Red Wine Color Research Articles

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.

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.

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.

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 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 modified pararosaniline hydrochloride method for determination of total and bound sulfur dioxide in wine

An improved pararosaniline hydrochloride (PRA) method for rapid and accurate determination of total and bound sulfur dioxide (SO2) in wine was established. The determination conditions for total SO2 were optimized in model wine systems. The pH of the acidified PRA reagent had a significant effect on the color and the maximum absorption wavelength (λmax) of the reaction system, with its optimum pH 0.48 and a λmax at 549 nm. The addition of ethylene diamine tetraacetic acid (EDTA) could effectively shield the interference of coexisting metal ions present in wine, and a novel approach to double background subtraction was confirmed to remove the matrices interference of red wine color. Under the optimum conditions, the linear range for total SO2 in wine was within 1.00–8.00 mg L−1 (R = 0.9975), with the detection and quantification limits (MDL and MQL) found as 0.02 and 0.06 mg L−1, respectively. The recovery of SO2 ranged from 85.73 % to 105.70 % with the relative standard deviations (RSD) of 0.21 % - 7.78 %, suggesting high sensitivity and accuracy of the method. Combining with the optimized Monier-Williams method, the determination of bound SO2 in wine was also achieved. Sulfite determination can be performed in wine using the rapid, accurate and sensitive method without any pretreatment, and the results were comparable with those of the standard methods.

Application of Turbiscan Lab® to study the mechanism of fining in red wine using a specific yeast protein extract: A comparison with gelatine

Fining of wines using proteins is a standard practice in the winemaking process. Gelatine is a common fining agent used for red wines. However, the consumer demand for wines that are free of animal-derived products has reinforced the search for alternative protein sources such as yeast origin as the latter is originally present in wine. In 2012, the International Organization of Vine and Wine (OIV) authorized yeast protein extract (YPE) as a processing aid for the fining of musts and wines (OIV-Eno 452–2012). The present work aimed at better understanding the fining mechanisms of a specific YPE, to evaluate the part played by interactions in solution with polyphenols, but also at the interfaces with suspended particles. Polyphenols from the soluble phase of red wine were separated from the suspended particles by centrifugation, and these particles were resuspended in a wine model solution. Interactions with YPE were studied with each fraction separately through static multiple light scattering (SMLS) using the Turbiscan Lab® apparatus and optical microscopy. The impact on wine color and astringency was assessed by UV–visible spectrophotometry and BSA assay test. Faster aggregation and sedimentation kinetics were observed with gelatine than with YPE, but the levels of clarification and lees were similar for both fining agents after a couple of hours (4 h maximum). Gelatine resulted in higher tannin and pigment removal, likely to decrease astringency but also derived pigments involved in red wine color stability. Meanwhile, the impact of the YPE was moderate, likely to modulate astringency while preserving wine color and structure. In addition to interacting directly with polyphenols in solutions such as gelatine, YPE exhibited the additional ability to trap particles and promote their sedimentation in the absence of tannins. This double performance of the YPE used in this work, is likely to guarantee an effective fining of red wines as well as for low tannin content matrices such as rosé and white wines.

Copper (II) Level in Musts Affects Acetaldehyde Concentration, Phenolic Composition, and Chromatic Characteristics of Red and White Wines.

Copper (II), a vital fungicide in organic viticulture, also acts as a wine oxidation catalyst. However, limited data are currently available on the impact that maximum allowed copper (II) ion doses in wine grapes at harvest can have on aged wine quality. This was the focus of the present study. We investigated the copper (II) effects by producing both white and red wines from musts containing three initial metal concentrations according to the limits set for organic farming. In detail, the influence of copper (II) on fermentation evolution, chromatic characteristics, and phenolic compounds was evaluated. Interestingly, the white wine obtained with the highest permitted copper (II) dose initially exceeded the concentration of 1.0 mg/L at fermentation completion. However, after one year of storage, the copper (II) content fell below 0.2 ± 0.01 mg/L. Conversely, red wines showed copper (II) levels below 1.0 mg/L at the end of fermentation, but the initial copper (II) level in musts significantly affected total native anthocyanins, color intensity, hue, and acetaldehyde concentration. After 12-month aging, significant differences were observed in polymeric pigments, thus suggesting a potential long-term effect of copper (II) on red wine color stability.

