Vinification Process Research Articles

Yeast strain effect on the concentration of major volatile compounds and sensory profile of wines from Vitis vinifera var. Treixadura

The fermentative ability of five Saccharomyces cerevisiae strains and their influence on the aroma and sensory properties of wine from Treixadura were evaluated to determine the most suitable yeast that produces a high quality wine from this grapevine variety. The results indicated that all strains, except T2, were able to lead the vinification process and have good fermentative powers. The chemical composition of wines obtained with resident cellar yeasts consisted of a significant amount of glycerol, a compound that contributes to the structure and smoothness in taste of the wine. In addition, these strains were good producers of acetates, ethyl esters and fatty acids, compounds that positively influence wine aroma. Compounds with a direct contribution to the aroma of Treixadura wines (Odour Activity Value >1) included 2-methyl-1-butanol, 3-methyl-1-butanol, 2-phenylethanol, isoamyl and ethyl acetate and the ethyl esters, ethyl butyrate, ethyl hexanoate, ethyl octanoate and ethyl decanoate. Sensory analysis supported the fact that cellar strains produced more fruity and floral wines than commercial or spontaneous fermentations. We conclude that resident cellar yeasts enhanced sensory quality of wines from Treixadura.

Selenium biotransformation by Saccharomyces cerevisiae and Saccharomyces bayanus during white wine manufacture: Laboratory-scale experiments

The main purpose of this laboratory-scale study was to evaluate the transformation of inorganic selenium, as sodium selenite, when added to white grape juice as part of the fermentation process of white wine. The participation of yeast, added in the fermentation of the must, is necessary to convert inorganic selenium into organoseleno species. Two different yeasts, Saccharomyces cerevisiae and Saccharomyces bayanus were used for fermentation. The effects of different Se concentrations on cells and their viability during fermentation were evaluated. The alcoholic fermentation that produced wine was not affected by the presence of selenium, regardless of the type of Saccharomyces used. After 21 days of fermentation, the white wine and residual yeast were separated and analysed by ICP-MS and LC–ICP-MS for determination of total selenium and speciation. Selenomethionine was found to be the main Se-species in the selenised white wine. The results obtained are preliminary but they could be considered for future studies using both pilot and full-scale vinification processes.

Presence of non- Saccharomyces yeasts in cellar equipment and grape juice during harvest time

The purpose of this study was to analyze the presence of different yeasts in the facilities of four wineries from the D.O.Ca. Rioja region in Spain. The study was conducted through the identification of the yeasts via the PCR-RFLP technique of the ITS region of rDNA. The diversity of non- Saccharomyces yeasts found in wineries has previously only been studied to a limited extent, despite the fact that these yeasts take part both in the start of spontaneous fermentation and in the changes which occur in the wines during their subsequent conservation. Most earlier studies carried out on cellar ecosystems have focussed on the clonal diversity of Saccharomyces cerevisiae. The results obtained in this study indicated that the presence of non- Saccharomyces yeasts in facilities is higher than that of the S. cerevisiae, with percentages of over 60% in all the wineries analyzed. Yeasts belonging to 10 genera and 18 species were isolated, but the only genera present in all four wineries were Cryptococcus, Pichia, and Saccharomyces. The Zygosaccharomyces bailii yeast responsible for taint was detected in one cleaned winery, in both the winemaking equipment and the fermenting must. It was also noted that the quantity and type of yeasts present in the facilities are related to the product used for cleaning them. It is also necessary to point out that the cleaning of the cellars prior to the reception of the grapes does not completely eliminate the yeasts present, so that these can subsequently become part of the vinification process.

