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The effects of temperature and ethanol concentration on the kinetics of anthocyanin adsorption and desorption interactions with five cell wall materials (CWM) of different composition were investigated. Using temperatures of 15 °C and 30 °C and model wine with ethanol concentrations of 0% and 15% ( v / v ) over 120 min, the adsorption and desorption rates of five anthocyanin-glucosides were recorded in triplicate. Small-scale experiments were conducted using a benchtop incubator to mimic a single berry fermentation. Results indicate that more than 90% of the adsorption occurs within the first 60 min of the addition of anthocyanins to CWM. However, desorption appears to occur much faster, with maximum desorption being reached after 30 min. The extent of both adsorption and desorption was clearly dependent not only on temperature and ethanol concentration but also on the CWM composition.

The rate of tannin extraction was studied in a vinification of red grapes and the results compared with another vinification made with white grapes fermented as for typical red wine, in the presence of skins and seeds. Even though the grapes presented a quite similar skin and seed tannin content, the differences in tannin concentration between both vinifications was very large, despite the fact that the only apparent difference between the phenolic composition of both wines was the anthocyanin content. This suggests that anthocyanins play an important role in tannin extractability, perhaps because they affect the extent of the tannin-cell wall interaction, a factor that largely controls the resulting quantity of tannins in wines. To confirm this observation, the effect of anthocyanins on the tannin extractability from grape seeds and skin and on the interaction between tannins and grape cell walls suspended in model solutions were studied. The results indicated that anthocyanins favored skin and seed tannin extraction and that there is a competition for the adsorption sites between anthocyanins and tannins that increases the tannin content when anthocyanins are present., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

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

BACKGROUND: Berry pomaces obtained after commercial juice production contain phytochemicals which may find use as antioxidants, food additives and biomedical products. Oil extraction from seeds provides additional value but the availability of phytochemicals before and after oil extraction is not well established. OBJECTIVE: This pilot study defines the content and composition of phytochemicals from raspberry and black currant pomaces after extraction with water-ethanol mixes, but also before and after milling/ oil extraction. METHODS: The total phenol (TPC), total anthocyanin (TAC) and antioxidant content of extracts was assessed. Their phytochemical composition was studied using liquid chromatography-mass spectrometry (LC-MSn). RESULTS: TPC and TAC increased with increasing % ethanol. Anthocyanins were major components in blackcurrant pomace and were more readily extracted than total phenols. Total oil content and composition was not influenced by solvent pre-extraction. Milling/ oil extraction markedly increased TPC from raspberry but not from blackcurrant pomace. LC-MSn confirmed characteristic phytochemical compositions and that increasing % ethanol increased yield of certain components. Milling increased specific ellagitannins, proanthocyanins and triterpenoids from raspberry. CONCLUSIONS: Milling/ oil extraction increased the yield and phytochemical diversity of extracts from raspberry but not from blackcurrant pomace which suggests that the phytochemicals from blackcurrant pomace are largely available on the pomace surfaces. [ABSTRACT FROM AUTHOR]

This study examined the impact of leaf removal timing, rootstock, and clone selection on Pinot noir grape composition and subsequent impact on tannin extractability. Results showed that leaf removal increased anthocyanin levels in berries and tannins in stems and seeds, while also raising the mean degree of polymerisation (mDP) of skin tannins. Schwarzman rootstock had lower seed tannins but higher mDP in skin and seed tannins compared to own roots. UCD5 clone exhibited higher mDP in skin tannins than AM10/5 clones in acetone extraction. Tannin extractability was determined by the ratio of model wine-extracted tannins and acetone-extracted tannins. For the first time, this study reported that stems had the highest tannin extractability (64%-78%) compared to skins (37–52%) and seeds (26–34%). Compositional differences in grape tissues from different treatments had no impact on tannin extractability except for grape skins from two treatments. This suggests that tannin extractability is mainly influenced by grape ripeness which largely determines the composition of cell wall materials that can interact with tannins and thus influence tannin extractability. The differences in grape skin tannin extractability observed in this study between treatments were likely due to the significantly different galloylation (G%) levels in the extracted tannins. [Display omitted] • Leaf removal increased anthocyanin and tannin content, and mDP of skin tannin. • Schwarzman rootstock showed higher mDP in skin and seed tannins than own roots. • UCD5 clone showed higher mDP in skin tannins than AM10/5 clone. • Grape stems showed the highest tannin extractability than skins and seeds. • Grape skin tannin extractability seems correlating with the galloylation level. [ABSTRACT FROM AUTHOR]

