Evolution of flavonols in berry skins of different grape cultivars during ripening and a comparison of two vintages

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.     

Evaluation of pathogenesis-related protein content and protein instability of seven white grape (<Emphasis Type="Italic">Vitis vinifera</Emphasis> L.) clones from Casablanca Valley,Chile

Thaumatin-like proteins and chitinases are the main pathogenesis-related (PR) proteins found in grapes, grape juice and wine and are responsible for protein haze formation in bottled white wine during storage and transport. We have studied the effect of the content of both thaumatin-like proteins and chitinases on protein instability of Sauvignon blanc (clones 1, 107 and 242) and Chardonnay (clones 4, 5, 75 and Mendoza) grape juices from both a warm and a cold production zone in the Casablanca Valley, Chile. The PR proteins were identified and quantified by reversed-phase liquid chromatography (RP-HPLC). Protein instability was determined using a heat test and was expressed in nephelometric turbidity units (NTUs). Thaumatin-like (TL) proteins were identified as the major PR proteins present in all grape juices studied. Three TL proteins were identified and named Vitis vinifera thaumatin-like proteins 1, 2 and 3 (VVTL1, VVTL2 and VVTL3). Chitinase A (ChitA) was identified in the Sauvignon blanc and Chardonnay grape juices, and chitinase B (ChitB) was found only in Chardonnay grape juices. Significant differences in the protein content and in the type of protein were observed between grapes from different production zones and between grapes of different varieties, respectively.     

EVALUATION OF VARIETAL GRAPE JUICE—INFLUENCE OF PROCESSING METHOD,SUGAR AND ACID ADJUSTMENT,AND CARBONATION1

This study investigated the influence of processing method, sugar and acid adjustment, and carbonation on the quality of grape juice from 5 cultivars of wine grapes. A sensory panel found the juices with adjusted sugar and/or acid rated higher in flavor than the juices with no sugar and/or acid adjustment. Carbonation improved the ratings of the juices with no sugar and/or acid adjustment, but generally had no effect on the adjusted juices. The heat process treatment produced higher color ratings as determined by CDM values in most cultivars. The Riesling and Chelois produced juices that rated comparable to those of Niagara and Concord, the juice industry standards.     

Detection Thresholds for 2-Isopropyl-3-Methoxypyrazine in Concord and Niagara Grape Juice

ABSTRACT:  2-Isopropyl-3-methoxypyrazine (IPMP) is the compound responsible for the off-flavor known as ladybug taint, which occurs when Harmonia axyridis beetles become incorporated with the grapes during juice processing. It is also an important grape-derived component of juice flavor in some varieties. The main objective of this study was to determine the orthonasal (ON) and retronasal (RN) detection thresholds for IPMP in juice. The ASTM E679 ascending forced choice method of limits was used to determine detection thresholds for 26 individuals in Concord and Niagara juices. Group best estimate thresholds (BETs) averaged 0.93 ng/L and were 50% and 21% higher in Concord than in Niagara juices for ON and RN evaluation, respectively. Group BETs for IPMP (ng/L) for Concord were ON: 1.11; RN: 1.02 and for Niagara were ON: 0.74; RN: 0.84. Variation in individual detection thresholds was observed, although familiarity with ladybug taint was not associated with individual threshold values. We conclude that humans are very sensitive to IPMP in juice, and that detection thresholds are more strongly influenced by grape variety than evaluation mode. These results may assist juice producers in establishing tolerance levels for IPMP in juice affected by ladybug taint or derived from grapes of suboptimal ripeness.     

Effect of UV–Vis Irradiation on Enzymatic Activities and Physicochemical Properties of Four Grape Musts from Different Varieties

The influence of ultraviolet–visible irradiation on some quality attributes (pH, soluble solids content, color parameters, absorption spectrum, vitamin C, total acidity, total phenolics, formol index, and total and reducing sugars) and polyphenol oxidase, peroxidase, and pectinmethylesterase activities of fresh grape juices was investigated. Grape juice was made from two varieties of white grapes (Victoria and Dauphine) and two varieties of pink grapes (Emperor and Red Globe). Each juice was irradiated for 140 min with a high-pressure mercury lamp of 400 W that emits in a range between 250 and 740 nm. Polyphenol oxidase was not completely inactivated during irradiation, reducing only 80% of its initial activity in juices from white grapes and only 50% in those from pink grapes. On the contrary, peroxidase was completely inactivated. A slight or nonexistent variation was observed in most of the measured physicochemical parameters, showing high stability during irradiation. Only vitamin C and color had a significant variation, with an average decrease of 30% for vitamin C in all varieties and a more important variation of color parameters in the pink varieties than in the white ones.     

