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Color is a crucial sensory indicator of wine quality. However, changes in anthocyanin concentration and profile occur during wine aging, resulting in noticeable reductions in chroma and shifts in hue from purple to brick red. This is because monomeric anthocyanins degrade and derivative anthocyanins form. The rate of color changes can vary depending on complex factors, such as the anthocyanin content of the must, oenological technology, and environmental conditions, which makes the management of red wine color evolution challenging. To address this issue, appropriate winemaking techniques are required to achieve an elegant wine color. This review summarizes the mechanisms related to anthocyanin stability, including glycosylation, acetylation, and derivatization. The review also discusses factors influencing red wine color fading for specific grape varieties and wine appellations, offering time- and cost-efficient techniques to accelerate anthocyanin derivatization and color stabilization.

A dry-farmed vineyard block with vines of varying ages including young vines (5 to 12 years old), control vines (2:1 ratio of old to young vines), and old vines (40 to 60 years old) was either submitted to irrigation or dry-farmed. The experimental design yielded six treatments, namely, Irrigated Control, Irrigated Young, Irrigated Old, Dry-farmed Control, Dry-farmed Young, and Dry-farmed Old. Irrigated Young wines were lower in alcohol, anthocyanins, and tannins, as well as higher in pH and hue angle values (H*), than the remaining treatments. Dry-farmed Young wines were higher in anthocyanins and small polymeric pigments, and showed higher color saturation and red hue. However, the magnitude of these differences was small. At pressing, the anthocyanin composition of these Zinfandel wines was largely dominated by malvidin-3-glucoside (60 to 65%), but after 15 months of bottle aging their anthocyanin profile shifted to 60% of anthocyanin derivatives, with small polymeric pigments accounting for more than 70% of the total polymeric pigment content of the wines. Irrigated Old wines and Dry-farmed Old wines did not differ to any significant extent in their basic chemistry, phenolic chemistry (including detailed anthocyanin composition), and chromatic composition. [ABSTRACT FROM AUTHOR]

Adding pomace or juice runoff during maceration is a traditional winemaking process. To mitigate the negative effects of rainfall during harvest and examine the effects of adjusting the pomace ratio during fermentation on the flavor profile of Marselan grape wines, the prefermentation addition of Petit Manseng grape pomace (PAP) and prefermentation juice runoff (PJR) was determined. The phenolic and volatile compounds were investigated using HPLC–MS and GC–MS. PAP enriched the flavanols and PJR enriched the pigment and copigment matrix. Approximate 10% increase in the ratio of pomace promoted the formation of anthocyanin derivatives. The increased pomace ratio reduced the concentration of volatile compounds without impacting the aroma quality. Sensory analysis revealed PAP wines scored higher for acidity and astringency and PJR wines scored higher for color. In conclusion, an appropriate increase in the pomace ratio of approximately 10% can enhance the color and mouthfeel of the wine while having a limited influence on aroma.

Nowadays, the development of naturalness as a concept is illustrated in the oenological field by the development of wine produced with lower inputs, sometimes even without any addition of SO2 throughout the winemaking process, up to the bottling stage. Despite the increase in the offer of these wines, they remain poorly explored in the literature and require characterization. This study was developed to evaluate the color of Bordeaux red wines without SO2 addition using colorimetric and polymeric pigments analysis. From a batch of commercial Bordeaux red wines with and without SO2 addition, and experimental wines produced from homogenous grapes according to different winemaking processes, colorimetric analyses (CIELab and color intensity (CI)) revealed a large difference in wine color depending on the presence or absence of SO2. Indeed, wines without SO2 were significantly darker and presented with a deeper purplish color. According to these observations, polymeric pigments were quantified using UPLC-DAD/ESI QTof, and a higher concentration of polymeric pigments bound by the ethylidene bridge was observed in wines without SO2. This correlated with differences observed for CIELab and CI. Finally, a comparison with polymeric tannins bound by ethylidene bridge was made and revealed that no differences were observed between wines with and without added SO2. This underlines the affinity difference between tannins and anthocyanins to react with acetaldehyde to form ethylidene bridges. [ABSTRACT FROM AUTHOR]

[Objective] This study screened proper storage pattern for long-term storage of bottled domestic red wines to provide evidence for their scientific storage. [Method] Different storage patterns of bottle position (vertical or horizontal) and storage conditions (cabinet, cellar or room) were applied and the effects on color parameters, chemical components and aromatic characteristics of Cabernet Sauvignon red wines were examined during 14 months of storage. [Result] Storage patterns had significant impacts on color and sensory quality of Cabernet Sauvignon wines during storage. Bottle position was less effective than storage conditions. Room storage had greatest effects, followed by wine cellar and wine cabinet. During the first 9 months of storage, wine color stability and aroma complexity were improved with the increase of temperature. After storage for 14 months, aging characteristics appeared in samples stored in room condition, such as highlighted yellow color hue and aged red wine aroma, while wines stored in cabinet kept intense ruby color and red berry aroma. The correlation analysis further showed that the changes were mostly related to oxidation occurred in wine samples, and higher storage temperature accelerated the aging of red wine. [Conclusion] The color and sensory evolution of Cabernet Sauvignon wines were closely related to oxidation during bottle storage, resulted from the combination of oxygen, storage temperature and time. Low temperature and horizontal position are suggested for long-term storage. [ABSTRACT FROM AUTHOR]

