Scielo RSS <![CDATA[South African Journal of Enology and Viticulture]]> vol. 35 num. 2 lang. pt <![CDATA[SciELO Logo]]> <![CDATA[<b>Phenolic characterisation and antioxidant capacity of young wines made from different grape varieties grown in Helanshan Donglu wine zone (China)</b>]]> The Helanshan Donglu wine zone (China) is one of the most successful wine region of China, and the phenolic characterisation and antioxidant capacity of the primarily young, monovarietal wines from there were evaluated. The result showed that Helanshan Donglu wines contained abundant phenolic compounds, especially flavan-3-ols, and possessed high antioxidant capacity. In different grape varieties, the phenolic profiles varied greatly in both red and white wines. For red wines, Cabernet Sauvignon represented the highest total phenols (2 631 mg/L GAE), total flavonoids (1 840.83 mg/L CTE) and antioxidant capacity. Gamay and Cabernet Gernischt possessed the highest total flavan-3-ols (1 108.08 mg/L CTE) and total anthocyanins (258.78 mg/L CGE). Amongst the white wines, Chardonnay and Chenin blanc showed the highest phenolic contents and antioxidant capacity. (+)-Catechin and (-)-epicatechin were dominant phenolic constituents in both the red and white wines. Gallic acid and salicylic acid were the second most abundant in red wines, while gentisic acid was the second most abundant in white wines. <![CDATA[<b>The influence of different winemaking techniques on the extraction of grape tannins and anthocyanins</b>]]> The aim of this study was to determine the effect of different maceration techniques on the extraction of grape tannins and anthocyanins. Two cultivars (Cabernet Sauvignon and Shiraz) were harvested in two different climatic regions (Durbanville and Simondium) at two different ripeness levels for the 2008 and 2009 harvest seasons. Five basic winemaking processes were applied, namely a normal alcoholic fermentation (C), enzyme treatment (E), cold soaking (CM), post-maceration (PM), and a combination of cold and post-maceration (CM+PM). At harvest the phenolic ripeness was determined with the Glories method, while the tannin concentration was determined with the methyl cellulose (MCP) method. The grapes in the warmer area had higher tannin levels than grapes harvested in the cooler area in both years. In the 2009 harvest season, the enzyme treatment extracted the highest levels of tannin. CM+PM showed the best results of tannin extraction with early ripeness (Cabernet Sauvignon), and CM with fuller ripeness in the warm area. CM showed the best results with both early and fuller ripeness levels in the cooler area. PM showed the best results with the early ripeness levels, and the E treatment with the fuller ripeness levels, in the warm area. CM+PM showed the best results with the early ripeness level in the cooler area, and varied results with the fuller ripeness levels. In both years, grapes from the cooler area contained more anthocyanin than those from the warmer area. At a fuller ripeness level (2009) the treatments had no effect. <![CDATA[<b>Characterisation of <i>Hanseniaspora </i>isolates with potential aroma-enhancing properties in Muscat wines</b>]]> The sensorial characteristics of the wines produced with Muscat grapes are related to the level of terpene alcohols, so an improvement of such a level is expected as a result of hydrolytic processes conducted by Hanseniaspora. The aim of this work was to select and identify new strains for this purpose. In a second step, the strains were assayed to evaluate their oenological abilities. H. uvarum H107 and H. vineae G26 and P38 were proven to be good candidates to be used in commercial vinification processes to enhance wine properties. Wine inoculated with yeasts showed an increase in the level of aromatic compounds. <![CDATA[<b>The effect of foliar potassium and seaweed products in combination with a leonardite fertigation product on flame seedless grape quality</b>]]> Berry colour and size are important factors determining Flame Seedless quality. Supplementary to standard cultivation, foliar application of potassium (K) and seaweed or soil application of vegetable extracts affect grape quality. The purpose of this trial was to determine if combined product application (CPA) of K, seaweed and leonardite (organic material of vegetable origin) can improve Flame Seedless grape colour, berry size and composition. This study was conducted on Flame Seedless in the Berg River Valley in two seasons. In 2011/2012, leonardite was applied through fertigation six, four and three weeks before harvest, while K and seaweed were applied as foliar sprays four and three weeks before harvest. In 2012/2013, all products were applied eight and six weeks before harvest. Treatments included (1) control (ethephon/ ethephon and abscisic acid - ABA); (2) CPA with ethephon/ethephon and ABA (CPA-plus); and (3) CPA without ethephon/ethephon and ABA (CPA-minus). All