首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 31 毫秒
1.
Polyphenol levels in wines are affected by the wine-making process. Resveratrol is one polyphenol which has been the subject of a commendable amount of recent research. In this work, we found that resveratrol is immediately degraded by tyrosinase. A novel tyrosinase was purified from Carignan grapes. The purification process included salting out and separation on a cation-exchange column, followed by gel filtration. Tyrosinase was purified in a homogeneous form by SDS-PAGE and was characterized: its specific activity toward 3-(3,4-dihydroxyphenyl)-L-alanine (DOPA) increased by a factor of 24 with an overall recovery of 3% of initial activity. The apparent molecular mass of the purified tyrosinase was 40 kDa as determined by SDS-PAGE, and 42 kDa as determined by gel filtration. Its activity was optimal at pH 6 and at 25 degrees C. The enzyme exhibited high activity toward phenylenediamine, epicatechin, pyrogallol, DOPA, and resveratrol. Tyrosinase activity was inhibited by KCN, thiourea, and SO(2). Resveratrol levels were stable following the removal of proteins from the juice, suggesting that early spraying of grapes with SO(2) is an important factor affecting the final amount of resveratrol in wine.  相似文献   

2.
Resveratrol is a stilbene phytoalexin well-known for its presence in grape, wine, and peanut. As a result of its antioxidant and chemopreventative properties, it has gained much attention as a functional food ingredient. A gas chromatography-mass spectrometry method for the detection of resveratrol, its 3-glucopyranoside piceid, and the cis isomers of both compounds has been developed and used to quantitate the levels of these compounds in the skin of commercially available tomato fruit (Lycopersicon esculentum Mill.). The resveratrol concentration remains relatively stable during fruit maturation, reaching a maximum concentration in the skin of 18.4 +/- 1.6 microg/g dry weight at 4 weeks postbreaker. No stilbenes were detected in the flesh of tomato fruit.  相似文献   

3.
A modeling method for the induction of resveratrol synthesis by UV irradiation pulses in Napoleon table grapes is proposed. The method is based on the combination of four main parameters: irradiation power (IW), irradiation time (IT), irradiation distance (ID), and number of elapsed days to achieve the highest resveratrol accumulation (D(m)). Maximum resveratrol content (11-fold higher than untreated grapes) was achieved using the combination: IW = 510 W, IT = 30 s, ID = 40 cm, and D(m) = 3 days. Sensory characteristics and main features of irradiated grapes (color, weight, firmness, flavor, size, ripening index and vitamin C content) remained unaltered after 1 week of storage. UV induction signal migrated to the hidden side of the grape skin with a delay of 3 days as compared to the directly irradiated side. Phenolic compounds were not detected in Napoleon grape flesh. Resveratrol content per standard serving (200 g) of irradiated grape was about 3 mg, an amount more than 10-fold higher than that of untreated Napoleon grapes. This means that a serving of irradiated grape (unpeeled) could supply the resveratrol content equivalent to 3 glasses of a red wine with high resveratrol content ( approximately 1 mg/glass). Therefore, controlled UV irradiation pulses are useful as a simple postharvest treatment (and alternative to genetic engineering) to obtain possible "functional" grapes (with enhanced health-promoting properties) as a dietary source of high resveratrol content.  相似文献   

4.
Piceid, the major resveratrol derivative in grape juices   总被引：6，自引：0，他引：6  
The levels of trans-piceid, cis-piceid, trans-resveratrol, and cis-resveratrol have been measured in 36 grape juices using an HPLC system with spectral analysis of eluting peaks. The piceid (glucosides) were the major component in the grape juices. In red grape juices the average concentrations were 3.38 mg/L for trans-piceid, 0.79 mg/L for cis-piceid, 0.50 mg/L for trans-resveratrol, and 0.06 mg/L for cis-resveratrol. In white grape juices the levels were, on average, 0.18 mg/L for trans-piceid, 0.26 mg/L for cis-piceid, and 0.05 mg/L for trans-resveratrol, and cis-resveratrol was not detected in any sample. Levels of total resveratrol (trans- and cis-resveratrol and -piceid) found in red and in white grape juices are similar to those described in Spanish red and white wines. Due to their resveratrol content, as well as other phenolics, grape juices may have a beneficial health effect of interest to those who cannot drink wine.  相似文献   

