Production Of Volatile Phenols Research Articles

Sulphur dioxide affects culturability and volatile phenol production by Brettanomyces/ Dekkera bruxellensis

The effect of different sulphur dioxide concentrations on culturability and viability of seven strains of Brettanomyces bruxellensis was tested in a synthetic wine medium (SWM) and a different response to molecular SO 2 among strains was detected. Sulphur dioxide induced a viable but non culturable (VBNC) state in all the strains. The greater percentage of VBNC cells were identified for five strains at molecular SO 2 concentrations of 0.2 mg/L and for two strains at the concentration of 0.4 mg/L. Vinyl phenols were detected in media containing VBNC or not viable B. bruxellensis, suggesting that its spoilage metabolism could be maintained during wine storage. Overall, this study indicates that SO 2 is a chemical stressor inducing VBNC state in B. bruxellensis grown in synthetic wine medium . Further studies are needed to evaluate the effects of SO 2 on the metabolism of this yeast in wine spoilage.

Enhanced volatile phenols in wine fermented with Saccharomyces cerevisiae and spoiled with Pichia guilliermondii and Dekkera bruxellensis

To investigate whether the presence of Pichia guilliermondii impacts on the production of volatile phenols from mixed wine fermentations with Dekkera bruxellensis and Saccharomyces cerevisiae. Four inoculation strategies were performed in small-scale fermentations involving P. guilliermondii, D. bruxellensis and S. cerevisiae using Syrah grape juice supplemented with 100 mg l(-1) of p-coumaric acid. High pressure liquid chromatography was used for the quantification or volatile phenols. Significant high levels of 4-ethylphenol and 4-ethylguaicol (720 and 545 microg l(-1), respectively), as well as the highest levels of 4-vinylphenol (>4500 microg l(-1)), were observed when P. guilliermondii species was inoculated from the beginning of the fermentation. The metabolic interaction occurring between the high vinylphenol producer species P. guilliermondii and D. bruxellensis exhibiting a high vinylphenol reductase activity resulted in an increased production of volatile phenols in wine. Pichia guilliermondii must be considered a very important spoilage yeast in the wine industry capable of producing large amounts of volatile phenols.

Brettanomyces bruxellensisevolution and volatile phenols production in red wines during storage in bottles

The presence of Brettanomyces bruxellensis is an important issue during winemaking because of its volatile phenols production capacities. The aim of this study is to provide information on the ability of residual B. bruxellensis populations to multiply and spoil finished wines during storage in bottles. Several finished wines were studied. Brettanomyces bruxellensis populations were monitored during two and a half months, and volatile phenols as well as chemical parameters regularly determined. Variable growth and volatile phenols synthesis capacities were evidenced, in particularly when cells are in a noncultivable state. In addition, the volatile phenol production was clearly shown to be a two-step procedure that could strongly be correlated to the physiological state of the yeast population. This study underlines the importance of minimizing B. bruxellensis populations at the end of wine ageing to reduce volatile phenols production risk once the wine in bottle. Moreover, the physiological state of the yeast seems to have an important impact on ethyl-phenols production, hence demonstrating the importance of taking into account this parameter when analysing wine spoilage risks. Little data exist about the survival of B. bruxellensis once the wine in bottle. This study provides information on the alteration risks encountered during wine storage in bottle and reveals the importance of carrying on further studies to increase the knowledge on B. bruxellensis physiology.

Influence of Inoculation with Malolactic Bacteria on Volatile Phenols in Wines

Malolactic fermentation (MLF) can help to preserve the quality of wine by hampering the development of <i>Brettanomyces</i> yeast. Wines that underwent MLF inhibited the growth of <i>Brettanomyces</i>, resulting in a product containing little or no volatile phenols. Wines that did not undergo MLF allowed proliferation of <i>Brettanomyces,</i> resulting in a product containing more volatile phenols. This phenomenon was seen in the laboratory and in the cellar. Wines in which the MLF did not occur showed <i>Brettanomyces</i> growth. Early inoculation of wine with malolactic bacteria may be a tool for lowering the risk of volatile phenol production.