Ethyl carbamate content in wines with malolactic fermentation induced at different points in the vinification process

Ethyl carbamate (EC) is a carcinogenic compound found in fermented food and beverages such as wine. Although its carcinogenic potential in animals is known, information regarding its effects in humans remains insufficient, thus there is increasing interest in its research. EC content is higher in products with high alcohol content and in aged products. The main precursor involved in EC production in wine is urea, which is produced by metabolism of arginine by yeast, but there is also evidence that EC levels can increase after malolactic fermentation (MLF). Some lactic acid bacteria (LAB) can degrade the arginine present in must and wine via the arginine deiminase pathway, producing citrulline and carbamyl phosphate. Both compounds can react with ethanol in acidic conditions and produce EC. Our research group is studying the influence of MLF induced at different points of wine-making on the quality of the resulting wine. Among other parameters, the content of toxic compounds such as EC was evaluated. Results so far indicate that EC levels at the end of MLF were quite low (less than 3 μg/l) in all cases, i.e. below the existing legal limit (e.g. 30 μg/l in Canada). In almost all wines, EC concentrations increased after 8 months of storage as has been described by other authors. In some of the wines in which MLF was carried out by selected LAB, the increase in EC concentration was lower.

Pesticide residues in grapes and during vinification process

Pesticide residues in vinification process of two white and two red grapevine varieties were monitored during the 2007 vintage. Crushed grapes, cake, must, lees and wine were sampled during the vinification process. Additionally, grapes were sampled during the ripening process. All samples were taken in triplicate and analyzed for the presence of 117 pesticides. The pesticide residues were determined by three validated internal analytical methods: the multi-residual GC-MS method (71 pesticides), the multi-residual LC-MS-MS method (45 pesticides) and GC-MS method for the determination of dithiocarbamates (the sum of their concentrations is given as a concentration of carbon disulfide). Boscalid and phosalone were the most persistent pesticides in grapes during ripening. The concentrations of pesticide residues in must and wine were significantly diminished through separations during the solid and liquid phases of the vinification process, particularly the pressing of crushed grapes and wine racking after alcoholic fermentation. The pesticides detected throughout the vinification process were boscalid, cyprodinil, dimethomorph, fenhexamid, metalaxyl and procymidone and their concentrations in the wines were 0.01–0.02, 0.04, 0.01–0.08, 0.12–0.13, 0.09–0.11 and 0.07–0.13 mg L −1 respectively.

Efficacy of new commercial formulations to control downy mildew and dissipation of their active fungicides in wine after good agricultural practices

AbstractBACKGROUND: The efficacy of common fungicides to control downy mildew (Plasmopara viticola) in vines decreases when the same commercial formulations are applied over several years. For this reason, new commercial formulations (containing new fungicides) have to offer to grape‐growers to increase the efficacy of antifungal treatments. The efficacy of five new commercial formulations (Cabrio Top, Equation Pro, Fantic M, Mikal Premium and Fobeci) to control downy mildew in an experimental vineyard producing white grapes (Vitis vinifera cv. Godello) was studied. All these products have in common a new fungicide (pyraclostrobin, famoxadone, benalaxyl‐M, iprovalicarb and benalaxyl, respectively) in their chemical formulation.RESULTS: Two commercial formulations, Cabrio Top and Fobeci, gave the highest efficacy to control this fungal disease. Once treated white grapes were harvested, the fate of these fungicides from vine to wine was studied. The white winemaking process allowed the dissipation of fungicide residues in high percentages (∼95%), except for iprovalicarb (45%). Concentrations in final filtered white wines were close to or lower than 0.01 mg L−1 for all detected fungicides except iprovalicarb and fludioxonil. The following dissipation rate was found: famoxadone > cyprodinil > pyraclostrobin > benalaxyl > folpet > fludioxonil > benalaxyl‐M > penconazole > iprovalicarb.CONCLUSION: From the data obtained in the vinification process, estimated maximum residue levels for white wines were proposed for future EU legislation to control the presence of pesticides in white wines. Thereby one helps to assure also the wine quality and protection of consumer health. Copyright © 2009 Society of Chemical Industry

