Investigating the relationship between cell wall polysaccharide composition and the extractability of grape phenolic compounds into Shiraz wines. Part II: Extractability during fermentation into wines made from grapes of different ripeness levels

Grape-Derived Polysaccharide Extracts Rich in Rhamnogalacturonans-II as Potential Modulators of White Wine Flavor Compounds

Many authors have investigated the role of mannoproteins on wine quality, but very few have analyzed the use of grape-derived polysaccharides as they are not commercially available. In this study, purified grape-derived polysaccharides from red wine (WPP) and winemaking by-products (DWRP: Distilled Washing Residues Polysaccharides) were used as potential fining agents to modulate white wine flavor. Phenolics and volatile compounds were analyzed in the control and wines treated with WPP, DWRP, and commercial mannoproteins (CMs) after one and twelve months of bottling, and a sensory analysis was conducted. WPP and DWRP, rich in rhamnogalacturonans-II, showed themselves to be good modulators of wine aroma and astringency. Improvement in wine aroma was related to an increase in all volatile families expect higher alcohols and volatile acids. The modulation of astringency and bitterness was related to a reduction in the proanthocyanidin content and its mean degree of polymerization. Extracts with polysaccharides with higher protein contents presented a higher retention of volatile compounds, and DWRP extract had more positive effects on the overall aroma. Our novel results present the possibility of obtaining valuable polysaccharides from distilled washing residues of wine pomaces, which could promote its valorization as a by-product. This is the first time the potential use of this by-product has been described.

Focus on the relationships between the cell wall composition in the extraction of anthocyanins and tannins from grape berries

Concentrations of anthocyanins and tannins after extraction from berries in wines and from skin macerations in model solutions have been studied for two grape varieties, two maturation levels and two vintages berries. Characterization of the cell wall polysaccharides has also been performed, the classical method based on the analysis of the neutral sugars after depolymerization being completed by a comprehensive microarray polymer profiling (CoMPP). Extraction was lower in model solutions than in wines, with the same ranking: non acylated anthocyanins> tannins > p-coumaroylated anthocyanins. The polysaccharidic composition suggested a role of homogalacturonans, rhamnogalacturonans and extensins in the extraction process. A global explanation of the interactions between anthocyanins, tannins and polysaccharides is proposed.

Comparative phenolic, chromatic, and sensory composition of five monovarietal wines processed with microwave technology

The effect of MW technology (1,200 Watts for 10 min) on the chemical and sensory composition of five monovarietal wines with different phenolic composition was studied relative to untreated Control wines. MW improved polymeric pigment content by 30, 22 and 31% in Cabernet Sauvignon, Malbec, and Syrah wines, respectively, and anthocyanin extraction and non-tannin phenolics by 24% in Malbec and Syrah wines, respectively. In Nebbiolo and Pinot noir, MW had no effect on phenolics or chromatic characteristics. Anthocyanins in Nebbiolo wines were the lowest and their pigment profile was composed of 18% pyranoanthocyanins, but tannins were the highest, resulting in a tannin to anthocyanin ratio of 16. Pinot noir and Nebbiolo wines had comparable polymeric pigment content, despite dissimilar tannin to anthocyanin ratios, suggesting different mouthfeel characteristics in their respective wines. Conversely, wines of comparable tannin to anthocyanin produced wines of vastly different polymeric pigment content. MW-treated Cabernet Sauvignon wines showed an improved sensory profile.

Investigating the Relation between Skin Cell Wall Composition and Phenolic Extractability in Cabernet Sauvignon Wines

In this study, phenolic extractability of Cabernet Sauvignon grapes from two California regions (Sonoma County and Central Coast) and its relation with skin cell wall composition was investigated. Phenolic grape composition, wine phenolic content as well as berry and pomace cell wall composition of three sites per region were determined. Grape cell wall material (CWM) composition, and thus pomace CWM composition, was impacted by the growing region. The process of fermentation modified CWM composition, solubilizing some of the compounds such as pectin and polysaccharides making pomace CWM composition from different sites more similar in the case of Sonoma County and more different for the samples grown in the Central Coast. Growing region had a significant impact on grape phenolics, particularly on flavan−3-ols and polymeric phenols, whereas polymeric pigments and anthocyanin contents were more similar among samples. Wines made from Sonoma County grapes showed higher anthocyanin and polymeric phenol content when compared to wines made from Central Coast grapes. Comparing wine to grape phenolic composition suggests a large difference in extractability based on region. Of all the CWM components analyzed, only lignin and the amount of cell wall isolated were found to have a significant impact on phenolic extractability.

