Changes in Concentration of Certain Elements During Maturation of Muscadine Grapes (Vitis rotundifolia)

Changes in percent ash and certain elements were followed during maturation of berries of two cultivars of muscadine grapes (Vitis rotundifolia). Analyses were done on deseeded berries. Percent ash increased significantly during maturation of Carlos berries, but did not increase significantly during maturation of Noble berries. Potassium was the element in highest concentration in both cultivars during maturation and at harvest. Potassium, calcium, phosphorus, and sodium were the major elements found to be significantly correlated with maturation and were found in concentrations similar to those reported in the literature for V. vinifera grapes. Iron, copper, zinc, and manganese were minor components. Four additional muscadine cultivars, sampled only at full maturity, had similar concentrations of elements to those found in ripe berries of Carlos and Noble. The averaged values of ash (%) and elements (ppm) for all six cultivars when sampled at their normal harvest dates are: ash = 0.57; Na = 58.6 (Carlos and Noble only); P = 99.6; K = 1641.0; Ca = 124.2; Mg = 59.2; Mn = 7.2; Cu = 0.5; Zn = 0.5; Fe = 3.0.     

圆叶葡萄种子发育过程中多酚积累特性

以栽培于广西地区2 个圆叶葡萄品种‘Noble’和‘Carlos’为实验材料,以真葡萄品种‘赤霞珠’和‘雷司令’为对照,使用超高效液相色谱-串联三重四极杆飞行时间质谱,分析其种子发育过程中多酚组成和积累特性。结果表明：在4种葡萄发育过程的种子样品中共检测到106种多酚,包括48种鞣花酸及前体物、24种黄酮醇、20种羟基苯甲酸、9种黄烷-3-醇、3种芪类和2种羟基肉桂酸。鞣花酸及前体物（主要是前体物）和黄烷-3-醇（主要是没食子酰化体和单体）分别是圆叶葡萄和真葡萄种子中最主要的多酚类型,但其含量在不同年份和品种间具有较大差异。前体物含量在圆叶葡萄‘Noble’幼果期种子中较高,然后逐渐下降,完全转色后再次上升;‘Carlos’则在浆果转色前种子中含量较高,随后略有下降。黄烷-3-醇在真葡萄‘雷司令’种子中2013年随着浆果发育含量显著升高,转色时含量达到最高,随后有所下降,2014年不受发育期的影响;‘赤霞珠’则分别在2013年幼果期和2014年果实完熟时的种子中含量最高。     

Sugar and acid concentrations in 98 grape cultivars analyzed by principal component analysis

A total of 98 grape cultivars were studied for content and composition of organic acids and sugars in grape juice during two consecutive years. Glucose and fructose were the predominant sugars in grape berries and ranged from 45.86 to 122.89 mg mL^?1, and 47.64 to 131.04 mg mL^?1, respectively, in two years. Sucrose was present at trace amounts in most cultivars, but two cultivars of hybrids between Vitis labrusca and V. vinifera contained large amounts of sucrose. Tartaric acid content in berries, varying from 1.57 to 9.09 and 1.54 to 9.05 mg mL^?1, respectively, in two years, was significantly higher than malic acid, which ranged from 0.38 to 6.05 and 0.36 to 7.06 mg mL^?1, respectively, in two years. Moreover, significantly higher total soluble sugars and fructose and lower total acids and malic acid were found in cultivars from hybrids between V. labrusca and V. vinifera than those in V. vinifera cultivars, and wine grapes had higher total sugars and acids than table grapes from V. vinifera. Principal component analysis (PCA) indicated that genotypic correlations among sugar and acid contents were stable and the first three PCs accounted for about 82% of total variance in both years. PC1 was highly connected with glucose and fructose contents, and sucrose was an important contributor to the variance for PC2, as well as for PC3. PC2 and PC3 were highly connected also with organic acids, but the contributor to variance differed from one year to the next. Tartaric acid was the main contributor to variance in 2003, and malic acid was important in 2004 for PC2 and PC3. In a scatter plot of the score values of all genotypes projected to the PC1 and PC2 plane, three groups of cultivars tend to cluster based on their genetic background or purpose of use. The cultivars of hybrid V. labrusca and V. vinifera were represented by high sugars, especially sucrose, and low acids. Among the cultivars of V. vinifera, wine grapes were found in general to have more sugars and acids than table grapes. The composition of sugars was stable in grape berries between the two years, while acids were sensitive to climate changes. Finally, the different responses of malic and tartaric acids to climate change is discussed. Copyright © 2006 Society of Chemical Industry     