Evaluation of Lysozyme to Control Vinification Process and Histamine Production in Rioja Wines

Lysozyme and the reduction of metabisulfite addition to red wine were evaluated during a winemaking process and after malolactic fermentation (MLF). Treatment, with lysozyme, of the must from Tempranillo grapes and at the end of alcoholic fermentation (AF) caused the 100% implantation of the inoculated bacterial strain and shortened the duration of MLF by 7 days. At the end of the MLF, wines treated with lysozyme showed lower volatile acidity, color intensity, and biogenic amine content. The differences in color intensity disappeared during wine stabilization. The lysozyme addition after MLF led to lower histamine concentrations in wines. These phenomena occurred irrespective of the lactic acid bacteria (LAB) proliferation control and of the Oenococcus oeni dominant strain identified at this period. The results of this study show the significance of preventive use of lysozyme in vinification of red wine to maintain low histamine levels and ensure a successful implantation of inoculated Oenococcus oeni starters.

Indigenous yeast communities in the environment of “Rovello bianco” grape variety and their use in commercial white wine fermentation

The indigenous yeast communities associated with several vineyard habitats were analysed. Wild yeasts were isolated, differentiated at strain level and identified. A phylogenetic tree based on partial 26S rRNA genes was constructed. The strains were characterized and the indigenous Saccharomyces cerevisiae GR1 was then used to carry out a vinification process and compared with a commercial yeast. Wines obtained were subjected to chemical and sensory analysis. The comparison between the two products highlighted differences due to the fermenting strains employed. The vineyard environment was found to strongly influence the composition of yeast communities, thus, confirming the theory of ‘terroir’ on the expression of wines. Moreover, vineyard inhabiting birds were in part responsible for the dissemination of fermentative yeasts during their feeding activities.

A moderate consumption of Côtes du Rhône red wines affects the progression of aortic lesions, and reduces oxidative stress and p22phoxNADPH oxidase activation in an experimental model of diet-induced atherosclerosis, according to the vinification process

Cotes du Rhone red wines prepared from both different types of grape and processing were tested in hamsters receiving an atherogenic diet for 12 weeks and a daily gavage with 12% ethanol, red wines from vinification by flash release (GRE FD, SYR FD and BLEND FD), by tanisage (BLEND TAN), by traditional vinification (BLEND), or water as control. Except BLEND TAN, consumption of wines lowered plasma total and LDL-cholesterol. Aortic lipid deposits were reduced by ethanol (30%), wines (54% on average) or BLEND TAN (65%). Cardiac production of superoxide anion decreased from 20% (BLEND and BLEND TAN) to 33% (SYR FD and BLEND FD). The expression of NAD(P)H oxidase decreased by 44% (SYR FD), 26% (BLEND), 47% (BLEND FD) and 44% (BLEND TAN). Except ethanol and GRE FD, wines increased uricemia by 15% on average. These findings indicate that chronic consumption of red wine has potential beneficial effects to prevent the development of atherosclerosis. Prevention of NAD(P)H oxidase induction and preservation of aortic lipids oxidation likely contribute to this effect.

Genetic manipulation of HSP26 and YHR087W stress genes may improve fermentative behaviour in wine yeasts under vinification conditions

Throughout wine production yeast cells are affected by a plethora of stress conditions that compromise their ability to carry out the whole process. In recent years important knowledge about the mechanisms involved in stress response in both laboratory and wine yeast strains has been obtained. Several studies have indicated that a correlation exists between stress resistance, expression of stress response genes and fermentative behaviour. In this work we introduce several genetic manipulations in two genes induced by several stress conditions: HSP26 (which encodes a heat shock protein) and YHR087W (encoding a protein of unknown function) in two different wine yeasts, ICV16 and ICV27. These manipulations include expression in multicopy and centromeric plasmids, and substitution of the promoter in one of the genomic copies of these genes for that of the SPI1 gene, encoding for a cell wall protein of unknown function, or the PGK1 gene, which encodes the phosphoglycerate kinase glycolytic enzyme. Our results indicate that some of these modifications result in strains with higher expression of these genes, better resistance to certain stress conditions, and even improved fermentative behaviour. The modifications of the YHR087W gene are particularly interesting, and suggest an important role of this gene in the vinification process.