The study of phenolic maturity in Vitis vinifera L. requires a multidisciplinary approach to understand how the evolution of berry flavonoids and cell wall material influence the colour and the textures of red wine. This is a challenging issue which involves researchers of viticulture and enology, and the results of their work are of particular interest for the producers of high-quality red wines. This review reports the current knowledge regarding phenolic maturity, describing the sensorial traits of the different compounds, the evolution of berry flavonoids and the methodologies used to evaluate their characteristics. Finally, the role of cell wall material in influencing the extractability of anthocyanins and proanthocyanidins was shown. By means of a critical review of the results, it can be hypothesised that prolonged ripening improved colour characteristics and mouthfeel properties, thanks to the higher amounts of extractable skin flavonoids associated with lower amounts of seed proanthocyanidins, and to the increased affinity of the cell wall material for the proanthocyanidins most involved in the perception of unpleasant astringency.

The Dranic plantation is one of the youngest in Dolj county and was founded in 2010 through the process of reconversion and restructuring of the wine sector in our country. Under the favorable ecologically conditions for viticulture in the Oltenia area, the varieties for red wines besides the superior potential of glucidic accumulation, have a remarkable ability for biosynthesis of anthocyanins. The chromatic structures of the anthocyanin extracts represented by the yellow, red and blue pigments are balanced, attractive and fully in line with current requirements. They are dimensioned by colour intensity values, but especially by the qualitative chromatic indicators: the colour tone and the proportions of the flavylium cations. This study may be the start for the suitability of this area for obtaining high-quality red wines. [ABSTRACT FROM AUTHOR]

Postharvest withering of grapes strongly affects the content and extractability of phenolic compounds in the production of sfursat, fortified and passito wines. This work evaluated the effectiveness of enzymes applied individually and/or in multi-enzyme blends, on the extraction of anthocyanins, oligomeric flavanols and polymeric flavanols from withered grape skins during simulated maceration. The study was performed on Vitis vinifera L. cv. Nebbiolo and Barbera because of their different skin phenolic profile and cell wall composition. Our findings highlight that the relationship between skin mechanical properties (berry skin break force and energy) and extraction yield of phenolic compounds is variety dependent. Significant correlations were found between the skin softening associated with cell wall degradation and the extraction of anthocyanins and flavanols in Nebbiolo, for which polygalacturonase, individually or in multi-enzyme blends, plays an important role. In Barbera, the extractability of phenolic compounds was not affected by the presence of exogenous enzymes. [ABSTRACT FROM AUTHOR]

BACKGROUND Double maturation raisonnée ( DMR) is a potential canopy measure that affects grape and wine composition. The aim of this work was to study for the first time the DMR impact on the physical, biochemical and sensorial characteristics of the berries and wines of Merlot, one of the world's fastest-expanding grapevine varieties. RESULTS DMR significantly increased the content of soluble solids (1.2-fold), free amino nitrogen (1.8-fold) and acidity in berries but decreased the weight of 100 berries on harvest (approx. 28%). Irrespective of the vintage, DMR-treated grapes had a significantly higher content of non-astringent tannins (0.73-0.78 mg L−1) and anthocyanin extractability (34.7-36.4%) but a lower index of astringency (31.2-33.7) when compared to the control. Consequently, the DMR wines achieved higher alcohol, total acidity and extract, hydroxycinnamic acids, flavanol and flavonol contents, whereas the content of anthocyanins was similar to that of the control. Sensorial evaluation showed that DMR wines were not rated higher and would not be appreciated more than control wines. CONCLUSION Changes in berries during DMR altered the wine characteristics only in terms of primary metabolites. A reduced accumulation of phenolics, especially anthocyanin content, in the berry skin of DMR-treated grapes was not reflected in their presence in wines. To the best of our knowledge, this is the first paper that has reported an impact of DMR on the grape and wine composition of Merlot, as one of the most promising red varieties. © 2017 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Recently the use of ozone as sanitizing agent has been proposed on winegrapes in order to control mycobiota after harvest. The aim of this work was to investigate possible indirect physico-chemical effects of ozone treatment on berry skin phenolic composition and extractability. Vitis vinifera L. cv Nebbiolo and Barbera, chosen for their different anthocyanin profiles, were post-harvest treated for 24 and 72 h with gaseous ozone (30 μL/L). Skin anthocyanin and flavanol extractability was assessed during maceration (6, 24, 48, 96, 168 and 240 h) using a wine-like solution. In our experimental conditions, ozone did not affect significantly the final extraction yield of anthocyanins (TA), proanthocyanidins (PRO), and flavanols reactive to vanillin (FRV) in Barbera, although TA and FRV extractabilities were higher in control samples than in ozone-treated samples during the first stages of maceration. In Nebbiolo, the final TA extraction yield was positively influenced by the ozone treatment (68.6, 64.2, and 59.9% for 24 h ozone-treated berries, 72 h ozone-treated berries and control samples, respectively). Final PRO and FRV extractability also increased in both ozone-treated samples compared to the control (+ 8.6–9.1% for PRO and + 7.3–11.7% for FRV). No significant differences were found among treatments for individual anthocyanins in both cultivars at the end of maceration. Therefore, the use of ozone as sanitizing agent in red varieties prior to winemaking process can be considered because it did not negatively affect the extractability of skin anthocyanins and flavanols. [ABSTRACT FROM AUTHOR]

