Wine Color Research Articles

Polysaccharide Functionality in Wine-like Model Systems with Oat and Egg White Model Proteins

Interactions between wine proteins and polysaccharides have the capacity to regulate the stability, shelf-life, and turbidity of red wines. Understanding these macromolecular interactions helps with maintaining stability and reproducing high quality wines. Model polysaccharides (carboxymethyl cellulose, mannoproteins, and fruit pectin) and model proteins (egg white and oat protein) were selected to assess protein–polysaccharide interactions within a model wine solution. The wine-like solution was created to simulate the correct pH, ethanol strength, and pigment content. Any interactions with polymeric pigments—anthocyanins and tannins—can also be investigated in this matrix. To analyze the aggregative potential of the macromolecules, particle size and Zeta-potential (ζ-potential) measurements were recorded for the samples with increasingly complex compositions. Carboxymethyl cellulose was found to increase particle sizes, likely binding more than proteins, but also improved the overall stability of the solution. Fruit pectin and mannoprotein were effective at causing precipitation while not removing the color of the model wine. The use of mannoprotein ensued in overall smaller particles for both suspended aggregate and precipitate sizes, indicating higher selectivity. Fruit pectin increased precipitate sizes and decreased suspended aggregate sizes. This study implements model proteins to evaluate complex macromolecular interactions using measurements of ζ-potential and particle size.

Effects of foliar applications of methyl jasmonate alone or with urea on anthocyanins content during grape ripening

Anthocyanins, the main phenolic compounds responsible for the color of red grapes and wines, exhibit antioxidant and antimicrobial properties and offer various health benefits for humans. Currently, climate change can affect grape quality by causing a decoupling between the technological and phenolic maturities of the grapes. Foliar application of methyl jasmonate (MeJ) and urea (Ur) can be a tool to mitigate the global warming effects in the vineyard. The aim of this work was to study i) the development of anthocyanin content in ‘Tempranillo’ grapes along the ripening process, and ii) the effect of foliar application of MeJ and MeJ+Ur on these phenolic compounds over two vintages (2019 and 2020). Overall, in the first vintage, anthocyanins peaked in their concentrations in the pre-harvest or harvest moments; whereas in the second vintage, the highest contents of these phenolic compounds were reached at harvest time, after that, a maintenance or decreased of their concentrations was observed. In both vintages, non-acylated anthocyanins was the most abundant family of anthocyanins. Foliar application of MeJ+Ur was more effective in enhancing anthocyanin biosynthesis than MeJ treatment, which also increased anthocyanin content compared to control grapes. Therefore, MeJ and Ur foliar treatment could present a synergy in anthocyanin biosynthesis by the plant. Moreover, the impact of these applications varied across vintages, and also the content of anthocyanins in grapes, probably due to different climatological conditions. Consequently, the two foliar treatments, MeJ and MeJ+Ur, could be a suitable tool to increase anthocyanins biosynthesis in grapes, and thus improve grape quality.

Mathematical Modelling and Chemical Analysis to Characterise Anthocyanin Self-association Interactions Influencing Colour Expression and Stability in Young Red Wines

AbstractAnthocyanins are phenolic compounds that provide colour to young red wines following extraction from grape skins, and their reaction kinetics are not well understood as they exist within a complex pH-dependent multistate system. For commercial wineries to best control anthocyanin colour expression that is a major determinant for red wine quality, there is a critical need for behaviours of all pH-dependent monomeric and self-associated anthocyanins to be considered together. In response, the current study employed mathematical and experimental techniques to reveal kinetic and steady-state behaviours of all species of a model anthocyanin, malvidin-3-O-β-D-glucopyranoside (M3G), within three Shiraz red wines throughout fermentation. Investigator-developed models represented the following: (i) acid–base reactions that form red, purple, and blue anthocyanin monomers; (ii) hydration reactions that result in monomeric colour loss; and (iii.) physical self-association interactions that temporally stabilise anthocyanin colour. Simulations were validated experimentally using high-performance liquid chromatography with diode array detector (HPLC–DAD) and colourimetric analysis of wine samples. Moreover, a unique predictive modelling framework was developed that takes in measured values for anthocyanin concentration, pH, and temperature at the onset of fermentation, and output data describing corresponding wine colour expression and stability characteristics that would arise after fermentation has progressed. Results of the current study elucidate complex reaction kinetics occurring between anthocyanin species under dynamic red wine conditions and provide meaningful predictions for future wine colour and shelf-life characteristics. Outputs may be used to inform key winemaking decisions influencing red wine quality and to optimise the use of winery resources throughout the fermentation process.