Anthocyanins and tannins in four grape varieties (<em>Vitis vinifera</em> L.). Evolution of their content and extractability

<p style="text-align: justify;"><strong>Aims</strong>: The knowledge of parameters as the quantity of anthocyanins and tannins present during grape maturation, their evolution during the ripening period and extractability data could improve the management of red wine fermentation and help predict the color of wines.</p><p style="text-align: justify;"><strong>Methods and results</strong>: Grapes from Vitis vinifera var. Cabernet Sauvignon, Syrah, Merlot and Monastrell were harvested in 2002, 2003 and 2004 from a commercial vineyards and their physicochemical characteristics together with the anthocyanin and tannin evolution during ripening were followed. The results showed that differences were found in the evolution of these compounds due to variety and year.</p><p style="text-align: justify;"><strong>Conclusions</strong>: Some of the studied parameters seemed to be clearly related to variety (berry weight and extractability index) and others seemed to be clearly affected by soil and edaphoclimatic conditions. The high extractability index in Monastrell reflects the difficulty involved in extracting their anthocyanins. The short maturation period observed for Merlot grapes and the high seed tannin index could lead to excessively astringent wines.</p><p style="text-align: justify;"><strong>Significance and impact of the study</strong>: This study demonstrate that the ripening period of some varieties (Merlot) in very warm conditions is too short, promoting the rapid accumulation of sugar in the pulp and an incomplete seed maturation that may lead to excessively astringent wines. Other varieties, e.g. Monastrell, show longer maturation period that usually permits pulp and seed maturity to be reached at the moment of harvest. The extractability index seems to be closely related to the grape variety and this is also an important fact to take into account when planning a vinification process.</p>

Evolution of ochratoxin A content during red and rose vinification

AbstractBACKGROUND: This work aims to investigate the effects of the common vinification steps on the fate of the ochratoxin A (OTA) during wine making. Two assays of red and rose microvinification, with artificially contaminated grapes, were performed. The content of this mycotoxin was also monitored throughout the process of red wine making from naturally contaminated grapes in a winery.RESULTS: The results from the different assays revealed that the maceration of pomace have a significant effect on the increase of OTA content in red wine (P < 0.05) whereas the alcoholic fermentation had a reducing effect. However, the spontaneous malolactic fermentation showed no significant effect on the OTA content in wine (P > 0.05). Storage of red wine in tanks followed by draining caused a significant decrease of OTA of about 55%. Clarification with a gelatin oenological fining agent contributed to the removal of up to 58% of OTA from red wine.CONCLUSION: Overall, a consistent decrease in OTA concentration was noticed throughout either red or rose vinification. This work has contributed to the understanding of the fate of OTA during different vinification processes, especially from naturally contaminated grapes. Copyright © 2008 Society of Chemical Industry

Terpenoids in Grapes and Wines: Origin and Micrometabolism during the Vinification Process

Terpenoids, which are typical components of the essential oils of flowers and fruits, are also present as free and glycosylated conjugates amongst the secondary metabolites of wine grape varieties of Vitis vinifera. Hence, when these compounds are present in wine, they are considered to originate from the grapes and not from fermentation. However, the biosynthesis of monoterpenes by Saccharomyces cerevisiae in the absence of grape derived precursors was shown recently to be of de novo origin in wine yeast strains. The contribution of yeast and bacterial fermentation metabolites to the aromatic profile of wine is well documented. However, the biotechnological application of this knowledge is still rather limited and often contradictory. Redox conditions, size of inoculums, temperatures of fermentation, osmotic pressure and the medium nutritional content can profoundly affect the profile of yeast and bacterial metabolites produced or their biotransformation capacity in wine. Results obtained in the last decades in relation to microbial micrometabolism of aroma compounds measured with more sophisticated GC-MS methods are discussed in relation to the known terpenoid biosynthetic pathways and wine composition. Further development of metabolic footprinting techniques for the discrimination of wine quality must be one of the main challenges for wine biotechnologists in the near future.