Influence of pressing method on juice stilbene content in muscadine and bunch grapes

ABSTRACT:  Juice stilbene contents of 2 muscadine ( Vitis rotundifolia) cultivars, Noble and Carlos, and 2 bunch grape ( Vitis labrusca) cultivars, Mid South and Miss Blanc were evaluated after crushing and pressing. Four commercial pressing methods were used to produce juice: (1) cold press of fresh berries (CP); (2) hot press of fresh berries (HP); (3) cold press of frozen and thawed berries (FCP); and (4) cold press of pectolytic enzyme treated berries (ECP). Free run juice (FRJ) from the crusher without pressing was also tested. An HPLC with a UV detector was used to verify the presence and quantity of resveratrol, piceid, and their isomers. For the muscadine juices, total stilbenes were greater for HP and FCP than for FRJ and CP treatments. Trans -resveratrol was only detected in HP juices of the muscadines at levels near the detection limits. The bunch grape cultivars behaved similar to the muscadines in the processing treatments. HP juice had the greatest total stilbene levels and was significantly greater than FRJ, CP, and FCP. Total stilbene levels in juices from the 2 bunch grape cultivars, were higher (up to 5 times greater depending on pressing method) than for the muscadine grape cultivars. Total stilbene levels in muscadine juices treated with pectinase before pressing (ECP) were similar to those of the FCP samples. Juice from FCP and ECP treated Noble muscadine had total stilbene levels greater than FRJ and CP but less than HP levels. Juices from HP-, ECP-, and FCP-treated Carlos muscadine had total stilbene levels greater than for FRJ and CP juices.     

The Proteins of Muscadine Grapes

The concentrations, molecular weights and isoelectric points of proteins present in muscadine grape cultivars were determined. The total protein contents of these grapes, are consistent with values reported in literature for V. vinifera grape proteins. Molecular weights of most of the protein fractions were, however, relatively high when compared with those of other grape cultivars. Isoelectric’ points of muscadine proteins ranged between pH 5.6 and pH 7.6.     

Effects of phenolic compounds in blueberries and muscadine grapes on HepG2 cell viability and apoptosis

Although blueberries and muscadine grapes have high contents of polyphenols, few studies have been conducted to assess their potential effects on cancer cells. The objective of this study was to systematically evaluate the effects of different fractions of phenolic compounds in blueberries and muscadine grapes on HepG2 liver cancer cell viability and apoptosis. Three cultivars of blueberries (‘Briteblue’, ‘Tifblue’ and ‘Powderblue’) and four cultivars of muscadine grapes (‘Carlos’, ‘Ison’, ‘Noble’, and ‘Supreme’) were assessed in this study. Polyphenols were extracted and further separated into phenolic acids, tannins, flavonols, and anthocyanins using a HLB cartridge and LH-20 column. The major compounds of different fractions were characterized. The phenolic acid fractions of muscadine grapes and blueberries showed a 50% inhibition of HepG2 cell population growth at the level of 1–2 mg/mL. The greatest inhibitory effects were observed from the anthocyanin fractions with 50% inhibitions of cancer cell population growth at concentrations of 70–150 and 100–300 μg/mL in blueberries and muscadine grapes, respectively. The flavonol and tannin fractions showed intermediate activities. In addition, DNA fragmentation was measured by using a Cell Death Detection ELISA kit to assess the induction of apoptosis. The anthocyanin fraction resulted in a two- to fourfold increase in DNA fragmentation compared to control in both muscadine grapes and blueberries. These findings of inhibition of cancer cell growth and induction of apoptosis suggest that blueberries and muscadine grapes may contribute to reduction in liver cancer risk.     

