Flavonoids and C13-norisoprenoids in Vitis vinifera L. cv. Shiraz: relationships between grape and wine composition,wine colour and wine sensory properties

Background and Aims: This study investigated flavonoid composition and C₁₃-norisoprenoids (β-damascenone and β-ionone) in Shiraz grapes and wines, their relationships and links to wine sensory properties. Methods and Results: Differences in the grape berry flavonoid profile were created by exposing bunches to varying levels of sunlight intensity through canopy manipulation. Grapes were harvested at similar maturity and three replicate wines were made for each treatment in both vintages. Grapes produced under shaded canopy conditions had reduced anthocyanins and skin tannins, but little effect on seed tannins was observed. Pigmented polymers and tannins in wines were related to berry flavonoid composition (anthocyanins, skin and seed tannins, and their ratios). In grapes and wines, no significant effects were observed in response to canopy manipulation for two hydrolytically released C₁₃-norisoprenoids, β-damascenone and β-ionone. Relationships were established for wine flavonoid composition, wine colour density, sensory perception of the astringency-related mouth-feel attributes and a quality scale. A positive relationship between wine quality score and hydrolytically released β-damascenone in both berries and wines was found, but not for free β-damascenone or any quantified forms of β-ionone. Conclusion: Higher concentrations of anthocyanins and skin tannins in berries, coupled with a lower concentration of seed tannins were associated with higher wine quality. The ratio anthocyanins*skin tannins/seed tannins is proposed as an indicator of wine flavonoid composition, wine colour and wine quality. Excessive canopy shade was detrimental to berry and wine composition and intensified sensory detection of ‘straw’ and ‘herbaceous’ characters in the wines. Significance of the Study: This study increases the understanding of the balance and composition of flavonoid compounds and C₁₃-norisoprenoids in berries and their relationship with wine composition and wine sensory properties, but also highlights the importance of a canopy microclimate assessment.     

Shiraz berry size in relation to seed number and implications for juice and wine composition

This study was conducted over three seasons on irrigated Shiraz grapevines growing in a warm climate. We addressed the question of whether differences in berry size (within a population of berries from minimally pruned, own‐rooted or Ramsey‐grafted vines), would lead to differences in juice composition, wine composition or wine sensory score. Predictably, berry mass was found to increase with seed number, but berries in the smallest mass categories (0.3–0.7 g) still had similar juice soluble solids and pH; and similar concentrations of K+, tartaric acid and malic acid, compared with larger berries (1.4–2.0 g). Only for the very smallest mass category (0.3–0.55 g) was there any indication of better colour density (both for own‐rooted and Ramsey‐grafted vines) or higher anthocyanin concentration (for own‐rooted vines) compared with larger berries (1.4–2.0 g). Concentrations of tartaric acid and K+ in berry skins were highest in the smallest berry mass categories (0.3–0.7 g) and decreased with increasing berry mass (up to 1.4–2.0 g). A strong correlation (R²= 0.85) between skin tartaric acid and K+ concentrations was observed across that range. Small‐scale wine lots based on small berries (0.8–0.9 g) versus large berries (1.2–1.3 g) showed no differences in measures such as soluble solids, total acids or pH of juice; nor any differences in pH, total acids, K+, tartrate, malate, spectral characteristics or sensory score of corresponding wines. Moreover, small berries had a similar skin to fruit ratio, and a similar juice yield, compared to large berries. However, when measured post‐fermentation, the ratio of seed weight to skin weight was higher for small berries. The mass range of berries used here for small‐scale winemaking (i.e. from 0.8–0.9 g up to 1.2–1.3 g), covered the range of Shiraz berry mass typically found in irrigated vineyards (from 0.8 to 1.5 g), and thus confirms the relevance of present outcomes to practical winemaking. Finally, our data for variation in juice and wine composition as a function of berry size, showed consistent trends for all seasons, and thus implies that reported instances of improved wine quality from small berries (often associated with certain pruning treatments or deficit irrigation strategies), are more likely due to treatment effects that lead to small fruit, rather than to intrinsic developmental differences between large and small berries.     