盐碱荒漠化戈壁酿酒葡萄的果实品质比较分析

为分析10个酿酒葡萄品种和种植年份的成熟期葡萄的主要理化品质,以嘉峪关紫轩葡萄园区红葡萄品种（山葡萄、梅鹿辄、左优红、北冰红、赤霞珠）和白葡萄品种（霞多丽、威代尔、贵人香、白玉霓）为原料,分析比较不同品种葡萄的单粒质量、果粒径、总可溶性固形物、总糖、总酸、糖酸比、总酚及单宁含量。不同品种葡萄中不同物质的含量存在差异,红葡萄品种梅鹿辄、赤霞珠和白葡萄品种威代尔、贵人香4个品种的糖酸比、总酚含量和单宁含量比较高,品质较好,适宜于嘉峪关紫轩葡萄园区的栽培环境。     

Antiangiogenetic Effects of 4 Varieties of Grapes In Vitro

Abstract: The purpose of this study was to investigate the inhibitory effects of grapes on the human umbilical vein endothelial (HUVE) cells’ capillary tube formation and matrix metalloproteinase-2 (MMP-2) expression secreted into the medium. Four different grape varieties (Concord, Niagara, Chardonnay, and Pinot Noir) were extracted using 80% acetone and the extracts were stored at −80 °C. The total amount of phenolics and flavonoids for each of the 4 grape varieties were determined by spectrophotometry. Grape extracts were co-cultured with HUVE cells on Matrigel and inhibitory effects on tube formation were observed under a microscope. The inhibitory effects of grape extracts on MMP-2 expression were examined by zymogram. All 4 grape varieties inhibited the tube formation of HUVE cells in a dose-dependent manner on Matrigel. Except for Chardonnay, the other 3 grape varieties completely inhibited secretion of MMP-2 at 20 mg/mL. There was a significant positive relationship between the total phenolics and flavonoids and antiangiogenetic activities. The grapes tested have the potential to inhibit angiogenesis mainly by their phenolics and flavonoids contents, which partly contribute to their cancer chemopreventive efficacy.     

Stability of Non-Pasteurized, Refrigerated Muscadine Grape Juice

The stability of nonpasteurized muscadine grape juice processed with and without 100 mg/L potassium metabisulfite was monitored during storage at 3°C. The muscadine flavor intensity, sweetness, off-flavor levels, and color of white juices remained stable, and ethanol levels remained low for 7 wk. However, the flavor intensity and sweetness of nonsulfited white juice decreased, and off-flavor and ethanol levels increased after 7 wk. Sulfite lowered microbial levels in white juice throughout 9 wk. Red juices did not develop significant levels of off-flavors or ethanol during 9 wk, although the flavor intensity declined, especially in nonsulfited red juice. Sulfite lightened the color of red juice, but the color was stable in both sulfited and nonsulfited red juices.     

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.     

葡萄籽油中植物甾醇的提取与鉴定

以4种酿酒葡萄(美乐、赤霞珠、龙眼、霞多丽)的种籽为原料,提取葡萄籽油,经皂化、萃取制得植物甾醇。采用GC-MS方法首次分析了葡萄籽油中植物甾醇的组成及含量,结果从葡萄籽油中检测到6种植物甾醇(菜油甾醇、豆甾醇、β-谷甾醇、岩藻甾醇、豆甾烷醇、环木菠萝烯醇),其中白葡萄品种(龙眼、霞多丽)籽油中总甾醇含量高于红葡萄品种(龙眼、霞多丽)。在鉴定出的6种植物甾醇中,β-谷甾醇含量最高,其次是豆甾醇和菜油甾醇,岩藻甾醇含量最低。     

Impact of Multicolored Asian Lady Beetles on the Sensory Properties of Concord and Niagara Grape Juice