Effects of exogenous abscisic acid on antioxidant capacities,anthocyanins, and flavonol contents of muscadine grape (Vitis rotundifolia) skins

The objective of this study was to evaluate the effect of exogenous abscisic acid (ABA) on the antioxidant capacity and phenolic content of muscadine grape skins (cvs. Noble and Alachua). ABA was applied on grapes during and after veraison. Average berry weight, total soluble solids (⁰Brix) and pH of the juice from both cultivars were not affected by the ABA treatment. Antioxidant capacity was enhanced by 38% and 18% in treated Noble at the first and second sampling, respectively. High performance liquid chromatography analysis revealed a significant increase in individual anthocyanins in treated Noble grapes at both sampling times. However, increase in the content of ellagic acid, myricetin, quercetin and kaempferol was observed at first sampling only. No effects of ABA treatment were seen in Alachua grapes. Our results indicate that exogenous application of ABA enhances the antioxidant capacity, anthocyanins and phenolic content of muscadine grapes but these effects may vary depending upon the cultivar.     

Consumer Acceptability of Fresh‐Market Muscadine Grapes

The objective of this research was to investigate the acceptability of muscadine grape (Vitis rotundifolia) genotypes (cultivars and selections) and to correlate overall liking to other quality measurements to determine the main drivers of liking. Twenty‐two genotypes grown at the Univ. of Georgia–Tifton Campus were evaluated. Four retail commercial grape genotypes (Vitis vinifera and “Concord”) were also evaluated for comparison. Panelists familiar with muscadine grapes used the hedonic general labeled magnitude scale (HgLMS, –100 = strongest disliking of any kind ever experienced, +100 = strongest liking of any kind ever experienced) to rate overall liking and the liking of appearance, flavor, pulp texture, and skin texture. Puncture testing was done to assess grape berry texture, and compositional attributes soluble solids and pH were also measured. The sensory results indicated that the grapes were variable with overall liking scores from 12.2 to 39.6. The factors highly correlated with overall liking scores were muscadine flavor, pulp and skin liking, while a significant negative correlation was found between skin liking and skin texture and mechanical texture measures. The muscadine grapes with the highest overall liking scores were Ga. 5‐1‐34 and Ga. 2‐8‐21. Principal component analysis confirmed that grapes with a thinner skin and a higher pH tended to group around overall liking and flavor points. These results indicate that even among panelists familiar with muscadine grapes, skin thickness is a negative characteristic. Breeding for thinner skins may be a positive step in muscadines gaining a more widespread appeal in the fresh fruit market.     

Mass-spectrometry evidence confirming the presence of pelargonidin-3-O-glucoside in the berry skins of Cabernet Sauvignon and Pinot Noir (Vitis vinifera L.)

Background and Aims: Anthocyanins are a group of important phenolic compounds which are responsible for the colour of red grape and wine. This study aimed to confirm the existence of pelargonidin-3-O-glucoside in Vitis vinifera grape berry skins. Methods and Results: The anthocyanin profiles in the berry skins of Cabernet Sauvignon and Pinot Noir were analysed by high performance liquid chromatography – electronic spray ionization – tandem mass spectrometry. Besides 17 anthocyanins that are commonly determined in the berries of these two varieties, pelargonidin-3-O-glucoside was also detected at trace levels. Conclusions: The mass-spectrometry evidence confirmed the existence of pelargonidin-3-O-glucoside in non-teinturier V. vinifera grapes. Significance of the Study: This finding will be beneficial for the further understanding of anthocyanin profile and its biosynthesis in grape berries.     

