Impact of phytosanitary treatments with fungicides (cyazofamid, famoxadone, mandipropamid and valifenalate) on aroma compounds of Godello white wines

Cyazofamid, famoxadone, mandipropamid and valifenalate, four new fungicides for controlling downy mildew in vine, were applied to an experimental vineyard producing Vitis vinifera white grapes of the Godello variety. Following harvest, the grapes were subjected to single vinification runs. The odour activity values (OAVs) for the Godello white wines obtained were estimated with a view to assessing potential alterations of their aroma composition by effect of the phytosanitary treatments. Several fatty acids, their esters and acetates were formed during the winemaking process in high levels and could be expected to strongly influence the aroma of the wines by introducing floral, fruity and spicy nuances. The concentrations of six compounds (2-phenylethyl acetate, ethyl butanoate, ethyl octanoate, 4-vinylguaiacol, 3-methylbutanoic acid and methionol) were found to suffice with a view to discriminating between wines from grapes treated with fungicides under Critical Agricultural Practices (CAP) and under Good Agricultural Practices (GAP).     

Decay of fungicide residues during vinification of white grapes harvested after the application of some new active substances against downy mildew

Cyazofamid, famoxadone, mandipropamid and valifenalate are new fungicides recently proposed to control downy mildew (Plasmopara viticola) in vines. In this study, three of them were applied in an experimental vineyard producing white grapes (Vitis vinifera cv. Godello) as commercial formulations: Mildicut (2.5% cyazofamid), Equation Pro (22.5% famoxadone + 30% cymoxanil) and IR-5885 (6% valifenalate + 60% mancozeb), meanwhile mandipropamid was directly applied as an active substance. The last treatments to control this disease were made out under critical agricultural practices, without obeying the preharvest interval. Besides the above products, the control of powdery mildew (Erisiphe necator) and grey mould (Botrytis cinerea) was made by employing standard commercial formulations. Once treated white grapes were harvested, the fate of all these fungicides from vine to wine was studied. Residues of cyazofamid, famoxadone and valifenalate in grapes were higher than their EU MRL, except for mandipropamid. The white wine-making process allowed the dissipation of fungicide residues in high percentages (ca. 95%), except for valifenalate that remained in wine at 32%.     

Changes of the sensorial attributes of white wines with the application of new anti-mildew fungicides under critical agricultural practices

Although the winemaking process could allow the dissipation of residues of fungicides applied under critical agricultural practices (CAP), their residual levels could alter the biosynthesis of volatile compounds. The purpose of this work is to look for changes in the aroma profile of those wines in comparison with wines treated under good agricultural practices (GAP). Four new fungicides (mandipropamid, valifenalate, cyazofamid and famoxadone), used to control downy mildew (Plasmoparaviticola), were applied under CAP in an experimental vineyard producing white grapes (Vitisvinifera) of Godello var. Once grapes were harvested, single vinifications were performed. Possible modifications of sensorial properties of wines were evaluated by a trained sensorial testing panel constituted of 7 experts. The fungicide residues induced an increment of typical fermentative odours associated with esters in treated wines. The critically treated wine was moved to a sweeter balance with a ripe fruit taste, associated with higher viscosity and greater cloudiness.     

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

BACKGROUND: 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     

Residues of the fungicide famoxadone in grapes and its fate during wine production

Famoxadone is a recently applied fungicide to vines that belongs to the oxazolidinedione family. The fate of famoxadone was studied by considering the decay ratio of this fungicide during the maturation of grapes and wine production. The main factors affecting the presence of fungicide residues such as fruit growth, photodegradation, evaporation, thermodegradation and co-distillation were studied with model systems. An experimental field was treated with a commercial product containing famoxadone at the recommended dose. After this application, residues of famoxadone were found in grapes at 0.27 ± 0.06 mg kg^-1. In this field experiment, the half-life (t_1/2;) of famoxadone, which is described by pseudo-first-order kinetics (R² = 0.74), was 18 ± 6 days, resulting from the photodegradation. The famoxadone residue levels in grapes were below the established maximum residues level for Europe (2 mg kg^-1), whilst levels in wine, carried out with and without maceration, were below the calculated limit of detection of the method.     