vines received standard gibberellic acid treatments. Berry quality was determined. In 2011/2012, CPA-minus reduced anthocyanin concentration significantly compared to the control. CPA-plus increased berry diameter significantly compared to the control on the first harvest date in 2012/2013. Compared to the control, CPA-plus significantly increased total soluble solids (TSS) on all harvest dates in 2011/2012, and on the first harvest date of 2012/2013. Compared to the control, CPA-plus did not improve colour, but it retarded total titratable acidity breakdown in both seasons. Ethephon/ethephon and ABA must be applied for acceptable colour. The consistent effect on TSS shows the ability of CPA-plus to enhance Flame Seedless ripening. <![CDATA[<b>Effect of simulated shipping temperatures on the sensory composition of South African Chenin blanc and Sauvignon blanc wines</b>]]> This work investigated the effect of constant and simulated shipping temperatures on the sensory composition of Chenin blanc and Sauvignon blanc wines. Wines exposed to elevated temperatures during the trial developed unwanted aromas, such as over-aged, sulphur-like and a yellow colour, while those left at a cooler temperature retained tropical aromas. However, varying temperatures did not lead to large aroma differences in wines compared to those left at a constant lower temperature. It thus seems that average temperatures play a larger role in the development of unwanted over-aged aromas in certain South African white wines than temperature variations. <![CDATA[<b>Characteristic aroma compounds in two new <i>Vitis vinifera </i>cultivars (table grapes) and impact of vintage and greenhouse cultivation</b>]]> 'Zaoheibao' (a red tetraploid hybrid) and 'Wuhecuibao' (a white triploid hybrid) grapes have been obtained from Guibao ♀ (diploid, Vitis vinifera) x Zaomeigui ♂ (diploid, V. vinifera) and Guibao ♀ (diploid, V. vinifera) x Wuhebaijixin♂ (triploid, V. vinifera) respectively. Aroma characterisation of the two new table grape cultivars was firstly done by the investigation of volatile compounds. The influence of greenhouse cultivation and vintage on berry aroma was studied as well. The results showed that linalool, decanal, β-damascenone, hexanal and (E)-2-hexenal were the main volatile compounds of the two cultivars, which meant that the floral, fruity and sweet odour were prominent, followed by the herbaceous aroma. Greenhouse cultivation enhanced herbaceous odour in both 'Wuhecuibao' and 'Zaoheibao' berries, and reduced the floral aroma, contributed mainly by β-damascenone, in 'Wuhecuibao', and the sweet aroma, represented mainly by linalool, in 'Zaoheibao'. The concentrations of the main aroma compounds were greatly affected by vintage and the intensity of sensorial perception was correspondingly changed, but varietal odour attributes were not significantly altered. These results will not only help promote the cultivation and popularisation of these cultivars, but also will provide valuable data for the use of these cultivars in future breeding. <![CDATA[<b>The effect of pre-fermentative freezing treatment on the sensory quality of 'Meili' rosé wine</b>]]> In this study, the effect of a pre-fermentative freezing treatment on quality attributes of 'Meili' rosé wine was assessed. Prior to fermentation, 'Meili' grapes (berries and must) were subjected to a freezing treatment considering factors of freezing temperatures, freezing time, and thawing method. Colour-related indices were measured by spectral methods. Wine aroma characteristics and sensory attributes were assessed by trained panellists. The results revealed that lower freezing temperature and longer freezing time had positive effects on wine quality attributes. The treatment of frozen berries might help extract colour-related compounds. Microwave thawing improved wine colour, but decreased taste quality. In the work, the MF-10°C/6 h treatment (microwave-thawed berries that had been frozen at -10°C for 6 h) contributed to the best colour characteristics, whereas the NP-20°C/4 h treatment (naturally-thawed must that had been frozen at -20°C for 4 h) contributed to the best taste attributes. <![CDATA[<b>Selection of <i>Saccharomyces cerevisiae </i>strains applied to the production of Prieto Picudo rosé wines with a different aromatic profile</b>]]> The aim of this work was to select indigenous Saccharomyces cerevisiae strains based on a combination of genetic and aroma analyses to be used for inoculation in industrial fermentations and produce rosé wine with a different aromatic profile. A total of 118 indigenous strains of S. cerevisiae and one hybrid strain from five wineries and three different vintages were isolated from spontaneous microfermentations and genetically characterised according to the restriction fragment length polymorphism of their mitochondrial DNA (RFLP-mtDNA). From this group, 30 strains were subjected to phenotypic/oenological