Volatile phenols in virgin olive oils: Influence of olive variety on their formation during fruits storage

The potential significance as odorants and markers of olive fruits degradation has been recently pointed out for volatile phenols in virgin olive oil (VOO) and related to the appearance of VOO sensory defects. The few studies carried out in order to elucidate the factors affecting their formation in olive fruits or VOOs, indicated that they could be considered as analytical indices of olive fruits degradation during storage, likely reflecting the microbiological activity. In the present study, the effect of the olive variety (‘Arbequina’, ‘Arbosana’ and ‘Leccino’) on the production of volatile phenols during twelve days of storage in closed plastic bags was evaluated. The different resistance of each variety to the microbiological attach was observed during olive fruit storage, and it was reflected by the evolution of guaiacol, 4-ethylphenol and 4-ethylguaiacol, and related to free acidity values. On the contrary, a scarce dependence on the microbial growth or varietal factors was observed for 4-vinyl derivatives, which appeared more directly related to the time of olives storage. The evolution of volatile phenols found certain correspondence in the sensory characteristics of the resulting VOOs, while the rest of VOO chemical quality indices did not show major variations during fruits storage.

Evidence for differences between B. bruxellensis strains originating from an enological environment

Evidence for differences between B. bruxellensis strains originating from an enological environment Vincent Renouf1,2, Cécile Miot-Sertier2, Marie-Claire Perello2, Gilles de Revel2, Aline Lonvaud-Funel21Laffort, Bordeaux, France; 2UMR Œnologie, INRA-Université Bordeaux, FranceAbstract: The aim of this paper is to study and compare the physiological diversity of different strains of a wine spoilage yeast species: Brettanomyces bruxellensis. The minimum inhibitory concentrations of several drugs on different B. bruxellensis strains were scored on solid nutrient media. This revealed variations in resistance among the B. bruxellensis strains. Their capacity to develop in different wine and must environments: pH, ethanol, and SO2 concentrations, were evaluated by measuring the direct incubation survival rate. The results, compared with those obtained for other wine yeast species, confirmed the remarkable resistance of B. bruxellensis strains to various conditions which inhibit the growth of other species. Nevertheless some differences were observed among the B. bruxellensis strains, thus confirming their physiological diversity. A comparison of their volatile phenol production revealed intraspecific heterogeneity among B. bruxellensis strains. B. bruxellensis is one of the microbial species most resistant to environmental constraints in wine. It is the best adapted to growing in wine and spoiling it by volatile phenol production. However, different B. bruxellensis strains exhibit varying characteristics, particularly their capacity to produce volatile phenols. This implies that certain strains are more prejudicial than others. Further studies are required to determine the molecular causes of this intraspecific diversity.Keywords: Brettanomyces bruxellensis, strain diversity, physiology, volatile phenols

Molecular Screening of Wine Lactic Acid Bacteria Degrading Hydroxycinnamic Acids

The potential to produce volatile phenols from hydroxycinnamic acids was investigated for lactic acid bacteria (LAB) isolated from Spanish grape must and wine. A PCR assay was developed for the detection of LAB that potentially produce volatile phenols. Synthetic degenerate oligonucleotides for the specific detection of the pdc gene encoding a phenolic acid decarboxylase were designed. The pdc PCR assay amplifies a 321 bp DNA fragment from phenolic acid decarboxylase. The pdc PCR method was applied to 85 strains belonging to the 6 main wine LAB species. Lactobacillus plantarum, Lactobacillus brevis, and Pediococcus pentosaceus strains produce a positive response in the pdc PCR assay, whereas Oenococcus oeni, Lactobacillus hilgardii, and Leuconostoc mesenteroides strains did not produce the expected PCR product. The production of vinyl and ethyl derivatives from hydroxycinnamic acids in culture media was determined by high-performance liquid chromatography. A relationship was found between pdc PCR amplification and volatile phenol production, so that the LAB strains that gave a positive pdc PCR response produce volatile phenols, whereas strains that did not produce a PCR amplicon did not produce volatile phenols. The proposed method could be useful for a preliminary identification of LAB strains able to produce volatile phenols in wine.

