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•High throughput sequencing, Illumina HiSeq 2500, was applied to investigate the microbial diversity of rain-shelter cultivated vineyard.•Microbial community pattens of different ...grapevine compartments and vine soils were compared during grape development to determine the impacts of rain-shelter cultivation.•Altered vineyard microclimate under rain-shelter treatment effectively minimized potential microbial diseases caused by Alternaria, Colletotrichum, etc.•Our research signified the rain-shelter as an alternative way with limited chemicals/fungicides usage for an optimal vineyard management.
Rainfall particularly under continental climates with monsoonal tendency impacts the vineyard microbial niches during grapevine growth. With microbial community shifts, vine traits (grape flavor and yield) cultivated/protected under rain-shelter may ultimately be altered. Such cultivation may influence microflora dynamics via meteorological parameter variations, however this is unclear yet. Here, we used Cabernet Sauvignon, a prevalent red cultivar among wine growing regions, to evaluate the effects of the rain-shelter cultivation on the microorganism diversity. We found that average air temperature under rain-shelter conditions was 2–3 °C higher than the non-covered group, while air humidity the maximum reduction was 5.79% (p < 0.05). After grape setting stage, similar trends were observed on soil temperature (increased) and humidity (lowered) under the treatments (p < 0.05). UV and precipitation of rain-shelter treatment were less by a total of 72% and 96%, respectively (p < 0.05). The rain-shelter management presented lower fungal and bacterial OTUs. The fungal alpha diversity on leaves and branches under rain-shelter was lower (p < 0.05) than the control as the grape ripeness, with Ascomycota, Mycosphaerella and Cladosporium as the principal fungi. Our results revealed that the fungal microbiota patterns were differentiated by the cultivations from setting stage to the entire véraison and then tended to be similar at harvesting. Only branch fungal patterns were observed asymmetrically at all stages. Meanwhile, bacterial diversity and distribution varied on colonization locations where Proteobacteria and Actinobacteria were the primary bacteria phyla. Bacterial community structures overlapped at harvest, while the differences were observed between two cultivations at other stages, excluding grape berry. The rain-shelter cultivation reduced the abundance of Alternaria and Colletotrichum that may adversely affect grapevine health. Multivariate statistical analysis suggested that the effect of vineyard microclimate on microbiota distribution and succession were influenced by cultivation modes and grapevine developmental stages. This research provides evidence to address the dynamics of microbial ecology from vineyard to grape under rain-shelter cultivation, and its benefits as a sustainable vineyard management.
Grapes are one of the most important fruits because of their economic and nutritional benefits, and grapevines are widely cultivated in arid and semi-arid areas. Therefore, it is critical to study ...the mechanism by which grapevines respond to water stress. In this research, micro-morphological and metabolomic analyses were conducted to evaluate the effects of water stress on stomatal morphology and volatile compounds extracted from the leaves of grapevine plants. There were two treatments: well-watered plants (watered daily) and drought-stressed plants (no irrigation). Plant weights were recorded, and the well-watered plants were irrigated daily to replace the water lost to evapotranspiration. The water status of the grapevines was determined according to their relative water content. The changes in proline content, hydrogen peroxide content, lipid peroxidation and antioxidant activities, as well as those of photosynthetic parameters and chlorophyll fluorescence, were monitored as markers of water stress. The microscopic changes in stomatal behavior were observed using a scanning electron microscope. A total of 12 secondary volatile compounds, including aldehydes, ketones and alcohols, were detected in the grapevine leaves. Among them, (E)-2-hexenal and 3-hexenal showed a significant increase after water stress. Multivariate statistical analysis revealed that the levels of 3-hexenal and (E)-2-hexenal were closely related to the changes in proline, hydrogen peroxide (H2O2), malondialdehyde (MDA), catalase (CAT) and superoxide dismutase (SOD). These results suggested that water stress could regulate the accumulation of green leaf volatiles, especially (E)-2-hexenal and 3-hexenal, in coordination with the reactive oxygen species (ROS) scavenging system. These compounds may act as signaling compounds in response to water stress in grapevines.
•The concentrations of (E)-2-hexenal and 3-hexenal significantly increased under water stress.•The variation in the concentrations of accumulations of C6 volatiles under water stress were related to leaves.•The accumulations of C6 volatiles were correlated to the activities of antioxidant enzymes.•C6 compounds may act as signalling compounds in response to water stress in grapevine.•The information about changes at microscopic level on stomata structure under drought stress are more interesting.
•Bud dormancy onset was not related to the onset of fruit ripening in both cultivars.•‘Cabernet Sauvignon’ showed an earlier initiation of dormancy compared to ‘Chardonnay’.•A wide range of ...temperatures was effective for chilling in both cultivars.•‘Chardonnay’ required less heat accumulation causing an earlier budbreak.•The phenology model showed satisfactory accuracy for both cultivars.