Additions/removals of seeds before fermentation alters Cabernet Sauvignon wine color via modulating anthocyanins and derivatives

The advance of the grape harvest caused by global warming has to some extent resulted in poor or unstable wine color, this study investigated the potential benefits of grape seeds on wine color to mitigate this negative effect. Anthocyanins and their derivatives, and chromatic characteristics were measured by targeted UHPLC-QqQ-MS/MS and CIELab methods, respectively. The addition of seeds was beneficial to the formation of polymeric pigments and flavanyl-pyranoanthocyanins, while decreased the accumulation of other yranoanthocyanins, monomeric anthocyanins, and acylated anthocyanins during fermentation. All pigment levels in seed wine can be better maintained over time. Compared with the removal of seeds during fermentation, the addition of seeds significantly enhanced the color intensity, bluish hues, and Chroma, while an appropriate amount of seeds favored wine red hue. PLSR showed that the addition/removal of seeds during fermentation could alter red wine chromatic characteristics via modulating anthocyanin profiles. These results can be used as reference to further explore the technological applications of seeds during fermentation for optimizing the potential benefits on red wine color.

Effect of micro-oxygenation on color of wines made with toasted vine-shoots.

Toasted vine-shoots (SEGs) are an enological tool to improve wines, to differentiate them, and to encourage sustainable wine production. Micro-oxygenation (MOX) is typically combined with the use of alternative oak products to simulate the oxygen transmission rate of traditional barrel aging, affecting wine color. Its use alongside SEGs has been studied. Tempranillo wines were treated with SEGs at two doses (12 and 24 g L-1) after malolactic fermentation at two fixed micro-oxygenation levels: (a) low, which received 6.24 ± 0.87 mg L-1·month-1 of oxygen; and, (b) high, which received 11.91 ± 0.71 mg L-1·month-1 of oxygen. The wines were bottled and stored for 6 months. At the end of the treatment, MOX affected the anthocyanins and color parameters, but not the enological characteristics. At this time, the anthocyanins content reduction presented a negatively significant correlation with oxygenfor wines treated with 12 g L-1. The factors that most influenced the development of color parameters during the time after bottling were the period for which the wine evolved in the bottle and SEG dose. The visual sensorial descriptors showed an evolution according to aged red wines, but without differences according to the SEG-MOX treatments. The SEG-MOX treatments caused significant changes in wine color. It would be advisable to adjust SEG-MOX techniques to increase their effectiveness. © 2024 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

A Versatile Ultra-High-Performance Liquid Chromatography-Full-Scan High-Resolution Mass Spectrometry Method to Quantify Wine Polyphenols.

Polyphenols are responsible for wine colour and astringency, and, as antioxidants, they also have beneficial health properties. In this work, we developed a robust full-scan high-resolution mass spectrometry method for the quantification of 90 phenolic compounds in wine samples (either red, rosé, or white wine), using a UHPLC-OrbitrapTM system. With this method, we could conduct a detailed analysis of phenolic compounds in red, rosé, and white wines with great selectivity due to sub-ppm mass accuracy. Moreover, accessing the full-scan spectrum enabled us to monitor all the other compounds detected in the sample, facilitating the adaptability of this method to new phenolic compounds if needed.

