Lerno L.,University of California at Davis |
Reichwager M.,University of California at Davis |
Ponangi R.,E and J Gallo Winery |
Hearne L.,E and J Gallo Winery |
And 2 more authors.
American Journal of Enology and Viticulture | Year: 2015
The phenolic content of red wine is responsible for the color, mouthfeel, and aging potential of the wine. Although many fermentation parameters and winemaking techniques affect phenolic extraction, it is generally agreed that one of the prime factors is fermentation temperature, however, temperature is not uniform during fermentation and thermal gradients form between the cap and the liquid. To determine the effects of temperature on phenolic extraction, research scale (120 L) Cabernet Sauvignon fermentations were performed in which the cap and must were either maintained at the same temperature or a constant thermal gradient was maintained between the two during the period of active fermentation. All fermentations were sampled twice daily and phenolic content was determined by reverse-phase high-performance liquid chromatography for the monomeric phenolics and UV-vis spectroscopy for the total anthocyanins and condensed tannins. These experiments showed that cap and must temperature had noticeable effects on phenolic extraction based on where the phenolics originated. For skin phenolics, temperature affected the rate of extraction but not the final concentration, and increasing temperatures favored faster extraction. For seed phenolics, increases in fermentation temperature increased both the rate of extraction and the final concentration. Results showed that must temperature was more important than cap temperature in driving extraction of phenolics. © 2015 by the American Society for Enology and Viticulture. All rights reserved.
Mendez-Costabel M.P.,E and J Gallo Winery |
Mendez-Costabel M.P.,University of Adelaide |
Wilkinson K.L.,University of Adelaide |
Bastian S.E.P.,University of Adelaide |
And 3 more authors.
American Journal of Enology and Viticulture | Year: 2013
A field study was conducted from 2007 to 2010 to examine regional and seasonal variability of the main compounds responsible for green aromas in grapes and wines, 3-isobutyl-2-methoxypyrazine and C6 compounds. Sixty-nine commercial Vitis vinifera L. Merlot vineyards located in three distinctly different winegrape growing regions within the Central Valley of California were sampled at commercial harvest, fruit samples were analyzed for green aroma compounds and standard chemometrics, and several weather parameters such as growing degree days and rainfall were recorded at the vineyard level. Seasonal variation was found to be more important than regional variation, and similar trends among regions were found within each season. Temperature during the spring, a period of active growth, was found to be a significant driver of fruit green aroma compounds at harvest, likely due to its interactions with vine vigor and fruit shading. © 2013 by the American Society for Enology and Viticulture. All rights reserved.
Cousins P.,E and J Gallo Winery |
Zhong G.-Y.,U.S. Department of Agriculture
Acta Horticulturae | Year: 2015
Grapevines of most species and cultivars produce lateral meristems (tendrils and inflorescences) on at least two successive nodes in three. Lateral meristems complicate rootstock cutting production, since tendrils are removed from rootstock cuttings prior to propagation and since tendrils clinging to wires, canes, or other tendrils make collecting cuttings more time consuming and expensive. To develop improved grapevine rootstocks with reduced lateral meristems, an elite nematode resistant rootstock selection ((Vitis berlandieri × V. riparia) × V. Biformis) was crossed with 'Roger's Red' (Vitis hybrid), and 'Roger's Red' was also self-pollinated. Seedlings from controlled pollinations were grown in a greenhouse and trained up a stake. Starting at the first node in alternate phyllotaxy (that is, a node with a lateral meristem) and continuing for twelve nodes, the presence or absence of lateral meristems was observed and the type of lateral meristem was reported. There were 141 cross-pollinated seedlings. There were 83 seedlings from 'Roger's Red' selfpollination. The expected pattern of lateral meristem distribution was wild type: two successive lateral meristem bearing nodes, followed by a single lateral meristem-free node. However, 43 of 83 seedlings from 'Roger's Red' self-pollination showed two or more successive lateral meristem-free nodes (flanked by lateral meristem-bearing nodes), and 12 of these 43 showed at least two sets of two successive lateral meristem-free nodes. One self-pollinated seedling showed three successive lateral meristem-free nodes in the alternate phyllotaxy. In contrast, in the hybrid population only 33 of 141 seedlings showed the non-wild type pattern of two successive lateral meristem-free nodes, and only 6 of these 33 showed at least two sets of two successive lateral meristem-free nodes. Tendril distribution is under genetic control and the production of extra tendril-free nodes was segregating in these populations. Dominant alleles at two genes are required for the mutant phenotype. A genetic model and the gene names Successive Tendril free Node-1 and Successive Tendril free Node-2 are proposed. © 2015 ISHS.