Variation in Shiraz berry size originates before fruitset but harvest is a point of resynchronisation for berry development after flowering

Background and Aims:  Asynchronous berry development results in variation in berry size and berry composition. Variation in berry size affects vineyard yield, wine quantity and berry composition, while variation in berry composition affects fruit flavour and wine quality. The objective of this study is to identify when variation in berry size begins.
Methods and Results:  Shiraz bunches were sampled at seven stages throughout the growing season and the development of individual berries was characterised by measurements of weight, volume, surface area, deformability, seed number and seed weight. Coefficients of variation with respect to berry weight, volume and surface area were elevated throughout the post-flowering period but declined as the berries approached harvest ripeness.
Conclusions:  Variation in berry size originates prior to berry set, most probably during differentiation in the floral primordium at budburst. Harvest represents a point of resynchronisation in berry development when a number of physiological changes become synchronised between berries and within the bunch.
Significance of the Study:  Variation in berry size is presumed by the wine industry to have a negative impact on crop level, fruit composition and wine quality. Much of this presumption is scientifically unsubstantiated. The findings of this paper should encourage grapegrowers and winemakers to modify the timing of the harvest to coincide with a reduction in variation in berry size.     

Antioxidant activity and antimicrobial effect of berry phenolics--a Finnish perspective

In Finland, berries are part of the traditional diet significantly contributing to the intake of flavonoids and other phenolic compounds. Compositional data on phenolic compounds in berries has been rapidly accumulating and included in the national food composition database. Among the different bioactive substances in berries, phenolic compounds including flavonoids, tannins, and phenolic acids have received considerable interest due to their effects in food and health. A great amount of in vitro evidence exists showing that berry phenolics are powerful antioxidants. However, the antioxidant effect of berry phenolics is strongly dependent on the choice of berry raw material, as the antioxidant activity differs between the different phenolic constituents, including anthocyanins, ellagitannins, and proanthocyanidins. In foods, the antioxidant effect is also influenced by the structure of food. Tannin-containing berries exhibit antimicrobial properties against pathogenic bacteria, thus offering many new applications for food industry. Much of the interest in berry phenolics has focused on cranberries and both cultivated and wild blueberries, although also other berries including black currants, cloudberries, lingonberries, and red raspberries possess promising bioactivities that may have relevance to human health. Antioxidant activity of berry phenolics, in addition to other mechanisms, may contribute to human health, but the possible relationship remains yet to be scientifically substantiated.     

Assessment of grey mould (Botrytis cinerea) impact on phenolic and sensory quality of Bordeaux grapes,musts and wines for two consecutive vintages

Background and Aims: The impact of grey mould (Botrytis cinerea (B. cinerea)) was quantified on chemical, phenolic and sensory qualities of grapes, derived musts and wines. Methods and Results: Analyses were carried out by using naturally or artificially infected grape berries at ripeness or overripeness. In grape seeds, chemical analyses revealed no major differences between healthy and rotten grapes. In grape skins of Botrytis‐affected berries, concentrations of all the phenolic compounds (anthocyanins and proanthocyanidin monomers, dimers and trimer) decreased drastically. Mean degree of polymerization of the proanthocyanidin polymeric fraction was also affected in skins. Chemical analyses of musts and wines made with different percentages of rotten berries showed a moderate impact of the pathogen on their phenolic composition. Nevertheless, sensory analyses underlined a loss of wine sensory quality perceptible from a threshold as low as 5% of Botrytis‐affected grapes onwards. Conclusion: Phenolic variations and the associated negative impact in grapes, derived musts and wines may be related to oxidation phenomena from B. cinerea. The main effects of severity/age of grey mould and the level of berry maturity are also discussed. Significance of the Study: B. cinerea drastically affects the phenolic and organoleptic properties of grape skins and derived wines. Therefore, prophylactic actions early in the vineyard, evaluation of the sanitary status of the harvested grapes and berry sorting are primordial even under low disease pressure.     