Processing factors and variability of pyrimethanil, fenhexamid and tolylfluanid in strawberries

An HPLC-MS/MS method for the analysis of three pesticides in strawberries was developed and validated. Recoveries were measured at three spiking levels and ranged from 85 to 99% (mean recoveries). The effects of processing of strawberries ranging from rinsing to jam production were investigated for the three fungicides tolylfluanid, fenhexamid and pyrimethanil, which were applied under field conditions. Kresoxim-methyl was also applied in the field, but was not found in any of the samples investigated. The effect of parameters such as preharvest interval, dose, harvest time and observed pesticide concentration after harvest (initial concentration, mg kg^-1), were examined with respect to possible reduction of the pesticides. The results from rinsing showed that all three pesticides were reduced on average by 37% for tolylfluanid, by 34% for fenhexamid and by 19% for pyrimethanil. For tolylfluanid and fenhexamid, the initial concentration significantly affected the reduction. For fenhexamid, dose could also have a minor influence on reduction. For pyrimethanil, none of the parameters significantly influenced the reduction. For jam production, cooking significantly reduced tolylfluanid by an average of 91%. For fenhexamid and pyrimethanil, a smaller reduction was seen, 25% and 33%, respectively. The reduction of tolylfluanid and pyrimethanil was affected by the preharvest interval, while fenhexamid was affected by the initial concentration. The unit-to-unit variability of fungicide contents was also investigated and the variability factors for the three fungicides were from 1.9 to 2.8.     

Impact of fungicides on Aspergillus carbonarius growth and ochratoxin A production on synthetic grape-like medium and on grapes

A study was undertaken to evaluate the impact of the application of several fungicide treatments used in Spanish vines on Aspergillus carbonarius growth and ochratoxin A production. Three trials were designed in order: (1) to screen 26 fungicides at the doses recommended by manufacturers on grape-like synthetic medium at 20 and 30°C; (2) to find out the minimum inhibitory concentration of each fungicide for A. carbonarius growth on synthetic medium; and (3) to investigate the effect of several fungicides on A. carbonarius-inoculated grapes. In synthetic medium nine fungicides significantly reduced A. carbonarius growth rate. Meanwhile, 13 fungicides completely inhibited its growth. In general, growth was faster at 30°C than at 20°C, contrary to ochratoxin A production. Fungicides that stopped fungal growth also inhibited ochratoxin A production, but not all the fungicides that reduced growth reduced the ochratoxin A synthesis. In general, fungicides that contained copper or strobilurins reduced both growth and ochratoxin A production, contrary to sulphur fungicides. At the optimum temperature for A. carbonarius growth of 30°C, higher amounts of fungicide were needed to prevent fungal growth than at 20°C. Among the fungicides that inhibited A. carbonarius growth on synthetic medium at the initial doses, cyprodinil seemed to be the active ingredient more effective at stopping fungal growth when testing reduced doses. The fungicide effect on grapes was similar to that on synthetic medium. Both infection and ochratoxin A production were reduced when using cyprodinil (37.5%) plus fludioxonil (25%) and azoxystrobin (25%). Penconazole (10%) also showed a clear reduction in ochratoxin A production at both temperatures, although infection was only reduced at 20°C. Ochratoxin A reduction was strain and temperature-dependent. In general, fenhexamid (50%), mancozeb (80%) and copper hydroxide (80%) plus copper (50%) enhanced infection and ochratoxin A production.     

