The use of furfural as a metabolic inhibitor for reducing the alcohol content of model wines

Climate has a huge influence on the ripening of grapes and therefore on the composition of any wine made from them. Wines from regions with high mean temperatures where water is scarce can suffer imbalances such as an excessively high alcohol content and low acidity, making it difficult to turn out a high-quality product. Work is now underway, however, to develop methods of processing very ripe grapes in order to produce red wines with a standard alcohol content (12.5–13.5% v/v). The use of metabolic blockers that redirect the glycolytic pathway in yeasts is one of the most interesting possibilities. The present work investigates how furfural, a well-known aromatic aldehyde with metabolic inhibitory effects on Saccharomyces, can be used to modify alcoholic fermentation in winemaking. The use of this compound led to a significant reduction in the final alcohol content of certain experimental fermentations. When furfural was added at the beginning of fermentation, a maximum reduction of 0.37% v/v alcohol was achieved after the addition of 10 mg/L, and of 0.6% v/v after the addition of 50 mg/L. The natural aromatic profile of the fermentation product suffered no negative variations. The intensity of the effect of furfural on fermentation with respect to the moment of its addition was also studied. Additions made later in fermentation or additions made periodically also inhibited alcohol production, in some cases more so than when added at the beginning of fermentation. The effects of furfural on alcohol production were variable depending on the yeast strain used. Variation of the pH between 3.2 and 3.8 and of temperature between 18 and 25 °C did not modify the intensity of furfural’s effect on alcohol production.     

Fermentative aptitude of non-Saccharomyces wine yeast for reduction in the ethanol content in wine

Over the last few decades, there has been a progressive increase in the ethanol content in wines due to global climate change and to the new wine styles that are associated with increased grape maturity. This increased ethanol content can have negative consequences on the sensory properties of the wines, human health, and economic aspects. Several microbiological approaches for decreasing the ethanol content have been suggested, such as strategies based on genetically modified yeasts, the adaptive evolution of yeasts, and the use of non-Saccharomyces yeast. In the present study, we investigated the interspecies and intraspecies variability of some non-Saccharomyces wine yeast species under anaerobic fermentation conditions. Across different grape juices and fermentation trials, Hanseniaspora uvarum, Zygosaccharomyces sapae, Zygosaccharomyces bailii, and Zygosaccharomyces bisporus promoted significant reductions in ethanol yield and fermentation efficiency in comparison with Saccharomyces cerevisiae. The diversion of alcoholic fermentation and the abundant formation of secondary compounds might explain the marked reduction in ethanol yield, as determined through the segregation of the majority of the strains according to their species attributes observed using principal component analysis. These data suggest that careful evaluation of interspecies and intraspecies biodiversity can be carried out to select yeast that produces low-ethanol yields.     

Dynamics and diversity of non-Saccharomyces yeasts during the early stages in winemaking

This detailed study observed the yeasts present in the ecological niche of "wine must". The dynamics and identity of non-Saccharomyces yeasts during the cold maceration and alcoholic fermentation of grape must were investigated under real production conditions in the Bordeaux region. Furthermore, we studied the impact of two oenological parameters on the development and diversity of non-Saccharomyces yeasts during cold maceration: temperature management and the timing of dried yeast addition. The non-Saccharomyces community underwent constant changes throughout cold maceration and alcoholic fermentation. The highly diverse non-Saccharomyces microflora was present at 10(4)-10(5) CFU/mL during cold maceration. The population increased to a maximum of 10(6)-10(7) CFU/mL at the beginning of alcoholic fermentation, then declined again at the end. The population at this point, evaluated at around 10(3)-10(4) CFU/mL, was shown to be dependent on the timing of yeast inoculation. The choice of temperature was the key factor for controlling the total yeast population growth, as well as the species present at the end of cold maceration. Hanseniaspora uvarum was a major species present in 2005 and 2006, while Candida zemplinina was very abundant in 2006. A total of 19 species were isolated.     