Dependence of wine sensory attributes on vine water status

The dependence of wine sensory attributes on the water status of the source vines was determined following vineyard irrigation treatments which included early and late season water deficits and continually irrigated vines. In both seasons, the experimental wines made from the different irrigation treatments did not differ in the concentration of residual sugar or ethanol, titratable acidity, or pH. The concentrations of anthocyanins and total soluble phenolics in the wines were greater from water deficit treatments than from continually irrigated vines. For sensory evaluation, a novel protocol for paired comparisons was developed to test separately for differences in wine appearance, flavour, taste and aroma; differences were detected for each wine comparison. In both seasons, continually irrigated wine differed from early and late season water deficit wine, and early season water deficit wine differed from late season water deficit wine in appearance, flavour, taste and aroma. The sensory differences were not attributable to differences in vine yield or fruit maturity. When professional wine tasters were sampled using similar tests, a majority was able to detect visual but not flavour differences between a selected pair of wines. It is concluded that, where vine water status can be altered, irrigation offers a means to manipulate wine sensory characteristics in the vineyard.     

外源脱落酸处理对葡萄果实及葡萄酒中抗氧化成分的影响

以天津蓟州区栽培的"美乐"和"赤霞珠"葡萄为试验品种,分别在其始熟期的初、中和末期3个阶段利用外源脱落酸(200 mg/L)处理果实,采用分光光度法测定葡萄和葡萄酒中酚类总含量和抗氧化活性,利用液质联用技术分析花色苷的含量和组成.研究结果表明:始熟期的外源脱落酸处理对成熟果实的质量、可溶性固形物、可滴定酸和pH值,以及葡萄籽的酚类含量和抗氧化活性没有显著影响,但对葡萄皮和葡萄酒的酚类物质含量和活性具有显著影响.在始熟期中期(30％ ～50％果实转色)以前,对果实喷施外源脱落酸可以显著提高葡萄皮和葡萄酒的酚类总含量、花色苷总含量和抗氧化活性.始熟期外源脱落酸处理使"美乐"和"赤霞珠"果实的酚类总含量分别提高了14％ ～39％和73％ ～172％,花色苷总含量和抗氧化活性分别提高了18％ ～143％和88％ ～178％;外源脱落酸处理使葡萄酒的3个指标(酚类总含量、花色苷总含量和抗氧化活性)分别提高了17％ ～69％、18％ ～36％和21％ ～46％,而这些影响可以有效改善葡萄酒的感官品质和营养价值.外源脱落酸处理时期的精准控制可以提高酿酒葡萄及葡萄酒中酚类物质含量及抗氧化作用,进而提高葡萄酒品质和营养价值.     

Effects of defoliation on quality attributes of Nero di Troia (Vitis vinifera L.) grape and wine

Field studies were conducted in Puglia (Italy) to evaluate the influence of defoliation around cluster zones on grape and wine quality. Nero di Troia grapes were subjected to four different treatments: N: no leaf removal; E: leaf removal in the area of the clusters along the east side (at complete veraison); E/W: leaf removal in the area of the clusters along the east and west side (at complete veraison); and F: almost complete leaf removal along the west side (at complete veraison) and at pre-harvest also along the east side. Grapes of defoliated vines generally showed higher sugar content, lower titratable acidity, total flavonoids, flavonoids different from anthocyanins, and total phenolic content than grapes from non-defoliated vines while their total anthocyanin concentration was not affected by defoliation at a significant level. Concerning wines, alcohol content, residual soluble solids, different forms of anthocyanins but also volatile acidity were generally higher in samples from defoliated vines. Differences were also highlighted among the defoliation treatments: the best results in terms of dry matter, sugar and alcohol content were observed in the samples submitted to the more severe defoliation as a consequence of the higher light availability and berry temperature. Concerning the concentration of the individual phenolics, significant differences were highlighted for: caffeic and caftaric acids, peonidin- and malvidin-3-p-coumaroylglucoside, which were higher in the E wines; quercetin-3-glucoside, galactoside, and rhamnoside, and procyanidins, which were higher in F wines.     

