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.

Use of Microwave Maceration in Red Winemaking: Effect on Fermentation and Chemical Composition of Red Wines.

The objective of this study was to evaluate the effect of microwave treatment of crushed grapes on the yeast population of the must and on the development of alcoholic fermentation, as well as on the extraction of different compounds from the grapes such as polysaccharides and amino acids that can affect the organoleptic quality and stability of the wine. This study demonstrated for the first time the effect of the microwave treatment of grapes on native yeast species and their diversity, producing an increase in fermentation kinetics and a decrease in the lag phase. The microwave treatment produced a positive effect on the extraction of amino acids and polysaccharides from the grapes, resulting in significantly higher amounts of the main amino acids of the must and some major volatile compounds in the treated samples. The polysaccharides most affected by the microwave treatment were the PRAGs, the main polysaccharides liberated from grapes during the maceration.

Effect of Sonication Treatment and Maceration Time in the Extraction of Polysaccharide Compounds during Red Wine Vinification.

The application of high-power ultrasounds (US) at 28 kHz to the crushed grapes and the use of different pomace contact times caused changes in the content and composition of monosaccharides and polysaccharides in the musts and wines. These differences were maintained from the moment of pressing (end of maceration) until the end of the alcoholic fermentation. The US increased the content of monosaccharides and polysaccharides in the musts by facilitating their extraction from the solid parts during maceration. The application of medium maceration time (3 days) to sonicated grapes led to an extraction of polysaccharides rich in arabinose and galactose, rhamnogalacturonan type II (RG-II) and mannoproteins (MP), similar to that observed in the control wines made with an extended maceration of 7 days (968.21 vs. 1029.45; 895.04 vs. 1700.50; 356.81 vs. 343.95, respectively). This fact was attributed to a higher extraction in the must during the sonication process and to an important release of pectic polysaccharides during the pressing of the sonicated pomace, which is reported here for the first time. Therefore, the US technology could be useful for increasing the polysaccharide content in the wines or for reducing the maceration time needed to achieve certain levels of wine polysaccharides.

Evaluation of grape ripeness, carbonic maceration and pectolytic enzymes to improve the chemical and sensory quality of red sparkling wines.

BACKGROUND: Red sparkling wines are and innovative product for the oenology market, and oenologists are looking for technologies to improve their winemaking. The present study aimed to use both carbonic maceration and pectolytic enzymes applied to premature grapes during the winemaking of red sparkling wines. Both could modify the release of polyphenols, as well as improve the foaming, aroma and sensory properties of the wines. RESULTS: Red sparkling wines made with mature grapes showed the highest content of polyphenols, ethyl esters, alcohol acetates, total volatile acids and foam stability time. They were characterised by a high foam collar and foam area, full-body, astringency, persistence, and olfactory intensity, and were the best evaluated with respect to global perception in the sensory analysis. Treatment with pectolytic enzymes was not effective with unripe grapes. These wines showed a high content of total ethyl esters and the highest content of lactones, producing wines with high olfactory intensity and fruity aromas. Red sparkling wines made by carbonic maceration showed the lowest content of total polyphenols, anthocyanins and proanthocyanidins, as well as high contents of C6 alcohols and total ethyl esters, and were characterised by vegetal aroma notes. Both treatments produced red sparkling wines with good foam characteristics. CONCLUSION: Winemaking of red sparkling wines with premature grapes and pectinolytic enzymes or carbonic maceration did not achieve an improvement with respect to their chemical and sensory qualities. The use of mature grapes and traditional winemaking is the best option for elaborating red quality sparkling wines. © 2020 Society of Chemical Industry.

Phenolic composition of Tempranillo Blanco (Vitis vinifera L.) grapes and wines after biostimulation via a foliar seaweed application.