Gold nanoparticles capped with α-cyclodextrin for dual colorimetric sensing of Fe3+ and Cr3+ in tap water

Abstract A rapid colorimetric assay for the dual detection of Fe3+ and Cr3+ using gold nanoparticles (AuNPs) capped with α-cyclodextrin was developed. The synthesized AuNPs produced a red wine color with a particle size of 8.60 ± 1.55 nm and were stable for 9 months. Detection of Fe3+ and Cr3+ changed the color of the AuNPs solution to bluish purple with a detection time of &lt;1 and 10 min, respectively. Reaction of the AuNPs with Fe3+ and Cr3+ also increased the particle size of the AuNPs to 16.18 ± 2.28 nm and 17.33 ± 1.71 nm, respectively. Characterization of the AuNPs using Fourier-transform infrared spectroscopy and X-ray diffraction showed that the presence of Fe3+ would damage the structure of the AuNPs, whereas Cr3+ would not. This colorimetric sensor is sensitive toward Fe3+ and Cr3+ with limits of detection of 265.92 and 430.80 μg/L, respectively. The dual ion sensing ability of the AuNPs was also assessed by individually detecting Fe3+ and Cr3+ in tap water samples in South Tangerang, Banten, Indonesia.

Gallic acid improves color quality and stability of red wine via physico-chemical interaction and chemical transformation as revealed by thermodynamics, real wine dynamics and benchmark quantum mechanical calculations

The aim of this study was to explore the copigmentation effect of gallic acid on red wine color and to dissect its mechanism at the molecular level. Three-dimensional studies, e.g., in model wine, in real wine and in silico, and multiple indicators, e.g., color, spectrum, thermodynamics and phenolic dynamics, were employed. The results showed that gallic acid significantly enhanced the color quality and stability of red wine. Physico-chemical interactions and chemical transformations should be the most likely mechanism, and physico-chemical interactions are also a prerequisite for chemical transformations. QM calculations of the physico-chemical interactions proved that the binding between gallic acid and malvidin-3-O-glucoside is a spontaneous exothermic reaction driven by hydrogen bonding and dispersion forces. The sugar moiety of malvidin-3-O-glucoside and the phenolic hydroxyl groups of gallic acid affect the formation of hydrogen bonds, while the dispersion interaction was related to the stacking of the molecular skeleton.

Pectin forms polymeric pigments by complexing anthocyanins during red winemaking and ageing

The long-term stability of red wine color depends on the formation of polymeric pigments from anthocyanins. Although there is still a lot of uncertainty about the specific structure of this diverse group of pigments, there is consensus that they are reaction products of anthocyanins and other polyphenols. Interactions between anthocyanins and pectic polysaccharides have been suggested to stabilize anthocyanins. This study explores the impact of such interactions by adding pectin during red winemaking.The results demonstrate that these interactions induce the formation of additional polymeric pigments which enhance the pigment stability during fermentation and aging. While initial pigment formation is higher in wines with added pectin, a notable proportion of the complexes degrades in the later stages of fermentation. Presumably, tannins form insoluble complexes with pectin, reducing tannin concentration by more than 300 mg/L. Anthocyanin concentrations decrease by over 400 mg/L, and polymeric pigments double.Anthocyanins that form polymeric pigments with pectic polysaccharides expand the range of pigments in red wines with possible consequences for the sensory properties of the wine. These findings highlight the complex interactions between pectin, anthocyanins, and tannins, and their influence on pigment formation and wine composition during fermentation and aging.

Comprehensive analysis of colloid formation, distribution, and properties of monovarietal red wines using asymmetrical flow field-flow fractionation with online multidetection

Red wine colloids, crucial in determining wine quality and stability, are understudied due to inadequate techniques for studying them effectively in the natural wine environment. Recently, Asymmetrical Flow Field-flow Fractionation (AF4) with online multidetection has emerged as a novel analytical tool for quantifying, fractionating, and characterizing red wine colloids in their native state. This study aimed to characterize the colloidal composition of 24 monovarietal Italian wines produced without filtration, oak contact, fining treatments, malolactic fermentation, macerating enzymes or ageing on yeast lees. AF4 analysis allowed quantification and characterization of wine colloids based on light scattering signal (MALS; gyration radius − Rg), size (hydrodynamic radius – Rh) and absorbance (A280 & A520 nm).The results showed that each wine contained up to five distinct colloids’ populations, varying in size and gyration radii. Despite possessing very similar Rh, most colloids exhibited great differences in compactness, as indicated by their varying Rg values. Comparing the A280 signal of whole wines to those of wines containing only species larger than 5 kDa (considered colloids) allowed to calculate the percentage of molecules involved in colloidal particles assembly, ranging from 1 to 44 % of the total A280 absorbing compounds, reflecting the diversity among wines. The A520 signal indicated the presence of polymeric pigments in the colloidal fraction. Notably, colored colloids all had Rg > 20 nm, indicating their association with other colloidal-forming compounds. This observation led to the conclusion that, apart from free anthocyanins and polymeric pigments, the color of red wines is also due to colloidal particles formed by the latter bound to proteins, with their quantity being highly variable across wines of different origin. These findings, which highlight the fundamental role of proteins in shaping the colloidal status of red wines, were utilized to propose an updated hypothetical model for colloidal aggregation in red wine.