Phenolic and Anthocyanin Profile of Valea Calugareasca Red Wines by HPLC-PDA-MS and MALDI-TOF Analysis

The quality of red wines is given by phenolic compounds and anthocyanins and is associated with colour, taste and therapeutic effects on human health. This work aims to provide a detailed profile of phenolic compounds and anthocyanins that are found in five red wine samples from Dealu Mare-Valea Calugareasca region. The phenolic and anthocyanin profiles of the red wine samples were determined by high-performance liquid chromatography-photodiode array-mass spectrometry and matrix-assisted laser desorption/ionisation–time of flight, respectively. The results obtained showed that Feteasca Neagra had the highest content of phenolic compounds followed by Pinot Noir while the preponderant compound was gallic acid. Amongst anthocyanins, malvidin was found to be the major compound and the highest anthocyanin content was found also for Feteasca Neagra wine. A simple high-performance liquid chromatography-photodiode array-mass spectrometry method was developed, optimised and applied for the quantification of phenolic compounds in red wine samples from Dealu Mare-Valea Calugareasca region. In the same time, a rapid matrix-assisted laser desorption/ionisation–time of flight method that does not need sample preparation was applied for the identification of anthocyanins. Moreover, the phenolic and anthocyanin composition of red wines from Dealu Mare-Valea Calugareasca region is reported for the first time. The phenolic and anthocyanin profile determination will be beneficial for the Romanian winemakers to produce high-quality red wines.     

避雨栽培对蛇龙珠果实及葡萄酒质量影响研究初报

研究避雨栽培对酿酒葡萄果实采收期、果实品质和葡萄酒质量的影响,为酿酒葡萄避雨栽培技术的实施提供理论依据.以蛇龙珠(Vitis vinifera L cv.Cabernet Gernischt)为材料,采用简单避雨方式和露地栽培(对照),在果实转色期后监测果实糖酸变化,并测定成熟果实还原糖、总酸、花色素、总酚和单宁等指标;采用小容器酿造工艺酿制蛇龙珠干红葡萄酒,测定葡萄酒的颜色、花色素、总酚和单宁等指标.结果表明:(1)避雨栽培推迟了蛇龙珠果实的成熟期;(2)避雨栽培对蛇龙珠果实花色素、葡萄果皮中单宁含量影响极显著,对其他指标没有显著影响;(3)避雨栽培对蛇龙珠干红葡萄酒花色素含量及颜色影响极显著,对总酚和单宁含量无显著影响.     

Exclusion of sunlight from Shiraz grapes alters wine colour, tannin and sensory properties

The aim of this study was to determine how changes in grape composition brought about by artificial shading (sunlight exclusion) influence wine properties including colour, flavonoid composition and sensory attributes. Prior to flowering, bunches of Shiraz grapes were enclosed in boxes designed to eliminate light without altering bunch temperature and humidity. This artificial bunch shading had little effect on berry ripening and accumulation of sugar but at harvest the shaded bunches had smaller berries and higher seed weight, juice pH and titratable acidity. The amount of anthocyanins in the fruit was not changed significantly but anthocyanin composition in the shaded berries was shifted towards dioxygenated anthocyanins (the glucosides of cyanidin and peonidin derivatives). Shaded fruit had increased seed tannins and decreased skin tannins but the largest relative change in flavonoids was a marked decrease in flavonols in the shaded fruit, similar to previous studies. Wines made from shaded fruit had lower wine colour density, total phenolics, anthocyanins and tannins when the wine was bottled and after ageing for up to three years. Analysis of potential flavour compounds following acid hydrolysis indicated that the wines made from shaded fruit had decreased levels of glycosides of β-damascenone and 1,1,6-trimethyl-1,2-dihydronaphthalene (TDN). Sensory analysis of the wines indicated no significant difference in aroma attributes but the wines made from shaded fruit were rated lower for astringency, fruit flavour and flavour persistence in-mouth sensory attributes. The results indicate that extreme shading of Shiraz fruit can decrease wine colour, anthocyanins and tannins as well as altering sensory attributes.     