BACKGROUND: Seaweeds are defined as novel elicitors in many crops, allowing the synthesis of secondary metabolites to be triggered in different plant tissues. Currently, the phenolic composition of Tempranillo Blanco grapes and wines is unreported. The present study aimed to investigate the effects of an Ascophyllum nodosum seaweed extract applied to Tempranillo Blanco grapevines, at low (Ld) and high (Hd) dosages, on grape and wine phenolic compounds during two consecutive seasons (2017-2018). RESULTS: The results obtained showed that catechin was the most abundant phenolic compound in Tempranillo Blanco grapes and wines. Season affected the weight of 100 berries and some enological parameters. Catechin and flavonols concentrations in grapes were increased after Hd application to grapevines, independently of season. The concentration of hydroxycinnamic and hydroxybenzoic acids in wines was affected by vintage, probably as a result of oxidation reactions, as well as pinking phenomena, whereas the stilbenes content in wines was conditioned by the affect of cryptogamic diseases in grapes. CONCLUSION: Seaweeds might act as an elicitor of several phenolic compounds in grapes, enhancing the content of some phenolic compounds in wines. © 2019 Society of Chemical Industry.

Effects of different oenological techniques on the elaboration of adequate base wines for red sparkling wine production: phenolic composition, sensory properties and foam parameters.

BACKGROUND: In red sparkling winemaking it is essential to obtain base wines with moderate alcohol content, adequate mouthfeel and color intensity. The aim of this work was to study oenological techniques to obtain adequate base wines for production of red sparkling wine by traditional methods: pre-fermentative cold maceration with dry ice and délestage with premature grapes; and sugar reduction in must and partial dealcoholisation of wine with mature grapes. The effect on oenological parameters, e.g. phenolic content, foam and sensory characteristics, was studied in sparkling wines aged on the lees in bottles for 9 months followed by aging for12 months in bottles after disgorging. RESULTS: Pre-fermentative cold maceration was the only treatment that increased the content of anthocyanins in sparkling wines at both stages of aging. Sparkling wines elaborated using délestage showed the highest mean values of the degree of polymerization of proanthocyanidins. Sparkling wines from mature grapes were given higher valuation in the gustatory phase. Sparkling wines elaborated using pre-fermentative cold maceration were given the highest valuation for foam quality. CONCLUSIONS: Pre-fermentative cold maceration is a viable alternative to common techniques for increasing the anthocyanin content in wines from premature grapes. It would therefore be a good option to obtain adequate base wines. © 2019 Society of Chemical Industry.

Polysaccharides, oligosaccharides and nitrogenous compounds change during the ageing of Tempranillo and Verdejo sparkling wines.

BACKGROUND: Verdejo and Tempranillo are traditional varieties for producing still wines; however, they could provide an alternative for the manufacturing of sparkling wines. Sparkling wines were elaborated by the traditional method, followed by ageing on lees for 9 months. A study on the changes that take place in polysaccharides, oligosaccharides and nitrogenous compounds during the ageing on lees of Tempranillo and Verdejo sparkling wines has been undertaken. RESULTS: Mannoproteins and the glucose residue of oligosaccharides were the major carbohydrates detected in all vinification stages. Yeast polysaccharides and glucan-like structures of the oligosaccharides increased after 3 months of ageing. The evolution of yeast polysaccharides and the composition of PRAG-like structure were different among grape varieties. A decrease in amino acids and biogenic amines was observed during the ageing. The contents of polysaccharides, oligosaccharides and nitrogenous compound were significantly higher in Tempranillo than in Verdejo sparkling wines at the end of the ageing period. CONCLUSION: Polysaccharides and oligosaccharides from yeast were more significant autolysis markers of sparkling wines than the nitrogenous compounds. Our data suggest a potential cultivar effect on the evolution of yeast polysaccharides and on the composition of PRAG, which may influence the physico-chemical and sensory properties of sparkling wines. © 2017 Society of Chemical Industry.

The Generation of Suspended Cell Wall Material May Limit the Effect of Ultrasound Technology in Some Varietal Wines.

The disruptive effect exerted by high-power ultrasound on grape cell walls enhances phenolic extraction, improving chromatic characteristics during red wine maceration. However, short maceration times may, sometimes, hinder this enhancement, and this effect could be attributed to the suspended cell wall material formation facilitated by sonication. This suspended material, having a strong affinity for phenolic compounds, can lead to their precipitation and elimination during subsequent vinification stages and, consequently, a significant portion of extracted phenolic compounds may not contribute to the final phenolic composition of the wine, impacting its chromatic features. To demonstrate this effect, sonicated grapes of two different varieties were vinified with No modified process that eliminated part of this suspended material. Results confirm our hypothesis; that is, the lack of positive outcomes in some cases is due to phenolic compound adsorption on suspended material.