characterisation and, of these, nine were chosen as starters in wine fermentations due to their ability to ferment well and their appearance in consecutive vintages or in two or more wineries. Wines produced by these nine selected strains were aromatically and chemically characterised, revealing great differences in their sensory profiles. One of these strains (C9-I) showed the most complex aroma profile in the sensory characterisation, so it was selected to produce an industrial wine. A principal component analysis showed that the industrial wine produced was aromatically very different from several commercial wines produced by different wineries. In fact, their main aromatic attributes were not found in the commercial rosé wines selected for the sensory evaluation. The study shows that a combination of microbiological and chemical techniques can be an effective tool to improve the winemaking process to produce industrial wines with a distinctive organoleptic profile. <![CDATA[<b>Use of boundary lines to determine effects of some salinity-associated soil variables on grapevines in the Breede River Valley</b>]]> The boundary line concept was used to assess grapevine responses to salinity-associated soil variables. Soil chemical status and grapevine responses were measured in 13 vineyards in the Breede River Valley during the 2001/2002 season. Chardonnay grafted onto 110R and 101-14 Mgt, as well as Ruby Cabernet on the same two rootstocks, was included. The selected vineyards were representative of the variation in salinity-associated soil variables, as well as of leaf and juice element contents previously reported for South African vineyards. Under the prevailing conditions, the four scion-rootstock combinations responded similarly to the salinity-associated variables. The results confirm that soil pH should be at least 6.0 for grapevines. The salinity threshold for vineyards in the Breede River Valley should be between 0.7 dS/m and 1.5 dS/m to avoid growth and yield reductions. To reduce the risk of Na toxicity, the SAR should be below 3, and the soluble Na content in the soil should not exceed 5 mg/kg. If gypsum is used to reduce soil Na, it should be applied judiciously to avoid soil SO4 accumulation, thereby reducing the risk of K and Mg deficiencies. Under the prevailing conditions, B and Cl toxicity apparently contributed to reduced vegetative growth. Therefore, soil Cl and B should be kept as low as possible, but care should be taken that B is not reduced to deficient levels. The boundary line concept proved to be useful for determining the effect of a single salinity-associated soil variable on grapevine response. <![CDATA[<b>Separation and purification of four stilbenes from <i>Vitis vinifera </i>L. cv. cabernet sauvignon roots through high-speed counter-current chromatography</b>]]> A method for preparative separation and purification of trans-resveratrol, δ-viniferin, ε-viniferin and trans-vitisin B from the roots of Vitis vinifera L. cv. Cabernet Sauvignon was successfully established and is reported on in this paper. The four important stilbenes were purified by high-speed counter-current chromatography (HSCCC) with a suitable quaternary solvent system composed of chloroform-methanol-n-butanol-water (4:3:0.05:2, v/v). A total of 7.1 mg ± 0.2 mg of trans-resveratrol, 1.1 mg ± 0.1 mg of á-viniferin, 18.7 mg ± 0.5 mg of ε-viniferin, and 12.2 mg ± 0.2 mg of trans-vitisin B, with purities of 97.89%, 90.61%, 94.37% and 78.38% respectively, were obtained from 241 mg of crude sample in a one-step HSCCC separation. The chemical structures of trans-resveratrol and á-viniferin were further confirmed with the retention time using the method of standard addition, while the structural identification of ε-viniferin and trans-vitisin B was performed with LC-ESI/MS, Ή-NMR, and 13C-NMR. <![CDATA[<b>Trace element partitioning in 'Sibera' grapevines as affected by nitrogen fertilisation</b>]]> A study on grapevine cv. Sibera was carried out in a vineyard located near Kraków (Poland) in 2010 and 2011. The plants were treated with three nitrogen application rates (0, 50 and 100 kg N ha-1), administered as ammonium nitrate in a single application three weeks before flowering. Samples of leaf petioles and blades, as well as grapes, were taken. After wet microwave digestion in HNO3, the nutrient elements boron (B), copper (Cu), iron (Fe), zinc (Zn), manganese (Mn), molybdenum (Mo) and sodium (Na), and the trace elements aluminium (Al), barium (Ba), cadmium (Cd), chromium (Cr), lithium (Li), nickel (Ni), lead (Pb), strontium (Sr), titanium (Ti) and vanadium (V), were measured using the ICP-OES technique. Environmental factors such as temperature and available water had a significant effect on the nutrient concentration in the grapes. In the wet and warm 2010 vintage, higher amounts of B, Cu, Cd, Ti and V were measured in the leaves, and of Mn, Al, Ba and Ti in the grape juice. The