5 个调色葡萄品种酚类物质轮廓分析

对调色葡萄品种‘烟73’、‘烟74’、‘Kolor’、‘Tintorera’和‘Dornfelder’成熟期果实和小规模发酵的葡萄酒进行基本理化指标和酚类物质分析。结果表明,‘Kolor’和‘烟73’果实花色苷含量较高,均超过4?000?mg/kg（以果实鲜质量计）;‘Tintorera’和‘烟73’果实黄酮醇含量较低,分别为43.99?mg/kg和59.6?mg/kg（以果实鲜质量计）;‘Dornfelder’果皮黄烷醇含量最低。在5?个调色葡萄酿造的葡萄酒中,‘烟73’的花色苷质量浓度最高（1?827.87?mg/L）;‘Tintorera’葡萄酒中黄酮醇（19.87?mg/L）、黄烷醇（35.34?mg/L）和酚酸（43.77?mg/L）质量浓度都低于其他品种。对果实花色苷含量进行主成分分析,能将大部分品种很好地区分。在此基础上构建正交偏最小二乘判别分析模型,能将各品种的果皮和果肉很好地区分,筛选出的差异物质大多为F3’5’H羟基取代花色苷。利用葡萄果实和葡萄酒中共同的酚类物质构建Pearson相关系数模型,结果显示,有70.37%的物质具有较强的相关性。本研究针对调色葡萄的酚类物质轮廓进行分析,能为干红葡萄酒以颜色和辅色为目的的调配提供基础。     

Canopy microclimate and berry composition: The effect of bunch exposure on the phenolic composition of Vitis vinifera L cv. Shiraz grape berries

Studies on the effect of light exposure on specific phenolic compounds of berries from Shiraz vines grown in a hot climate are reported. Berries that had developed on bunches receiving high levels of ambient light generally had the highest relative levels of quercetin-3-glucoside and a lower proportion of their malvidin anthocyanins as the coumarate derivative, compared to berries that had developed on bunches in shaded canopy conditions. The response of total anthocyanin levels to treatment conditions was variable and depended on the degree of bunch shading and the resultant berry temperature. It appears that a high degree of bunch exposure in hot climates is not conducive to optimal anthocyanin accumulation in berries. The interactive effects of light and temperature on berry phenolic content and concentration are discussed.     

The impact of high voltage electrical discharge plasma on the chromatic characteristics and phenolic composition of red and white wines

The cold plasma is an emerging electrotechnology for the improvement of food safety without loss of physicochemical or sensory properties. The purpose of this study was to evaluate the effects of plasma treatments on the chromatic characteristics and phenolic composition of red and white wines. The red wine Cabernet Sauvignon and white wine Graševina were treated with high voltage electrical discharge plasma considering the variations in frequency (60, 90 and 120 Hz) and processing time (3, 5 and 10 min). Total phenolics, total anthocyanins, total tannins and chromatic characteristics were analyzed by spectrophotometry while free anthocyanins, phenolic acids and flavan-3-ols by the HPLC-UV/Vis. Obtained results illustrated that plasma treatments have influenced the stability of phenolic compounds in wines without major changes in color parameters. Also, among two different processing parameters, the duration time was the most significant factor inducing changes on wines.Industrial relevanceHigh voltage electrical discharge plasma has been shown to affect the stability of wine phenols without any significant change in the color. An increase in the concentration of certain phenolic compounds in white wine suggest that this technique could be used in the wine industry as an alternative technique for enhancing the oxidative stability of wine and consequently the wine quality during the aging process.     