5.
In the skin of cv. Napoleon table grapes, the anthocyanins malvidin 3-glucoside (and its acetyl and p-coumaroyl derivatives), cyanidin 3-glucoside, peonidin 3-glucoside, cyanidin 3-glucoside, petunidin 3-glucoside, and delphinidin 3-glucoside were identified by HPLC-DAD-MS. In addition, quercetin 3-glucoside and 3-glucuronide, caffeoyltartaric, piceid, and resveratrol were also detected. The content of most phenolics remained quite constant during postharvest refrigerated storage (10 days at 0 degrees C) while the resveratrol derivatives increased 2-fold. Postharvest treatments of grapes with UVC and UVB light induced a large increase in resveratrol derivatives (3- and 2-fold, respectively). This means that a serving of mature Napoleon grapes (200 g) provides approximately 1 mg of resveratrol, which is in the range of the amount supplied by a glass of red wine. This can be increased to 2 or 3 mg of resveratrol per serving in grapes that have been irradiated with UVB or UVC, respectively. These results show that refrigerated storage and UV irradiation of table grapes can be beneficial in terms of increasing the content of potentially health-promoting phenolics.  相似文献   

6.
Resveratrol in the fruits of bilberry (Vaccinium myrtillus L.), the lowbush "wild" blueberry (Vaccinium angustifolium Aiton), the rabbiteye blueberry (Vaccinium ashei Reade), and the highbush blueberry (Vaccinium corymbosum L.) were measured using a new assay based on high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS). The LC-MS/MS assay provided lower limits of detection than previous methods for resveratrol measurement, 90 fmol of trans-resveratrol injected on-column, and a linear standard curve spanning >3 orders of magnitude. The recoveries of resveratrol from blueberries spiked with 1.8, 3.6, or 36 ng/g were 91.5 +/- 4.5, 95.6 +/- 6.5, and 88.0 +/- 3.6%, respectively. trans-Resveratrol but not cis-resveratrol was detected in both blueberry and bilberry samples. The highest levels of trans-resvertatrol in these specimens were 140.0 +/- 29.9 pmol/g in highbush blueberries from Michigan and 71.0 +/- 15.0 pmol/g in bilberries from Poland. However, considerable regional variation was observed; highbush blueberries from British Columbia contained no detectable resveratrol. Because blueberries and bilberries are often consumed after cooking, the effect of baking on resveratrol content was investigated. After 18 min of heating at 190 degrees C, between 17 and 46% of the resveratrol had degraded in the various Vaccinium species. Therefore, the resveratrol content of baked or heat-processed blueberries or bilberries should be expected to be lower than in the raw fruit. Although blueberries and bilberries were found to contain resveratrol, the level of this chemoprotective compound in these fruits was <10% that reported for grapes. Furthermore, cooking or heat processing of these berries will contribute to the degradation of resveratrol.  相似文献   