Anthocyanin composition and content in grape berry skin in Vitis germplasm

The composition and content of anthocyanins were surveyed by HPLC–MS for assessing genotypic variation in berry skin of 110 grape cultivars, including 3 species and 5 interspecific hybrids. Twenty-nine anthocyanins were identified. For total anthocyanin content, Vitis vinifera and hybrids of Vitis labrusca and V. vinifera were low, and in general, wild species and rootstock were higher than interspecific hybrids, and wine grapes were higher than table grapes in the same species. As regards the composition of anthocyanins, malvidin-derivatives were the most abundant anthocyanins in the majority of germplasms. All anthocyanins were monoglucoside derivatives in V. vinifera, but all the other Vitis germplasms had both mono- and di-glucoside derivatives. Moreover, peonidin-derivatives and malvidin 3-O-glucoside were, respectively, main anthocyanins in table and wine grapes of V. vinifera. Via principal component analysis, the distribution of the cultivars in a scatter plot depended upon their total anthocyanins content, mono- and di-glucoside derivatives.     

Polyphenolic profiles detected in the ripe berries of Vitis vinifera germplasm

Polyphenolic profiles in the berry samples of 344 European grape (Vitis vinifera) cultivars were evaluated for two consecutive years. These cultivars represent a diverse collection of V. vinifera germplasm maintained at the USDA-Agricultural Research Service Vitis Clonal Repository in Davis of California, USA. A total of 36 polyphenolic compounds, including 16 anthocyanins, 6 flavonols, 6 flavanols, 6 hydroxycinnamic acids and 2 hydroxybenzoic acids, were identified via HPLC–MS and quantified by HPLC–DAD. The mean contents for anthocyanins, flavanols, flavonols, hydroxycinnamic acids and hydroxybenzoic acids were 0.946 (coloured cultivars), 0.147, 0.043, 0.195 and 0.016 mg g⁻¹ FW, respectively. On average, wine grapes had higher concentrations than had table grapes for all of these compounds except hydroxycinnamic acids. Berry colours affected the total contents of anthocyanins, but not others. Positive correlations (0.151–0.535) were found among these groups of compounds. As expected, these groups of compounds were all negatively correlated with berry weight.     

Identification of anthocyanins in muscadine grapes with HPLC-ESI-MS

Muscadine grapes are important fruits grown in the southeastern United States. They are a good source of anthocyanins, but confirmatory analyses of the structure of individual anthocyanins in muscadine grapes using more advanced instrument are lacking. In this study, the anthocyanins of muscadine grapes were analyzed using HPLC-MS with electrospray ionization. Approximately 90% of the total anthocyanins were 3,5-diglucoside of delphinidin, cyanidin and petunidin; the remaining 10% were 3,5-diglucoside of peonidin and malvidin. There was a significant difference of total anthocyanin content among different cultivars of muscadine grapes with purple-skinned muscadine grapes having significantly higher levels of anthocyanins than bronze-skinned muscadine grapes. The total anthocyanin content in purple-skinned Jumbo and Cowart muscadine was 4.1 and 2.6 mg/g dry weight, respectively, while the total anthocyanin content in bronze-skinned Higgin and Carlos was negligible. The anthocyanins were mainly concentrated in the skin of the grapes. The results of the present study confirmed some of the anthocyanins reported by previous studies and also found one anthocyanin that might be falsely identified by previous studies.     

Phytochemicals from berries and grapes inhibited the formation of advanced glycation end‐products by scavenging reactive carbonyls

Phenolic phytochemicals were extracted from blueberries, blackberries, strawberries, raspberries, cranberries, and Noble muscadine grapes. These extracts were purified to remove free sugars. Blueberry extract was separated into five fractions using a Sephadex LH‐20 column. Berry extracts and fractions significantly inhibited AGEs generation in (bovine serum albumin) BSA‐fructose, BSA‐methylglyoxal, and arginine‐methylglyoxal models, respectively. Their capacity to scavenge methylglyoxal suggested carbonyl scavenging as a major mechanism of protein glycation inhibition. Procyanidins were detected in all berry extracts and blueberry subfractions and were deduced to be one class of active compounds. (+)‐Catechin, constituent unit of procyanidins, was used as a model compound to react with glyoxal and methylglyoxal. Five catechin‐carbonyl adducts were detected and their structures were tentatively identified using HPLC‐ESI‐MSⁿ. Results in this study suggested that sugar‐free phytochemicals extracted from berries were effective carbonyl scavengers and protein glycation inhibitors. These phytochemicals could be beneficial to prevent AGE‐related chronic diseases.     