Cell wall characterization of new Monastrell hybrid descendants and their phenolic wine composition

Monastrell grape variety is grown for the elaboration of quality red wines, but climate change has meant the study of new grape varieties from Monastrell, to adapt to the new edaphoclimatic scenario in hot climates. Three new varieties have recently been registered from Monastrell (M) from directed crosses with others such as Cabernet Sauvignon (C) and Syrah (S). These new varieties are MC80 known as Calnegre, MC98 Gebas, and MS10 Myrtia. In this work, cell wall characterization of these new varieties has been carried out. Results from three seasons showed high significant differences in the concentration of carbohydrates present in the Monastrell and MC80 cell walls. As for lignin concentration, MS10 was highlighted. However, the concentration of phenolic compounds and proteins was different as regards each variety and season studied. To find some correlation between the characterization of the walls and extractability of different compounds in the wine, the phenolic composition of these wines from these varieties was analysed following alcoholic fermentation. All crosses presented a higher concentration of total polyphenols (IPT) and total anthocyanins (AT) in addition to color intensity (IC), highlighting the high significant differences found in MS10.

Untangling the impact of red wine maceration times on wine ageing. A multidisciplinary approach focusing on extended maceration in Shiraz wines

Phenolic composition of young red wines has been shown to play an important role in their ageing potential. Therefore, the modulation of phenolic extraction during maceration may influence the subsequent phenolic evolution of these wines. The present work aimed to evaluate the impact of three different maceration times on the phenolic levels and evolution observed over time, using spectrophotometric and chromatography methods, and the effect on the aroma, taste, and mouthfeel sensory properties using Projective Mapping. Additionally, grape cell wall deconstruction was monitored during the extended maceration phase by GC-MS and Comprehensive Comprehensive Microarray Polymer Profiling (CoMPP). Our findings demonstrated that longer maceration times did not always correspond to an increase in wine phenolic concentration, although the level of complexity of these molecules seemed to be higher. Additionally, continuous depectination and possible solubilisation of the pectin is observed during the extended maceration which may be influencing the sensory perception of these wines. Maceration time was also shown to influence the evolution of the polymeric fraction and sensory perception of the wines.

Recent advances in interactions between polyphenols and plant cell wall polysaccharides as studied using an adsorption technique

Polyphenols include flavonoids, phenolic acids, tannins and lignans which are known to have antioxidant, UV protection and antimicrobial properties. Among them the most commonly investigated are flavonoids and phenolic acids, which, due to their plant origin, may interact with the plant cell wall (PCW) components, specifically with its polysaccharides. Knowledge concerning the nature of the interactions between these components may be used in the production of functional food or in the development of food packaging materials with additional properties. The content of polyphenols in such products is responsible for their colour and taste, and may also act as a natural preservative. On the other hand, the PCW components may have protective role of polyphenols which has impact on their release in the human digestive system. Therefore, this review is an attempt to summarize the current state of knowledge that emerged after 2017 concerning the interaction of PCW components with polyphenols, with a particular focus on hemicellulose and pectin.

In-mouth attributes driving perceived quality of Pinot noir wines: Sensory and chemical characterisation

We investigated perception of mouthfeel in Pinot noir wines and its physicochemical determinants. Seventeen wine professionals judged 18 Pinot noir wines via two tasting tasks, Descriptive Rating and Directed Sorting, the latter based on perception of in-mouth attributes. Selected chemical measures of the same 18 wines were determined. Sensory results demonstrated that mouthfeel attributes driving high quality were smoothness/silky/velvety, volume/fullness/roundness, overall body, and viscosity/mouth-coating, while the taste of bitterness and perceived tannin harshness drove low quality judgments. Perceived astringency and expressions of tannin (e.g., soft; harsh; fine) drove sorting behaviour of participants. Partial least squares regression (PLSR) was used to associate perceived in-mouth phenomena and chemical composition. The phenolic profile, in particular tannin concentration and structure, was the most important predictor of astringency and its sub-components. These results have important implications for wine producers aiming to enhance perceived quality in their Pinot noir wines.