Background and Aims The study aimed to determine how fresh grape mesocarp modifies the extraction and composition of tannin under wine-like conditions. A further aim was to observe whether addition of anthocyanin during extraction exerted an effect on the concentration of recovered tannin. Methods and Results Fresh red grape berries were dissected into skin, mesocarp and seed. Different combinations of the berry components were extracted in model wine or fermented. Initial results indicated that mesocarp material bound seed tannin more selectively than skin tannin. Further experiments pointed towards a more complex system, whereby adsorption of tannin by mesocarp facilitated ongoing extraction of tannin from the skins. The effect exerted by mesocarp was potentially to increase the concentration gradient between skins and the liquid medium by the continuous removal of tannin. Under these conditions, both skin and seed tannin could be removed from extracts or wines by suspended mesocarp material. White grape skins or mesocarp were also extracted with the addition of a variable concentration of purified anthocyanin and found to facilitate the extraction of otherwise non-extractable tannin. This effect was observed to be greater for grape mesocarp than for white grape skins. Conclusions The concentration and composition of tannin were shown to be modified by the presence of mesocarp material. A role for anthocyanin in enhancing the extraction of tannin was confirmed. Significance of the Study The results show that multiple factors interact to influence tannin extraction and retention from grapes. [ABSTRACT FROM AUTHOR]

Aims: The knowledge of parameters as the quantity of anthocyanins and tannins present during grape maturation, their evolution during the ripening period and extractability data could improve the management of red wine fermentation and help predict the color of wines. Methods and results: Grapes from Vitis vinifera var. Cabernet Sauvignon, Syrah, Merlot and Monastrell were harvested in 2002, 2003 and 2004 from a commercial vineyards and their physicochemical characteristics together with the anthocyanin and tannin evolution during ripening were followed. The results showed that differences were found in the evolution of these compounds due to variety and year. Conclusions: Some of the studied parameters seemed to be clearly related to variety (berry weight and extractability index) and others seemed to be clearly affected by soil and edaphoclimatic conditions. The high extractability index in Monastrell reflects the difficulty involved in extracting their anthocyanins. The short maturation period observed for Merlot grapes and the high seed tannin index could lead to excessively astringent wines. Significance and impact of the study: This study demonstrate that the ripening period of some varieties (Merlot) in very warm conditions is too short, promoting the rapid accumulation of sugar in the pulp and an incomplete seed maturation that may lead to excessively astringent wines. Other varieties, e.g. Monastrell, show longer maturation period that usually permits pulp and seed maturity to be reached at the moment of harvest. The extractability index seems to be closely related to the grape variety and this is also an important fact to take into account when planning a vinification process.