Profiles of free amino acids in grapes of grafted Chardonnay grapevines

Chardonnay grapes from a rootstock trial in the Murray Valley region of South Australia were sampled for two seasons and concentrations of free amino acids in grape extract ('juice') were determined. The lowest concentrations of free assimilable amino-N were measured in Chardonnay grapes from vines on 140 Ruggeri and 101–14 rootstocks, and the highest concentrations were in grapes from vines on their own roots, Schwarzmann and K51–40. Free assimilable amino-N concentrations were sufficient to sustain fermentation through to completion. Arginine concentrations were generally too low to expect significant concentrations of urea in the wine. Amino-S concentrations were much lower and varied less than amino-N concentrations. The effect of any particular rootstock on the concentration of total free amino acids in Chardonnay grape 'juice' did not appear to be related to the known effects of those rootstocks on the NO₃-N status of petioles at flowering. The concentrations of leucine, iso-leucine, valine, threonine, tyrosine and phenylalanine were generally higher in Chardonnay grapes grafted onto K51–40 in comparison to grapes from Chardonnay vines grafted on the other rootstocks. Any of these amino acids may be associated with the presence of specific higher alcohols in wine.     

Integration of strobilurins and other fungicides for the control of powdery mildew on grapes

The strobilurin fungicides Amistar (azoxystrobin) and Flint (trifloxystrobin) were evaluated in 1999/00 and 2000/01 in programs that included various combinations with Thiovit (sulfur) and Topas (penconazole) for the control of powdery mildew on grapes. In most experiments the application of 6 sprays per season that included Thiovit (3 g/L) followed by various combinations of Topas (0.125 mL/L), Amistar (0.5 g/L), Flint (0.15 g/L) and Thiovit (2 g/L) controlled powdery mildew. Although strobilurins were applied from flowering to after fruit set, the order in which various fungicides were applied had little influence on the level of powdery mildew control. In experiments where the bunch or leaf area diseased was 60% or higher in unsprayed plots, the severity was less than 5% where combinations of Thiovit and Topas with either Amistar or Flint were applied. In one experiment, 3 applications of either Legend (quinoxyfen) or Prosper (spiroxamine) following 2 applications of Thiovit also provided excellent control of powdery mildew. In programs where the application of Amistar and Flint were directly compared, Flint was the most effective fungicide for controlling powdery mildew. In the experiments where downy mildew also developed, Amistar was more effective than Flint in controlling this disease.     

Effect of the addition of ammonium and amino acids to musts of Airen variety on aromatic composition and sensory properties of the obtained wine

Musts from Airen grapes to which ammonium (100, 300 mg/l) and amino acids had been added (doubling the level of amino acids in that must) were fermented with three different yeast strains. Statistical treatments showed that the strain of yeast is the major factor affecting wine volatile composition, but must nitrogen supplementation also has an influence. The addition of any source of nitrogen to the must reduces the contents in the wine of β-phenylethanol (ca. 65% reduction), methionol (ca. 70%) and isoamyl alcohol (40–65%) and increases wine content of propanoic acid by 30–130%. Wines from musts supplemented with ammonium are richer in ethyl lactate and c-3-hexenol and wines supplemented with amino acids are richer in γ-butyrolactone and isobutanol. From the sensory point of view, must supplementation with ammonium brings about a decrease in sulphury notes and an increase in citric flavour. The effect of amino acid supplementation depends on the yeast strain. In one case, the effect is similar to that of ammonium supplementation; in the others an increase in fruity and fusel notes was obtained.     