Sweet Red Wine Production: Effects of Fermentation Stages and Ultrasound Technology on Wine Characteristics

Three different sweet red wines were produced using Tempranillo grapes with three different sugar concentrations: 25, 50 and 75 g/L, using sulfur dioxide and low temperature to stop the alcoholic fermentation. They were compared to the wine produced without stopping the alcoholic fermentation. Cold pre-fermentation macerations and ultrasound during the post-fermentation stage were applied to try to improve the organoleptic properties specifically for sweet wines. The treatment with ultrasound after stopping the fermentation enhanced the extraction of anthocyanins compared to the wines produced without ultrasound, increasing the red color of the final wines, resulting in increments in the range of 16–30%. In any case, significant differences were found between the regular dry red wine and the sweet wines in terms of polyphenolic content, anthocyanin, tannin concentration and absorbance at 520 nm, with lower contents for the sweet wines. The wines were evaluated by different tasting panels showing different results depending on the tasting panel composition. First, an inverse relationship was observed between the sweetness of the wines and their acidity, bitterness, and astringency descriptors. Additionally, wines with higher sugar levels were described as having the most fruity aromas. Finally, no differences in vegetal aromas were found in the different wines.

New approaches for screening grape seed peptides as colourimetric modulators by malvidin-3-O-glucoside stabilisation

The colour of red wine is due to the presence of anthocyanins and their derived pigments, with malvidin-3-O-glucoside being the most predominant. Due to their chemical conformation, anthocyanins are susceptible to several conditions and have limited stability. Through copigmentation processes, anthocyanins can interact non-covalently with other molecules to enhance their stability. As a natural source of proteins and peptides, grape seeds are of particular interest because they may be of significant techno-functional value in the modulation of wine quality characteristics, such as acting as copigments to enhance colour stability. The proposed methodology allowed predicting in-depth insights into the molecular-level nature of interaction between the identified peptides when complexed with malvidin 3-O-glucoside and their colour stabilising properties. Thereby, allowing a prior screening in silico to facilitate their future application in experimental assays, such as obtaining the tested peptides with the characteristics already studied by means of grape seed meal directed hydrolysis.

THE IMPACT OF ULTRASOUND TREATMENT ON THE QUALITY OF DIFFERENT WINE VARIETIES

The aim of the present study was to characterize the quality of four varieties of wines obtained from grapes of Vrancea area: Feteasca Alba (FA), Tamaioasa Romaneasca (TR), Cabernet Sauvignon (CS) and Muscat Hamburg (MH) ultrasonicated (US) at different times (10 and 30 minutes), in terms of physico-chemical and sensory properties. The sensory characteristics (clarity, color, aroma, taste) and the physicochemical properties (density, sugar and alcohol content, pH, acidity, electrical conductivity, turbidity) were determinated on must and wine samples. Sonicated wine (energy intake in liquid) gives a more uniform degree of dispersion to the components, which improves the taste and quality (intensification of the color, flavor, and taste of the wine by extracting valuable ingredients from grape seeds and skin, such as polyphenolic substances), but also accelerates its maturation. The results revealed that the ultrasonic samples had a lower fermentation rate due to the inactivation of the yeasts.The wines have a more intense color than the untreated samples, results also related by physico-chemical parameters tested.

Effects of different low-temperature maceration times on the chemical and sensory characteristics of Syrah wine

This study aimed to investigate the effects of three different cold maceration times on the color, volatiles, and sensory of Syrah wine. The results showed that the physicochemical parameters were not influenced by maceration time. Extending the maceration time significantly increased the color intensity and decreased the hue of the wines. The content of monomeric anthocyanins and monomeric phenols increased gradually with the prolongation of immersion time, however, there was no significant difference between 72 and 120 h. Malvidin-3-O-glucoside was the most abundant monomer in anthocyanins, accounting for 67 % of the total content. Moreover, the highest flavanol content (95.42 ± 0.66 mg/L) was found in 120-h sample. The aroma contents of wines macerated for 72 and 120 h were significantly higher than that of 24 h (p < 0.05). Sensory evaluations showed that extended maceration enhanced the color intensity and floral-fruity aromas of the Syrah wines, while increasing astringency.