Effect of Pre-fermentative Treatments on Polysaccharide Composition of White and Rosé Musts and Wines.

This paper studied the effect of conventional pre-fermentative techniques (direct pressing "CP" and cold maceration "CM") and an innovate technique (high power ultrasounds "S"), applied to Viogner and Monastrell grapes on the polysaccharide content of the musts, white and rosé wines, and after six months of bottle aging. The results showed that the longer pre-fermentation maceration time applied with the CM technique compared to the short ultrasonic maceration was key in the extraction of polysaccharides from the grape to the must. CP treatment produced wines with the lowest content of total soluble polysaccharide families since it was the least intense pretreatment for the disruption of the grape berry cell wall polysaccharides. Ultrasonic pretreatment could be used as a new tool to increase the solubilization of polysaccharides in wines, positively affecting the wine colloidal properties. During bottle aging, there wasn't a clear effect of pretreatments on the evolution of polysaccharides.

High-Power Ultrasound in Enology: Is the Outcome of This Technique Dependent on Grape Variety?

The disruptive effect exerted by high-power ultrasound (US) on grape cell walls is established as the reason behind the chromatic, aromatic and mouthfeel improvement that this treatment causes in red wines. Given the biochemical differences that exist between the cell walls of different grape varieties, this paper investigates whether the effect of the application of US in a winery may vary according to the grape variety treated. Wines were elaborated with Monastrell, Syrah and Cabernet Sauvignon grapes, applying a sonication treatment to the crushed grapes using industrial-scale equipment. The results showed a clear varietal effect. The wines made with sonicated Syrah and Cabernet Sauvignon grapes showed an important increase in the values of color intensity and concentration of phenolic compounds, and these increases were higher than those observed when sonication was applied to Monastrell crushed grapes, whereas Monastrell wines presented the highest concentration in different families of polysaccharides. These findings correlate with the differences in the composition and structure of their cell walls since those of Monastrell grapes presented biochemical characteristics associated with a greater rigidity and firmness of the structures.

Characterization of polysaccharide extracts recovered from different grape and winemaking products.

One of the most important challenges of the oenological industry is the recovery and valorization of valuable compounds from grapes and grape by-products. Recent studies have focused on the obtention of phenolic compounds, but little attention has been paid to the extraction of grape polysaccharides, which could have a great potential as oenological products but also for their benefits to human health. This study aimed to recover polysaccharides from different grape and winemaking products and provide information about its composition. The results obtained with the white pomace and white lees revealed its potential to be exploited to obtain extracts rich in polysaccharides. White pomace revealed as a good source to obtain polysaccharides rich in arabinose and galactose (PRAG) and glucosyl polysaccharides. White lees showed a potential to be used to recover mannoproteins and glucans. Both extracts showed high polysaccharide purity (55.5% and 51.9%, respectively). Extracts rich in rhamnogalacturonan type II (RG-II) were obtained from a red wine (89.7% polysaccharide purity) and from the wash water used by the distillery after draining the distilled wine pomace (40.6% polysaccharide purity). Our results open new lines to obtain extracts with different polysaccharide composition, non-available in the market. Future studies are needed to evaluate their potential as stabilizing or finning agents and possible alternative solutions to traditional animal-origin protein fining agents.

Feasibility study on the use of ATR-FTIR spectroscopy as a tool for the estimation of wine polysaccharides.