Effect of nitrogen regulation on berry quality and flavonoids during veraison stage

Nitrogen regulation can effectively promote the improvement of berry components and the formation of flavor compounds in wine grapes. In order to understand the effects of foliar nitrogen spraying on grape quality and flavonoid substance, took Cabernet Sauvignon as the test subject, grape leaves were sprayed by ammonium sulfate, calcium ammonium nitrate, urea, phenylalanine, and glutamate during veraison, and clear water was used as the control. The results showed that spraying ammonium sulfate could improve the contents of soluble solids, anthocyanins, and total phenols of grape berries; spraying phenylalanine significantly increased the content of titratable acid and tannin and decreased the ratio of sugar to acid in grape berries; compared with the control group, spraying glutamate could significantly upregulate some flavonol monomers; spraying calcium ammonium nitrate can adjust the monomer content of some flavanols; urea spraying significantly increased the contents of most anthocyanins, flavanols, and flavonol and increased the contents of total anthocyanins, total flavanols, and total flavonol in grape skins, laying a foundation for the improvement of the nutritional value of grapes and wine in the future.

Grape polysaccharides: compositional changes in grapes and wines, possible effects on wine organoleptic properties, and practical control during winemaking

Polysaccharides present in grapes interact with wine sensory-active compounds (polyphenols and volatile compounds) via different mechanisms and can affect wine organoleptic qualities such as astringency, color and aroma. Studies on the role that grape polysaccharides play in wines are reviewed in this paper. First, the composition of grape polysaccharides and their changes during grape ripening, winemaking and aging are introduced. Second, different interaction mechanisms of grape polysaccharides and wine sensory-active compounds (flavanols, anthocyanins and volatiles) are introduced, and the possible effects on wine astringency, color and aroma caused by these interactions are illustrated. Finally, the control of the grape polysaccharide content in practice is discussed, including classical winemaking methods (applying different maceration enzymes, temperature control, co-fermentation, blending), modern vinification technologies (pulsed electric field, ultrasound treatment), and the development of new grape polysaccharide products.

Effect of Cooking Methods on Bioactivity of Polyphenols in Purple Potatoes

Purple-fleshed potato (Solanum tuberosum L.) is a good dietary source of anthocyanins, flavonols, and polyphenolic acids, mostly chlorogenic acid. The objective of this study was to examine the impacts of cooking methods including boiling, steaming, and the newly developed vacuum-sealed boiling (VSBoil) on extractability and bioactivity of polyphenolic compounds in a purple potato (PP) cultivar, Purple Pelisse. Data showed that boiling and steaming reduced the total polyphenolic content in PP. High-performance liquid chromatography analysis showed that steaming slightly reduced the extractable chlorogenic acid content, while VSBoil increased it. For DPPH free radical scavenging activities, VSBoil and steaming effectively preserved the antioxidant activity of a polyphenol-rich extract of PP, while boiling resulted in a significant reduction compared to raw potato extract. All extracts effectively suppressed bursts of intracellular reactive oxygen species in human colonic epithelial cells upon hydrogen peroxide induction, of which the extract from the VSBoil group showed the highest antioxidant potential. In addition, all extracts showed anti-inflammatory effects in Caco-2 cells induced with tumor necrosis factor-α. In conclusion, the content and bioactivity of extractable polyphenols were largely retained in PP subjected to different cooking processes. VSBoil resulted in the highest content of extractable polyphenolic compounds and bioactivity among tested cooking methods.