A study has been carried out during the 2001 ripening period with Tempranillo variety grafted onto 110R, in order to know the productive and qualitative differences provoked by different geographic locations in the region of Castilla y León (Spain), through experimental plots located on the West side of the Duero river valley, in the Apellation of Origin (A.O.C.) Ribera del duero, and on the East side, in the Cigales A.O.C. The vines were head trained and 2-bud spur pruned, with a radial distribution of the spurs and 10 buds per vine. The Ribera del Duero vineyard was planted in 1987. The annual rainfall along the last 10 years has been 421 mm 3 layers can be distinguished on the soil of the trial with the following kind of textures: the first one is a loamclay- sandy soil, the second is clayey and the third one, deepest, is clayey-loam. The Cigales vineyard was planted in 1993. The annual rainfall along the last 10 years has been 399 mm 3 layers can be distinguished on the soil of the trial with the following kind of textures: the first and second layers are sandy-loam soil and the third one, deepest, is sandy-clay. The average temperature during the vegetative cycle in Cigales A.O.C. is higher than in Ribera del Duero A.O.C. On the other hand, at the beginning of the ripening period the temperatures are lower in Cigales, which together with the soil conditions have provoked a lower vegetative development and the variations on the vegetative-reproductive balance. The soil and climate conditions in the Ribera del Duero experimental plot have provoked a higher vegetative development of the vines and different characteristics of the berries with respect to the Cigales plot, probably due to a lower water stress along the vegetative cycle. The berry weight in the Cigales A.O.C. has been 25% lower than in Ribera del Duero A.O.C. The differences in berry weight were maintained along the ripening period. The vineyard conditions of the Ribera del Duero A.O.C. have allowed to obtain, for a similar yield per vine to the Cigales A.O.C., berries with higher sugar concentration and lower pH. However, the total acidity has shown statistical differences only in the first sample, becoming the results similar over the ripening period. The differences in pH are not correlated with the total acidity evolution, which could be due to the higher potassium concentration in the Cigales A.O.C, being in this case lower the total acidity of the berries. The phenolic maturity has also been affected by the soil and climate conditions, so the Ribera del Duero plot has shown a higher total polyphenols index along the ripening period than the Cigales plot. The total anthocyanins concentration maintained similar values in both plots, although the final concentration at harvest was lower in the Cigales A.O.C. The extractable anthocyanins concentration, measured by Glories method, has followed a similar evolution than the total anthocyanins in both areas of study.

Abstract: The accumulation of anthocyanins in grape skin and their extractability evolution along ripening were evaluated in Galician red cultivars during 2005 and 2006 harvests. Seed tannin maturity and total phenolic compounds were also investigated through seed phenolic maturity and total polyphenol indexes, respectively. Furthermore, statistical correlations between phenolic composition and classical parameters were established through ripening in order to find a more rapid and simpler methodology, which permits to predict the maximum anthocyanin concentration in red wines. So, statistical correlation was found for total polyphenol index and total acidity in all the cultivars studied, while the greatest anthocyanin accumulation can only be estimated from titrable acidity for the most coloured cultivars. The cultivars studied were characterised on the basis of their phenolic composition (anthocyanins, proanthocyanidins, catechins) in order to know their oenological potential. Principal component analysis allowed a first approximation to the characterisation and differentiation of the red cultivars studied on the base of their phenolic composition in vintage, as measured by spectrophotometric methodologies. Simple phenolic determinations, which can be carried out in winery, provided fundamental information for the oenologist during the planning and management of pressing and maceration processes. [Copyright &y& Elsevier]

Abstract: We present characterisation data for two Spanish autochthonous grapevines, Bobal and Crujidera, in comparison with the well-known cultivars Tempranillo and Cabernet Sauvignon. Microsatellite markers were used for the molecular characterisation of Crujidera grapevines. Leaf macronutrient contents of the four cultivars were evaluated, as well as their changes at different vine developmental stages, and veraison was seen as the most suitable time to evaluate the nutritional status. Quantitative changes in some physiological parameters and the phenolic composition of the four grape varieties were measured during the last month of ripening. Polyphenols, tannins and anthocyanins increased with grape maturation, although the accumulation of these phenolic compounds and their patterns of evolution varied considerably with the cultivar. The biosynthetic potential of these grapes to produce resveratrol largely depended on the grape variety, with a remarkably high content found in Bobal berry skins. [Copyright &y& Elsevier]

The study of phenolic maturity in Vitis vinifera L. requires a multidisciplinary approach to understand how the evolution of berry flavonoids and cell wall material influence the colour and the textures of red wine. This is a challenging issue which involves researchers of viticulture and enology, and the results of their work are of particular interest for the producers of high-quality red wines. This review reports the current knowledge regarding phenolic maturity, describing the sensorial traits of the different compounds, the evolution of berry flavonoids and the methodologies used to evaluate their characteristics. Finally, the role of cell wall material in influencing the extractability of anthocyanins and proanthocyanidins was shown. By means of a critical review of the results, it can be hypothesised that prolonged ripening improved colour characteristics and mouthfeel properties, thanks to the higher amounts of extractable skin flavonoids associated with lower amounts of seed proanthocyanidins, and to the increased affinity of the cell wall material for the proanthocyanidins most involved in the perception of unpleasant astringency. [ABSTRACT FROM AUTHOR]