The effect of rosé wine colors on expected flavor and tastiness: A cross-modal correspondence explanation

How and why do wines with different colors influence consumer responses? Despite strong evidence from research on cross-modal correspondences that food and drink colors influence flavor perceptions and subsequent consumer responses, it is unclear from the wine literature whether consumers prefer paler or slightly darker colors of rosé. The aim of this research is twofold: (1) identify from an existing set of (relatively pale) prototypical color shades of Rosé de Provence what specific color (paler vs. slightly darker) leads to more positive consumer responses and (2) shed light on the underlying mechanisms that explain this relationship. Using a large sample of French wine consumers (n = 601), we test our hypotheses via a within-subjects design experiment. We first examined the effect of five shades of Rosé de Provence wines (nacre, light melon, sand, melon, and peach) on consumer responses (willingness to pay, willingness to buy, color liking). To further investigate the underlying roles of fruity flavor and expected tastiness (in that order), we conducted a series of two-condition within-subjects serial mediations. Our findings consistently show more positive consumer responses for Rosés de Provence with peach and melon shades (i.e., slightly darker colors) compared to nacre, light melon, and sand shades (i.e., paler colors). Further, a stronger association between slightly darker colors and fruity flavor enhances expected tastiness, which leads to more positive consumer responses. Our findings provide key theoretical contributions and managerial implications by suggesting consumer responses for Rosés de Provence and corresponding explanations based on cross-modal correspondences.

Hydroxycinnamate decarboxylase in Metschnikowia pulcherrima promotes the formation of vinylphenolic pyranoanthocyanins to enhance the color stability of blueberry wine

Blueberry wine is popular among consumers due to its high nutritional value, appealing color, and potential health benefits. However, the instability of its color during the brewing process poses challenges for storage and the overall growth of the blueberry wine industry. This study found that vinylphenolic pyranoanthocyanins in blueberry wine provide a more stable color than their anthocyanin precursors. The presence of yeast with hydroxycinnamic acid decarboxylase (HCDC) enhances the formation of vinylphenolic pyranoanthocyanins. Metschnikowia pulcherrima Y4, isolated from decayed blueberry peels, promotes the production of six specific vinylphenolic pyranoanthocyanins in blueberry wine: malvidin-4-vinylcatechol, delphinidin-3-arabinoside-4-vinylcatechol, cyanidin-3-galactoside/glucoside (C3G)-4-vinylcatechol, cyanidin-3-O-arabinoside-4-vinylcatechol, malvidin-3-O-glucoside/galactoside-4-vinylcatechol, and C3G-4-vinylphenol. Blueberry wine fermented solely with M. pulcherrima Y4 exhibits a 25% increase in light stability under direct outdoor light conditions and a 19% increase in temperature stability at 60 °C compared to Saccharomyces cerevisiae K1. Furthermore, the use of M. pulcherrima Y4 in fermenting blueberry wine significantly decreases the time required to form vinylphenolic pyranoanthocyanins to eight days. Hence, M. pulcherrima Y4 is highly effective in accelerating the synthesis of these compounds, providing a valuable approach for improving the stability and color of blueberry wine.

Investigating biological mechanisms of colour changes in sustainable food systems: The role of Starmerella bacillaris in white wine colouration using a combination of genomic and biostatistics strategies