Interregional and interannual variability of ethanol site-specific deuterium content in Italian wines

The site-specific natural isotope fractionationnuclear magnetic resonance (SNIF-NMR)²H analysis is at present the reference method for determining the origin of ethanol and has been successfully applied for analysing all grape products. The method has also been used to identify the origin of wines and the aim of this study was to verify this application. In all, 3309 samples belonging to the Italian wines data bank were analysed from all 20 Italian regions to study the possibilities of determining and controlling the exact origin and year of the product. The dependency of the deuterium/hydrogen ratio of the methyl site (D/H_I) with latitude was confirmed but this was not the case for the D/H ratio of the methylene site (D/H_II) and the parameter R [2(D/H_II)/(D/H_I)] did not add any additional information. The frequency distribution of the NMR parameters follows a regular North-South gradient but they are not sufficiently different in each region to allow unique characterisation. The lack of effectiveness of the method, when applied to identification, depends on interannual and interregional variability. As a consequence, all but some very different regions overlap. The SNIF-NMR method is particularly suitable for detecting simple adulterations but, in the Italian situation, seems not to be so useful for solving problems of geographical origin. For this, it could be helpful to use other isotopic parameters and to ameliorate the sampling technique, to improve the effectiveness of the method.

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Regionale und jährliche Variabilität des Ethanolgebundenen Deuteriumgehaltes italienischer Weine

Zusammenfassung Die SNIF-NMR²H-Analytik wird derzeit als Referenzmethode zur Bestimmung der Herkunft des Ethanols bei Produkten aus Weintrauben erfolgreich angewandt. Die Methode wird auch zur Ermittlung der geographischen Herkunft von Wein eingesetzt. Ziel der vorliegenden Arbeit war es, die Brauchbarkeit dieser Analysenmethode zur Bestimmung des geographischen Ursprungs italienischer Weine zu überprüfen. Dazu wurden Analysenergebnisse von 3309 Weinen aus allen 20 Weinbaugebieten Italiens im Rahmen einer Datenbank des D/H-Verhältnisses gesammelt. Während für die D/H_I-Werte eine deutliche Abhängigkeit von der geographischen Breite bestätigt werden konnte, zeigten die D/H_II-Werte keinen derartigen Zusammenhang. Auch der Parameter R erbrachte keine weiteren Informationen. Die Häufigkeits-Verteilung der NMR-Werte folgt deutlich einem Nord-Süd-Gradienten, aber sie sind nicht in jeder Region so unterschiedlich, daß eine signifikante Differenzierung möglich ist. Dies resultiert aus den jahrgangs- und gebietsabhängigen Schwankungen. Die SNIF-NMR Methode ist zur Aufklärung bestimmter Verfälschungen (Zuckerzusatz) gut geeignet, bei italienischen Weinen ist jedoch mit dieser Methode das Problem der Bestimmung der geographischen Herkunft nicht lösbar. Durch Messung weiterer stabiler Isotopen sowie durch eine Verbesserung der Probennahme kann eine Erhöhung der Effizienz zum Nachweis der geographischen Herkunft erzielt werden.

     

The use of transgenic yeasts expressing a gene encoding a glycosyl-hydrolase as a tool to increase resveratrol content in wine

Resveratrol, a phenolic compound produced in grapes, exhibits properties that may contribute to the reduction of the incidence of coronary heart disease and other human health related processes. Recombinant yeast strains expressing the Aspergillus niger abfB gene encoding an alpha-L-arabinofuranosidase or the Candida molischiana bgIN gene encoding a beta-glucosidase have been used in vinifications as tools to increase the resveratrol content of white wine. Glycosylated resveratrol isomers (trans- and cis-piceid) and free resveratrol isomers (trans- and cis-resveratrol) were detected and quantified in white wines. Wines fermented with the strain expressing BgiN showed an increased amount of total resveratrol derivatives, particularly the non-glycosylated forms.     

RAPD with microsatellite as a tool for differentiation of Candida genus yeasts isolated in brewing

Fifteen wild yeast strains were isolated in two factories of a lager brewing company in Poland. Their identification with API 32C system showed mainly the presence of Candida sake species (7/15). To differentiate the isolates, randomly amplified polymorphic DNA (RAPD) with (GTG)(5), (GAC)(5), (GACA)(4) microsatellite primers and M13 core sequence (5'-GAG GGT GGC GGT TCT-3') were chosen. The results of patterns similarity are presented as dendrograms for each RAPD analysis and for overall patterns. On the overall patterns, all isolates identified as C. sake, except Strain No. 1, were regrouped in one cluster. Collection strain C. sake CBS 617 was similar in 46% to the cluster with six isolates (Strain Nos. 3, 6, 8, 11, 13, 14). The second reference strain C. sake CBS 159 and the Strain No. 1 were regrouped with other Candida species (collection strains) showing, respectively, only 20% and 42% of similarity to other C. sake strains. The similarity based on the overall dendrogram between isolate Nos. 3, 6, 8, 11, 13, 14 and C. sake CBS 617 was 49%. Between those strains and other Candida, the similarity was only 37%.     