The maceration process is one of the indispensable winemaking steps in red wine production that has a marked impact on phenolic compound extraction and can strongly influence the color and gustatory quality. Seed removal can have a substantial impact on the intensity of bitterness and astringency which are mainly influenced by the presence of flavanols. The main aim of this study was to investigate the influence of seed removal and extraction time on the phenolic composition, color parameters, and organoleptic properties of Plavac mali wines produced from the grapes from the Pelješac Peninsula. The achieved results showed that the control wines differ in terms of their highest content of total anthocyanins in both years and total flavonols in one year of investigation, while prolonged maceration without seeds decreases the concentration of phenolic acids as well as that of flavan-3-ols. A prolonged extraction time influenced the color intensity and tonality, moving it towards more yellow pigments. These changes could possibly be explained by the pronounced interaction between phenolic compounds and the formation of the new ones. Interestingly, seed removal probably diminished that change because the potential absorption of the anthocyanins by grape seeds and tannins were excluded. The highest quality was sensory defined in wines produced by prolonged maceration without seeds. [ABSTRACT FROM AUTHOR]

The enology industry in North Dakota is extremely young, with less than twenty years of existence. At times throughout the development of the North Dakota viticulture and enology industries, commercial wine producers have elected to purchase or store fresh harvested grapes as frozen musts. To investigate the fermentation outcomes related to skin contact for red grapevine musts, a postfreeze fermentation experiment was conducted with fruit from 'Frontenac', one of the most widely grown red grapevines in the Upper Midwest U.S. and North Dakota. Four fermentation treatments were applied to frozen 'Frontenac' grapevine musts: steam juice extraction, rosé, 1 day after inoculation (DAI) skin contact, and 9 DAI skin contact. Samples were collected daily for ten days and analyzed for fermentation progress and spectrophotometric monitoring of wine color attributes and total phenolics. The final wines were analyzed two years after bottling. Steam-extracted musts were initially darkest; however, they were lighter as final wines than the 9 DAI wines and similar to rosé wines in lightness. Total phenolics were greatest for 9 DAI wines and total red pigments were lowest for steam-extracted wines. While differences between treatments were detected, the wines remained visually similar; this indicates that color extraction within the freeze–thaw processes of musts may obliterate subtly and make it difficult to produce wines of light color when stored under these conditions. Continued work with additional grapevines beyond 'Frontenac' may help fine-tune must and fermentation extraction procedures for small-scale wineries growing cold-hardy grapevines. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine the impact of glutathione addition before and during primary processing on the basic physicochemical parameters and sensory properties of Pošip wine. The following measurement results were compared between the control sample, the glutathione treatment of fresh grapes (GG) and the addition of glutathione to must (GM): dissolved oxygen in wine, total phenols, color and sensory evaluation of wine. The results have shown the glutathione to have the greatest impact on oxygen dissolution and color hue and intensity in the GM sample, while the most total phenols were obtained in GG treatment. Sensory evaluation did not reveal significant differences in the aromatic profile, taste, and general impression between Pošip wines.

The purpose of this study was to explore the physico-chemical properties of grapes, as well as the anatomical impact and structure of grapes. We also delved into the chemical and biochemical composition of grapes and wine, both during and after the fermentation phase. In the second part of the study, we elaborated in greater detail on water as the primary component of grapes, followed by sugars which are elementary and essential to the fermentation process and to achieving successful alcohol production. In the methodology section, we discussed the analysis that I made in the laboratory at "Sone Castle Vineyards and Winery", for each analysis we paused to describe the progress and applied methodologies. In the final section, we dexamined the questionnaire administered to150 respondents. This questionnaire focused on wine consumption and the respondents' knowledge about wine and its significance. Our findings indicated that, in general, Albanian people do not yet have a strong tradition of wine consumption, partly due to the influence of various dominant religions. However, it is interesting to note that a majority of the respondents claimed to possess knowledge about the external evaluation of wine. Based on the responses, we realized that citizens are knowledgeable about perceiving wine products. Some individuals mentioned that they use it for entertainment at various family parties, for the end of the year holidays and others. In conclusion, the journey from production, processing to the end consumer involves multiple stages, all of which are necessarily to be met, so that we have a final wine with perfect taste and texture. [ABSTRACT FROM AUTHOR]

The color of wine is an important quality parameter essential for the first impression of consumers. The International Organization of Vine and Wine (OIV) recommends two methods to describe wine color: color calculation according to Glories and the determination of coordinates in the CIE L*a*b* color space. The measurement of wine color is often not feasible for winemakers because the required instrumentation is expensive and bulky. In this study, the influence of photometer settings on the calculated color was investigated based on 14 wines. Furthermore, the CIE L*a*b* and Glories system were compared using 56 red and 56 white wines. Photometer settings were found to influence the reproducibility of color determination. In addition, CIE L*a*b* system do not correlate in all wines with the Glories system and Glories probably provides less information about wine color. Using interpolation, CIE L*a*b* coordinates were calculated from single wavelength measurements taken by a small-sized and inexpensive portable analysis system, which could be used by winemakers in the future. [ABSTRACT FROM AUTHOR]

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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.

