Since hydrogen sulfide (H2S) is a newly discovered gas signal molecule in plants, minimal studies are available regarding its role in grape berries color changes. This study found that 0.1 mM NaHS ...(H2S donor) could significantly promote color changes in grape berries, mainly by affecting the upregulated expression of anthocyanin synthesis-related genes. Further studies showed that the endogenous H2S content gradually accumulated as the grape berries ripened and mainly depended on the upregulation of the H2S synthetase gene VvSiR and its enhanced enzyme activity. More results showed that VvWRKY30 gene expression was also significantly upregulated during veraison. The overexpression of VvWRKY30 could induce VvSiR expression and H2S accumulation. Experiments involving the yeast one-hybrid and dual-luciferase reporter assay system showed that VvWRKY30 could directly interact with the VvSiR promoter. The overexpression of VvWRKY30 and VvSiR during the grape berry development stage, both promoted the anthocyanin accumulation and berry color changes. These findings indicated that H2S encouraged anthocyanin accumulation and color changes in grape berries, while the H2S accumulation in vivo depended on VvWRKY30 promoting the expression of its synthetase gene, VvSiR.
The evolution of flavonoids under altered temperature and light conditions in the fruit zone was followed in Cabernet Sauvignon (
Vitis vinifera
L.) grapes during ripening. The study was conducted ...over two consecutive seasons in 2010/2011 and 2011/2012 comprising two main treatments in which the light quantity was manipulated in the bunch zone: (1) standard (STD) with no lateral shoot or leaf removal and (2) leaf removal west (LRW) treatment with leaf removal on the western side of the bunch zone. Furthermore, the light quality was altered by installing ultraviolet B-suppression sheets within the bunch zone in both seasons. Tannin evolution was dependent on the prevailing light quality/quantity and temperatures during berry development in a particular season. Grape seed tannin accumulation coincided with seed development and commenced at the early stages of berry development. Seed proanthocyanidin composition was not influenced by the treatments. The largest impact on proanthocyanidin accumulation and structure in the skin was due to seasonal variations highlighting the complex interaction between light quality and/or quantity across the two growing seasons and eventually the complex interaction with temperature. Flavonol accumulation was significantly influenced by the light quality, which is known to be the main abiotic driver of flavonol biosynthesis regulation. Anthocyanin concentration and content were largely dependent on the temperature and light quality in a particular season. Anthocyanin composition was altered by the season rather than the treatment.
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•CSDRW treatment had potential anti-atherosclerotic effect in AS mouse model.•CSDRW treatment decreased the AS lesion size by 53.47% compared to AS mice.•CSDRW regulated the hepatic ...lipid metabolism pathway.•CSDRW regulated specific gut microbiota which were significantly correlated with AS.
Limited evidence suggests that the abundance of antioxidant polyphenols in dry red wine (DRW) may prevent cardiovascular diseases, a benefit likely attributed to abundant antioxidant polyphenols present in DRW. Here, we examined the anti-atherosclerotic effect of Cabernet Sauvignon DRW (CSDRW) in a mouse model of atherosclerosis (AS) using metabolomic profiling and molecular techniques. Oral administration of CSDRW reduced atherosclerotic lesion size in ApoE-/- mice, alleviated hyperlipidemia, ameliorated hepatic lipid accumulation mediated by AMPK activation, and promoted lipid metabolism via PPARγ–LXR-α–ABCA1 pathway regulation. CSDRW increased the relative abundance of beneficial gut microbiota, including Bacteroidetes, Verrucomicrobiota, and Akkermansiaceae. Metabolic analysis using liquid chromatography–tandem mass spectrometry revealed that CSDRW contained various polyphenols, including flavanol, phenolic acid, flavonol, and resveratrol, which possibly mediate the beneficial effects in AS by reducing inflammation, restoring normal endothelial function, regulating hepatic lipid metabolism, and modulating gut microbiota composition.