Review: critical appraisal of methods to investigate the effect of temperature on grapevine berry composition

The grapevine is an economically important crop and a model species of long‐lived perennials widely used in bioclimatic studies. Ambient temperature modulates berry composition, hence the significant research effort in establishing links between temperature, berry composition and wine attributes. Our current understanding of the effect of temperature on berries and wines has been largely gained from indirect methods or direct methods in controlled conditions. Indirect methods include comparisons of thermally contrasting locations and vintages; this approach is of value but is bound to be inconclusive as the effect of temperature is often confounded with other weather and climate factors (solar radiation, vapour pressure deficit and rainfall), management practices and soils. Direct experimental methods comparing fruit grown at a range of temperature are required to prove cause‐and‐effect, but attempts to modify the thermal regime of the plant often generate secondary effects. Experimental artefacts in controlled environments often include small soil volume, lack of wind and altered radiation regimes, with direct implications for plant physiology and berry composition. Experiments involving controlled temperature in vineyards aim at a higher degree of realism, but are constrained by cost, issues of scale in space and time, and are not necessarily free from artefacts. Indirect and direct methods are of course non‐mutually exclusive but complementary. This review critically assesses the methods used to elucidate the effect of temperature on grape berry composition. It emphasises the limitations of studies where confounded effects are overlooked. With the focus on selected berry traits (total soluble solids, total and titratable acidity and anthocyanins), we analyse the dominant effect of temperature and highlight discrepancies and agreements between indirect and direct research methods.     

Anthocyanin profile in berry skins and fermenting must/wine, as affected by grape ripeness level of Vitis vinifera cv. Shiraz/R99

The release of anthocyanin compounds from berry skins into the wine is affected by several viticulture and oenological practices. Ripeness level seems to play a significant role. The study aimed to evaluate the extraction kinetics of individual anthocyanins from grape skins into wine under controlled conditions of small-scale vinification of Shiraz grapes, harvested at three ripeness levels (23, 25 and 28°Brix). The anthocyanin profile of intact berry skins, fermenting musts/wines and crushed skins during the period between crushing and pressing was analysed by HPLC. Ripeness level greatly impacted on the skin?/?juice ratio (ranging from 169?± 4.5?g?L^?1 at 23°B, 185?±?7.2?g?L^?1 at 25°B and 256?±?10.7?g?L^?1 at 28°B) and on grape anthocyanin concentration (ranging from 0.80?±?0.13?g?kg^?1 at 23°B, 0.78?±?0.07?g?kg^?1 at 25°B and 1.21?±?0.13?g?kg^?1 at 28°B) and profile (%) at harvest. In addition, it affected the rate and amount of individual anthocyanin extraction from skins into wine and their transformation during fermentation, consistent with the relevant chemical group classification (3-glucoside, 3-acetyl-glucoside, 3-p-coumaroyl-glucoside). At pressing, the anthocyanin concentration of the three wines was similar (319?mg?L^?1, on average), but the anthocyanin profile was different, particularly the ratio of 3-glucoside?/?3-p-coumaroyl-glucoside derivatives, which was on average 3.55 at 23°B and 25°B and 2.6 at 28°B. Viticultural choices, such as to harvest earlier or later, influencing the chemical and physical composition of the berries, may influence the extraction kinetics of individual anthocyanins and their destiny in the fermenting must, offering to winemakers different basic wines suitable for the production of different wine products. These findings are valuable to improve viticultural and oenological practices for Shiraz wine production, allowing the improvement of wine quality and the purposeful creation of different styles of wine.     