Objective: This study aimed to explore the effects of different concentrations of dissolved oxygen and free SO2 on the color and related parameters of Cabernet Sauvignon dry red wine during aging, and to provide basic data for enterprises to improve the aging process of Cabernet Sauvignon dry red wine. Methods: Cabernet Sauvignon dry red wine from Xinpuwang Wineyard in Shanshan County, Turpan, Xinjiang was used as the brewing material. The effects of different concentrations of free SO2 and dissolved oxygen on wine color, hue and anthocyanin content were observed during wine aging. Results: The wine was bright red when the concentration of dissolved oxygen and free SO2 was low. When the content of oxygen was 2 mg/（L·30 d）, the moderate polymerization of anthocyanin and tannin in wine was promoted, and the quality of the wine was improved. When the concentration of free SO2 was 15 ~ 30 mg/L, it had little effect on the hue value of grape wine, but it had an obvious effect on the color. When the concentration of free SO2 was more than 30 mg/L, the color of grape wine gradually became orange. Conclusion: The suitable concentration of free SO2 for Cabernet Sauvignon dry red wine aging was 25 mg/L, and the oxygen content was 2 mg/（L·30 d）.

Copyright of Glasnik Zastite Bilja is the property of Zadruzna Stampa D.D. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Nowadays, the development of naturalness as a concept is illustrated in the oenological field by the development of wine produced with lower inputs, sometimes even without any addition of SO2 throughout the winemaking process, up to the bottling stage. Despite the increase in the offer of these wines, they remain poorly explored in the literature and require characterization. This study was developed to evaluate the color of Bordeaux red wines without SO2 addition using colorimetric and polymeric pigments analysis. From a batch of commercial Bordeaux red wines with and without SO2 addition, and experimental wines produced from homogenous grapes according to different winemaking processes, colorimetric analyses (CIELab and color intensity (CI)) revealed a large difference in wine color depending on the presence or absence of SO2. Indeed, wines without SO2 were significantly darker and presented with a deeper purplish color. According to these observations, polymeric pigments were quantified using UPLC-DAD/ESI QTof, and a higher concentration of polymeric pigments bound by the ethylidene bridge was observed in wines without SO2. This correlated with differences observed for CIELab and CI. Finally, a comparison with polymeric tannins bound by ethylidene bridge was made and revealed that no differences were observed between wines with and without added SO2. This underlines the affinity difference between tannins and anthocyanins to react with acetaldehyde to form ethylidene bridges.

The maceration process is one of the indispensable winemaking steps in red wine production that has a marked impact on phenolic compound extraction and can strongly influence the color and gustatory quality. Seed removal can have a substantial impact on the intensity of bitterness and astringency which are mainly influenced by the presence of flavanols. The main aim of this study was to investigate the influence of seed removal and extraction time on the phenolic composition, color parameters, and organoleptic properties of Plavac mali wines produced from the grapes from the Pelješac Peninsula. The achieved results showed that the control wines differ in terms of their highest content of total anthocyanins in both years and total flavonols in one year of investigation, while prolonged maceration without seeds decreases the concentration of phenolic acids as well as that of flavan-3-ols. A prolonged extraction time influenced the color intensity and tonality, moving it towards more yellow pigments. These changes could possibly be explained by the pronounced interaction between phenolic compounds and the formation of the new ones. Interestingly, seed removal probably diminished that change because the potential absorption of the anthocyanins by grape seeds and tannins were excluded. The highest quality was sensory defined in wines produced by prolonged maceration without seeds.

In this paper, experiments were conducted to investigate the effects of ultrasound irradiation on the co-pigmentation of caffeic acid added in wine and the coloration of wine during storage. The wine color, chroma, level of the monomeric, combined and polymerized anthocyanins and the concentrations of malvidin-3-O-glucoside and syringic acid in wines were determined by the high-performance liquid chromatography (HPLC), ultraviolet-visible spectroscopy, respectively. The results indicate that ultrasound irradiation could definitely affect the color characteristic of wine to a certain extent. Compared with the wine without addition of caffeic acid, the co-pigmentation effects of wine added with caffeic acid could be significantly promoted by ultrasound irradiation, such as the wine color, color density and the polymerized anthocyanins. Furthermore, ultrasound irradiation had a continuous effect on the co-pigmentation of caffeic acid and wine coloration with the extended storage time. In summary, ultrasound could significantly modify the color properties of wine by enhancing the co-pigmentation between caffeic acid and monomeric anthocyanins in the wine, resulting in the improvement of wine quality. [ABSTRACT FROM AUTHOR]

Anthocyanins are important compounds in grapes and wine and significantly influence their characteristics. Ultraviolet light-C (UV-C) can be used as a tool to induce secondary metabolism, and in this study, it was used in 'Cabernet Sauvignon' grapes in the postharvest period to improve the anthocyanin profile and sensory attributes in wine produced with irradiated grapes. Grapes in the postharvest period were exposed to 0, 2, or 3 kJ m−2 UV-C radiation. After winemaking and storage time (6 months), physicochemical and color analyses, anthocyanin quantification and identification (HPLC–PDA-MS/MS), and sensory analyses were carried out. 'Cabernet Sauvignon' wine produced with grapes irradiated with 3 kJ m−2 UV-C showed increased spectrophotometric color, which is likely due to a 22.5% increase in total anthocyanin monomers, 59.3% of pyranoanthocyanins, 92.3% of direct condensation products, and 62.8% of acetaldehyde-mediated condensation products. In addition, this irradiated dose presented higher perception scores for visual color, aroma, taste, and was preferred by the tasters over the wine produced with non-irradiated grapes. This study is the first of its kind to show that the UV-C radiation treatment of grapes in the postharvest period can be a promising tool to improve the anthocyanin profile and sensorial quality of 'Cabernet Sauvignon' wine. [ABSTRACT FROM AUTHOR]

