Three-dimensional approach for identification of red grape cultivars by fingerprint of wine anthocyanins

SUMMARYThe effects of cultivars and environment on phenolic composition were analysed in a 7-year experiment comprising 18 grape cultivars (10 red, 8 white) in Spain. A total of 37 flavonoids (14 anthocyanins in red cultivars; 14 flavonols and 9 dihydroflavonols in white cultivars) were analysed by high performance liquid chromatography (HPLC). Significant differences between years were observed for most of the compounds (11 of the 14) studied in red cultivars and seven compounds in white cultivars. A significant year×cultivar interaction was observed for some of the flavonoids studied. All the phenolic compounds determined showed significant differences among grape cultivars. A high coefficient of variation was found for five flavonoid compounds: dihydroquercetin-3-glycoide, dihydrokaempferol-3-glycoside, kaempferol-3-glycoside, quercetin-3-glucoside and kaempferol-3-rhamnoside. Principal component analysis (PCA) of the variation observed in the phenolic compounds identified four relatively compact groups for the white and red grape cultivars. It was found that the variation of the phenolic composition among years for white grape cultivars was higher than for red cultivars. Stable profiles between years were found for Sousón, Garnacha, Caiño Tinto and Verdejo Negro. These results also indicate that the effect of year on grape phenolic composition was less than that of cultivar.

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. 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. 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.

Value of high-performance liquid chromatographic analysis of anthocyanins in the differentiation of red grape cultivars and red wines made from them

Free amino acids in grape juice are important as nitrogen source for yeast strains during alcoholic fermentation. The aim of this research was to determine amino acid profiles in musts from nine grapevine cultivars (six white and three red). The cultivars were located in a homogeneous soil and climatic zone of Bilogora growing hill (West continental region, Prigorje–bilogora subregion), grown on the same training system. The experiment was conducted in vintage 2015. The results showed significant influence of grape cultivar on the amino acids composition in musts of white and red grape cultivars. Arginine was dominant in most analyzed varieties of amino acids. The highest concentration of arginine in white cultivars was measured in Chardonnay must (470.18 mg/L) and in red cultivar must from Saint Laurent (280.65 mg/L). Statistically significant difference was also found in the total amino acid composition of white and red cultivars. The highest concentration of total amino acids in white cultivars was determined in Manzoni juice (1639.51 mg/L) and among the red cultivars in Pinot noir juice (1173.12 mg/L).

Development of electronic technologies for precise identification of fruit crop cultivars in agricultural production provides an effective means for assuring product quality and authentication. The capabilities of discriminating between grape (Vitis vinifera L.) cultivars is essential for assuring certification of varieties sold in world markets. Machine olfaction, based on electronic-nose (e-nose) technologies, is readily available for rapid identification of fruit and vegetative agricultural products. This technology relies on detection of and discrimination between volatile organic compound (VOC) emissions from plant parts. It may be used in all stages of agricultural production to facilitate crop maintenance, cultivation, and harvesting decisions prior to marketing. An experimental e-nose device was constructed and tested in combination with five chemometric methods, including PCA, LDA, QDA, SVM, and ANN, as rapid, non-destructive tools for identification and classification of grape cultivars. An e-nose instrument equipped with nine metal oxide semiconductor (MOS) sensors was utilized to identify and classify five grape cultivars based on leaf VOC emissions using supervised and non-supervised methods. Grape leaf samples were first identified as belonging to specific cultivar types using PCA analyses, which are non-supervised classification methods, with the first two principal components (PC-1 and PC-2) accounting for 89% of the total variance. Four supervised statistical methods were further tested, including DA, QDA, SVM, and ANN, and provided effective discrimination accuracies of 98%, 99%, 92%, and 99%, respectively. These findings confirmed the suitable applicability of an MOS e-nose sensor array with supervised methods for accurate identification of grape cultivars, which is useful for authentication of vine cultivar types for commercial markets.