Remediation of fungicide residues on fresh produce by use of gaseous ozone

Ozone fumigation was explored as a means for degrading organic fungicide residues on fresh produce. Fungicides sorbed onto model abiotic glass surfaces or onto grape berries were fumigated separately in a flow-through chamber. Gaseous ozone at a constant concentration of 150 ± 10 ppmv (μL·L(-1)) selectively oxidized fungicides sorbed to model surfaces. Over 140 min, boscalid and iprodione levels did not change significantly based on a single-factor analysis of variance (ANOVA) at the 95% level of confidence (p = 0.05); however, pseudo-first-order losses resulted in observable rate constants of ozonolysis, k(ozonolysis) (min(-1)), of 0.0233 ± 0.0029 (t(1/2) ≈ 29.7 min), 0.0168 ± 0.0028 (t(1/2) ≈ 41.3 min), and 0.0127 ± 0.0010 (t(1/2) ≈ 54.6 min) for fenhexamid, cyprodinil, and pyrimethanil, respectively. The relative degradation of fungicides on berries at gaseous ozone concentrations of 900 ± 12 ppmv (μL·L(-1)) over 2 h was similar to that on glass; decreases in residue concentration were observed for only fenhexamid (～ 64%), cyprodinil (～ 38%), and pyrimethanil (～ 35%) with corresponding k(ozonolysis) (min(-1)) of 0.0085 ± 0.0021 (t(1/2) ≈ 81.5 min), 0.0039 ± 0.0008 (t(1/2) ≈ 177.7 min), and 0.0036 ± 0.0007 (t(1/2) ≈ 192.5 min). Heterogeneous rate constants of gaseous ozone reacting with a sorbed fungicide, k(O(3)) (M(-1)·min(-1)), were calculated for both surfaces and indicate losses proceed ～ 15-fold slower on grapes. The kinetics and mechanism of fungicide removal, supported by gas chromatography- and liquid chromatography-mass spectrometry product analyses, is discussed in the context of facilitating compliance with maximum residue level (MRL) tolerances for fresh produce.     

Fenhexamid residues in grapes and wine

The behaviour of the fungicide, fenhexamid, on grapes, and during wine-making, as well as its effect on the microflora of alcoholic and malolactic fermentation has been studied. After treatment, the residue on grapes decreased rapidly to one-third of the initial level after the first week, while it remained constant during the following two weeks. At harvest, in the wine obtained by vinification without skins, the fungicide residue decreased on average by 49% , while in the wine obtained by vinification with skins, the decrease was on average 62% . The presence of this fungicide on grapes and in the wine did not affect alcoholic and malolactic fermentation, nor did fermentation cause any degradation of the fungicide. A simple and rapid gas chromatograhic method (GC-NPD) for the determination of fenhexamid residues in grapes, must and wine is described.     

Residues of insecticides, and fungicides in fruit produced in Ontario, Canada, 1986-1988

Between 1986 and 1988, 306 composite samples of fruit representing eight commodities were collected from farm deliveries to the marketplace in Ontario, Canada. All samples were analysed for insecticides and fungicides. The analysis procedure included tests for organochlorine, organophosphorus, synthetic pyrethroid and methylcarbamate insecticides and dithiocarbamate, dicarboximide and organochlorine fungicides. The commodities tested included apples, blueberries, cherries, grapes, peaches, pears, raspberries and strawberries. In 14% of all fruit samples, pesticide residues were below the detection limits, which ranged between 0.005 and 0.02 mg/kg. A further 14% had total combined pesticide residues below 0.1 mg/kg. Total combined fungicide and insecticide residues ranged from 0.1 to 11 mg/kg in 72% of samples. Six different pesticides were in violation of maximum residue limits (MRL) on 11 (3.6%) of fruit samples. Captan exceeded the 5 mg/kg MRL in five samples and EBDC exceeded the 7 mg/kg MRL in two. Other violations included single fruit samples with dicofol, endosulphan, phosalone and iprodione above the MRL. Raw grapes harvested for wine contained residues of 10 pesticides and the number changed little following the crushing of the grapes; however, fermentation into wine significantly reduced residues. Six insecticides and four fungicides were present on the raw grapes and 4/105 were above the MRL. Following crushing, four insecticides and five fungicides were identified and 4/40 were above the MRL. In wine only three insecticides were identified and all were well below the MRL. Carbaryl appeared to be the most persistent, declining very little between raw grapes and wine.     