Spine grape (Vitis davidii Foex.) is an important wild grape species native to China. Fifteen red spine grape clones and three red Vitis vinifera grape varieties were used to evaluate the differences in the anthocyanin profiles and color properties of wines made from V. davidii and V. vinifera grapes. Among spine wines, ‘Junzi #2’ wine had the highest total phenolic and total anthocyanin, ‘Xiangzhenzhu’ wine had the highest total flavonoids, and ‘Junzi #1’ wine had the highest total tannin. The anthocyanin compositions of all of the spine wines were dominated by Mv-3,5-diglucoside. The total individual anthocyanin contents in spine wines, except ‘Gaoshan #5’, ‘Junzi #5055’, ‘Junzi #5061’, and ‘Junzi #5044’, were significantly higher than in V. vinifera wines. Most of the spine wines had a stronger red intensity and a brighter chroma with a bluer hue than V. vinifera wines. Correlation analysis revealed that the color properties were closely related to the anthocyanin composition. These results suggest that wines made from spine grapes may be useful for the wine industry for their color properties and high individual anthocyanin contents.

Acetaldehyde is a key compound in determining wine color evolution and sensory properties. Major wine metabolites reactive to acetaldehyde are phenolic compounds, mainly flavan-3-ols and anthocyanins. Many studies have been conducted with the purpose of investigating acetaldehyde reactivity in model solutions, but very poor are the reports of its fate in real wines. By means of LC-HRESIMS and UV/Vis HPLC, red and white wines exposed to an excess of acetaldehyde were analyzed with a specific focus on low molecular weight phenolics. The chemical behavior of acetaldehyde turned out to be different in white and red wines. In white wines, it mainly mediated the formation of vinyl-flavan-3-ol derivatives, while in red wines it led to the formation of ethylidene-bridged red pigments. These latter positively enhanced the color properties of red wines. Conversely, in white wines, the formation of compounds, such as xanthylium ions, causing the undesired browning effects were not detected. [ABSTRACT FROM AUTHOR]

Viticulture is particularly sensitive to climate change, as temperature is critical to the two key concepts of terroir and vintage. Vitis vinifera L. 'Pinot Noir' is known to not grow well in hot climates. A trial was run over two years in a commercial vineyard in the Adelaide Hills, South Australia, to determine the impact of higher temperatures on the 'Pinot Noir' grape and wine colour. A factorial experiment combining two sources of variation in temperature was established: three positions on a steep vineyard slope, and two thermal treatments: unheated control and heated with passive open-top transparent chambers. Elevated temperature decoupled sugars and anthocyanins in grape berries, with the heated treatment grapes producing a lower anthocyanin concentration for the same concentration of total soluble solids. Temperature effects were less defined for small batches of wines prepared from these grapes, with the wines from heated vines having higher total phenolics, and perhaps consequently lower CIELab b* values (i.e., less blue pigmentation/ anthocyanins). The study provides a unique insight into temperature gradients on a steeply sloping site and the effects on colour development of 'Pinot Noir' grape berries and wine. [ABSTRACT FROM AUTHOR]

Wine quality is influenced by the presence of over 500 different chemical compounds, with polyphenols having a crucial role in color intensity and tonality, astringency, mouthfeel, and overall impression formation, especially in red wine production. Their concentrations in wine can vary notably depending on the grape variety, the temperature and the length of maceration process, aging duration, and yeast selection. Therefore, in this work, the main goal was to determine the influence of five commercially available Saccharomyces yeasts provided from Lallemand, France and AEB, Italy, on the phenolic compound composition and chromatic parameters of Plavac mali wines produced from the grapes from coastal Dalmatia, grown at two different micro-locations. The achieved results pointed out the marked difference in individual polyphenol compound adsorption between tested yeasts. Fermol Super 16 was the one with the lowest and Lalvin D21 the strongest adsorption ability, regardless of vine growing location. These differences can be explained by the content of some anthocyanins (delphinidin and petunidin-3-O-glucoside) and gallic acid, and some flavan-3-ols. Tested strains also influenced wine color intensity, pointing out the possibility of modulating the style of a Plavac mali by the use of commercial yeasts. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the effects of 10 Starmerella bacillaris strains inoculated as planktonic or biofilm-detached cells on the chromatic characteristics of Montepulciano d'Abruzzo wine. Wines inoculated with biofilm-detached cells of St. bacillaris were characterized by a higher content of glycerol and viable yeast cells and a lower content of ethanol than those obtained with planktonic cells. Pyruvic acid content ranged from 45.99 mg/L to 48.19 mg/L and from 41.13 mg/L to 45.9 mg/L in wines fermented with biofilm-detached and planktonic cells, respectively. Wines obtained with biofilm-detached cells showed levels of anthocyanins ranging from 506.8 mg/L to 659.9 mg/L, while those fermented with free cells of St. bacillaris ranged from 518 mg/L to 612.6 mg/L. Similarly, the content of polyphenols was higher in wines inoculated with biofilm-detached cells. The different amounts of these compounds resulted in differences in the wine's color. Wines obtained with biofilm-detached cells of St. bacillaris had lower b* and h* values than those obtained with planktonic cells. These wines also showed higher a* values, indicating the presence of a stronger red color than the others, and lower clarity (L*). Moreover, the data obtained highlighted that it is possible to predict the color of young wines from must measurements. Further studies will be done to evaluate the role of other non- Saccharomyces yeasts, grown under different aggregation states, in the definition of wine color. [Display omitted] • St. bacillaris biofilm-detached cells improves the color of red wines. • St. bacillaris planktonic cells better adsorb anthocyanins. • St. bacillaris biofilm-detached cells increased content of glycerol and polyphenols. [ABSTRACT FROM AUTHOR]