This study explores the biological mechanisms behind colour changes in white wine fermentation using different strains of Starmerella bacillaris. We combined food engineering, genomics, machine learning, and physicochemical analyses to examine interactions between S. bacillaris and Saccharomyces cerevisiae. Significant differences in total polyphenol content were observed, with S. bacillaris fermentation yielding 6 % higher polyphenol content compared to S. cerevisiae EC1118. Genomic analysis identified 12 genes in S. bacillaris with high variant counts that could impact phenotypic properties related to wine color. Notably, SNP analysis revealed numerous missense and synonymous variants, as well as stop-gained and start-lost variants between PAS13 and FRI751, suggesting changes in metabolic pathways affecting pigment production. Besides that, high upstream gene variants in SSK1 and HIP1R indicated potential regulatory changes influencing gene expression. Fermentation trials revealed FRI751 consistently showed high antioxidant activity and polyphenol content (Total Polyphenol: 299.33 ± 3.51 mg GAE/L, DPPH: 1.09 ± 0.01 mmol TE/L, FRAP: 0.95 ± 0.02 mmol TE/L). PAS13 exhibited a balanced profile, while EC1118 had lower values, indicating moderate antioxidant activity. The Weibull model effectively captured nitrogen consumption dynamics, with EC1118 serving as a reliable benchmark. The scale parameter delta for EC1118 was 23.04 ± 2.63, indicating moderate variability in event times. These findings highlight S. bacillaris as a valuable component in sustainable winemaking, offering an alternative to chemical additives for maintaining wine quality and enhancing colours profiles. This study provides insights into the biotechnological and fermented food systems applications of yeast strains in improving food sustainability and supply chain, opening new avenues in food engineering and microbiology.

Amelioration of Smoke Taint in Wine via Addition of Molecularly Imprinted Polymers during or after Fermentation.

The adsorbents used to remove taint compounds from wine can also remove constituents that impart desirable color, aroma, and flavor attributes, whereas molecularly imprinted polymers (MIPs) are tailor-made to selectively bind one or more target compounds. This study evaluated the potential for MIPs to ameliorate smoke taint in wine via removal of volatile phenols during or after fermentation. The addition of MIPs to smoke-tainted Pinot Noir wine (for 24 h with stirring) achieved 35-57% removal of guaiacol, 4-methylguaiacol, cresols, and phenol, but <10% of volatile phenol glycoconjugates were removed and some wine color loss occurred. Of the MIP treatments that were subsequently applied to Semillon and Merlot fermentations or wine, MIP addition post-inoculation of yeast yielded the best outcomes, both in terms of volatile phenol removal and wine sensory profiles. Despite some impact on other aroma volatiles and red wine color, the findings demonstrate that MIPs can ameliorate smoke-tainted wine.

Impact of Fining Agents on Color, Phenolics, Aroma, and Sensory Properties of Wine: A Review

Impact of Fining Agents on Color, Phenolics, Aroma, and Sensory Properties of Wine: A Review

Enhancing the color and astringency of red wines through white grape seeds addition: Repurposing wine production byproducts

The clear juice fermentation technique for white wines suggests that white grape seeds, rich in flavan-3-ols and proanthocyanidins, are not effectively utilized in the winemaking process. This study incorporated ‘Gewürztraminer’ grape seeds into ‘Cabernet Sauvignon’ must before cold soak to investigate how the resultant red wines' phenolic compound profiles, color, and astringency were affected. The results showed that adding seeds primarily inhibited the leaching of flavan-3-ols from both skins and seeds. A significant increase in the levels of flavan-3-ols, tannins, and phenolic acids, as well as direct and aldehyde-bridged flavan-3-ol-anthocyanin polymers, were observed in the wines with additional seeds. This led to the improvement in the wine’ red hue and its resistance to SO2 bleaching. Furthermore, the wine added with seeds exhibited stronger astringency compared to those without. The findings provide a promising winemaking strategy to improve color stability and intensify the astringency of red wines through the utilization of grape seeds.

The composition and structure of plant fibers affect their fining performance in wines

In recent years, the wine industry has shifted towards plant-based fining agents for food safety reasons and consumer preferences. This study analysed the interaction of five plant fibers with red wine phenolic compounds to determinate their performance as fining agents. Chemical composition, polysaccharide profile, and physical properties were examined. Pea, cellulose, and Sauvignon Blanc pomace fibers effectively reduced tannin content while minimally affecting the concentration of anthocyanins, flavonols and wine color. Contrary to previous beliefs, the presence of pectins in fibers didn't play a crucial role in phenolic compound interaction since cellulose-rich fibers with low pectin concentration also bound tannins effectively, especially those with small particle size and high contact surface. Pea fiber, rich in cellulose and pectins, showed remarkable tannin retention while minimally affecting wine color. This research highlights the potential of plant fibers as effective fining agents in wine production and how their composition affects their performance.