Relationship between anthocyanins, proanthocyanidins, and cell wall polysaccharides in grapes and red wines. A current state-of-art review

Numerous research studies have evaluated factors influencing the nature and levels of phenolics and polysaccharides in food matrices. However, in grape and wines most of these works have approach these classes of compounds individually. In recent years, the number of publications interconnecting classes have increased dramatically. The present review relates the last decade's findings on the relationship between phenolics and polysaccharides from grapes, throughout the entire winemaking process up to evaluating the impact of their relationship on the red wine sensory perception. The combination and interconnection of the most recent research studies, from single interactions in model wines to the investigation of the formation of complex macromolecules, brings the perfect story line to relate the relationship between phenolics and polysaccharides from the vineyard to the glass. Grape pectin is highly reactive toward grape and grape derived phenolics. Differences between grape cultivars or changes during grape ripeness will affect the extractability of these compounds into the wines. Therefore, the nature of the grape components will be crucial to understand the subsequent reactions occurring between phenolics and polysaccharide of the corresponding wines. It has been demonstrated that they can form very complex macromolecules which affect wine color, stability and sensory properties.

Biotechnological processes for regulating the quality and safety of wine products

The production of a competitive wine industry in Russia is an important task for the successful development of the country’s agro-industrial complex. The purpose of this research is to consider the ways of harmonious development of competitive Russian winemaking, based on the advanced bioecotechnologies of developed countries. This paper presents biotechnological processes and classes of enzymes or individual representatives. Established that both the enzymes of the grape and the enzyme systems of wine yeast are involved in the processes of wine production. During delivery of grapes for processing, means of inactivation of the activity of oxidative enzymes such as sulfur dioxide, liquid nitrogen, carbon dioxide should be used. Improvement and acceleration of clarification of grape must have to be done with the use of pectinesterases, polymethylgalacturonases, polygalacturonases, pectin transeliminases. In order to obtain wines stability to protein turbidity, the use of the technology of two-stage fermentation with deep protein transformation is recommended. Depending on the tasks of malolactic fermentation (MF) or its prevention, yeast strains that prevent the development of MF and strains that support the development of MF have been isolated. A relationship between the content of various groups of phenolic compounds and the activity of MF was established.

Trunk Girdling Increased Stomatal Conductance in Cabernet Sauvignon Grapevines, Reduced Glutamine, and Increased Malvidin-3-Glucoside and Quercetin-3-Glucoside Concentrations in Skins and Pulp at Harvest

Girdling is a traditional horticultural practice applied at fruit set or other phenological stages, and is used mostly as a vine management. In grapevines, it is used primarily for table grapes to improve berry weight, sugar content, color, and to promote early harvest. The objective of this study was to evaluate the effect of trunk girdling applied at veraison, in 'Cabernet Sauvignon' wine grapes (Vitis vinifera L.), on agronomical and physiological parameters during vine development from the onset of ripening (veraison) to harvest, and additionally to quantify the effect of girdling on primary and secondary metabolism. Girdling was applied 146 days after pruning (dap) at veraison, when berry sampling for metabolomics and agronomical evaluations commenced, with a further three sampling dates until harvest, at 156 dap (30% maturation, 10 days after girdling-dag), 181 dap (70% maturation, 35 dag), and 223 dap (commercial harvest, 77 dag). Skin/pulp and seed tissues were extracted separately and metabolomics was performed using one-dimensional proton nuclear magnetic resonance (1D 1H NMR) spectroscopy and high performance liquid chromatography (HPLC-DAD). At harvest, girdling significantly increased stomatal conductance (gs) in vines, decreased glutamine concentrations, and increased anthocyanin and flavonol concentrations in the skin/pulp tissues of grape berries. Berry weight was reduced by 27% from 181 dap to harvest, and was significantly higher in grapes from girdled vines at 181 dap. Sugars, organic acids, and other amino acids in skin/pulp or seeds were not significantly different, possibly due to extra-fascicular phloem vessels transporting metabolites from leaves to the roots. Using a metabolomics approach, differences between skin/pulp and seeds tissues were meaningful, and a greater number of secondary metabolites in skin/pulp was affected by girdling than in seeds. Girdling is a simple technique that could easily be applied commercially on vine management to improve berry color and other phenolics in 'Cabernet Sauvignon' grapes.