In this paper, experiments were conducted to investigate the effects of ultrasound irradiation on the co-pigmentation of caffeic acid added in wine and the coloration of wine during storage. The wine color, chroma, level of the monomeric, combined and polymerized anthocyanins and the concentrations of malvidin-3-O-glucoside and syringic acid in wines were determined by the high-performance liquid chromatography (HPLC), ultraviolet-visible spectroscopy, respectively. The results indicate that ultrasound irradiation could definitely affect the color characteristic of wine to a certain extent. Compared with the wine without addition of caffeic acid, the co-pigmentation effects of wine added with caffeic acid could be significantly promoted by ultrasound irradiation, such as the wine color, color density and the polymerized anthocyanins. Furthermore, ultrasound irradiation had a continuous effect on the co-pigmentation of caffeic acid and wine coloration with the extended storage time. In summary, ultrasound could significantly modify the color properties of wine by enhancing the co-pigmentation between caffeic acid and monomeric anthocyanins in the wine, resulting in the improvement of wine quality.

Abstract We evaluated the quality of wines produced in Nepal in terms of phenolic, flavonoid, anthocyanin and tannin content, antioxidant capacity, and color parameters using spectrophotometric methods. The total phenolic content, total flavonoid content, and total antioxidant activities in Nepali wines ranged from 85.5 to 960.0 (mean = 360.5 ± 268.7) mg/L GAE, 40.9–551.3 (mean = 188.9 ± 161.5) mg/L QE, and 66.6–905.0 (mean = 332.8 ± 296.5) mg/L AAE, respectively. These parameters were significantly higher in red wines compared to white wines. The phenolic and flavonoid content showed strong correlation with each other as well as with antioxidant activities. Additional parameters measured included various color parameters and carbohydrates. The wine color showed strong correlation with phenol, flavonoid, and antioxidant activity, whereas this correlation was not significant with anthocyanin content. Multivariate analysis was carried out to better describe and discriminate the wine samples. Finally, we compared Nepali wines with wines from other countries.

BACKGROUND The single high‐wire system is a free canopy trellis system suitable for warm to hot climates. In a global warming scenario, it arouses as a technological solution since it prevents berry overheating and sunburn. Canopy management practices manipulate leaf‐to‐fruit ratios, affecting berry and wine composition. We aimed to evaluate the phenolic and sensory profiles of Malbec wines from single high‐wire trellised vineyards in a hot region in Mendoza (Argentina) and to assess the effect of varying leaf‐to‐fruit ratios on these attributes. We manipulated leaf‐to‐fruit ratios by varying shoot trimming (experiment 1: 0.45 m, 0.80 m, and untrimmed) and winter pruning severity (experiment 2: 16, 24, 32, and >32 countable buds per meter). We characterized wine attributes by a descriptive analysis, color by the CIELAB space, and global phenolics compounds and anthocyanins by high‐performance liquid chromatography with diode array detection. RESULTS: We found that wines where shoots were trimmed to 0.80 m or left untrimmed had similar and greater intensity of color, violet hue, astringency, and alcohol and a richer aroma profile than wines where shoots were trimmed to 0.45 m. Meanwhile, wines from 16 and >32 buds/m treatments (the latter simulating a box pruning) were similar to each other and had higher color intensity, violet hue, acidity, alcohol, and astringency and a more complex aroma profile than the other pruning treatments. CONCLUSIONS: The best quality wines were achieved by leaving 16 or >32 buds/m and by trimming shoots to 0.80 m or leaving them untrimmed. The modulation of cultural practices in sprawling canopies offers the potential to produce wines with different styles in hot regions. © 2020 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Microwave technology (MW) was applied to musts and stems over three consecutive vintages in Cabernet Sauvignon, Merlot and Syrah wines from California (USA). Stems were added to musts at a rate of 50 and 100% (50% Stems and 100% Stems), either as untreated or after MW (50% MW Stems and 100% MW Stems). Stem additions lowered ethanol (up to 1.15% v/v reduction), but increased pH (up to 0.16 units) and the tannin content of the wines. In 2016, tannins increased by 103% (100% Stems), and 124% (100% MW Stems). In 2017, tannins increased by 39% in stem-added Merlot wines and by 63% (100% Stems) and 85% (100% MW Stems) in Syrah wines. In 2018, tannins in Syrah wines increased by 250% (100% MW Stems) and by 743% (100% Stems). Wines made with 50% Stems exhibited intermediate tannin contents. Must MW increased flavonols (up to 278% in Syrah wines), monoglucosylated, acylated and anthocyanin-derived pigments. Stem additions reduced wine color and polymeric pigment formation in Syrah. Must MW decreased the perception of coarseness and herbaceous flavors in Merlot, whereas stem additions increased herbaceous aromas in Syrah. Despite higher tannin contents in stem-added wines, no concomitant increases in astringency were observed.