ABSTRACT: The presence of Multicolored Asian Lady Beetles (MALB) in grape juice is increasingly problematic. The overall objective of this study was to determine the specific sensory impacts of MALB on Concord and Niagara grape juice. The aroma threshold for MALB-taint in both juices was determined and expressed as the best estimate threshold (BET). The aroma BET for MALB-taint in Concord grape juice was 1.8 and 0.65 MALB/L Niagara grape juice. The specific sensory attributes of the grape juices influenced by the presence of MALB were then described. In Concord grape juice, trained panelists (n = 9) found significant increases in vegetal aroma and earthy flavor as MALB concentration increased from 0.45 to 7.2 MALB/L. In Niagara grape juice, with increasing MALB concentration, trained panelists (n = 8) indicated significant decreases in honey and sweetness with corresponding increases in sourness, astringency, and vegetal and earthy aromas and flavors (P < 0.05). For both aroma and flavor, consumer rejection studies were performed using paired preference comparisons of control juice to MALB-tainted grape juice. For Concord grape juice, consumers (n = 60) rejected the aroma of MALB-tainted juice at 1.8 MALB/L and the taste/flavor of the MALB-tainted juice at 3.6 MALB/L. For Niagara juice, consumers rejected the aroma of the juice at 3.6 MALB/L. This study demonstrated the presence of MALB negatively impacts the sensory properties of Concord and Niagara grape juice. Grape juice processors may use this research for quality control measures and for establishing tolerance limits. Practical Application: The Multicolored Asian Ladybeetle (MALB), initially used for biocontrol, has been shown in previous literature to impact the sensory properties of wines. The presence of MALB in grape juice is now becoming problematic; however, there is little research describing the specific sensory impacts of MALB on grape juice. This study examined the sensory impact of MALB on both Concord and Niagara grape juice. While the threshold and trained panel evaluations from this study provide valuable sensory profile information, grape juice processors may be particularly interested in the consumer rejection of MALB-tainted grape juice as they can use this research for quality control measures and for establishing tolerance limits.     

ROLE of CULTIVAR and PRESS AID IN PRESSING CHARACTERISTICS and JUICE YIELDS of CRUSHED GRAPES

The stress-volume characteristics of crushed grape cultivars: Baco Noir, Cabernet Sauvignon, Catawba, Cayuga White, Chardonnay, Concord, Delaware, Melody, Niagara, Johannisberg Riesling, and Seyval Blanc, with and without paper and rice hulls press aids were studied in an expression cell and an Instron Universal Testing Machine. the slopes of ln stress vs volume in compression were significantly (P< 0.001) dependent on the grape cultivar. Addition of 1–3% press aid by weight decreased the magnitudes of slopes by about 11% with Seyval Blanc to about 51% with Catawba; i. e., the ease with which pressing could be performed increased with the addition of press aid. With Cabernet Sauvignon grapes, addition of press aid 0.5, 1.0, and 2.0% resulted in increase in slopes ranging between 14.7 and 24.9%. the slopes of the ln stress-ln time during the relaxation portion of the experiment were also significantly dependent (P< 0.001) on the grape cultivar; the magnitudes of the slopes increased with the addition of 1–3% paper press aid. the juice yields were affected significantly (P< 0.001) by the addition of paper press aid, with maximum yields being obtained when 1–2% (w/w) paper press aid was added. As expected, juice yields (w/w%) were significantly dependent (P< 0.001) on grape cultivars.     

Effect of freezing grape berries and heating must samples on extraction of components and composition parameters of red wine grape varieties