Application of pulsed electric fields for improving the maceration process during vinification of red wine: influence of grape variety

The effect of the application of pulsed electric fields (PEF) treatments (2, 5 and 10 kV/cm) to the grape skin on the evolution of colour intensity, anthocyanins and index of total polyphenols along the vinification process of three grape varieties (Garnacha, Mazuelo and Graciano) has been investigated. It has been demonstrated that the ability of PEF to permeabilize cellular tissues is an effective treatment to improve the extraction of phenolic compounds. The influence of the intensity of the PEF treatment on colour intensity, anthocyanins and index of total polyphenols depended on the grape variety investigated. As compared with the control, the application of a PEF treatment was more effective in Mazuelo than in Garnacha and Graciano varieties. Increasing the electric field strength from 2 to 10 kV/cm led to a significant increment in treatment efficiency in Mazuelo but not in Garnacha and Graciano. The low energy consumption for cell permeabilization of grape skins (0.4–6.7 kJ/kg) and the short processing time required are key advantages of PEF technology to reduce the duration of the maceration during vinification or to increase the quantity of phenolic compounds in the final wine.

Effects of pulsed electric fields on the extraction of phenolic compounds during the fermentation of must of Tempranillo grapes

Abstract The effects of a pre-treatment of the grape skin with electric field treatments (PEF) at 5 and 10 kV/cm on the evolution of colour, anthocyanin and index of total polyphenols during the Tempranillo grape vinification and on the wine characteristics after fermentation have been investigated. Results showed that the permeabilization of the grape skin by application of a PEF treatment at room temperature caused an increment of the colour intensity, anthocyanin content and of total polyphenolic index with respect to the control during all the vinification process. Generally along the maceration process the values of these three parameters increased when the electric field strength raised from 5 to 10 kV/cm. Colour intensity and anthocyanin content of the wine significantly increased when the PEF treatment was applied at 10 kV/cm. However, the total phenolic index increased considerably with the application of a PEF treatment at 5 kV/cm. A further increment on the electric field strength did not appreciably augment this attribute. PEF did not affect the ratio between the components of the red wine colour (tint and yellow, red and blue components) and other wine characteristics such as alcohol content, total acidity, pH, reducing sugar concentration and volatile acidity. These results indicate that the PEF treatment previous to the maceration step in the winemaking process of the red wine can contribute to reduce the duration of the maceration during vinification or to increase the quantity of these attributes in the final wine. Industrial relevance This study investigates the effect of the application of a PEF pre-treatment of the grape skin on the evolution of colour, anthocyanin and index of total polyphenols during the Tempranillo grape vinification. Results obtained indicate that the application of a PEF treatment preceding the maceration step in the winemaking process of red wine could contribute to reduce the duration of the maceration during vinification or to increase the quantity of these parameters in the final wine. Latter effect could be of interest in grapes poor in polyphenols.

Polysaccharide Profile and Content during the Vinification and Aging of Tempranillo Red Wines

Passing from must to wine produced a loss of low-molecular-weight grape structural glucosyl polysaccharides, and an important gain in yeast mannoproteins (MP) and grape-derived arabinogalactan proteins (AGP), and rhamnogalacturonans-II (RG-II). AGP were more easily extracted than RG-II, and small quantities of RG-II monomers and galacturonans were detected. Postmaceration produced a reduction in all grape polysaccharide families, particularly acute in AGP. The reduction of polysaccharides during malolactic fermentation only affected grape AGP, and MP were continuously liberated during the entire vinification process. Wine oak and bottle aging was associated with a relative stability of the polysaccharide families. AGP were thus the majority polysaccharides in young wines but, contrary to what may be thought, structural glucosyl oligosaccharides dominated in musts and MP in aged wines. Precipitation of polysaccharides was noticeable during vinification, and it mainly affected high-molecular-weight AGP and MP. Hydrolytic phenomena affected the balance of wine polysaccharides during late maceration-fermentation.

