungi were predominant when compared with yeasts and the diversity was higher in Alentejo. BAs levels mainly due to putrescin were about ten times higher in grapes and musts from Alentejo. As bacteria isolated from Alentejo grapes showed a great BAs-production potential, namely putrescin, our results suggest a bacterial grape origin for the high putrescine levels found in fresh musts of this region.