Molecular identification of Brettanomyces bruxellensis strains isolated from red wines and volatile phenol production

The spoilage yeast Brettanomyces/Dekkera can persist throughout the winemaking process and has the potential to produce off-flavours that affect the sensory quality of wine. The main objective of this study was to select different strains of Brettanomyces bruxellensis isolated from red wines and to compare their volatile phenol production. From a collection of 63 strains, eight strains of B. bruxellensis were selected for volatile phenol production after the application of molecular techniques such as ISS–PCR, PCR–DGGE and REA–PFGE. All strains showed three large chromosomes of similar size with PFGE. However, unique restriction profiles of the chromosomes were visible after NotI digestion that clearly distinguished the strains. All strains were capable of producing large quantities of 4-ethylphenol and 4-ethylguaiacol from p-coumaric acid and ferulic acid, respectively in synthetic media. However, the diversity among strains for volatile phenol production differed between synthetic media and wine with regard to the maximum production levels of 4-ethylphenol and 4-ethylguaiacol. This study illustrated the diversity of B. bruxellensis strains that occur during winemaking.

The effect of sugar concentration and temperature on growth and volatile phenol production byDekkera bruxellensisin wine

The wine spoilage yeast Dekkera bruxellensis was evaluated for the production of 4-ethylphenol under low concentrations (0.02-20 g L(-1)) of glucose and fructose in synthetic media. Measurable amounts of 4-ethylphenol were produced over 0.2 g L(-1) of each sugar. The yeast growth rate and amount of biomass formed increased from 0.2 to 20 g L(-1) of glucose or fructose, being accompanied by increasing production of 4-ethylphenol. In red wines, the production of 4-ethylphenol was only observed in the presence of growing populations of indigenous or inoculated strains of D. bruxellensis. The production rate of 4-ethylphenol varied between 22 and 93 mug day(-1) either with inoculated strains or wild populations in bottled wines. The production rate of 4-ethylphenol as a function of the increase in the number of cells varied from 349 to 1882 mug L(-1) per one log CFU mL(-1). The effect of temperature on cellular viability and 4-ethylphenol production was tested in red wines with indigenous or inoculated strains of D. bruxellensis. Incubation temperatures of 15, 20 and 25 degrees C allowed cellular growth and volatile phenol production. Increasing incubation temperatures to 36 degrees C induced full viability loss of 10 strains of D. bruxellensis within <12 h.

Physiological and oenological traits of differentDekkera/Brettanomyces bruxellensisstrains under wine-model conditions

Contamination of wine by Dekkera/Brettanomyces bruxellensis is mostly due to the production of off-flavours identified as vinyl- and especially ethyl-phenols, but these yeasts can also produce several other spoiling metabolites, such as acetic acid and biogenic amines. Little information is available about the correlation between growth, viability and off-flavour and biogenic amine production. In the present work, five strains of Dekkera bruxellensis isolated from wine were analysed over 3 months in wine-like environment for growth, cell survival, carbon source utilization and production of volatile phenols and biogenic amines. Our data indicate that the wine spoilage potential of D. bruxellensis is strain dependent, being strictly associated with the ability to grow under oenological conditions. 4-Ethyl-phenol and 4-ethyl-guaiacol production ranged between 0 and 2.7 and 2 mg L(-1), respectively, depending on the growth conditions. Putrescine, cadaverine and spermidine were the biogenic amines found.