Potential health benefits of phenolic compounds in grape processing by-products

Prevention emerges as a powerful approach in minimizing the risk of deleterious lifestyle diseases because therapies do not necessarily guarantee a permanent cure. Accordingly, consumers' growing preference for natural and health-promoting dietary options that are rich in antioxidants has become widespread. Grape (Vitis vinifera) is an antioxidant-rich fruit extensively grown for fresh or processed consumption. The long-term consumption of its polyphenolic antioxidants may promote multiple health benefits. However, grape pomace (GP), consisting of peel, seed, stem, and pulp, is discarded during grape processing, including juice extraction and winemaking, despite its substantial antioxidant content. Polyphenolic extraction techniques have been widely explored to date, but the consolidation of reported physiological impacts of GP-derived polyphenolic constituents is limited. Thus, this review highlights current studies of the potential applications of GP extract in disease prevention and treatment, emphasizing the major influence of polyphenolic compositions and origins of different grape varieties.

Microwave-Assisted Extraction Applied to Merlot Grapes with Contrasting Maturity Levels: Effects on Phenolic Chemistry and Wine Color

Merlot grapes were harvested with three maturity levels (21.1, 23.1, and 25.1 Brix), and processed with or without the application of microwave-assisted extraction (MW). The detailed phenolic composition and color were followed during winemaking. The MW treatment did not affect the basic chemical composition of the wines. Upon crushing, MW caused a 211% improvement in anthocyanins in the wines of the first harvest and an 89% improvement in the wines of the third harvest. At bottling, MW favored the formation of pyranoanthocyanins and tannin-anthocyanin dimers. Tannin extraction was not affected by MW just after application of this process, but improvements of 30, 20, and 10% on MW-treated wines of the first, second, and third harvest, respectively, were recorded at pressing. The formation of polymeric pigments during aging generally increased along with harvest date and was only favored in MW-treated wines of the first and third harvest, with preferential formation of small polymeric pigments, in accordance with enhanced anthocyanin extraction in these wines. Initial improvements of wine color upon application of MW in the wines of the first, second, and third harvest were of 275, 300, and 175%, respectively. Although these differences subsided or disappeared for the wines of the second and third harvest during aging, the wines of the first harvest treated with MW retained 52% more color than Control wines at day 150 post-crushing. Results suggest the MW treatment was more efficient in extracting and retaining phenolics and color when applied to unripe fruit.

Deconstructing Wine Grape Cell Walls with Enzymes During Winemaking: New Insights from Glycan Microarray Technology

Enzyme-aid maceration is carried out in most modern winemaking industries with a range of positive impacts on wine production. However, inconsistencies in enzyme efficiency are an issue complicated by unclear targets (limited information available on berry cell wall architecture of different cultivars) and the complex wine environment (i.e., fermenting must). Recent studies have been performed to develop a clearer picture of grape cell wall structures, maceration effects, and interactions between important wine compounds and grape-derived polysaccharides. This review highlights critically important recent studies on grape berry cell wall changes during ripening, the importance of enzymes during maceration (skin contact phase) and deconstruction processes that occur during alcoholic fermentation. The novelty of the Comprehensive Microarray Polymer Profiling (CoMPP) technique using cell wall probes (e.g., antibodies) as a method for following cell wall derived polymers during different biological and biotechnological processes is discussed. Recent studies, using CoMPP together with classical analytical methods, confirmed the developmental pattern of berry cell wall changes (at the polymer level) during grape ripening. This innovative technique were also used to track enzyme-assisted depectination of grape skins during wine fermentation and determine how this influence the release of wine favourable compounds. Furthermore, polysaccharides (e.g., arabinogalactan proteins) present in the final wine could be identified. Overall, CoMPP provides a much more enriched series of datasets compared to traditional approaches. Novel insights and future studies investigating grape cell wall and polyphenol interactions, and the tailoring of enzyme cocktails for consistent, effective and "customized" winemaking is advanced and discussed.