Changes in Muscadine Grape Juice Quality During Cold Stabilization and Storage of Bottled Juice

Muscadine grapes (Vitis rotundifolia, Michx.) of two cultivars (Noble and Carlos) were washed and extracted. The resulting juice was cold stabilized for 0, 7 and 60 days at 2°C, then treated, bottled, pasteurized and stored at 2°C and 24°C for 0, 4, 8, and 12 months. Carlos juice was lower in phenols and pH and higher in acidity than Noble. The high total anthocyanins and phenols in the Noble juice caused a significant loss in pigment during cold stabilization. Dilution of juice with 40% water and adjustment of the sugars was beneficial to flavor and color of Carlos, yet 40% dilution was too high for Noble juice. Treatment of either juice with CaCO₃ increased pH and decreased acidity. During 12 months storage, the Carlos juice became darker due to browning, while the Noble juice became lighter by losing pigment, especially at 24°C.     

Effects of solar ultraviolet radiation and canopy manipulation on the biochemical composition of Sauvignon Blanc grapes

Background and Aims: New Zealand is exposed to relatively high solar ultraviolet (UV) radiation; such high irradiances of UV radiation having the potential to change the biochemical composition of plants. The aim of this study was to investigate the effects of UV radiation and the role of canopy leaves on berry biochemical composition in Vitis vinifera var. Sauvignon Blanc. Sauvignon Blanc is the major grape variety grown in New Zealand. Methods and Results: Leaves were removed from around the fruiting zones of vines and screens that altered UV radiation exposures were placed over the grape bunches. Samples taken throughout development were analysed for changes in total phenolic compounds (including flavonols), amino acids and methoxypyrazines. Total phenolic compounds increased substantially in response to UV‐B exposure and this was reflected in changes taking place within the skins of the berries. Flavonol levels were determined by UV‐B radiation exposure and accumulated to maximum concentrations at veraison, subsequently declining to harvest. UV radiation did not have a significant effect on the majority of amino acids or methoxypyrazine concentrations. The most noticeable change in amino acid and methoxypyrazine accumulation was caused by the presence of leaves over the fruiting zone, retaining these leaves maintained significantly higher concentrations in the berries at harvest. Conclusions: UV‐B radiation determines the composition of flavonols in the skins of grapes. Amino acid and methoxypyrazine concentrations are not predominantly determined by UV‐B, but retention of leaves over the fruiting zone promotes their accumulation in berries. Significance: Canopy manipulations are routinely used commercially in the vineyard to help control vigour and reduce disease pressure. The findings presented here are important for viticulturists to understand how management of the vine leaf canopy can determine the biochemical composition of the grapes and can therefore, ultimately affect wine quality.     

Rootstock and vineyard floor management influence on ‘Cabernet Sauvignon’ grape yeast assimilable nitrogen (YAN)

This is a study on the influence that two rootstocks (110R, high vigour; 420A, low vigour) and three vineyard floor management regimes (tilled resident vegetation – usual practise in California, and barley cover crops that were either mowed or tilled) had upon grape nitrogen-containing compounds (mainly ammonia and free amino acids recalculated as YAN), sugars, and organic acids in ‘Cabernet Sauvignon’ clone 8. A significant difference was observed for some of the free amino acids between rootstocks. In both sample preparation methods (juiced or chemically extracted), 110R rootstock grapes were significantly higher in SER, GLN, THR, ARG, VAL, ILE, LEU, and YAN than were 420A rootstock grapes. Differences in individual free amino acid profiles and concentrations were observed between the two sample preparations, which indicate that care should be taken when comparing values from dissimilar methods. No significant differences among vineyard floor treatments were detected, which suggests that mowing offers vineyard managers a sustainable practise, alternative to tilling, without negatively affecting grape nitrogen compounds, sugars, or organic acids.     