ВЛИЯНИЕ МИКРООКСИДАЦИИ МЕЗГИ НА ХИМИЧЕСКИЕ И ОРГАНОЛЕПТИЧЕСКИЕ ПОКАЗАТЕЛИ КРАСНЫХ ВИН

An urgent problem in modern wine-making is to ensure long-term preservation of the color of red wine, including when it is stored in bottles. The problem is associated with the oxidation of phenolic substances under the influence of oxygen. One of the ways to prevent oxidation is the use of microoxidation – introducing a certain amount of oxygen in order to oxidize labile fractions of polyphenols at an early stage of the wine production process. However, oxygen dosages require clarification and further research. The purpose of the research is to study the effect of microoxidation with various doses of oxygen on physical and chemical parameters, including the mass concentration of phenolic substances, of wine materials from the Cabernet Sauvignon grape variety. The objects of the study were production and experimental batches of wines made from the Cabernet Sauvignon grape variety. The oxygen dosage varied from 2 to 10 mg/dm3 . A significant difference in the mass concentration of oxygen in industrial samples was established – from 0.5 to 4.3 mg/dm3 . A correlation was revealed between the color of the wine and the oxygen content: the test samples with the highest mass concentration of oxygen had garnet-red shades of color. It was shown that the concentration of all groups of phenolic substances depended on the location of the grapes and the wine producer. The greatest accumulation of the amount of phenolic substances was in wine produced in the geographical area of Novorossiysk. A general trend of changes in the concentration of various groups of phenolic compounds depending on the dosage of oxygen was revealed: with an increase in the dosage of oxygen, the concentration of the components of the phenolic complex decreases, with anthocyanins undergoing the greatest change. The concentration of catechins decreased gradually with increasing oxygen dosage. For procyandins, dosing 2-4 mg/dm3 immediately led to a decrease in their concentration by 10-15 %. A further increase in the oxygen dosage did not cause a change in the concentration of procyanidins. It has been proven that an oxygen dosage of 2-4 mg/dm3 ensures high organoleptic properties of red wine. Key words: RED WINES, PHENOLIC COMPOUNDS, MICROOXIDATION, OXIDATION, ORGANOLEPTIC EVALUATION

The Application of the Ultrasound Technique in the Production of Rosé and Red Wines

The application of the ultrasound technique (US) in the production of rosé and red wines has demonstrated that the aromatic composition of rose wine can be affected and that it contributes to increasing the color of red wines without increasing the extraction of astringent tannins. The ultrasound treatment has favored the extraction of anthocyanins, which has had an impact on the increase in color density (C.D.) and has allowed greater color stability over time. Moreover, significant differences have been found between the two US systems applied, with continuous treatment being more effective in the extraction of phenolic compounds than pulsed treatment. The application system of the US also affects the aromatic composition of the wines. These results are of interest, as some esters have been described as important odorants in wines.

Exploring the Stabilization of Phenolic Material and Red Wine Color through Different Polysaccharide Extraction and Addition Strategies

Exploring the Stabilization of Phenolic Material and Red Wine Color through Different Polysaccharide Extraction and Addition Strategies

Studiul compoziției antocienilor monomerici în vinurile roşii din soiurile de struguri autohtone şi de selecţie nouă prin metoda HPLC

The data on the composition of monomeric anthocyanins, which determine the color of dry red wines from the new selection grape variety Codrinschi and local grape varieties: Copceac, Feteasca neagra, Negru de Causeni, have been obtained by the modern instrumental method of analysis – HPLC. The quantities of these compounds, characteristic for each variety, have been determined.

Manganese sulfate application promotes berry flavonoid accumulation in Vitis vinifera cv. 'Cabernet Sauvignon' by regulating flavonoid metabolome and transcriptome profiles.