Effect of different deficit irrigation regimes on vine performance, grape composition and wine quality of the “Primitivo” variety under mediterranean conditions

Climate change represents one of the current major challenges and the improper use of water resources is an impeding threat. Agricultural research can play a crucial role by developing innovative strategies and techniques to reduce water use without affecting crop productivity and quality, particularly in grapevine growing in Mediterranean areas, as both productivity and wine quality are quintessential for the economic and ecologic sustainability of this crop. The present study aimed to define a deficit irrigation strategy for the “Primitivo” grapevine cultivar, taking into account the overall pathway of the vineyard performance in terms of leaf functionality, starch reserves, vine productivity, and wine quality. The trial was carried out in Southern-Italy on a three year-old, drip irrigated vineyard, imposing four deficit irrigation regimes for two consecutive seasons, consisting of 29 (T29), 55 (T55), 85 (T85) and 100% (T100) of crop evapotranspiration (ETC). Mild water restriction (T85) did not affect vegetative nor reproductive vine performance. Deficit irrigation at 55% ETC lowered leaf functionality, starch accumulation, vine vigour and yield, due to a reduction of cluster weight; however, wine acidity and phenolic compounds were increased. T29 further decreased yield, as also the number of clusters was reduced. The most water-stressed treatment revealed a low concentration of malic acid in the must and a consequent increase of the ethanol sensation in the wine. After 9 months ageing, T85 had the highest wine colour intensity suggesting this treatment as the most promising in terms of quality and quantity of wine as well as for water saving.

The Effects of a Saccharomyces cerevisiae Strain Overexpressing the Endopolygalacturonase PGU1 Gene on the Aminoacidic, Volatile, and Phenolic Compositions of Cabernet Sauvignon Wines

The addition of pectinase enzymes during the maceration stage of grape skins in order to improve the extraction yields and color of red wines is a common practice in many wineries. The objective of this work was to study in depth the changes that occurred in the aminoacidic, volatile, and phenolic compositions of Cabernet Sauvignon wines fermented with a Saccharomyces cerevisiae strain genetically modified with the gene encoding for endopolygalacturonase (PGU1) in transcriptional fusion with the promoter of the phosphoglycerate kinase (PGK1) gene, both from S. cerevisiae origin. A higher yield extraction of wine was obtained in wines fermented with the modified strain (PW), increasing by around 6.1% compared to the control wine (CW). Moreover, there was a 40% decrease in the malic acid content in the PW, thus suggesting that this modified yeast could be investigated as a malic acid-reducing agent. There were slight differences in other aroma volatile compounds studied as well as in the phenolic content. However, there was a considerable increase in the amino acid content in the PW.

A comprehensive study on the effect of foliar mineral treatments on grapevine epiphytic microorganisms, flavonoid gene expression, and berry composition

Foliar treatments with mineral-based compounds have aroused interest as a sustainable approach to cope with high-temperature stress in vineyards, improving the colour of grapes and wines without altering the sugar concentration. Since berry-associated microorganisms are crucial for wine production, composition and stability, the present study aims to unravel the effects of kaolin and zeolite treatments on berry quality, flavonoid gene expression and epiphytic microorganisms (total fungi, Hanseniospora uvarum, Metschnikowia pulcherrima, plant-associated bacteria and lactic acid bacteria). Experiments were performed on 'Sangiovese' during ripening in two growing seasons (2019 and 2020). Both mineral treatments were able to cause the elicitation of several flavonoid-related genes and to increase the anthocyanin concentration in berries without an alteration of the final technological maturity (TSS, TA, pH) of the grapes. Interestingly, neither kaolin nor zeolites negatively affected the analysed microbial population at harvest despite transient alterations observed in the more stressful year (2019). These results support the use of foliar mineral treatments to increase anthocyanin concentration in grape berries and protect them from excessive heat without altering their native microorganisms.