7.
以山西吕梁山南部乡宁县为代表,基于乡宁站1972?2015年的气象观测资料、乡宁戎子酒庄有限公司2009?2015年的酿酒葡萄实验观测数据,运用数理统计和相关分析等方法,分析乡宁地区酿酒葡萄种植的光、热、水等气候条件,并通过葡萄生长季的温度、降水、日照、光热系数以及成熟期的水热系数等指标,评价乡宁地区酿酒葡萄种植的气候适宜性,揭示吕梁山南部地区发展酿酒葡萄生产的气候优势。结果表明：（1）乡宁地区年无霜期平均为202.8d,≥10℃积温平均为3498.0℃·d,最冷月低温均值?4.4℃,极端最低气温?21.6℃,气候条件十分优越,适宜酿酒葡萄种植。（2）20世纪90年代以前,葡萄生长季积温少,可种植中、早熟酿酒葡萄品种,随着气候变暖,90年代以后,积温大幅增加,满足了种植晚熟酿酒葡萄品种的热量条件。（3）葡萄生长季光、温、水资源及其在关键发育时段的分布特征总体有利于葡萄生长发育和优质品质的形成,但4月中旬葡萄萌芽期霜冻概率为22.7%,存在低温灾害风险,夏季无38℃以上高温天气,7、8月个别年份降水偏多,易出现连阴雨天气,对葡萄糖度造成一定影响。（4）相关分析表明,葡萄糖度与葡萄成熟期光、热因子呈正相关,与水分因子呈负相关,成熟期湿度对葡萄糖度影响极显著。葡萄成熟前一个月（9月）平均气温21.9℃,降水量74.4mm,日照时数6.7h,气温日较差为10.6℃,水热系数为1.5,温度条件优越、日照充足、早晚温差大、降水少,具有优质酿酒葡萄生长的气候环境。种植试验表明,乡宁县葡萄含糖量达到酿造高品质葡萄酒的标准,具有经济栽培的价值。  相似文献   

8.
Resveratrol is a phytoalexin produced in different unrelated plant species such as grapevine and peanut. The effect of resveratrol and its glucoside trans-resveratrol-3-O-beta-D-glycopyranosid (piceid) against Venturia inaequalis, the causal agent of apple scab, was evaluated using a newly established test based on enzymatically isolated cuticular membranes (CMs) from apple (Malus domestica Borkh.) leaves. The test substances resveratrol and piceid were either sorbed to CMs before inoculation with spores or were applied simultaneously with the Venturia inaequalis spores to the CMs, and their effect on germination, appressoria formation, and penetration was examined. Resveratrol had no influence on spore germination but a significant inhibiting effect on penetration when applied simultaneously as well as before. A percentage inhibition of 89.7 +/- 11.5 and 61.8 +/- 35.1 was observed for simultaneous and preapplication, respectively. The resveratrol glucoside piceid had a significant inhibitory effect on germination and completely inhibited penetration of the fungus at concentrations between 200 and 400 microg mL(-1) when applied simultaneously with the spores to the CMs. On piceid-enriched CM (preapplication), spores germinated but penetration was inhibited nearly completely (96.1 +/- 5.1%). Thus, in vitro experiments showed that resveratrol and its glucoside in fact could contribute to improving the pathogen resistance of apple leaves.  相似文献   

9.
Because of the health implications of resveratrol and piceid, which are widely present in foods, we focused our attention on the development of a highly efficient methodology for their characterization and measurement. On the basis of our experience in capillary electrophoresis for separation of polyphenolic compounds, we developed a general analytical method for piceid identification which was also applicable to complex natural mixtures such as red wine. In view of its very limited availability from natural sources, we first directed our attention to the development of a synthetic route suitable to produce an adequate amount of polydatin (piceid or resveratrol 3-O-beta-D-glucopyranoside). The latter was synthesized by a new one-step procedure which afforded the expected product in a good yield. The studied compounds were also investigated for their stability to UV irradiation.  相似文献   

10.
Dissipation of the fungicide spiroxamine in grapes of two vine varieties, Roditis and Cabernet Sauvignon, exposed to field treatments was evaluated. Vines of a grape vineyard located in central Greece were sprayed once or twice with a commercial formulation of the fungicide at 30 g a.i./hL. Residues in grapes, must, and wine were determined by gas chromatography/IT-MS after extraction with cyclohexane-dichloromethane (9:1), with a limit of quantitation 0.02 mg/kg in grapes and 0.012 mg/kg in wine. Under field conditions, spiroxamine dissipation on grapes was faster during the first 2 weeks and then slower to the sixth week. About 7 days after application, half of the initial spiroxamine concentration remained on the grapes; the respective proportion at 42 days was about 10%. At 14 and 35 days, residues were lower than 0.44 and 0.22 mg/kg, respectively, values below the maximum residue levels set by the European Union (1 mg/kg). Spiroxamine residues transferred from grapes into the must and through the vinification process into the wine were also studied. Mean transfer factors of 0.26 and 0.55 were found from grapes into wine for the wines obtained without maceration and with maceration, respectively. Residues in wine, prepared from grapes with a spiroxamine content of 0.11-0.20 mg/kg, varied from <0.026 to 0.09 mg/kg. Spiroxamine diastereomer B was found to dissipate slower than diastereomer A in the field as well as during the vinification process.  相似文献   