Influence of winemaking techniques on the resveratrol content, total phenolic content and antioxidant potential of red wines

In this paper, the influence of winemaking techniques and cultivars on the resveratrol content, total phenolic content and antioxidant potential of red wines was studied. Wines were made from the cultivars Merlot, Cabernet Sauvignon, Pinot Noir and Prokupac. Applied winemaking technologies included thermovinification and separation of must from pomace. The analysis of trans- and cis-resveratrol in wines was performed by HPLC, while the total phenolic content and antioxidant potential was determined by spectrophotometric methods. The total resveratrol content in analysed samples ranged from 0.35 to 4.85 mg/l; Merlot wines had the highest average resveratrol content, while the lowest was found for native cultivar Prokupac. Although the resveratrol content depended on grape variety, correlation between the winemaking technology applied and the resveratrol level in wines was not observed. The total phenolic content (TPC) varied from 544.4 to 1410.4 mg/l expressed as gallic acid equivalents, and the antioxidant potential, assayed by DPPH in terms of SC₅₀ (mean scavenging concentration), ranged from 0.58 to 2.91 μl/ml. Obtained results showed that thermovinificated wine samples had higher amount of phenolic compounds. Significant negative correlation was observed (p < 0.05) between the total phenolic content and SC₅₀, but there was no significant correlation (p > 0.05) between the resveratrol content and SC₅₀ or TPC. This study could contribute to the establishment of optimal conditions for producing red wines which contain more beneficial phenolic compounds.     

Influence of aerobic and anaerobic conditions and yeasts on the reaction between (+)-catechin and glyoxylic acid

The reaction between (+)-catechin and glyoxylic acid in wine model solutions was studied under aerobic and anaerobic conditions in the presence and absence of yeasts with a view to determine their contributions to browning of white wine. Under aerobic conditions, the presence of yeasts reduced the production of colored products, the formation rate of which was similar to that observed under anaerobic conditions and in the absence of yeasts. These results reveal that yeasts and intermediate reaction products compete for oxygen. In the absence of oxygen, the production of colored compounds was even smaller in presence of yeasts, as a result of their ability to retain browning products as they form. Because the absence of oxygen not inhibited the formation of intermediate products resulting from oxidation reactions, an alternative oxidation pathway are proposed acting the glyoxylic acid as oxidant. In the usual concentrations of catechin in white wines, the studied reaction of (+)-catechin-glyoxylic acid can contribute significantly to the alteration of the wine color.     

Arsenic content in some Spanish wines Influence of the wine-making technique on arsenic content in musts and wines

Summary All of the essential technological means of treating grapes, must and wine were examined systematically. The main reasons for the differences in the arsenic (As) content of rosé and red wines are explained. In this study a relationship has been found between the As level and the wine-making technique. Rosé wines contain more As than red wines because they require a shorter period of contact with the skins. In order to prove this, the average values for the rosé and red wine samples from the same winery were compared.

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Arsen-Gehalt in einigen spanischen Weinen. Beeinflussung des Arsengehaltes von Most und Weinen durch kellertechnische Maßnahmen

Zusammenfassung Durch systematische Überprüfung aller wesentlichen kellertechnischen Schritte der Most- und Weinbehandlung wurden die Hauptursachen der großen Unterschiede im Arsengehalt von Weinen aufgeklärt. Dieser vermindert sich schon beim ersten Abstich nach der Gärung und weiterhin durch die Entfernung der Trübstoffe. Bei starkstreuenden Gehalten zeigte sich, daß die Rotweine geringere Werte als die Roséweine aufwiesen. Außerdem unterschieden sich vergleichbare Weine aus verschiedenen Betrieben deutlich im Arsengehalt.