Polysaccharides are the main macromolecules of colloidal nature in wines. These compounds play a critical role in stabilizing other molecules in solution and thus modifying the wine processing and organoleptic properties. Different analytical techniques have been proposed for their determination. However, most of them are complicated and time-consuming. To overcome these drawbacks, Fourier transform infrared spectroscopy (FTIR) has been evaluated in this study for the estimation of wine polysaccharides in a fast and non-destructive way. Spectral data have been correlated with wine polysaccharide contents by modified partial least squares regression (MPLS) using different spectral pretreatments. MPLS models developed have revealed the potential of FTIR analysis for the routine screening of polysaccharides rich in arabinose and galactose (PRAG), rhamnogalacturonans types II (RG-II), mannoproteins (MP) and total soluble polysaccharides (TSP) in wine samples, obtaining standard errors of prediction from 6.07 to 8.44%. Monitoring the wine polysaccharides can assist in the elaboration of the wines according to their requirements and improving quality to satisfy consumer preferences.

Optimization of a method to extract polysaccharides from white grape pomace by-products.

The aim of this paper is to optimize a method to recover polysaccharides from white grape pomace (non-fermented), the main waste by-product of the food industry. Different conditions are tested and the polysaccharides extracted are analyzed by high performance size exclusion chromatography with refractive index detector (HPSEC-RID) and gas chromatography with mass detector (GC-MS). The extraction solvent did not show a significant effect on the polysaccharide extraction, acid pH yielded to higher efficiencies, and longer extraction times extracted more smaller polysaccharides (≤5.4 kg mol-1). The highest efficiencies were obtained with both solvents at pH 1 and 1:4 solid to liquid ratio. The optimum conditions selected (TA as solvent of extraction, 2.5 g L-1 solvent concentration, pH = 1, 1:4 solid to liquid ratio, and 18 h of extraction time) allow the extraction of polysaccharides rich in arabinose and galactose, rhamnogalacturonans, homogalacturonans and glucosyl polysaccharides, under efficient and food-safe conditions.

Ultrasound treatment of crushed grapes: Effect on the must and red wine polysaccharide composition.

This paper studied the effect on the molecular weight and polysaccharide composition of musts and wines of the application of high-power ultrasound (US) at 20 and 28 kHz on crushed grapes. Two different pomace maceration times (short and mid) were tested for sonicated and control vinifications. A long pomace maceration time was also tested for non-treated wines. In must samples, US significantly increased the content of monosaccharides and polysaccharides rich in arabinose and galactose (PRAG), and the average molecular weight of smaller PRAG, mannoproteins (MP) or mannans. The 28 kHz had a major effect on most wine monosaccharides and grape polysaccharides. The wine obtained from sonicated grapes at 28 kHz and with mid maceration had higher rhamnogalacturonans type II and PRAG content than its control, and closer polysaccharide and monosaccharide content to long maceration control wines. No significant differences were obtained in the MP content between sonicated and control wines.

Effect of the winemaking process on the volatile composition and aromatic profile of Tempranillo Blanco wines.

The effects of the carbonic maceration and conventional winemaking on the volatile composition and aromatic sensory characteristics of Tempranillo Blanco wines were studied for the first time, during three consecutive vintages. Relationships between instrumental (volatiles) and sensory variables were analyzed applying partial least squares regression (PLS). Carbonic macerated wines had higher contents of alcohols and carbonyl compounds, yet lower concentrations of C6 alcohols and volatile acids than wines conventionally produced. The Odor Activity Values (OAV) exhibited an increase in wines when carbonic maceration was applied. According to the geometric mean (% GM) obtained from aroma descriptors the effect of the winemaking process was significant for seed fruit, ripe fruit and floral notes. When subjected to PLS the data from the instrumental analysis yielded a satisfactory model for the prediction of aroma descriptors in this set of wines.

Effect of egg albumin fining, progressive clarification and cross-flow microfiltration on the polysaccharide and proanthocyanidin composition of red varietal wines.

The effect of egg albumin fining, progressive clarification and cross-flow microfiltration on the polysaccharide and proanthocyanidin composition of four red varietal wines was studied in this work. Discriminant analyses were applied to achieve a possible differentiation of the wines according to treatment or grape variety. Egg albumin fining did no produce a significant decrease in the content of wine polysaccharides. Progressive clarification caused a significant reduction of mannoproteins, homogalacturonans and polysaccharides rich in arabinose and galactose in Graciano wines. However, both treatments reduced the total content of proanthocyanidins in all varietal wines. Cross-flow microfiltration produced the highest retention of polysaccharides and proanthocyanidins in all the wines, mainly polysaccharides rich in arabinose and galactose, yeast mannoproteins and highly polymerized phenols. Polysaccharides rich in arabinose and mannoproteins were more retained on the ceramic membrane than polysaccharides rich in galactose and proanthocyanidins. Discriminant analyses allowed a clear differentiation of cross-flow microfiltrated wines from the rest of the wines.