11.
Knowledge about the relation between grape and wine phenolics is of key interest for the wine industry with respect to being able to predict wine quality from analyses of grapes. Prediction of the phenolic composition and color of experimentally produced red wines from the detailed phenolic composition of the corresponding grapes was investigated using a multivariate approach. Grape extracts and wines were produced from 55 different grape samples, covering 8 different Vitis vinifera cultivars: Alicante, Merlot, Syrah, Cinsault, Grenache, Carignan, Cabernet Sauvignon, and Mourvedre. The phenolic composition of the grapes and wines showed that the average ratios between wine and grape phenolics ranged from 0.25 to 7.9 for the different phenolic compounds. Most interestingly, the average ratios were low for anthocyanins (0.31) and tannins (0.32), intermediate for (+)-catechin (0.75) and polymeric pigments (0.98), and high for gallic acid (7.9). Individual wine phenolics in general correlated well with several grape phenolics, indicating that a multivariate approach might be advantageous for prediction of wine phenolics from grape phenolics analysis. However the use of multivariate prediction of individual wine phenolics from the complete grape phenolic composition only improved the prediction of wine polymeric pigments, whereas wine anthocyanins were predicted with the same precision as from the direct relation with grape anthocyanins. Prediction of color attributes of pH normalized experimental wines from the phenolic profiles of grapes was accomplished using a multivariate approach. The correlation between predicted and measured total wine color was high ( r = 0.958) but was very similar to the correlation coefficient obtained for the direct relation between grape anthocyanins and total wine color ( r = 0.961). Color due to copigmentation, color due to anthocyanins, and color intensity were also predicted well.  相似文献   

12.
Proline is typically the most abundant amino acid present in grape juice and wine. The amount present is influenced by viticultural and winemaking factors and can be of diagnostic importance. A method for rapid routine quantitation of proline would therefore be of benefit for wine researchers and the industry in general. Colorimetric determination utilizing isatin as a derivatizing agent has previously been applied to plant extracts, biological fluids, and protein hydrolysates. In the current study, this method has been successfully adapted to grape juice and wine and proved to be sensitive to milligram per liter amounts of proline. At sugar concentrations above 60 g/L, interference from the isatin-proline reaction was observed, such that proline concentrations were considerably underestimated in grape juice and dessert wine. However, the method was robust for the analysis of fermentation samples and table wines. Results were within ±10% agreement with data generated from typical HPLC-based analyses. The isatin method is therefore considered suitable for the routine analysis required to support research into the utilization or release of proline by yeast during fermentation.  相似文献   

13.
为深入研究酿酒葡萄果-蒂振动分离特性,寻求影响分离效果因素的最优组合,该文基于酿酒葡萄做变速运动产生惯性力克服葡萄果-蒂连接力实现分离的原理,搭建了曲柄摇杆机构分离率测定装置。通过对曲柄摇杆机构运动及果-蒂分离临界条件的分析,构建了果-蒂振动分离模型,确定电机转速、偏心距离及摇杆长度为主要影响因素,并针对霞多丽和赤霞珠品种开展试验研究。结果表明:影响酿酒葡萄分离率显著因子的主次顺序为偏心距离、摇杆长度和电机转速;赤霞珠品种较霞多丽品种更适合机械采收;当转速为245 r/min,偏心距离为75 mm,摇杆长度为200 mm时,赤霞珠分离率为95.2%,葡萄果-蒂分离的频率范围为2.11~3.69 Hz,葡萄穗梗处的振幅为169.8 mm。该文研究结果可为酿酒葡萄收获装置的设计提供理论依据。  相似文献   