Juices from grape samples subjected to two storage methods (fresh and frozen) and two post-homogenisation treatments (21^oC and 71^oC) were examined for extraction of grape berry components and compared to a microvinified wine made from the same lot of fresh grapes. Cabernet Franc ( Vitis vinifera ) and Cynthiana ( Vitis aestivalis ) grapes were evaluated in 2003. Cabernet Franc, Cabernet Sauvignon ( Vitis vinifera ), Chambourcin (interspecific hybrid) and Cynthiana grapes were evaluated in 2004. Fresh grapes from each variety were sampled, analysed and prepared for microvinification. Frozen grapes of all varieties were thawed and analysed at the same time. For all varieties in both years, heating the must of fresh or frozen grapes increased the titratable acidity (11–58%), tartaric acid levels (12–110%), potassium content (15–62%), darkness (31–97%), red colour (54–1517%) and total red pigment values (36–1171%) of juice as compared to the juice from unheated must. For all varieties in 2004, heating the must from fresh or frozen grapes increased total phenolics (43–619%) of juice as compared to the juice from unheated must. Compared to fresh grape processing, freezing the grapes and then processing at 21^oC or 71^oC had varying results (increases and decreases) regarding the extraction of components in all varieties and both years but usually provided juice with composition most similar to that of the red wine produced by microvinification. Although the degree of extraction of individual components in the juice is influenced by selection of grape storage and must processing procedures, consistency of handling and procedure provided consistent results with low variability.     

Response surface methodological study on HMF and fluorescent accumulation in red and white grape juices and concentrates

White and red grape juices and their concentrates were subjected to thermal treatments at different temperatures ranging from 50 to 70 °C at different times. 5-Hydroxymethylfurfural (5-HMF) and fluorescence relative index (FLRI) were measured. Response surface methodology (RSM) was applied to determine the effect of temperature and time on the HMF and FLRI formation at the different Brix (bx) degrees. An increase in temperature (from 50 to 70 °C) and time (from 12 to 192 h) for 15°, 45° and 65° Brix degrees was associated with an increase in HMF and FLRI development of white and red grape juices. HMF formation was higher in white grape juice and concentrates than in red ones. Optimum conditions were confirmed and these fitted the experimental data well. Thus, regression equations can be used to estimate HMF and FLRI values at various Brix degrees for white and red grape juices and concentrates.     

Detection of ochratoxin A in tropical wine and grape juice from Brazil

BACKGROUND: Ochratoxin A (OTA) is the main mycotoxin found in grapes, wines and grape juices and is considered one of the most harmful contaminants to human health. In this study, samples of tropical wines and grape juices from different grape varieties grown in Brazil were analysed for their OTA content by high‐performance liquid chromatography. RESULTS: The detection and quantification limits for OTA were 0.01 and 0.03 µg L^?1 respectively. OTA was detected in 13 (38.24%) of the samples analysed, with concentrations ranging from < 0.03 to 0.62 µg L^?1. OTA was not detected in any of the grape juice samples. Most of the red wine samples proved to be contaminated with OTA (75%), while only one white wine sample was contaminated. However, the OTA levels detected in all samples were well below the maximum tolerable limit (2 µg L^?1) in wine and grape juice established by the European Community and Brazilian legislature. CONCLUSION: The results of this study indicate a low risk of exposure to OTA by consumption of tropical wines and grape juices from Brazil. © 2012 Society of Chemical Industry     

Variation of linalool and geraniol content within two pairs of aromatic and non-aromatic grapevine clones

Backgrounds and Aims:  In order to assess the suitability of some genotypes for functional genomics studies on terpenol synthesis in grapevine, two pairs of cultivars differing in their aromatic pattern were compared: Gewurztraminer and Savagnin Rose and two clones of Chardonnay (76 and 809).
Methods and Results:  The genetic analysis based on microsatellite markers showed that Gewurztraminer and Savagnin Rose were clones derived from a single mother plant. The same result was found for Chardonnay clones 76 and 809. Analyses of wines, musts and berries showed that linalool and geraniol were present only at very low concentrations in Savagnin Rose and Chardonnay 76, both considered as non-aromatic cultivars. On the contrary, Gewurztraminer was characterised by a high geraniol content and Chardonnay 809 by a profile where linalool was predominant. Results obtained in the vineyard were consistent with data on fruiting cuttings in the greenhouse. Analyses of the terpenol content of berries from self-progenies plants of Gewurztraminer and Chardonnay 809 showed that this trait was heritable.
Conclusions:  We provide evidence that clonal variation, through somatic mutations, can modify the aromatic profile of fruits.
Significance of the Study:  We have characterised grapevine clones consistently differing in the terpenol content of both grapes and wines. Such plant material is appropriate for functional genomics studies.     