     

Lactic acid fermentation as a tool for increasing the folate content of foods

Folate is an essential micronutrient involved in numerous vital biological reactions. The dietary consumption of naturally occurring vitamin B9 is often inadequate in many countries, and supplementation or fortification programs (using synthetic folic acid) are implemented to alleviate folate deficiency. Other food-based alternatives are possible, such as the use of lactic acid bacteria (LAB) to synthesize folate during fermentation. Many studies have been conducted on this topic, and promising results were reported for some fermented dairy products. However, in other studies, folate consumption by LAB or rather low folate production were observed, resulting in fermented foods that may not significantly contribute to the recommended B9 intake. In addition, the optimum conditions for folate biosynthesis by LAB are still not clear. The aim of this review was thus to (i) clarify the ability of LAB to produce folate in food products, (ii) check if the production of folate by LAB in various fermented foods is sufficient to meet human vitamin B9 requirements and (iii) suggest ways to optimize folate production by LAB in fermented food products.     

三种不同陈酿工艺的杨梅干红酒香成分对比分析

采用GC-MS联用技术对3种不同陈酿条件下的杨梅干红主要芳香香成分进行对比分析.结果表明,瓶装室温陈酿3年酒样酯类成分较高,特征成分为丁二酸二乙酯(17.67%)、柠檬酸二乙酯(9.29%)、丁二酸乙酯(8.87%)、2-羟基丁二酸二乙酯(4.01%)等;瓶装5 ℃陈酿2年的酒样以原果香萜烯醇类为主,特征成分为四甲基环癸二烯甲醇(15.89%)、桉叶-4(14)-烯-11-醇(14.78%)、戊醇(4.39%)和β-苯乙醇(3.77%)等,但酯类形成较少;橡木桶17 ℃陈酿1年的酒样特征成分为橡木桶和原果香萜烯醇类,如反式橙花叔醇(18.69%)、戊醇(9.65%)、β-苯乙醇(7.72%)、桉叶-4(14)-烯-11-醇(4.99%)等,橡木桶丰富了其酒香风格.以上结果证明,3种杨梅干红酒样的特征成分明显不同,酒香风格与陈酿条件密切相关.     

Arsenic content in some Spanish wines. Influence of the wine-making technique on arsenic content in musts and wines

All of the essential technological means of treating grapes, must and wine were examined systematically. The main reasons for the differences in the arsenic (As) content of rosé and red wines are explained. In this study a relationship has been found between the As level and the wine-making technique. Rosé wines contain more As than red wines because they require a shorter period of contact with the skins. In order to prove this, the average values for the rosé and red wine samples from the same winery were compared.     

Cork-borne bacteria and yeasts as potential producers of off-flavours in wine

Bacteria and yeasts were found to be present within cork lenticels, covered by mucous or fibrous substances. They survived heating, peroxide treatment and contact with the alcohol and sulfur dioxide of wine. 187 bacteria and 36 yeast strains were isolated from cork stoppers of wine bottles and, during various stages of production, from corkwood and new cork stoppers. After culturing, a number of isolates showed the ability to modify the aroma of model systems consisting of dilute or full strength wine and pulverised cork. The aromas produced by isolates of varying cork origin are tabled. A small number of isolates methylated 2,4,6-trichlorophenol, yielding 2,4,6-trichloroanisole, responsible for the typical cork taint. During the boiling of cork slabs, the internal temperature on the inside of a box made from cork slices did not exceed 87°C.     

Stable carbon isotope content in ethanol of EC data bank wines from Italy, France and Germany

In the present work we discuss the usefulness of carbon isotope analysis of wine ethanol for the assignment of origin and the proof of adulteration of Italian, French and German wines. At first the comparability of the results from three laboratories is demonstrated by the results of inter-laboratory comparison measurement and by tests of the distillation procedures applied to the same samples. Furthermore, a close correlation of carbon isotope content in sugars from must and ethanol from the related wine could be found for samples from all countries. Using the ¹³C values of EC data bank wines from 1991 to 1993 for Italy, France and Germany, we describe and discuss the main factors of influence which are responsible for the variation of those values. By examination of spiked samples, the usefulness of the ¹³C analysis in the detection of certain types of wine enrichment is demonstrated; especially if the carbon isotope analysis by¹³C-8 isotope ratio mass spectrometry is employed as an additional tool for improving the security of the already officially performed determination of the site-specific hydrogen isotope content in wine ethanol by²H-NMR.     