Mineral elements play an important role in the geographic traceability of wine, and understanding mineral element profiles in berry tissues helps to determine the relationship between elemental accumulation and regional flavor formation in grapes and wine. Eighteen trace elements and 15 rare earth elements were investigated in the skin, pulp, and seeds of grape cultivars Cabernet Sauvignon, Marselan, and Italian Riesling using inductively coupled plasma–mass spectrometry (ICP–MS). Most trace elements, except for B, Zr, Tl, and U, presented similar tissue-specific distributions in their concentrations in the order of seeds > skin > pulp, but concentrations varied within the three cultivars. The two red cultivars showed significantly higher concentrations of Cu, Cr, Ba, Mo, Cd, Ga, Ge, and Tl and lower concentrations of B, Mn, Sr, and U than the white cultivar Italian Riesling. However, the tissue distribution of rare earth elements was totally different from that of the trace elements. In Italian Riesling berries, concentrations of most rare earth elements in the skin were greater than or similar to those in the seeds and pulp, except that Yb was not detected. For the two red cultivars, concentrations of 11 rare earth elements (Y, La, Ce, Nd, Pr, Sm, Gd, Dy, Ho, Er, and Yb) in the seeds were not as high as those in the skin and pulp. These findings give new insights into the tissue distribution of trace and rare earth elements in white and red grape cultivars.

Background and Aims Several authors have demonstrated the interesting properties of wine polysaccharides. These compounds act as protective colloids and are able to interact with tannins and anthocyanins in wines, reducing their reactivity and increasing colour stability. Little, however, is known about the release of polysaccharides by winemaking technologies. We examine the effect of several winemaking techniques – cold prefermentative maceration, dry ice addition and grape skin freezing, and addition of two maceration enzymes – on the quantity and composition of polysaccharides extracted from the three red wine cultivars – Cabernet Sauvignon, Syrah and Monastrell. Methods and Results The molecular mass distribution and composition of polysaccharides were determined, respectively, by high-performance size-exclusion chromatography and by gas chromatography. The amount of some polysaccharide fractions extracted depended on the grape cultivar. The addition of commercial pectic enzyme preparations released a greater quantity of polysaccharides in all three cultivars studied and altered the polysaccharide composition of the Cabernet Sauvignon wine. The effect of the other treatments on the amount of polysaccharides depended on the cultivar. Conclusion This study confirms that grape cultivar and winemaking technique have a significant impact on the quantity and composition of polysaccharides extracted from grapes into wine. The concentration of polysaccharides rich in arabinose and galactose, and in rhamnogalacturonan II was greater in the Syrah wine than that in the Cabernet Sauvignon and Monastrell wines. Both enzymatic treatments and also dry ice addition had a significant influence on the polysaccharide concentration and composition of the wines made from a given cultivar, whereas cold prefermentative maceration or grape skin freezing had no effect. Significance of the Study This is the first report that shows that the polysaccharide composition of Cabernet Sauvignon, Syrah and Monastrell wines is affected by winemaking technique.

The influence of different types of winemaking technology on the contents of catechins, proanthocyanidins, and anthocyanins in Tinta Miúda red wines was studied. The Tinta Miúda red wines were made by fermentation with carbonic maceration, fermentation with stem contact, and fermentation without stem contact, respectively. The analysis of individual catechins, procyanidins, and anthocyanins in these wines was performed by HPLC, and quantification of total catechins, total oligomeric proanthocyanidins, total polymeric proanthocyanidins, and total anthocyanins was carried out by spectrophotometric methods. The wine made by carbonic maceration contained the highest amounts of both catechins and oligomeric and polymeric proanthocyanidins, followed by the wine made by fermentation with stem contact, whereas the wine made by fermentation without stem contact contained the lowest of these compounds. On the other hand, the concentrations of total anthocyanins and nearly all individual anthocyanins in the carbonic maceration wine were lower than those in the wines made by fermentation with stem contact and fermentation without stem contact. These results indicated that, although the carbonic maceration technique could retain higher amounts of catechins and proanthocyanidins in wine, it did not favor retaining or stabilizing anthocyanins in wine.

The anthocyanin pattern of 18 grape cultivars grown under the same conditions during several years, and also the anthocyanin pattern of wines made from them, using the same winemaking technology, has been studied by HPLC. Chromatographic data indicate that every grape cultivar present a characteristic anthocyanin pattern, that is reflected in wines made from them. Two-way ANOVA and variance component analysis point out that the anthocyanin pattern of grapes and wines is mostly affected by the genetic characteristics of grape cultivars. Moreover, the use of multivariate statistical analysis (principal component analysis and discriminant analysis) allows the classification of grapes and wines into several groups on the basis of their anthocyanin pattern, and shows that the anthocyanin pattern of young single-cultivar wines is related to the anthocyanin pattern of grapes used for winemaking. Results may be relevant for using the anthocyanin pattern of young single-cultivar wines as an analytical tool to determine the grape cultivar used to make them.