Volatile compounds formation in alcoholic fermentation from grapes collected at 2 maturation stages: influence of nitrogen compounds and grape variety

The aim of this work was to study the influence of nitrogen compounds on the formation of volatile compounds during the alcoholic fermentation carried out with 4 nonaromatic grape varieties collected at 2 different maturation stages. To do this, Monastrell, Merlot, Syrah, and Petit Verdot grapes were collected 1 wk before harvest and at harvest. Then, the musts were inoculated with the same Saccharomyces cerevisiae yeast strain and were fermented in the same winemaking conditions. Amino acids that showed the highest and the lowest concentration in the must were the same, regardless of the grape variety and maturation stage. Moreover, the consumption of amino acids during the fermentation increased with their concentration in the must. The formation of volatile compounds was not nitrogen composition dependent. However, the concentration of amino acids in the must from grapes collected 1 wk before harvest can be used as a parameter to estimate the concentration of esters in wines from grapes collected at harvest and therefore to have more information to know the grape oenological capacity. Application of principal components analysis (PCA) confirmed the possibility to estimate the concentration of esters in the wines with the concentration of nitrogen compounds in the must.     

Rootstock and vineyard floor management influence on ‘Cabernet Sauvignon’ grape yeast assimilable nitrogen (YAN)

This is a study on the influence that two rootstocks (110R, high vigour; 420A, low vigour) and three vineyard floor management regimes (tilled resident vegetation – usual practise in California, and barley cover crops that were either mowed or tilled) had upon grape nitrogen-containing compounds (mainly ammonia and free amino acids recalculated as YAN), sugars, and organic acids in ‘Cabernet Sauvignon’ clone 8. A significant difference was observed for some of the free amino acids between rootstocks. In both sample preparation methods (juiced or chemically extracted), 110R rootstock grapes were significantly higher in SER, GLN, THR, ARG, VAL, ILE, LEU, and YAN than were 420A rootstock grapes. Differences in individual free amino acid profiles and concentrations were observed between the two sample preparations, which indicate that care should be taken when comparing values from dissimilar methods. No significant differences among vineyard floor treatments were detected, which suggests that mowing offers vineyard managers a sustainable practise, alternative to tilling, without negatively affecting grape nitrogen compounds, sugars, or organic acids.     

Changes on free amino acids during the alcoholic fermentation of strawberry and persimmon

Changes in amino acids and ammonium were monitored during the alcoholic fermentation of strawberry and persimmon purees. Fermentations were carried out either by autochthonous or by commercial yeasts. The amino acid content in strawberry and persimmon was lower than that of grapes but enough to successfully perform the alcoholic fermentation, showing a different consumption pattern. Arginine, although is not present in the most strawberry substrates, appears in strawberry wines (2.75–3.36 mg L^?1). Additionally, as opposed to grape wine, an exceptional high consumption of proline was observed during the alcoholic fermentation of strawberry purees. The consumption of amino acids was highly influenced by the substrate and the S. cerevisiae strain used for the fermentation process. These results were confirmed by principal component analysis, which was able to group the samples based on substrate, harvest or yeast strain, considering the amino acids as variables.     

Changes in Free Amino Acid and Total Nitrogen Concentrations During Maturation of Muscadine Grapes (V. rotundifolia)

Free amino acids, ammonia and total nitrogen were followed during maturation of berries of Carlos and Noble muscadine grapes (V. rotundifolia). Chemical analysis was done on deseeded berries. Ammonia decreased in the berries of both cultivars during maturation. Total nitrogen content fluctuated and was not significantly correlated with maturity in either cultivar. Threonine (THR) and histidine + gamma aminobutyric acid (HIS + GABA) were the predominant free amino acids in both cultivars at an immature berry stage. At full berry maturity, arginine (ARG) was the predominant amino acid in Carlos, having increased over 100-fold during the sampling period while ARG, alanine (ALA), THR, and HIS + GABA accounted for 72.3% of the total free amino acids. ALA was the predominant free amino acid in mature berries of Noble and accounted for 30.4% of the total free amino acids. Of the additional cultivars sampled only at their normal harvest date, berries of Pride, Magnolia and Regale contained nearly equal amounts of ARG and ALA as the predominant amino acids. Mature Dixie berries had twice as much ALA (29.8%) as ARG (12.8%). In general, the free amino acids in berries of muscadine grapes were found in concentrations similar to those reported in the literature for V. vinifera and V. labrusca cultivars. However, the large increase in proline concentration reported to occur during maturation of berries of V. vinifera cultivars was not found in any of the muscadine cultivars examined.     