dry season of 2011 increased the leaf Fe, Mn, Zn, Mo, Na, Ba, Cr, Li and Ni content, which was associated with a higher Zn, Mo, Na, Sr, Cd and Ni concentration in the grape must. The study showed that, in slightly acid soils, mineral N fertilisers containing ammonium can augment the uptake and accumulation of microelements such as Fe, Mn, Zn, Al and Ti by the grape must. In contrast, nitrogen fertilisation depressed the concentrations of some elements, such as B, Fe, Mn, Cd, Cr, Ni and Ti in the leaves. Correlations between the mineral content of the analysed plant tissues are also discussed. <![CDATA[<b>Integrative effects of vine water relations and grape ripeness level of <i>Vitis vinifera </i>L. cv. Shiraz/Richter 99. II. grape composition and wine quality</b>]]> Regulation of grapevine water status is a common practice to manipulate grape composition and wine quality. In this investigation the effect of plant water status (two field water capacity-based irrigation levels, 75% and 100%, applied at single and combined vine developmental stages) and ripeness level (harvesting at different soluble solid levels) on grape composition and wine quality of Vitis vinifera L. cv. Shiraz/ Richter 99 was determined. Integrative effects of vine water relations and grape ripeness level, specifically in a Mediterranean high winter rainfall area, have not yet been investigated systematically. Source:sink mechanisms and dynamics and compositional and physical changes during both green berry and ripening periods (and in response to environment changes), seemed critical for the final grape composition and wine quality/style. Despite relatively favourable conditions of the experiment terroir, additional water was still required to obtain best grape and wine quality. Skin colour and total phenolic contents were stimulated in particular by 75% (field water capacity) pea size (PS) irrigation, post-véraison (PV) irrigation and 75% pea size+post-véraison irrigation, until the last harvest stage. Treatments that included post-véraison irrigation were not negative in terms of ripening parameters. Increasing total soluble solids with ripening were not followed in parallel by anthocyanin potential. Anthocyanin extractability increased with ripening. A late, overripe harvest may result in wines that are slightly better coloured, but highly alcoholic and tannic. Furthermore, at high ripeness level, differences between treatments largely diminished. Over-ripeness of grapes may have tempering and even negative effects on expected outcomes of seasonal cultivation efforts to produce unique wines. This would not favour economic viability. Although non-irrigated wines failed to result in exceptional wine quality at any harvest stage, a better result in overall quality was obtained in comparison to irrigation treatments applied at all stages. Berry and wine composition results corresponded with findings on wine sensorial quality. The 75% PS, PV irrigation, and 75% PS+PV irrigation consistently resulted in good quality wines. At the first harvest stage, 75% PV, 100% PV, 75% PS+V and 75% PS+PV irrigations gave most prominent wines; at the second harvest stage, vines irrigated 75% at PS, 75% at PS+PV and 75% at PV delivered most prominent wines; and at the third harvest stage, 75% PV, 100% PV, 75% PS and 75% PS+PV resulted in most prominent wines. These treatments represented different wine styles at each harvest stage. Restricted PS irrigation and PV irrigation, as single or combined treatments, featured prominently in favouring grape and wine composition and wine sensorial quality. Physical and compositional changes in ripening berries and the impact on wine quality and style were further clarified. New perspectives on managing time of harvesting with varying vine water status are given. Recommendations on vine water status management strategies required to obtain different grape composition and wine style are made. <![CDATA[<b>Effects of irrigation and cluster thinning on Tempranillo grape and wine composition</b>]]> With the aim of understanding the effects of water stress and cluster load on berry composition and wine quality, a four-year field test was conducted in a cv. Tempranillo vineyard in Extremadura (Spain). When the first berries appeared to be changing colour (onset of véraison), grapevines were subjected to two different irrigation regimes, one supplying 100% of crop evapotranspiration, and the other 25%. In addition, two cluster load levels were tested for each irrigation regime: seven to nine and four to five clusters/m² planting area. Both irrigation and thinning had an impact on most of the parameters analysed in the grapes and the wines, although the thinning effect was in general higher than the irrigation effect. Thus, deficit irrigation reduced malic acid and the titratable acidity of Tempranillo grape juice, while cluster thinning increased all parameters analysed, except potassium