Evolution of flavonols from the onset of ripening to commercial harvest was compared in seven grape cultivars (Vitis vinifera L.) in Qilian region of Gansu Province in northwest China for two consecutive years. The cultivars were three white-skinned (Chardonnay, Semillon, Italian Riesling), one pink-skinned (Gewurztraminer) and three red-skinned (Cabernet Sauvignon, Cabernet Gernischt and Merlot). Isorhamnetin-3-O-glucoside was found in the pink ‘Gewurztraminer’ grape and the three red cultivars, but not in the whites, while myricetin derivatives were found to be specific to the red grapes. Our results indicate that the flavonol synthesis in Gewurztraminer should be similar to that in white cultivars that do not have a flavonoid 3′,5′-hydroxylase-mediated branch pathway. In comparison with the white and pink grapes, the type and level of quercetin and kaempferol derivatives detected in red grapes were relatively variable, which may be attributable to the presence of an additional myricetin branch in flavonol biosynthesis pathway of red grape cultivars, consequently expanding the range of metabolite variation. We also consider that rain during the sampling period may be a major factor causing these changes in the flavonol profile found between the two vintages.

Determination of anthocyanins in wine based on flow-injection, liquid–solid extraction, continuous evaporation and high-performance liquid chromatography–photometric detection

The studies of the factors of formation SO2-binding complex of white and red grape cultivars from different soil and climatic regions of the Crimea were carried out. The formation of the SO2-binding complex of grapes is associated with a combination of endogenous and exogenous factors. It was found that the most significant factors (α&0.05) in the formation of SO2-binding complex are the cultivar, soil-climatic region of growth, harvest year, and concentration of sugar. Revealed that in the case of white grape cultivars – the cultivar (α = 0.0002) and the soil-climatic region of growth (α = 0.0003) had a significant effect on the accumulation of aldehydes. In red grape cultivars the accumulation of SO2-binding components (ketoacids and aldehydes) was determined by the grape cultivar (α&0.045); α-ketoglutaric acid – soil-climatic region of growth (α = 0.014). The relationship between the mass concentrations of aldehydes and sugars in red grape cultivars has been established.

The market value of grapes (Vitis vinifera L.) is affected by their quality and harvesting time. Veraison and stage of ripening are the most important factors determining table grape quality. Therefore, the present research was performed to determine the effects of various ripening stages on the combination and postharvest quality of two red grape cultivars. Based on color change, fruits were harvested at the veraison stage, two weeks after the veraison stage, and at the full ripening stage. Fruits harvested at the fully ripe stage were stored for 7, 14, and 21 days (at 1 °C with 85–90% relative humidity). The greatest soluble solids content (SSC) (16.1%) and SSC/TA ratio were observed in ‘Khoshnav’, while the greatest titratable acidity (TA) (0.45%) and pH (3.60) were observed in ‘Rashah’. The results of the present study showed that regardless of the storage period, fruits harvested at time V (veraison time) and two weeks after veraison (2WAV) had significantly higher firmness and vitamin C content. ‘Khoshnav’ had the lowest weight loss (2.05%), and ‘Khoshnav’ and ‘Rashah’ had the greatest firmness (5.95 N) and vitamin C content (89.48 mg 100 g−1 FW). The greatest anthocyanin content was observed on day 7 of storage in ‘Rashah’. Total phenol (TP) and total flavonoid (TF) contents and antioxidant capacity (AC) increased significantly until harvest and decreased thereafter during cold storage. ‘Rashah’ showed the greatest AC, TP, and TF values. Based on the findings of this study, the ‘Rashah’ grape cultivar is shown to be rich in vitamin C, anthocyanins, flavonoids, phenolics, and antioxidants. It holds potential for utilization in both processing and breeding programs as a functional food ingredient.

Varietal differences among the anthocyanin profiles of 50 red table grape cultivars studied by high performance liquid chromatography

Oenological potential, phenolic composition, chromatic characteristics and antioxidant activity of red single-cultivar wines from Castilla-La Mancha