The Glories method and CIE L * a * b * color space are poorly correlated in the light red high-saturation color area. Non-uniformities in the CIE L * a * b * color space have led to the CIEDE2000 formula, while the Euclidean color distance is still used in wine research. In this study, 112 white and red wines were examined to compare the Glories method, CIE L * a * b , and human perception using monovarietal wines from different grape varieties. The objective of this study was to investigate which of the two methods and which parameter of each method better aligned with human perception. The visual color threshold was re-evaluated with the CIEDE2000 formula and triangle testing. CIE L * a * b * more closely matched the human perception, elevating the use of CIE L * a * b * over the use of the Glories method. Visual color thresholds were better expressed with CIEDE2000 but still varied depending upon the color area in the CIE L * a * b * color space.

• Non-enzymatic browning widely occurs in wine during and after vinification. • Mechanisms of non-enzymatic browning induced by monomeric flavan-3-ols are reviewed. • Chromatic features and contribution of various xanthylium derivatives are discussed. • Factors that influence non-enzymatic browning in wine are summarized. • Insights into the complete reaction pathways of non-enzymatic browning are still lacking. Non-enzymatic browning occurs widely in both white and red wines, and it has a huge impact on the color evolution and aging potential. Previous studies have proved that phenolic compounds, especially those with catechol groups, are the most important substrates involved in browning reactions of wine. This review focus on the current knowledge of non-enzymatic browning in wine resulting from monomeric flavan-3-ols. First, some relevant aspects of monomeric flavan-3-ols are introduced, including their structures, origins, chemical reactivities, as well as potential impacts on the organoleptic properties of wine. Second, the mechanism for non-enzymatic browning induced by monomeric flavan-3-ols is discussed, with an emphasis on the formation of yellow xanthylium derivatives, followed by their spectral properties and effects on the color change of wine. Finally, attentions are also be given to the factors that influence non-enzymatic browning, such as metal ions, light exposure, additives in winemaking, etc. [ABSTRACT FROM AUTHOR]

[Display omitted] • Mannoproteins were able to delay continuous growth of tannin-BSA aggregates. • MPs polysaccharide-part compactness was a key-factor on retarding aggregation. • MPs induced mild hyperchromic effects on malvidine-3- O -glucoside absorbance. • Synergy between MPs and Quercetin induced higher hyperchromic effects. • Mannosyl-phosphorylation was a key-factor for MPs interactions with anthocyanins. 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. [ABSTRACT FROM AUTHOR]

Wine quality is influenced by the presence of over 500 different chemical compounds, with polyphenols having a crucial role in color intensity and tonality, astringency, mouthfeel, and overall impression formation, especially in red wine production. Their concentrations in wine can vary notably depending on the grape variety, the temperature and the length of maceration process, aging duration, and yeast selection. Therefore, in this work, the main goal was to determine the influence of five commercially available Saccharomyces yeasts provided from Lallemand, France and AEB, Italy, on the phenolic compound composition and chromatic parameters of Plavac mali wines produced from the grapes from coastal Dalmatia, grown at two different micro-locations. The achieved results pointed out the marked difference in individual polyphenol compound adsorption between tested yeasts. Fermol Super 16 was the one with the lowest and Lalvin D21 the strongest adsorption ability, regardless of vine growing location. These differences can be explained by the content of some anthocyanins (delphinidin and petunidin-3-O-glucoside) and gallic acid, and some flavan-3-ols. Tested strains also influenced wine color intensity, pointing out the possibility of modulating the style of a Plavac mali by the use of commercial yeasts.

Adding pomace or juice runoff during maceration is a traditional winemaking process. To mitigate the negative effects of rainfall during harvest and examine the effects of adjusting the pomace ratio during fermentation on the flavor profile of Marselan grape wines, the prefermentation addition of Petit Manseng grape pomace (PAP) and prefermentation juice runoff (PJR) was determined. The phenolic and volatile compounds were investigated using HPLC-MS and GC-MS. PAP enriched the flavanols and PJR enriched the pigment and copigment matrix. Approximate 10% increase in the ratio of pomace promoted the formation of anthocyanin derivatives. The increased pomace ratio reduced the concentration of volatile compounds without impacting the aroma quality. Sensory analysis revealed PAP wines scored higher for acidity and astringency and PJR wines scored higher for color. In conclusion, an appropriate increase in the pomace ratio of approximately 10% can enhance the color and mouthfeel of the wine while having a limited influence on aroma., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2023 The Author(s).)