Practical interventions that influence the sensory attributes of red wines related to the phenolic composition of grapes: a review

The phenolic composition of red wines is complex and intimately involved in colour, taste, mouth‐feel and aroma. There have been significant advances in knowledge of compounds with relatively simple structures, but understanding of those with more complex and probably diverse structures is challenging. A number of phenolic compounds may form temporary complexes with anthocyanins and/or be involved in reactions that lead to relatively stable coloured compounds. A wide range of phenolic compounds is implicated in the oral sensory attributes of red wines. Of particular importance are flavan‐3‐ols, including proanthocyanidins (PAs). The generally observed decline in the extractability of PAs during berry ripening is due to binding with cell wall material, which may occur within the developing berry and also from tissues brought into contact during processing. Studies have shown that exposure/reduced vigour results in an increasing proportion of skin PAs being extractable during wine making. Temperature and light influence anthocyanin with temperature probably being more important and the most sensitive stage being 1–3 weeks after véraison. Skin PAs are extracted earlier than those from seeds during wine‐making. Recent results suggest some rearrangement of skin and/or seed PAs occurs during vinification which involves the cleavage of large polymers or the aggregation of small ones. The polymeric material is particularly influential in wine astringency and is transformed by incorporation of anthocyanins into tannin‐like compounds during wine‐making and storage. Although some grape‐derived phenolic compounds contribute to the aroma of red wines, likely of greater importance are the effects of nonvolatile phenolics on the volatility of a diverse range of aroma compounds. Advances in analytical techniques are likely to provide greater insights into the structures and conformations of phenolic polymers and the role of cell wall material in relation to phenolic extraction and reaction during vinification. In relation to aroma, much more research is required to reveal the details of the interactions involving phenolics with volatile compounds. It seems likely that the ability to influence the relative extraction and subsequent reaction of skin and seed phenolics is important in the production of full colour, aromatic and long‐lived wines.     

Delayed winter spur-pruning in New Zealand can alter yield components of Merlot grapevines

The effects of delayed winter spur-pruning on yield, yield components and fruit composition of Merlot vines was evaluated within a commercial vineyard in Marlborough, New Zealand. Vines were spur-pruned, trained using vertical shoot positioning, trickle irrigated and grafted to Kober 5BB rootstock. Delaying pruning from July (usual winter pruning time in New Zealand) until up to October (when apical shoots on canes were 5 cm long) resulted in yield increases of up to 93%, 63%, and 82% over the three seasons of experimentation. These yield increases reflected higher average berry weight and in turn bunch weights. The increase in average berry weight was associated with a change in the relative abundance of different berry types. Later pruning increased the proportion of large seeded berries while the proportion of smaller seedless berries and live green ovaries (shot berries) decreased. The delayed pruning may have enhanced fertilisation of flowers and development of seeds by postponing flowering to a time when climatic conditions are more favourable; measurements of shoot lengths support this proposal. By delaying winter pruning until after budburst the development of basal nodes was inhibited, so that budburst on the resulting spurs was also delayed.     

Anthocyanin composition and extractability in berry skin and wine of Vitis vinifera L. cv. Aglianico

BACKGROUND: The present article reports the anthocyanin content in the berry skin and wine of the Italian red grape cultivar Aglianico (clone VCR11 grafted onto 1103 Paulsen), one of the most ancient vines and famous for its deep‐red colour. Anthocyanins were extracted from frozen berry skin in an acidified methanol solution. The extraction mixtures, monitored for 120 h, were analysed by high‐performance liquid chromatography. RESULTS: The extraction from berry skin of delphinidin, petunidin and malvidin appeared to be a time‐independent process, whereas the concentration of peonidin increased linearly with time. Peonidin‐O‐acetyl‐glucoside was transferred from skin more slowly than petunidin‐O‐acetyl‐glucoside and malvidin‐O‐acetyl‐glucoside. The anthocyanin composition of the resulting wine showed that the total anthocyanin content was about one‐tenth of the corresponding berry skin content. The ratio acetyl/coumaroyl anthocyanins in the wine was sharply higher than the value in berry skin (0.85 and 0.10, respectively), indicating an enrichment of acetyl derivatives in the wine. CONCLUSION: Levels of single anthocyanins in wine were not always correlated with those detected in grapes, as they were affected by winemaking. The high values of some anthocyanins in Aglianico wine could ameliorate its quality, increasing the chromatic properties, aging stability and product acceptance. Copyright © 2011 Society of Chemical Industry