Dunn B.,Stanford University |
Richter C.,E. and J. Gallo Winery |
Kvitek D.J.,Stanford University |
Pugh T.,E. and J. Gallo Winery |
Sherlock G.,Stanford University
Genome Research | Year: 2012
Although the budding yeast Saccharomyces cerevisiae is arguably one of the most well-studied organisms on earth, the genome-wide variation within this species - i.e., its "pan-genome" - has been less explored. We created a multispecies microarray platform containing probes covering the genomes of several Saccharomyces species: S. cerevisiae, including regions not found in the standard laboratory S288c strain, as well as the mitochondrial and 2-μm circle genomes-plus S. paradoxus, S. mikatae, S. kudriavzevii, S. uvarum, S. kluyveri, and S. castellii. We performed array-Comparative Genomic Hybridization (aCGH) on 83 different S. cerevisiae strains collected across a wide range of habitats; of these, 69 were commercial wine strains, while the remaining 14 were from a diverse set of other industrial and natural environments. We observed interspecific hybridization events, introgression events, and pervasive copy number variation (CNV) in all but a few of the strains. These CNVs were distributed throughout the strains such that they did not produce any clear phylogeny, suggesting extensive mating in both industrial and wild strains. To validate our results and to determine whether apparently similar introgressions and CNVs were identical by descent or recurrent, we also performed whole-genome sequencing on nine of these strains. These data may help pinpoint genomic regions involved in adaptation to different industrial milieus, as well as shed light on the course of domestication of S. cerevisiae. © 2012, Published by Cold Spring Harbor Laboratory Press.
Scheiner J.J.,Cornell University |
Vanden Heuvel J.E.,Cornell University |
Pan B.,E and J Gallo Winery |
Sacks G.L.,Cornell University
American Journal of Enology and Viticulture | Year: 2012
A study was conducted to determine the key environmental and viticultural variables affecting the concentration of 3-isobutyl-2-methoxypyrazine (IBMP) in Cabernet franc grapes. Berries were sampled from individual vines at 30 days after anthesis (DAA), 50 DAA, and harvest from 10 and 8 commercial New York State vineyards in 2008 and 2009, respectively. IBMP concentrations at 50 DAA were significantly higher in the warmer 2008 growing season (2008, 103 to 239 pg/g; 2009, 12 to 87 pg/g). However, in the cooler 2009 growing season a smaller percent decrease in IBMP from 50 DAA to harvest was observed, so that IBMP at harvest was not significantly different between years (2008, 1 to 13 pg/g; 2009, 5 to 14 pg/g). IBMP accumulation up to 50 DAA and log-fold decrease of IBMP from 50 DAA to harvest was modeled as a function of >120 viticultural and environmental variables (122 in 2008 and 140 in 2009). Important variables identified for modeling IBMP at 50 DAA were those associated with vine vigor, which was positively correlated with IBMP accumulation. Cluster light exposure did not explain differences in IBMP accumulation across sites, but it was important for modeling smaller differences within some sites. IBMP decrease could not be satisfactorily modeled across multiple sites, but within sites the decrease was most consistently correlated with classic fruit maturity indices (total soluble solids [TSS], TSS*pH 2). The intensity of herbaceous aromas in wines produced from each site was not correlated with IBMP concentration, but multivariate models indicated that lower vine water status was the best predictor of increased herbaceousness. © 2012 by the American Society for Enology and Viticulture. All rights reserved.