Flavonoids are vital for developing grapes and wine quality, and manganese deficiency decreases grape berry coloration. However, the effects and underlying mechanisms of action of manganese sulfate on grape metabolic profiles have not been well studied. In this study, three concentrations of manganese sulfate solutions: 0.5 μmol·L-1 (low, L), 5 μmol·L-1 (middle, M, the standard manganese concentration of Hoagland nutrient solution, control), and 1000 μmol·L-1 (high, H) were applied to "Cabernet Sauvignon" grapevine (Vitis vinifera L.) to explore the effect on berry composition. Manganese application effectively improved manganese concentration in grape organs. Furthermore, the concentrations of malvidin 3-O-(6-O-acetyl)-glucoside, malvidin 3-O-glucoside, malvidin-trans-3-O-(6-O-p-coumaryl)-glucoside, and peonidin 3-O-(6-O-acetyl)-glucoside were significantly increased under H treatment. More importantly, weighted gene co-expression network analysis (WGCNA) revealed that the structural genes (VvDFR, VvUFGT, and VvOMT) of flavonoid biosynthesis in brown module were upregulated under H treatment, and positively correlated with malvidin- and peonidin-derived anthocyanin concentrations. This study suggested that manganese application regulates berry transcriptional and flavonoid metabolic profiles, providing a theoretical basis for improving the color of red grapes and wines. This article is protected by copyright. All rights reserved.

Chemical and colorimetric study of the influence of grape soluble polysaccharides on the color and stability of malvidin 3-O-glucoside solutions

Red wine color is mainly due to anthocyanins’ flavylium cation. In wine, these pigments are involved in a pH-dependent equilibrium involving other forms, both colored and non-colored. This equilibrium is affected by the presence of other phenolic compounds, the so-called copigments. Moreover, other non-phenolic compounds that can be found in wine, such as polysaccharides, can also affect wine color. In this work, molecular dynamics simulations, tristimulus colorimetry and HPLC-DAD analyses have been performed to assess the effect of soluble polysaccharides (P) on the color and stability of malvidin 3-O-glucoside (Mv) solutions at different pH values, both in presence and absence of other compounds that can establish copigmentation interactions with the pigment. Results showed that P shifts the color of flavylium solutions towards a more intense color with bluer hues, which can be related to a stabilization of the blue quinoidal forms of anthocyanins. This effect is similar to that observed for quercetin 3-β-glucopyranoside (QG), although, in the case of P, it seems to be more relevant. This behavior could be due to the presence of hydrophobic regions in P that allows the interaction with the quinoidal forms, which in the case of the polysaccharide might be related to the type I rhamnogalacturonans.

Exploring the influence of S. cerevisiae mannoproteins on wine astringency and color: Impact of their polysaccharide part.

The impact of the polysaccharide moiety of mannoproteins (MPs) on the color and astringency of red wines was studied respectively through spectrophotometry and their impact on tannin interactions with BSA. To this end, MPs with conserved native structures from four different Saccharomyces cerevisiae strains were used: a Wild-Type strain (BY4742, WT) taken as reference, mutants ΔMnn4 (with no mannosyl-phosphorylation) and ΔMnn2 (linear N-glycosylation backbone), and a commercial enological strain. MPs affected tannin-BSA interactions by delaying aggregation kinetics. To achieve it, a well-balanced density/compactness of the polysaccharide moiety of MPs was a key factor. MP-WT and MP-Mnn2 acted as weak copigments and induced a slight increase in the absorbance of Malvidin-3-O-Glucoside. The same MPs also promoted a synergistic effect during the copigmentation of Quercetin-3-O-Glucoside with Malvidin-3-O-Glucoside. The intensity of these hyperchromic effects was related to the accessibility of anthocyanins to negatively charged mannosyl-phosphate groups within the polysaccharide moiety.

Sequential inoculation of flocculent Torulaspora delbrueckii with Saccharomyces cerevisiae increases color density of Pinot Noir wines.

Pinot noir grapes require careful management in the winery to prevent loss of color density and promote aging stability. Winemaking with flocculent yeast has been shown to increase color density, which is desirable to consumers. This research explored interspecies sequential inoculation and co-flocculation of commercial yeast on Pinot noir wine color. Sedimentation rates of six non-Saccharomyces species and two Saccharomyces cerevisiae strains were assayed individually and in combination. The most flocculent pairings, Torulaspora delbrueckii BIODIVA with S. cerevisiae RC212 or VL3, were used to ferment 20 L Pinot noir must. Sequential fermentations produced wines with greater color density at 420 + 520 nm, confirmed by sensory panel. Total and monomeric anthocyanin concentrations were decreased in sequentially fermented wines, despite being the main source of red wine color. BIODIVA adsorbed more anthocyanins than S. cerevisiae, indicating a greater number of cell wall mannoproteins in flocculent yeast, that could then result in a later release of anthocyanins and enhance copigment formation in red wines.