This research aimed to evaluate the impact of different options for winemaking on the color composition of Uruguayan Tannat red wines. The techniques evaluated were the substitution of ripe grape juice with immature grape juice and the heating of the crushed grapes before fermentation, called must replacement and hot pre-fermentative maceration, respectively. These procedures were proposed to reduce the alcohol content and increase the phenolic composition of the wine, according to the expected effects of climate change and current trends in consumer preferences. The investigation was made over three consecutive years (2016, 2017, and 2018). Both winemaking techniques allow the enhancement of the chromatic characteristics of wines via the modification of the phenolic composition. Additionally, such techniques allow the overcoming of the well-known limitations in the extractability of anthocyanins presented by the Tannat cultivar. Hot pre-fermentative maceration increases the proportion of the most oxidizable molecules delphinidin-3-O-glucoside, cyanidin-3-O-glucoside, and petunidin-3-O-glucoside, suggesting heat inactivation of polyphenoloxidases enzymes. Must replacement and hot pre-fermentative maceration are technological alternatives that could significantly improve the intensity and chromatic characteristics of red wines. [ABSTRACT FROM AUTHOR]

The aim of this research was to determine the effectiveness of the substitution of grape juice of grapes with different maturation degree and prefermentative hot maceration to obtain Pinot Noir and Tannat red wines with lower alcohol content and pH and higher color and phenolic compound concentrations. Immature grape juice was extracted of grapes harvested in veraison and kept at 4 °C until its use. In technological maturity, the grapes harvested were destemmed, crushed and distributed in 12 containers per cultivar. Six were controls while in the other six 3 L of the original grape juice were substituted by 3 L of unripe grape juice. Next, three containers from each experimental group were traditionally macerated, while the other three were submitted to a prefermentative hot maceration (one hour at 60–70 °C). All treatments performed a fermentative maceration of 7 days. Wines produced from substituted musts had lower alcohol content (14% off) and pH (9% off) and higher titratable acidity (48% more), but no other important changes in wine components were detected. Prefermentative hot maceration increased wine color intensity (50%), total phenolic compounds (66%), total anthocyanin (42%), proanthocyanidin (65%) and polysaccharide (95%) concentrations. The joint consideration of both techniques is an interesting tool to simultaneously mitigate the problems caused by climate change with respect to the maturity of the grape and improve the color of the wine and its concentration in polysaccharides and phenolic compounds. [ABSTRACT FROM AUTHOR]

The phenolic compounds of red wines are responsible for their color, astringency, and antioxidant properties. The fermentative yeasts might be used to modulate wines in terms of their color, aroma and probably healthy properties. In this study, six non- Saccharomyces species were tested because they might enhance the properties of red Tempranillo wines from Rioja. The results confirmed that the anthocyanins and stilbenes composition of wine can be modulated with the use of a specific fermentation starter. Metschnikowia pulcherrima , Zygosaccharomyces bailii , Candida zeylanoides , and Torulaspora delbrueckii achieved the greatest improvements of the monomeric anthocyanin composition, and the latter three yeast species achieved the best results of stilbene composition when compared to S. cerevisiae and the other non- Saccharomyces yeasts. Overall, results suggested that the use of M. pulcherrima, Z. bailii, C. zeylanoides and T. delbrueckii as fermentation starters could be of great interest to achieve wines with better color and likely healthy properties. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

We evaluated the quality of wines produced in Nepal in terms of phenolic, flavonoid, anthocyanin and tannin content, antioxidant capacity, and color parameters using spectrophotometric methods. The total phenolic content, total flavonoid content, and total antioxidant activities in Nepali wines ranged from 85.5 to 960.0 (mean = 360.5 ± 268.7) mg/L GAE, 40.9–551.3 (mean = 188.9 ± 161.5) mg/L QE, and 66.6–905.0 (mean = 332.8 ± 296.5) mg/L AAE, respectively. These parameters were significantly higher in red wines compared to white wines. The phenolic and flavonoid content showed strong correlation with each other as well as with antioxidant activities. Additional parameters measured included various color parameters and carbohydrates. The wine color showed strong correlation with phenol, flavonoid, and antioxidant activity, whereas this correlation was not significant with anthocyanin content. Multivariate analysis was carried out to better describe and discriminate the wine samples. Finally, we compared Nepali wines with wines from other countries. Nepali wines claimed to have characteristic flavor were analyzed. Phenolics and flavonoids showed strong correlation with each and with antioxidant activity. These parameters were significantly higher in red wines compared to white wines. The phenolic content of Nepali wine samples was lower compared to wines from other countries. [ABSTRACT FROM AUTHOR]

Important wine quality traits such as sensory profile and color are the product of complex interactions between the soil, grapevine, the environment, management, and winemaking practices. Artificial intelligence (AI) and specifically machine learning (ML) could offer powerful tools to assess these complex interactions and their patterns through seasons to predict quality traits to winegrowers close to harvest and before winemaking. This study considered nine vintages (2008–2016) using near-infrared spectroscopy (NIR) of wines and corresponding weather and management information as inputs for artificial neural network (ANN) modeling of sensory profiles (Models 1 and 2 respectively). Furthermore, weather and management data were used as inputs to predict the color of wines (Model 3). Results showed high accuracy in the prediction of sensory profiles of vertical wine vintages using NIR (Model 1; R = 0.92; slope = 0.85), while better models were obtained using weather/management data for the prediction of sensory profiles (Model 2; R = 0.98; slope = 0.93) and wine color (Model 3; R = 0.99; slope = 0.98). For all models, there was no indication of overfitting as per ANN specific tests. These models may be used as powerful tools to winegrowers and winemakers close to harvest and before the winemaking process to maintain a determined wine style with high quality and acceptability by consumers.