This review discusses the factors that affect the concentrations of methoxypyrazines (MPs) and the techniques used to analyze MPs in grapes, musts, and wines. MPs are commonly studied pyrazines in ...food science due to their contribution of aroma and flavor to numerous vegetables such as peas and asparagus. They are described as highly odorous compounds with a very low olfactory threshold. The grape varietals that exhibit green or herbaceous aromas that are characteristic of MPs are predominantly Vitis vinifera cv. Cabernet Sauvignon and Sauvignon Blanc, but include others. The most extensively studied MPs include 3-isobutyl-2-methoxypyrazine, 3-isopropyl-2-methoxypyrazine, and 3-sec-butyl-2-methoxypyrazine. It outlines the significance of methoxypyrazines in grapes, musts, and wines in terms of the concentrations that are capable of contributing their sensory characteristics to wines. This review discusses methods for analyzing MPs including gas chromatography-mass spectroscopy (one or two dimension) and high-performance liquid chromatography, the appropriate extraction techniques, and the efficacy of these methods. Additionally, this review explores factors that affect pyrazine content of grapes, must, and wines, such as the effects of different viticultural practices, effects of light exposure and grape maturation, climate, soil, the multi-colored Asian lady beetle and the effects of different vinification processes.
Food processing has been gradually adopting the use of clean technologies that aim to minimize the generation of by-products. The use of winemaking by-products for the extraction of phenolic ...compounds is still incipient due to the lack of fast and efficient techniques. Thus, the aim of this study was to use the Microwave Hydrodiffusion and Gravity (MHG) technique to extract phenolic compounds from a winemaking by-product, the grape pomace (GP). The phenolic content of the extracts was analyzed by High Performance Liquid Chromatography (HPLC). Physicochemical and antioxidant properties were evaluated in the MHG extracts and in the GP before and after (co-product - CP) extraction. The GP had significant antioxidant properties and good yields in operating conditions of 2 W/g. Hydroxybenzoic acid, procyanidins, flavan-3-ols, and one flavanol were the phenolic compounds identified. The CP maintained the physicochemical and antioxidant properties similar to the GP.
•Use of grape pomace (GP), winemaking by-product, as a source of phenolic compounds.•Phenolic extracts of GP were obtained by green technology.•The GP had antioxidant properties and good yields in operating conditions of 2 W/g.•The co-product showed satisfactory properties for its application in food products.•Microwave Hydrodiffusion and Gravity represents an efficient and clean technology.
This study was conducted to capitalize on the waste produced by the vinification process which proved to be important sources of bioactive compounds with significant antifungal properties. ‘Cabernet ...Sauvignon’ grape pomace extracts were characterized in terms of total polyphenol content, antioxidant potential, but also evaluated in terms of antifungal effect against phytopathogenic fungi (Fusarium sp. and Alternaria sp.). The isolates used in this study were grown on three potato-dextrose-agar culture media, Czapek Dox and Malt-Agar. The highest amount of polyphenols was determined from the extract obtained by the microwave-assisted method (42.76 mg/g GAE), followed by the extract obtained by maceration (30.37 mg/g GAE). The lowest amount was obtained by the ultrasound-assisted method (15.06 mg/g GAE). However, the highest antioxidant activity was determined in the macerated extract, TEAC = 0.0523. The results of in vitro tests clearly indicated a high inhibitory percentage on the mycelium growth rate and, respectively, a significant decrease in spore germination power in Fusarium sp. (91.56%). However, for the pathogen Alternaria sp. further studies are needed to correctly validate the percentage of inhibition, as alcohol has been shown to have a negative effect on it.
Climate change has an important impact on the phenological phases of the grapevine. The consequences are directly reflected in quantitative and qualitative characteristics of the grapes. In fact, ...there is a decrease in the skin-to-pulp ratio (therefore a decrease in production with an excess of alcohol) and a consequent reduction in the aromatic potential of white grapes (lowering of the quality of musts). Volatile tioles are important aromatic compounds found in various foods and drinks; in particular they contribute to forming the aroma of some types of white wines as they are characterized by extremely low perception thresholds.