Differentiation ofVitis viniferavarieties by MALDI‐MS analysis of the grape seed proteins

Until now the study of pathogenic related proteins in grape juice and wine, performed by ESI-MS, LC/ESI-MS, and MALDI/MS, has been proposed for differentiation of varieties. In fact, chitinases and thaumatin-like proteins persist through the vinification process and cause hazes and sediments in bottled wines. An additional instrument, potentially suitable for the grape varieties differentiation, has been developed by MALDI/MS for the grape seed protein analysis. The hydrosoluble protein profiles of seeds extract from three different Vitis vinifera grape (red and white) varieties were analyzed and compared. In order to evaluate the environmental conditions and harvest effects, the seed protein profiles of one grape variety from different locations and harvests were studied.

Biogenic amines in wines: Influence of oenological factors

Biogenic amines formation results from the decarboxylation of the corresponding amino acids by action of microorganisms. The presence of these compounds is considered by some authors a fundamental parameter for detriment of alcoholic beverages. The aim of this work was to assay the effect of some oenological factors (viticulture region, grape variety, anti-fungi treatment of grapes, fermentation activators, malolactic starters and storage on lees) from the point of view of their influence on the biogenic amines content of wines. According to our results, it was possible to show that the viticulture region affects the amounts of amines, since wines of some regions present higher contents of amines than wines from other regions. Grape varieties appear to influence the wine amines content. Commercial malolactic starters, after careful selection, should be added to the vinification process in order to decrease the formation of biogenic amines, since in our assays the wines that were inoculated with starters present lower amounts of biogenic amines. The wine storage on lees contributes for a biogenic amines increase.

Complexing capacity profiles of naturally occurring ligands in Tempranillo wines for Cu and Zn: An electroanalytical approach for cupric casse

Complexing capacity of naturally occurring ligands in Vitis vinifera (Tempranillo variety) wines has been studied with respect to two target metals (Cu and Zn) by differential pulse anodic stripping voltammetry (DPASV). Eight commercial wines of two certified brands of origin (CBO) and a young wine along its vinification process were monitored. Conditional stability constants and total complexing ligand(s) concentration(s) have been calculated for both metals. Discussion of the particular electrochemical responses for Cu and Zn for all samples is presented. A follow-up of the Cu stripping response allowed differentiating a commercial wine from one under processing related to the cupric casse phenomenon. Interaction of Cu with two molecular forms of cyanidin has been theoretically modeled at natural wine pH.

Exploring the applicability of MIR spectroscopy to detect early indications of wine fermentation problems

In this study we explore the applicability of MIR technology to detect early indications of wine fermentation problems. An oenologist could improve the chances of a vinification process finishing optimally if anomalies are detected early. A comparative analysis of three fermentations with artificial musts was performed; one of normal behaviour, one subject to a temperature gradient, and the third deficient in assimilable nitrogen. We tracked each fermentation through changes in spectra in addition to changes in must composition. It was easier to detect anomalous behaviour by monitoring wine metabolite concentrations than through direct spectra analysis, nevertheless, calibrations needed to be derived from fermenting must samples and so cost more. All measured compounds (glucose, fructose, ethanol, glycerol, succinic and acetic acids) exhibited behavioural changes at 30 h of fermentation in nitrogen deficient musts. Temperature deviations were reflected in the anomalous behaviour of ethanol, glycerol, succinic acid and acetic acid.