Huber F.,Julius Kuhn Institute |
Rockel F.,Julius Kuhn Institute |
Schwander F.,Julius Kuhn Institute |
Maul E.,Julius Kuhn Institute |
And 3 more authors.
Vitis - Journal of Grapevine Research | Year: 2016
The Vitis vinifera background of 'Catawba' and 'Concord' was investigated by using SSR analysis: 'Sémillon' was shown to be an ancestor of 'Catawba', while the wild parent remains unknown. 'Concord' was confirmed to be an offspring of 'Catawba' and another unknown wild parent. Since these two important American varieties most likely resulted from random natural crosses and successful selection, the original, wild growing wild donors remain unknown. © The author(s).
Musumeci L.E.,Cornell University |
Ryona I.,Cornell University |
Pan B.S.,E. and J. Gallo Winery |
Loscos N.,E. and J. Gallo Winery |
And 3 more authors.
Molecules | Year: 2015
Analyses of key odorous polyfunctional volatile thiols in wines (3-mercaptohexanol (3-MH), 3-mercaptohexylacetate (3-MHA), and 4-mercapto-4-methyl-2-pentanone (4-MMP)) are challenging due to their high reactivity and ultra-trace concentrations, especially when using conventional gas-chromatography electron impact mass spectrometry (GC-EI-MS). We describe a method in which thiols are converted to pentafluorobenzyl (PFB) derivatives by extractive alkylation and the organic layer is evaporated prior to headspace solid phase microextraction (HS-SPME) and GC-EI-MS analysis. Optimal parameters were determined by response surface area modeling. The addition of NaCl solution to the dried SPME vials prior to extraction resulted in up to less than fivefold improvement in detection limits. Using 40 mL wine samples, limits of detection for 4-MMP, 3-MH, and 3-MHA were 0.9 ng/L, 1 ng/L, and 17 ng/L, respectively. Good recovery (90%-109%) and precision (5%-11% RSD) were achieved in wine matrices. The new method was used to survey polyfunctional thiol concentrations in 61 commercial California and New York State wines produced from V. vinifera (Riesling, Gewürztraminer, Cabernet Sauvignon, Sauvignon blanc and non-varietal rosé wines), V. labruscana (Niagara), and Vitis spp. (Cayuga White). Mean 4-MMP concentrations in New York Niagara (17 ng/L) were not significantly different from concentrations in Sauvignon blanc, but were significantly higher than 4-MMP in other varietal wines. © 2015 by the authors; licensee MDPI.
Singh D.P.,Australian Department of Primary Industries and Fisheries |
Chong H.H.,E and J Gallo Winery |
Pitt K.M.,Australian Department of Primary Industries and Fisheries |
Cleary M.,E and J Gallo Winery |
And 2 more authors.
Australian Journal of Grape and Wine Research | Year: 2011
Background and Aims: Taint in smoke-exposed grapes have been associated with elevated levels of guaiacol and 4-methylguaiacol. Previous research has reported guaiacol and 4-methylguaiacol in both fruits and wines. In some cases, these compounds were not detected, or were detected at low levels in the fruit while high levels were subsequently identified during or after winemaking. Later research indicated that this was due to the presence of glycosidic conjugates. Here we report a method for the routine analysis of guaiacol and 4-methylguaiacol released after acid hydrolysis of glycoside precursors. Methods and Results: Chardonnay, Merlot, Shiraz, Sangiovese and Cabernet Sauvignon fruits were collected following bushfire events in 2006-2007 in the King Valley wine region of NE Victoria, Australia. Gas chromatography-mass spectrometry (GC-MS) was used to detect free guaiacol and 4-methylguaiacol in both fruits and wines. Low levels of free and bound forms were present in fruit not exposed to smoke. Substantial levels of free guaiacol and 4-methylguaiacol were detected in the wines made from the smoke-affected fruits. These compounds increased during bottle storage. Acid hydrolysis of wines and berries resulted in a several-fold increase in free guaiacol and 4-methylguaiacol. Conclusions: The validated GC-MS method is suitable for monitoring free and glycosidically bound guaiacol and 4-methylguaiacol after acid hydrolysis in both fruits and wines. Acid hydrolysis of wines provided evidence that bound volatiles, most probably glycosidically, act as reserve for guaiacol and 4-methylguaiacol, which are released during ageing of wines. Significance of the Study: This is the first study published in a refereed journal to demonstrate that smoke taint-associated volatiles increase during ageing of wine and bound forms of guaiacol and 4-methylguaiacol represent an aroma reserve for smoke taint in ageing/bottled wines. © 2011 Department of Primary Industries Victoria, Australia.