This work aimed to evaluate the effects of water stress on ecophysiology, technological maturity and on the thiol precursors of Vitis vinifera L. cv. Sauvignon Blanc vineyards in the Tuscan region (Italy) during two seasons. To this end, three treatments were established: WW (well watered), MW (medium watered), and WS (water stress with no irrigation). During the seasons, measurements were made of single-leaf gas exchange, pre-dawn and leaf midday water potential, leaf temperature, chlorophyll fluorescence, as well chlorophyll content. In addition, the parameters of plant yield, technological maturity (° Brix, acidity, pH and berries weight) and the precursors of 3-Mercaptohexanol (3MH) were analyzed: 3-S-cysteinylhexan-1-ol (Cys-3MH) and 3-S-glutathionylhexan-1-ol (GSH-3MH).
Well watered treatments (WW) showed less negative water potential, a higher rate of photosynthesis, of stomatal conductance, a lower leaf temperature (°C). Furthermore, WW showed higher levels of precursors accumulation (Cys-3MH and GSH-3MH) than the other treatments during two seasons. Technological analyses (° Brix and acidity) showed significant differences between WW and WS treatments. The lower berry weight was found in the WS treatment.
Finally as a result of climate change, precision irrigation has proved to be a good technique to rebalance the gap between technological and aromatic maturity in Sauvignon Blanc grapes.
•The role of water potential as a stress assessment tool.•Precision irrigation reduces water stress due to climate change.•Precision irrigation increase ecophysiological performance of vines.•Irrigation plays a key role in re-establishing optimal levels of tiol precursors.
•Specific fingerprints were extracted by Tri-step IR for red wine authentication.•Multivariate data fusion of IR with E-nose endowed better quantitative model.•Fusion models based on extracted ...spectral regions rendered the best rp and RPD.
A robust data fusion strategy integrating Tri-step infrared spectroscopy (IR) with electronic nose (E-nose) was established for rapid qualitative authentication and quantitative evaluation of red wines using Cabernet Sauvignon as an example. The chemical fingerprints of four types of wines were thoroughly interpreted by Tri-step IR, and the defined spectral fingerprint region of alcohol and sugar was 1200–950 cm−1. The wine types were authenticated by IR-based principal component analysis (PCA). Furthermore, ten quantitative models by partial least squares (PLS) were built to evaluate alcohol and total sugar contents. In particular, the model based on the fusion datasets of spectral fingerprint region and E-nose was superior to the others, in which RMSEP reduced by 47.95% (alcohol) and 79.90% (total sugar), rp increased by 11.95% and 43.47%, and RPD >3.0. The developed methodology would be applicable for mass screening and rapid multi-chemical-component quantification of wines in a more comprehensive and efficient manner.
Elemental sulfur is a fungicide traditionally used to control Powdery Mildew in the production of grapes. The presence of sulfur residues in grape juice has been associated with increased production ...of hydrogen sulfide during fermentation, which could take part in the formation of the varietal thiol 3-mercaptohexanol. This work examines whether elemental sulfur additions to Sauvignon blanc juice can increase the levels of sought-after varietal thiols. Initial trials were performed in South Africa and indicated a positive impact of sulfur on the levels of thiols. Further experiments were then carried out with New Zealand Sauvignon blanc and confirmed a positive relationship between elemental sulfur additions and wine varietal thiols. The formation of hydrogen sulfide was observed when the addition of elemental sulfur was made to clarified juice, along with an increase in further reductive sulfur compounds. When the addition of sulfur was made to pressed juice, prior to clarification, the production of reductive sulfur compounds was drastically decreased. Some mechanistic considerations are also presented, involving the reduction of sulfur to hydrogen sulfide prior to fermentation.
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•Two sulfur addition trials undertaken in both South Africa and New Zealand•Sulfur addition to grape juice proportionally increased varietal thiols in the wine.•Reductive compounds were also formed when sulfur was applied after juice clarification.•A pathway for the production of 3MH with S0 as sulfur donor is proposed.
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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