Growth and volatile compound production by Brettanomyces/Dekkera bruxellensis in red wine

Brettanomyces/Dekkera bruxellensis is a particularly troublesome wine spoilage yeast. This work was aimed at characterizing its behaviour in terms of growth and volatile compound production in red wine. Sterile red wines were inoculated with 5 x 10(3) viable cells ml(-1) of three B. bruxellensis strains and growth and volatile phenol production were followed for 1 month by means of plate counts and gas chromatography-mass spectrometry (GC-MS) respectively. Maximum population levels generally attained 10(6)-10(7) colony forming units (CFU) ml(-1) and volatile phenol concentrations ranged from 500 to 4000 microg l(-1). Brettanomyces bruxellensis multiplication was also accompanied by the production of organic acids (from C(2) to C(10)), short chain acid ethyl-esters and the 'mousy off-flavour' component 2-acetyl-tetrahydropyridine. Different kinds of 'Brett character' characterized by distinct metabolic and sensory profiles can arise in wine depending on the contaminating strain, wine pH and sugar content and the winemaking stage at which contamination occurs. We identified new chemical markers that indicate wine defects caused by B. bruxellensis. Further insight was provided into the role of some environmental conditions in promoting wine spoilage.

Diversity in Spoilage Yeast Dekkera/Brettanomyces bruxellensis Isolated from French Red Wine. Assessment During Fermentation of Synthetic Wine Medium

Yeast Brettanomyces bruxellensis is a contaminant found worldwide and is responsible for red wine spoilage due to the development of animal and phenolic off-odours. During this study, 24 Brettanomyces bruxellenis isolates were obtained from red wine samples from two French wineries and these were discriminated as 23 strains. Nine strains coming from 2 wineries and 4 vintages were cultivated in synthetic wine medium for 1500 hours and they gave nine different behaviours. Four main growth patterns (with different growth steps and durations) and three main different sugar consumption profiles were obtained. Glucose and fructose were not limiting substrates for all strains. The production level of 4-ethylphenol was found to vary from strain to strain (from 0.350 to 2.773 mg L−1) and was independent of the biomass concentration. Some strains presented a coupled-to-growth production of volatile phenols, others did not. This study showed that different strains of Brettanomyces bruxellensis behaved differently, one from another, under the given conditions taking into consideration several aspects. The results thus demonstrate a large intraspecific diversity.

The origin of &lt;em&gt;Brettanomyces bruxellensis&lt;/em&gt; in wines: a review

&lt;p style="text-align: justify;"&gt;&lt;strong&gt;Aims&lt;/strong&gt;: This work reviews the latest knowledge concerning the role of Brettanomyces bruxellensis in red wine alteration.&lt;/p&gt;&lt;p style="text-align: justify;"&gt;&lt;strong&gt;Results and conclusion&lt;/strong&gt;: The origin of this yeast species and its place in the wine microbial consortium are discussed as well as microbial equilibriums with the other species, notably Saccharomyces cerevisiae and lactic acid bacteria. As a consequence, fermentations are described as key steps in Brettanomyces development management. Furthermore, the influence of ageing through the use of traditional winemaking practices is explained.&lt;/p&gt;&lt;p style="text-align: justify;"&gt;&lt;strong&gt;Significance and impact of study&lt;/strong&gt;: Finally, this paper emphases the need for a better understanding of chemical and microbial analysis together in order to better control this undesirable yeast and prevent the production of volatile phenols.&lt;/p&gt;

Influence of Dekkera bruxellensis on the contents of anthocyanins, organic acids and volatile phenols of Dão red wine

The anthocyanin, organic acid and volatile phenol compositions of red wine obtained from Touriga Nacional grapes growing in the Dão region (Portugal) were determined by HPLC/DAD, HPLC/UV and GC/FID, respectively. By these means, nine anthocyanic compounds (malvidin-3,5- O-diglucoside, cyanidin-3- O-galactoside, cyanidin-3- O-glucoside, peonidin-3- O-glucoside, malvidin-3- O-glucoside, delphinidin, cyanidin, pelargonidin and malvidin), six organic acids (ketoglutaric, tartaric, malic, quinic, lactic and shikimic acids) and two volatile phenols (4-ethylguaiacol and 4-ethylphenol) were identified and quantified. Malvidin-3- O-glucoside, the pair lactic plus shikimic acids and 4-ethylguaiacol were the main anthocyanin, organic acids and volatile phenol, respectively. The effects of nine different Dekkera bruxellensis strains on these chemical parameters were also evaluated. The results obtained indicate that some strains of D. bruxellensis yeast are able to cause deterioration of red wine from the Dão region during its maturation by the production of volatile phenols, namely 4-ethylphenol.