Taylor J.A.,Cornell University |
Taylor J.A.,Northumbria University |
Sanchez L.,E and J Gallo Winery |
Sams B.,E and J Gallo Winery |
And 4 more authors.
Journal International des Sciences de la Vigne et du Vin | Year: 2016
Aims: Yield monitors are becoming more common in North America. This research evaluates the precision and accuracy of a retro-fitted, commercially available grape yield monitor mid-season, for crop estimation and crop thinning applications, and at harvest for yield mapping. Methods and Results: Several grape yield monitors were mounted on the discharge conveyor belt of grape harvesters in both commercial and research vineyards in North America. Sensor response was compared to manual measurements at multiple masses, ranging from 20 kg to 28 Mg over the course of three seasons. Measurements were taken during crop thinning and estimation (midseason) and at harvest. Results showed that the grape yield monitor performance was sufficient to generate good spatial maps of the relative variation in harvest yield and mid-season thinned yield. However, at harvest the sensor showed a shift in response between days of up to ±15 %, such that the generation of absolute yield maps required a daily calibration against a known mass. Within a day (single harvest operation) the sensor response did not appear to drift. Mid-season applications required a different calibration to harvest applications. Conclusion: The yield sensor worked well for both midseason and at harvest operations in North American vineyards but required a daily calibration to avoid drift issues. The mid-season yield calibrations were different between seasons; however, the harvest calibration factor was stable between seasons. Significance and Impact of study: The study showed that a commercial yield monitor with correct calibration was effective at even low fruit flow. This opens the possibility of using a harvest sensor mid-season to mechanically estimate fruit load from small point samples and to map the amount of fruit removed during fruit thinning operations. This will improve the quality of information available to viticulturist to understand fruit and crop load. The commercial yield monitor is suitable for use in North American vineyards. © Vigne et Vin Publications Internationales (Bordeaux, France).
Chong H.H.,E. and J. Gallo Winery |
Cleary M.T.,E. and J. Gallo Winery
ACS Symposium Series | Year: 2012
In 2008, unprecedented wildfires in California, most notably in Northern California, caused considerable concern within the winemaking industry. Mendocino County, home to approximately 300 vineyards and 50 wineries experienced significant exposure. Pyrolysis of wood components during wildfires generates a mixture of volatile compounds. Volatile phenols such as guaiacol and 4-methylguaiacol contribute to smoke-derived aroma, and are reported as principal chemical markers in smoke tainted grapes. Our study confirmed that smoke taint marker compounds, guaiacol and 4-ethylguaiacol, are bound to sugar in exposed berries. The glucose bound compounds will likely be released by yeast glucosidase during fermentation, whereas those that are non-glucose bound may be released by acid hydrolysis throughout wine aging in the bottle. An enzymatic hydrolysis method was developed to liberate the bound smoke-derived aroma and to quantify them via gas chromatography head space analysis. The proximity, intensity, and duration of wildfires were shown to correlate with the levels of glycosidic conjugates of guaiacol and 4-methylguaiacol in grapes. © 2012 American Chemical Society.