Study of the content in volatile compounds during the aging of sweet Sherry wines obtained from grapes cv. Muscat and fermented under different conditions

Several experiments of aging in oak wood and stainless steel of sweet Sherry wines obtained from grapes cv. Muscat fermented under different enological conditions have been carried out. These wines were periodically sampled and their volatile content was analyzed using SBSE–GC–MS. A sensory study was also carried out. Data were submitted to different statistical techniques. An important influence of the three factors considered, fermentation type, aging type, and aging time, have been observed. In cluster analysis, the grouping obtained demonstrated that the volatile compounds considered possess sufficient explanatory power to detect the type of aging process and differentiate the two yeast strains studied. In the case of the linear discriminant analysis, high percentages of correct classification were obtained for the three factors considered. Taking into account the global volatile profile, the factor “aging type” (oak cask or stainless steel) has demonstrated the highest influence on the volatile content of the wines, with those wines from Experiments D4 and D5 (fermented with S. bayanus) and aged in oak wood clearly differentiated from those ones fermented with S. cerevisiae and aged in wood or stainless steel. From a sensorial point of view, the wines fermented with S. Cerevisiae and aged in wood (D1C and D2C) were the most valued ones.     

不同果胶酶和酵母菌对葡萄酒中白藜芦醇及其二聚体的影响

采用高效液相色谱直接进样分析,测定了3种果胶酶处理、4种酵母发酵的葡萄酒中res、ε-viniferin、δ-viniferin等葡萄主要芪化物的含量.结果表明:7种葡萄酒中都含有较多的res、ε-viniferin和8-viniferin,不同果胶酶、酵母的选用均能影响到葡萄酒中的res、ε-viniferin和ε-viniferin的浸出效果.Uhrazyme Premium果胶酶酒样中ε-viniferin含量为2.187 mg/L,而Ex-v酒样中为1.926mg/L,796酵母酒样中res含量为1.193 mg/L,而CMS酒样仅为0.682 mg/L,δ-viniferin在D254酵母酒样中的含量为2.297 mg/L,而在Oneferm Color酒样中仅为1.850 me/L.Uhrazyme Premium果胶酶和D254、796酵母对果皮中上述芪化物的浸提效果较好.     

Biogenic amines content as a measure of the quality of wines of Abruzzo (Italy)

Aim of this research was to study the effect of some agronomic and oenological factors on the content of biogenic amines as quality index of sixty-five Abruzzo wines. Sum of amines was found to be decreasing in the order: red (19.3 ± 12.8 mg L⁻¹), rosé (9.20 ± 6.34 mg L⁻¹), white (7.67 ± 3.84 mg L⁻¹) wine. Significant differences in relationship among amines levels and chemical and chemico-physical characteristics of red, white and rosé wine are due to their different biotechnological process and winemaking. Besides the aging treatment, influential seems to be the effect of the winery, regardless of the area in which it is situated.     

Evaluation of the potential of high pressure technology as an enological practice for red wines

The impact of high hydrostatic pressure (HHP) treatments on the phenolic compounds composition of a red wine was studied after storage in order to evaluate the potential of this technology as an enological practice. Red wines pressurized at 500 and 600 MPa at 20 °C for 5 and 20 min, respectively, showed a lower content of monomeric anthocyanins (13 to 14%), phenolic acids (8 to 11%), and flavonols (14 to 19%) after 5 months of storage, when compared to the unpressurized wine. These results, together with the different degree of tannin polymerization and flavan-3-ol content in the pressurized wines led to propose an effect of HHP in the increase of polymerization and cleavage reactions of proanthocyanidins. The sensorial analysis of pressurized wines showed lower astringency, a higher intensity of cooked fruit aroma and lower intensity of fruity notes, when compared with the unpressurized wine. These effects are associated to those observed during wine aging.Industrial relevanceDuring the last decade, the use of high hydrostatic pressure (HHP) as a non-thermal technology for food preservation and modification has increased substantially. Recently, pressure treatments have shown to influence long term red wine physicochemical and sensorial characteristics, leading to aged wine-like characteristics. Therefore, the use of HHP technology to modify wine composition could benefit the wine industry, especially to improve wines with low aging potential. This work shows that HHP can be potentially used as enological practice, modulating the organoleptic properties of wine by decreasing astringency and increasing pleasant aromas. It seems possible to exploit commercially the production of young red wines with distinct characteristics using this technology, addressing the market and consumer demand.