Influence of Grape Maturity on Complex Carbohydrate Composition of Red Sparkling Wines.

This paper studied how grape maturity affected complex carbohydrate composition during red sparkling wine making and wine aging. Grape ripening stage (premature and mature grapes) showed a significant impact on the content, composition, and evolution of polysaccharides and oligosaccharides of sparkling wines. Polysaccharides rich in arabinose and galactose, mannoproteins, rhamnogalacturonans II, and oligosaccharides in base wines increased with maturity. For both maturity stages, polysaccharides rich in arabinose and galactose, and the glucuronic acid glycosyl residue of the oligosaccharides were the major carbohydrates detected in all vinification stages. The total glycosyl content of oligosaccharides decreased during the whole period of aging on yeast lees. The reduction of polysaccharides rich in arabinose and galactose and rhamnogalacturonans type II during the aging was more pronounced in mature samples. To our knowledge, this is the first report of the polysaccharide and oligosaccharide composition of red sparkling wines.

Role of major wine constituents in the foam properties of white and rosé sparkling wines.

The chemical composition of sparkling wines is directly related to their foam quality, but the compounds responsible are not yet completely established. This work aims at identifying the contribution of the different wine compounds to the foaming properties of white and rosé sparkling wines. Our results demonstrated the positive contribution of anthocyanins and amino acids to the foamability parameters HM (maximum height reached by foam after CO2 injection) and HS (foam stability height during CO2 injection), and the negative contribution of proanthocyanidins. Mannoproteins and polysaccharides rich in arabinose and galactose (PRAG) were poor foam formers but good foam stabilizers. The different forms of malvidin showed the highest influence on the HM and HS parameters, followed by amino acid compounds, mainly ß-alanine. The model to explain foam stability was only predicted by polysaccharides from grapes, concretely PRAG. To our knowledge, this is the first time these correlations in sparkling wines have been described.

Use of Commercial Dry Yeast Products Rich in Mannoproteins for White and Rosé Sparkling Wine Elaboration.

In sparkling wines, mannoproteins released during yeast autolysis largely affect their final quality. This process is very slow and may take several months. The aim of this work was to study the effect of several commercial dry yeast autolysates on the chemical composition, foam, and sensory properties of white and rosé sparkling wines aged on lees for 9 months during two consecutive vintages. The addition of these products in the tirage phase did not affect either the content of phenolic compounds, amino acids, and biogenic amines or the foam properties. The commercial product with the highest mannoprotein content and the highest purity caused significant changes in the volatile composition of the wines and enhanced the fruity aromas in both Verdejo and Godello sparkling wines.

Relationship between skin cell wall composition and anthocyanin extractability of Vitis vinifera L. cv. Tempranillo at different grape ripeness degree.

The relationship between cell wall composition and extractability of anthocyanins from red grape skins was assessed in Tempranillo grape samples harvested at three stages of ripening (pre-harvest, harvest and over-ripening) and three different contents of soluble solids (22, 24 and 26 °Brix) within each stage. Cell wall material was isolated and analysed in order to determine cellulose, lignin, non-cellulosic polysaccharides, protein, total polyphenols index and the degree of esterification of pectins. Results showed the influence of ripeness degree and contents of soluble solids on cell wall composition. Furthermore, principal components analysis was applied to the obtained data set in order to establish relationships between cell wall composition and extractability of anthocyanins. Total insoluble material exhibits the biggest opposition to anthocyanin extraction, while the highest amounts of cellulose, rhamnogalacturonans-II and polyphenols were positively correlated with anthocyanin extraction. Moreover, multiple linear regression was performed to assess the influence of the cell wall composition on the extraction of anthocyanin compounds. A model connecting cell wall composition and anthocyanin extractabilities was built, explaining 96.2% of the observed variability.