Dormancy is an evolutionary strategy to overcome adverse conditions during winter through the interruption of growth and metabolism. Winter dormancy is divided into two phases: endodormancy when bud growth is inhibited internally, and ecodormancy when adverse environmental conditions impede growth. The study of winter dormancy is limited because the onset and transition between the two dormancy phases do not have any visual symptoms. Therefore, the goal of this study was to develop a model to predict the occurrence of the onset and release of dormancy phases and budbreak in grapevines ‘Cabernet Sauvignon’ and ‘Chardonnay’. An integrated phenological model was developed assuming that the shortening of the photoperiod induces the onset of endodormancy when a critical day length specific for each cultivar is reached. Then, a period of exposure to chilling temperatures induces the transition from endodormancy to ecodormancy, followed by a period of warm temperatures that forces budbreak. The model showed that ‘Cabernet Sauvignon’ has a longer endodormancy period caused by the cultivar-specific sensitivity to shorter photoperiods, as well as a slower completion of the chilling requirements compared to ‘Chardonnay’. For both cultivars, relatively high temperatures were effective for chilling accumulation. The base temperature for heat effect accumulation was the same for the two cultivars at 5.6 °C, while ‘Chardonnay’ had a lower heat requirement causing a shorter ecodormancy period and earlier budbreak compared to ‘Cabernet Sauvignon’. Although the trendline for predicted-versus-observed budbreak dates was significantly different from the 1:1 line, it showed a high R2 value of 0.92. The model also presented high accuracy and performance based on other evaluation statistics such as a correlation coefficient of 0.96, an RMSE of 5 days, and an agreement index of 0.95. Future updates of the model should add the temperature effect on the estimation of endodormancy onset.
The analytical scope of static headspace–gas chromatography–ion mobility spectrometry (SHS–GC–IMS) was applied to wine aroma analysis for the first time. The method parameters were first fine-tuned ...to achieve optimal analytical results, before the method stability was demonstrated, in terms of repeatability and reproducibility. Succinct qualitative identification of compounds was also realized, with the identification of several volatiles that have seldom been described previously in Sauvignon Blanc wine, such as methyl acetate, ethyl formate, and amyl acetate. Using the SHS–GC–IMS data in an untargeted approach, computer modeling of large datasets was applied to link aroma chemistry via prediction models to wine sensory quality gradings. Six machine learning models were compared, and artificial neural network (ANN) returned the most promising performance with a prediction accuracy of 95.4%. Despite its inherent complexity, the ANN model offered intriguing insights on the influential volatiles that correlated well with higher and lower sensory gradings. These findings could, in the future, guide winemakers in establishing wine quality, particularly during blending operations prior to bottling.
•Irrigation with 60% evapotranspiration (ETc) increase the content of unsaturated fatty acids in grape berries.•Irrigation with 60% ETc treatment decrease the level of alcohols and esters volatiles ...in wines.•Irrigation with 70% and 80% ETc treatments enhance C6 volatiles in wines.•The accumulation of C6 compounds is closely related to UFAs, especially linolenic acid and linoleic acid.
The effect of regulated deficit irrigation (RDI) on fatty acids and their derived volatiles in ‘Cabernet Sauvignon’ grapes and wines was investigated during two growing seasons in the east foot of Mt. Helan, the semi-arid area. The vines received water with 60% (RDI-1), 70% (RDI-2), 80% (RDI-3), 100% (CK, traditional drip irrigation) of their estimated evapotranspiration (ETc) respectively. RDI treatments resulted in lower yield, berry weight and titratable acidity with higher total soluble solids. RDI-1 increased the content of unsaturated fatty acids in berries and decreased the level of alcohols and esters volatiles in wines. RDI-2 and RDI-3 enhanced 1-hexanol and esters in wines in comparison with CK. The concentrations of C6 aroma compounds were closely correlated with unsaturated fatty acids (p < .05), especially linolenic acid and linoleic acid. The present results provided direct evidence and detailed data to explain the effect of RDI on grapes and wines composition regarding fatty acids and their derived volatiles.
► Combination of infrared and chemometrics opens the possibility to discriminate between Australian and New Zealand Sauvignon Blanc. ► This type of method used by the wine industry will guarantee the ...provenance of the wines to the consumers. ► This method will also help to study and understand the effect of climate change on grape and wine production.
The combination of UV, visible (Vis), near-infrared (NIR) and mid-infrared (MIR) spectroscopy with multivariate data analysis was explored as a tool to classify commercial Sauvignon Blanc (Vitis vinifera L., var. Sauvignon Blanc) wines from Australia and New Zealand. Wines (n=64) were analysed in transmission using UV, Vis, NIR and MIR regions of the electromagnetic spectrum. Principal component analysis (PCA), soft independent modelling of class analogy (SIMCA) and partial least squares discriminant analysis (PLS-DA) were used to classify Sauvignon Blanc wines according to their geographical origin using full cross validation (leave-one-out) as a validation method. Overall PLS-DA models correctly classified 86% of the wines from New Zealand and 73%, 86% and 93% of the Australian wines using NIR, MIR and the concatenation of NIR and MIR, respectively. Misclassified Australian wines were those sourced from the Adelaide Hills of South Australia. These results demonstrate the potential of combining spectroscopy with chemometrics data analysis techniques as a rapid method to classify Sauvignon Blanc wines according to their geographical origin.