Volatiles of grape berries evaluated at the germplasm level by headspace-SPME with GC–MS

Volatile aroma compounds are one of the important characteristics determining fruit quality. Evaluation of volatiles at the germplasm level is useful for future breeding efforts, aimed at improvement of fruit quality, via effects on fruit aroma. The composition and concentration of volatiles in berries of forty-two grape cultivars belonging to seven genotypic groups were evaluated by headspace solid-phase microextraction with GC–MS. Sixty volatiles were detected, of which C₆ compounds were the dominant volatiles in V. amurensis grape, neutral cultivars V. vinifera grapes and hybrid grapes between V. vinifera with V. thunbergii or V. amurensis. Alcohols and carbonyls were relatively low in all Vitis germplasm studied. Terpenoids were abundant in V. vinifera with muscat aroma, while esters were dominant in V. labrusca and its hybrids with V. vinifera or V. amurensis. Via principal component analysis, all the grape germplasm studied could be divided into three groups: (1) V. labrusca and its hybrids with V. vinifera or V. amurensis, (2) V. vinifera with muscat aroma and (3) the others, including V. vinifera without muscat aroma plus V. amurensis, and hybrids between V. vinifera and V. thunbergii or V. amurensis. Seasonal quantitative variations of volatiles were observed, but the qualitative volatile composition of the cultivars was consistent.     

Do white grapes really exist?

Anthocyanins are natural coloured pigments representing part of the protective mechanism of many plants, including Vitis vinifera L., and they have a considerable influence on wine quality. Moreover, the presence of anthocyanins in ripe berries is used as the accepted qualitative parameter for distinguishing red from white grapes, since these pigments are known to be present only in red berries. On the other hand, pyranoanthocyanins are important pigments for the colour stability of red wines and are known to be formed after berry crushing, during vinification and wine ageing.In this work, for the first time we provide clear evidence that the skin of international white grape cultivars (Chardonnay, Sauvignon Blanc and Riesling) contains measurable traces of anthocyanins. In addition, for the first time we report clear proofs about the presence of pyranomalvidin 3-O-glucoside (B-type vitisin) and carboxypyranomalvidin 3-O-glucoside (A-type vitisin) in fresh grapes and we quantify them.     

避雨栽培对酿酒葡萄果实氨基酸含量的影响

本研究利用高效液相色谱技术,分析避雨栽培和露地栽培条件下赤霞珠和霞多丽果实发育过程中21种氨基酸含量的变化.结果表明:避雨栽培除了显著降低这两个品种的果实中赖氨酸和脯氨酸含量外,对其它氨基酸含量的影响不尽相同.在霞多丽果实中,避雨栽培促进了大多数氨基酸含量的增加,而在赤霞珠果实中这些氨基酸的积累受到抑制.该研究对避雨栽培技术在酿酒葡萄生产中的应用具有重要的参考价值.     

Pectin-derived oligosaccharides increase color and anthocyanin content in Flame Seedless grapes

BACKGROUND: Grapes grown in warm weather do not develop a desirable red color and require the use of products to enhance berry color. Pectin‐derived oligosaccharides (PDOs) have been shown to have a role in various responses including plant defense, growth and development. In this work a mixture of PDOs with 3–20 degrees of polymerization was applied to Vitis vinifera cv. Flame Seedless grapes under field conditions and compared to the effects of ethephon (an ethylene‐releasing compound). The effect of treatments on grape color, anthocyanin content and phenylalanine ammonia lyase (PAL) mRNA levels was evaluated. RESULTS: PDOs treatment increased berry color measured by the Color Index of Red Grapes (CIRG) and anthocyanin content, compared to ethephon and untreated berries (control); 1.5, 1 and 0.5 mg mL^?1 PDOs increased berry color by 30%, 27% and 26%, respectively, when compared to control berries. Levels of PAL mRNA accumulating in berries treated with PDOs were elevated within the first 24 h of treatment. CONCLUSIONS: PDOs enhanced the color and anthocyanin content of Flame Seedless grape berries possibly due by the induction of PAL mRNA expression. The results demonstrated that PDOs can be used to improve fruit quality aspects such as berry skin color. Copyright © 2011 Society of Chemical Industry