Since the beginning of enology and fermentation research, wine quality has been parametrized from a chemical and sensory point of view [...]

Aim: Evaluating Saccharomyces cerevisiae strains for their color adsorption aptitude by using Grape Skin Agar in order to protect the phenolic compounds responsible for the color of red wines; proposing a suitable and innovative medium to be included among the tests currently used for wine strain selection. Methods and results: The strains were identified by fluorescence-Internal transcribed spacer (f-ITS) PCR and PCR-Restriction fragment length polymorphism (RFLP), confirmed by sequencing of ITS fragment, and tested for the parameter “aptitude to adsorb polyphenolic compounds” on the innovative chromogenic medium Grape Skin Agar. Laboratory-scale fermentations were carried out in must with and without SO2. The SO2 determined a decrease in tint, color intensity, and total polyphenol content. The strains M2V CHU7 and M2F CHU9 produced wines with the lowest color intensity, with and without SO2, respectively. By contrast, the strains M2F VUP4 and M2V CHU1, with and without SO2, respectively, produced wines with the highest color intensity, and therefore, they could improve the production of red wines. Conclusion: The study highlights great variability and significant differences among strains in regard to their aptitude to modulate wine color. Grape Skin Agar should be a useful medium to be included in the selection tests currently performed for S. cerevisiae strains. Significance and impact of the study: Our study confirms that yeast strains can modulate the chromatic properties of red wines according to their aptitude to adsorb polyphenols, as tested on Grape Skin Agar. Combining colored polyphenolic compound adsorption assay on Petri plate and laboratory-scale fermentation trials provides an effective way to test yeasts for their capability to improve the chromatic quality of the wines.

The effects of fining with various plant proteins were assessed on Aglianico red wine, using both the young wine and wine aged for twelve and twenty-four months, and including wine unfined or fined with gelatin as controls. Color traits and fining efficiency were considered, along with the content of various types of phenolics and of aroma-related compounds of either varietal or fermentative origin. All agents had comparable fining efficiency, although with distinct kinetics, and had similar effects on wine color. Individual plant proteins and enzymatic hydrolyzates differed in their ability to interact with some anthocyanins, with specific proanthocyanidins complexes, and with some aroma components of fermentative origin. Changes in varietal aroma components upon fining were very limited or absent. Effects of all the fining agents tested in this study on the anthocyanidin components were most noticeable in young red wine, and decreased markedly with increasing wine ageing. [ABSTRACT FROM AUTHOR]

This study investigated the evolution of acetaldehyde and pyranoanthocyanins in wine during malolactic fermentation, and further evaluated the correlation between acetaldehyde and pyranoanthocyanins. Cabernet Gernischt wine after alcoholic fermentation was inoculated with four lactic acid bacteria strains. Malolactic fermentation kinetics and wine characteristics were compared. Results showed these strains exhibited different kinetics on wine malolactic fermentation. Wine with Lactobacillus plantarum had lower reducing sugar, total acid, and yellowness. Lactobacillus plantarum elevated the level of acetaldehyde in wine model medium and wine during malolactic fermentation. Malolactic fermentation using Lactobacillus plantarum significantly increased the concentration of pyranoanthocyanins, whereas O. oeni strain reduced the level of pyranoanthocyanins in wine. Polymerized anthocyanins percentage in wine was significantly enhanced after fermentation with Lactobacillus plantarum . Principal component analysis indicated that the characteristics of these strains inoculated wines after malolactic fermentation were segregated. The findings from this study could provide useful information on the wine color improvement through malolactic fermentation with suitable lactic acid bacteria strains. [ABSTRACT FROM AUTHOR]

• Aroma intensity ratings changed according to wine color and opacity of glassware. • Need for visual input suggests aroma evaluation is more cognitive than perceptual. • Presence of oak increased perception of red fruit and dark fruit aromas. • Color-driven descriptors do not foster objective assessments of wine aroma. The vocabulary used to describe wine aroma is commonly organized according to color, raising the question of whether they reflect the reality of olfactory perception. Previous studies have assumed this convention of color-aroma matching, and have investigated color's influence on the perception of aroma only in dyed white wine or in red wine from particular places of origin. Here the aromas of 48 white and red varietal wines from around the world were evaluated in black glasses then in clear glasses by a panel of wine experts. As wine color was made visible, ratings for green fruit , citrus fruit , and stone fruit generally decreased among the red wines and increased among the white wines, while the opposite occurred for red fruit , dark fruit , and oak. The dependence of these aroma descriptors on visual input suggests their usage is more cognitive than perceptual. The influence of color was indirectly evident even in black glasses: three oaked Chardonnays were rated highly in red fruit and dark fruit , relative to the unoaked white wines, suggesting the judges here associated oak with red wine and consequently used oakiness to deduce wine color before rating the aromas believed to be appropriate. Findings suggest color-driven descriptors, used when wine color can be seen or surmised, do not foster objective assessments of wine aroma. [ABSTRACT FROM AUTHOR]