Selective determination of thiram residues in fruit and vegetables by hydrophilic interaction LC-MS

Thiram belongs to the most important class of dithiocarbamate (DTC) fungicides including dimethyldithiocarbamates (DMDs), ethylenebis(dithiocarbamtes) (EBDs) and propylenebis(dithiocarbamates) (PBDs). During the surface extraction of fruit and vegetables for the LC-MS determination of residues of DMDs, EBDs and PBDs, thiram is reduced by the penicillamine buffer to the DMD anion, thus resulting in false-positive findings of DMD fungicides like ziram. Therefore, an alkaline sulfite buffer was applied for surface extraction, quantitatively transforming thiram into the DMD anion and a stable DMD–sulfite adduct that was used as a selective marker for thiram. Separation was performed isocratically on a ZIC-pHILIC column with acetonitrile–10 mM ammonium hydroxide solution (85/15). Mass selective detection was carried out on a single-quadrupole mass spectrometer coupled to an electrospray ionisation interface operating in negative mode. Using d₁₂-thiram as the internal standard, recoveries of 80–108% were obtained from apples, tomatoes, grapes and sweet peppers, spiked in the range of 0.02–1 mg kg^?1. Limits of detection and quantification were 0.6 and 2 µg kg^?1, respectively.     

不同棚膜颜色对赤霞珠葡萄果实氨基酸含量的影响

葡萄中的氨基酸含量是影响葡萄和葡萄酒香气品质的重要因素。试验以陕西泾阳的赤霞珠葡萄为试材，研究了不同颜色的避雨棚膜（白色、蓝色和紫色）对葡萄成熟时氨基酸含量的影响。结果表明，连续两年，蓝色和白色棚膜显著提高了葡萄中的谷氨酸、丝氨酸和天冬氨酸含量（P＜0.05）；蓝色棚膜显著提高了葡萄中精氨酸、甘氨酸和丙氨酸等大部分氨基酸的含量（P＜0.05）。综合考虑，蓝色棚膜是提升赤霞珠葡萄氨基酸含量的最佳棚膜。     

Ammonium exposure and pyruvate affect the amino acid metabolism of bovine blastocysts in vitro

The accumulation of ammonium is a major artefact of in vitro embryo culture. This study has examined ammonium production and potential mechanisms of disposal in preimplantation bovine blastocysts. Embryos were produced by in vitro maturation and fertilisation of oocytes, and cultured in synthetic oviduct fluid containing amino acids and BSA (SOFaaBSA). Ammonium/urea concentrations were determined enzymatically. Amino acid appearance/disappearance 'profiles' of single blastocysts were determined at 0, 1.25 and 2.5 mM NH(4)Cl (with or without 0.33 mM pyruvate), and with or without 10 mM dipicolinic acid (DPCA; a glutamate dehydrogenase (GLDH) inhibitor) or 2 mM amino-oxyacetate (AOA; a transaminase inhibitor). Free ammonium was produced at a rate of 4.281 (+/-0.362) pmol/embryo/h, while urea production was undetectable. The presence/absence of pyruvate affected amino acid profiles, especially alanine appearance (P < 0.001), glutamate disappearance (P < 0.05) and overall turnover (the sum of appearance and disappearance) (P < 0.001). GLDH inhibition with DPCA had no effect on amino acid overall disappearance, but glutamate disappearance increased, while that of arginine decreased (P < 0.05). The transaminase inhibitor, AOA, depressed turnover (P < 0.05), aspartate and glutamate disappearance, and alanine appearance. Thus, bovine blastocysts release ammonium as free ions or fix them, not as urea, but as alanine, possibly glutamine and, less likely, arginine. An active role for GLDH and transaminases in regulating blastocyst amino acid metabolism was demonstrated.