Cabernet Sauvignon grape juice and wine underwent in vitro digestion, resulting in a reduction of most phenolic compounds (10%–100% decline), notably impacting anthocyanins (82%–100% decline) due to ...pH variations. However, specific phenolics, including p–hydroxybenzoic, protocatechuic, vanillic, p-coumaric, gallic and syringic acids, and coumarin esculetin, increased in concentration (10%–120%). Grape juice and wine samples showed comparable polyphenolic profile during all phases of digestion. Antioxidant activity persisted, and inhibition of angiotensin-I converting enzyme was improved after the digestion process, likely because of increased concentrations of listed phenolic acids and esculetin. Digested grape juice displayed comparable or superior bioactivity to red wine, indicating it as a promising source of accessible grape polyphenols for a broader audience. Nevertheless, Caco-2 cell model metabolization experiments revealed that only 3 of 42 analyzed compounds passed to the basolateral compartment, emphasizing the significant impact of digestion on polyphenol bioactivity, suggesting potential yet unmeasurable and overlooked implications for human health.
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•Digestion caused a decline in concentration of most phenolics except phenolic acids.•Amount of anthocyanins was mostly reduced during digestion.•Digestion preserved antioxidant activity of grape juice and wine.•Only 3 of 42 analyzed compounds passed to the basolateral compartment of Caco-2 cells.•Grape juice is valuable source of grape polyphenols for wider consumption than wine.
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•Wines matured in different vessels had similar VOC profiles after 6 months.•Differences in the VOC content of wines among vessels are maximized after 4.5 months.•Using screwcaps led ...to wines with higher contents of VOCs, regardless of the vessel used.•Natural cork combined with alternative vessels increases the ionene content in wine.
A Sauvignon Blanc wine was subjected to a maturation period of six months by using four different types of vessels in triplicate: cylindrical stainless steel tanks, oval-shaped polyethylene tanks, cubic-shaped polyethylene tanks, and clay jars. After maturation in the different vessels, wines were bottled using three different closures (natural cork, synthetic cork, and screwcaps). The volatile compound profiles of the wine samples were recorded by SPME-GC–MS throughout vessel maturation as well as after the bottle storage period. In general terms, wines stored in stainless steel tanks showed the highest contents of volatile compounds when compared with the other tested vessels. Moreover, wines from bottles capped with screwcaps showed the highest contents of most of the volatile compounds when compared with the other closures. Moreover, an interaction between the vessel and the closure was observed: when screwcaps were used during bottle aging, the resulting wines were very similar to those matured in stainless steel vessels. These results suggest that the use of screwcaps hides the differences originating from wine composition during maturation in vessels other than stainless steel.
This study investigated the stability of wine anthocyanins under simulated gastrointestinal pH and temperature conditions, and further studied the evolution of anthocyanin degradation products ...through simulated digestive conditions. The aim of this study was to investigate the relation between anthocyanins' structure and their digestive stability. Results showed that a total of 22 anthocyanins were identified in wine and most of these anthocyanins remained stable under simulated gastric digestion process. However, a dramatic concentration decrease happened to these anthocyanins during simulated intestinal digestion. The stability of anthocyanins in digestive process appeared to be related to their structure. The methoxy group in the B-ring enhanced the stability of anthocyanins, whereas hydroxyl group resulted in a reduction of their stability. Acylation decreased the stability of malvidin 3-
-glucoside. Pyruvic acid conjugation enhanced the structural stability of pyranoanthocyanins, whereas acetaldehyde attachment weakened their stability. A commercial malvidin 3-
-glucoside standard was used to investigate anthocyanin degradation products under simulated digestion process, and syringic acid, protocatechuic acid and vanillic acid were confirmed to be the degradation products via anthocyanin chalcone conversion path. Gallic acid, protocatechuic acid, vanillic acid, syringic acid, and
-coumaric acid in wine experienced a significant concentration decrease during digestion process. However, wine model solution revealed that phenolic acids remained stable under gastrointestinal conditions, except gallic acid.
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•Adding caffeic and rosmarinic acids before the alcoholic fermentation of red wine.•The evolution of colors and polyphenolics was figured out by CIELAB and HPLC-MS.•The addition ...enhanced chromatic quality and copigmentation effect.•The addition can be applied as an alternative strategy for making premium red wines.
Although phenolic copigments are rarely colored, they can still influence color expression in red wine copigmentation. Here, prefermentative agents, such as caffeic and rosmarinic acids, were added as copigments during Cabernet Sauvignon red winemaking. The evolution of colors and polyphenols was analyzed by tristimulus colorimetry and high-performance liquid chromatography-tandem mass spectrometry during brewing and aging periods. The results showed that the addition of caffeic and rosmarinic copigments was beneficial to obtain more saturated and vivid hue of wines. The changes in color were correlated with a significant increase in anthocyanins concentration. Moreover, the results demonstrated that the addition of the two phenolic copigments increased the concentration of total phenols and enhanced the copigmentation effect, indicating improved chromatic intensity and color stability of wines. Therefore, the addition of caffeic and rosmarinic acids is a simple and useful enological technique to obtain red wines with high color quality and aging potential.
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