concentrations. Similarly, the wine composition was also affected differently by irrigation and by cluster thinning. Deficit irrigation reduced pH and increased titratable acidity, total phenol index and colour parameters, while cluster thinning increased alcohol content, anthocyanin and colour intensity, and reduced pH and colour. The effect of the cluster thinning technique was independent of the irrigation regime in most of the wine parameters analysed, except for total phenol index, where the effect of deficit irrigation (DI) was more pronounced in grapevines also subjected to the cluster thinning treatment. <![CDATA[<b>Suitability of different PCR-DGGE primer sets for the monitoring of lactic acid bacteria in wine</b>]]> Lactic acid bacteria (LAB) play a dual role in winemaking as they are the main effectors of malolactic fermentation, but some members can also cause wine spoilage. PCR-DGGE has proved to be a quick tool to study the LAB community and their fluctuation in wine. For detecting wine-associated LAB by PCR-DGGE, the primer sets WLAB1/WLAB2GC, WBAC1/WBAC2GC, Lac1/Lac1o/Lac2GC, 341f gC/518r and rpoBl/ rpoB1o/rpoB2GCwere tested and evaluated in this study. The primer systems were assessed by the separation of LAB reference strains on DGGE gels and by attributing the resulting amplicons to defined species. Subsequently, the detection of LAB in wine samples and enrichments thereof was compared. While the primer systems WBAC1/WBAC2GCand 341fGC/518r were not appropriate, the Lac1/Lac1o/Lac2GCprimer set performed well. However, multiple bands complicated the evaluation. The rpoB1/rpoB1o/rpoB2GCset seemed to be promising for the detection of LAB in wine, although further improvements in terms of the detection limit need to be done. Due to the pronounced sensitivity and the sufficient discrimination of LAB at species level, the WLAB1/WLAB2GCprimer system was found to be most suitable for studying the occurrence of LAB in wine. <![CDATA[<b>Application of sugar foam to vineyard acid soils under Mediterranean conditions</b>]]> Calcium (Ca) deficiency and aluminium (Al) toxicity are considered major chemical constraints that limit vine growth in vineyard acid soils under Mediterranean conditions. The main aim of this work was to evaluate the effects of three doses of sugar foam (900, 1 800 and 2 700 kg CaCO3/ha) on five soil properties (pH in water, Ca, Mg, K and Al exchangeable contents) and Ca concentrations in petioles and canes of one wine grape variety. Research was conducted over three seasons (2006 to 2008) in a random block design at León (Spain). The results for plants and soils were subjected to general lineal model analysis. As a result, one linear model, validated through a cross-validation procedure, has been proposed to predict exchangeable calcium levels in vineyard acid soils at véraison. Based on the results for the soils, the higher doses of sugar foam (1 800 and 2 700 kg CaCO3/ha) were the most effective doses in decreasing Al exchangeable and increasing Ca exchangeable contents. In addition, liming increased Ca content in petioles and decreased Ca content in canes, but in both cases these differences were not significant. <![CDATA[<b>Environmental stress and aroma production during wine fermentation</b>]]> The sensory description of wine uses the widest range of descriptive terminology of all food products, reflecting the complex nature of a product whose character depends on the balance of hundreds of individual flavour-active compounds. There are many tools that can influence flavour profiles or wine styles, one of which is the choice of a specific yeast strain. Yeasts contribute to wine flavour by producing volatile metabolites with different flavour profiles. The impact of changing environmental conditions on the production of flavour compounds by yeast strains remains largely unexplored. This is the first study investigating the impact of two mild fermentation stresses, hyperosmotic and temperature stress, on aroma production in synthetic must by commercial Saccharomyces cerevisiae wine strains. Hyperosmotic stress was imposed by cultivation of the yeast for 21 days in the must containing either 0.3 or 0.5 M sorbitol. The transient temperature stresses were applied for 16 h at 8° or 37°C for either two or eight days after commencement of the fermentation. Greater glycerol and acetic acid levels were produced by most yeasts when only hyperosmotic stress was applied. Hyperosmotic and temperature stress conditions produced a limited number of significant changes to the profile of the esters, higher alcohols and volatile fatty acids. These changes differed significantly for each strain and stress treatment, suggesting that the fermentation conditions can significantly alter the aromatic profile of a wine, although these stress impacts cannot be predicted in general. The changes to the aromatic profile are specific to each individual wine yeast strain.