Influence of Maceration Temperature and Enzymes on the Content of Volatile Phenols in Pinot noir Wines

Yeasts of the <i>Brettanomyces</i> type are found in red wines and are responsible for the production of volatile phenols characterized by animal, leather, ink, horse stable or barnyard odors. Certain winemaking techniques that have been developed to improve the extraction of phenolic compounds indirectly favor the production of volatile phenols in wines that have been contaminated by <i>Brettanomyces</i>. Two techniques, heating at the end of the maceration and the use of enological enzymes, can potentially cause an excess production of volatile phenols. Compared with the classic temperature of the maceration without use of enzymes, one of these alternative techniques may triple the presence of volatile phenols, even more so when both techniques are administered on the same wine. Cinnamyl-esterase, a secondary activity seen in most enzymatic preparations produced by <i>Aspergillus niger</i> (pectinases), is the cause of this problem. The use of a purified enzyme without cinnamyl-esterase does not seem to induce an overproduction of volatile phenols. This property is already present in enzymes used in the vinification of white wines, and it is important to use these same purified enzymes for red wine production.

Diet, bowel function, fecal characteristics, and large bowel cancer in Denmark and Finland.

Some 30 randomly selected men, aged 50-59 years, were investigated in each of 4 areas--Copenhagen, Them (rural Denmark), Helsinki, and Parikkala (rural Finland)--to determine the relationship of diet, gut transit time, fecal bulk, fecal bacteriology, bile acid concentration, and urinary volatile phenol production to large bowel cancer risk. Average daily fat intake was found to be high in all 4 areas, and no differences emerged between areas. Saturated fatty acid consumption was higher in low-incidence areas than in high-incidence areas. Intakes of nonstarch polysaccharides (the main component of dietary fiber), carbohydrate, and protein (mainly milk) were higher in the low-incidence area of Parikkala than in the high-incidence area of Copenhagen. The fecal bile acid concentration was higher in the high-incidence area than in the low-incidence area, with the other 2 areas having intermediate values. Fecal bulk showed an inverse association with colorectal cancer incidence. No differences were observed with regard to fecal bacteriology or mutagenic activity of the foods. These results indicate that a population can have a low risk of colorectal cancer despite a high intake of dietary fat, protein, and meat. Dietary carbohydrate and fiber may be considered protective. One mechanism limiting colorectal cancer risk could be the increase in fecal bulk resulting from such intakes, since increased fecal bulk dilutes the increased colonic bile acid concentrations of subjects on high-fat diets.

The production of urinary phenols by gut bacteria and their possible ce:role in the causation of large bowel cancer

Epidemiological evidence is presented to relate the amount of dietary meat to the risk of large bowel cancer; it has been suggested that this may be due to the production of cocarcinogenic volatile phenols by intestinal bacteria from tyrosine. This paper describes preliminary experiments to test this suggestion. In vitro, aerobic bacteria tended to produce phenol from tyrosine while anaerobic bacteria produced p-cresol. Urine from 10 normal healthy persons contained a mean of 9.8 mg phenol/day and 51.8 mg p-cresol/day. Results from studies on patients with ileostomy, colostomy, and diverticular disease indicated that p-cresol is largely produced by the anaerobic flora of the left colon while phenol was produced in the ileum (when colonized) and cecum. In patients with familial polyposis the activity of the aerobic flora was apparently normal but there was greatly reduced amounts of p-cresol produced. The amounts of urinary volatile phenols in six patients with newly diagnosed large bowel cancer were not different from the normal values, indicating that cocarcinogenic phenols were unlikely to be a major cause of the disease.