Effects of Maturity, Skin Contact and Carbonation on the Quality of Sterile-Filtered White Muscadine Grape Juice

The effects of grape maturity, skin contact and carbonation on the quality of sterile-filtered muscadine grape juice were investigated. A sensory panel preferred the late maturity juices that had a higher degree of muscadine character and lower total phenolics. Tartaric and malic acid levels decreased with increasing maturity, with malic decreasing to a greater extent. A 24 hr skin contact. at 2°C had no significant effect on sensory results, but increased color intensity, phenolic and organic acid levels as compared to immediate pressing. Carbonated juices were lighter in color and were preferred equally to non-carbonated juices. Juice obtained from a hard pressing regime had slightly higher levels of organic acids than free run juice at the early harvest only.     

Ochratoxin A in wine and grape juice sold in Canada.

Ochratoxin A (OTA) was determined in 251 samples of wines and grape juice collected over 3 years in Canada. In total, 25/84 samples of red wine, 22/96 samples of white wine, 3/46 red grape juices and 1/25 white grape juices contained OTA levels above the limit of quantitation (LOQ). Canadian wines, when compared with imported products, showed both a lower OTA occurrence, noted as positive (19 versus 48% above the limit of detection (LOD) for wines), and a lower level of OTA contamination (upper bound mean of 17.5 versus 163pg ml(-1) for wines). Wines from the USA contained no quantifiable levels of ochratoxin A. OTA was found in Canadian and US grape juice samples, with 12.9% above the LOD and an upper bound mean of 13.3pg ml(-1). It was extracted from a wine or grape juice sample by passing it through an immunoaffinity column. The sample matrix was washed off the column with water. OTA was eluted from the column with methanol and quantitatively determined by liquid chromatography using a fluorescence detector. The presence of OTA was confirmed by esterification with boron trifluoride-methanol. The LOQ of OTA was estimated as 20 pg ml(-1) in white wine (S/N 10:1) and 40 pg ml(-1) in red wine, white grape juice and red grape juice (S/N 20.1). The LOD was estimated as 4pgml(-1) for white wine and 8pgml(-1) for red wine and white and red grape juices (S/N 3:1).     

Method development and cultivar-related differences of nine biogenic amines in Ontario wines

We have developed a new high-performance liquid chromatographic method using pre-column derivatization with orthophthalaldehyde, gradient elution and fluorescence detection to assay the concentrations of nine biogenic amines in wines: histamine, 1-methylhistamine, methylamine, ethylamine, tyramine, tryptamine, 2-phenylethylamine, putrescine and cadaverine. The method shows excellent analytical characteristics. It has been used to measure the concentration of these biogenic amines in 73 monovarietal wines from five red and six white cultivars. All wines were from the Niagara viticultural region of southern Ontario and were certified as to origin. Pinot noir wines had the highest content of total amines, and also of histamine, putrescine, cadaverine, ethylamine and 1-methylhistamine. Among the white wines, those from Chardonnay had the highest content of total amines and also of histamine, tyramine, methylamine and 1-methylhistamine. It is suggested that longer ageing as well as Sur-lie fermentation (Chardonnay) can account, at least in part, for these findings.     

Optimisation of the Amido Black assay for determination of the protein content of grape juices and wines

While the heat/chill stability of white wines cannot be predicted from the total protein concentration, this information is useful in assessing the effectiveness of fining treatments. We have adapted the Amido Black assay for use in grape juice and wine. The response of bovine serum albumin (BSA) was similar in water, model wine and model juice. The linear range of the assay (<100 mg l^?1) extends beyond protein concentrations typically found in grape juices and wines. The limit of quantification was 11.1 mg l^?1 for BSA in model wine and 7.6 mg l^?1 in model juice, while the limit of detection was found to be less than 3 mg l^?1 in either solution. In contrast to other methods of protein determination, this assay is not affected by common wine phenolic and pectic compounds or by glutathione. The mean response of BSA was similar in model juice and red and white grape juices. The mean response of BSA in red wine was lower than in white wine and model wine (p < 0.001), and there was considerable variation in response among wines. Protein concentrations determined using this method were reproducible (CV < 10%). This optimised assay can be used to monitor protein levels in grape juices and wines. © 2001 Society of Chemical Industry