14.
Four vineyards from the eastern foot of Helan Mountain within the same climate classification, where the planted grapes were 4-year-old Cabernet Sauvignon, were selected for investigating the difference in grape and wine properties. Results showed that the grapes of Lilan vineyard had a higher sugar content and sugar–acid ratio than Huida, Yuquan and Zhihuiyuanshi vineyards. The grapes of Zhihuiyuanshi vineyard had the highest tannin and total phenols content. Concerning the wines, the wine of Yuquan vineyard had low pH but had a great ageing potential, and wine of Zhihuiyuanshi vineyard had highest tone, chroma, tannins, total phenols and alcohol content than other vineyards. Soil pH was positively correlated with anthocyanins in the grapes and negatively correlated with total acid in wine. The microbial biomass carbon (MBC) was correlated with the anthocyanins in grape. Microbial biomass nitrogen (MBN) was positively correlated with soluble solid in grapes, and positively correlated with tannin and total phenols in the wine. The MBC/MBN ratio was negatively correlated with tone in the wine. Our findings indicate that adjusting soil pH and choosing microbial fertiliser with high soil microbial carbon and nitrogen nutrients are effective ways to improve the quality of regional grapes and wine.  相似文献   

15.
A simple method for the quantitative extraction of resveratrol and its glycosides from grape berry skins has been developed. Optimal conditions for the extraction were investigated. Type of solvent, time, and temperature assayed influenced resveratrol and piceid yield. Adequate extraction was attained with ethanol/water (80:20 v/v) maintained at 60 degrees C for 30 min. Recovery (>96%) and reproducibility (6.83-15.13%) were satisfactory. After extraction, resveratrol and piceid isomers were quantified by high-performance liquid chromatography coupled to a ultraviolet-visible diode array detector. The amounts detected in 13 samples of 7 different varieties analyzed were, on average, 92.33 microg/g of dry skin for cis-piceid, 42.19 microg/g of dry skin for trans-piceid, and 24.06 microg/g of dry skin for trans-resveratrol. cis-Resveratrol was not detected in any sample. In grape berries infected by powdery mildew the contentw of these compounds were considerably increased and the degree of infection was positively related to their stilbene content.  相似文献   

16.
Postharvest treatment of seedless white table grapes (var. 'Superior') with different gas ozone concentrations (3.88 and 1.67 g/h) for 1, 3, and 5 h induced an increase in stilbenoid biosynthesis [trans-resveratrol, piceatannol, and viniferinas (resveratrol dehydrodimers and dehydrotrimers)] during storage at 22 degrees C and 95% relative humidity. The maximal resveratrol concentration was reached after 2 days of storage, and this amount was similar to that induced by optimized UV-C treatments (1 min, 510 W, 40 cm). Although similar resveratrol concentrations accumulated in grapes after both UV-C and O3 treatments (maximum ozone production and time), the ozone treatment was more efficient in inducing viniferins accumulation in grape berries. A sequence in the biosynthesis of stilbenoids was observed, starting with the resveratrol monomer, continuing with the resveratrol dehydrodimers epsilon-viniferin and delta-viniferin, and ending with four different resveratrol dehydrotrimers. These trimers were different from alpha-viniferin, a trimer previously reported to be induced in grapes after biotic and abiotic stresses. Two alpha-viniferin isomers were also detected in the ozone-treated grapes, although at very low concentrations that prevented their quantification.  相似文献   

17.
Extractable amounts of resveratrol in berry skins and seeds were studied in 120 grape (Vitis) germplasm cultivars during two consecutive years to determine the distribution of resveratrol among the main grape genotypes. Interspecific rootstock cultivars had much higher extractable amounts of resveratrol in skin and seed than all other grape genotypes studied in both years. Extremely high extractable amounts of resveratrol in berry skins [>100 microg g(-1) of skin fresh weight (FW)] and seeds (>20 microg g(-1) of seed FW) were observed on two rootstock cultivars obtained from hybrids of V. monticula x V. riparia. Extractable amounts of resveratrol in berries of rootstock cultivars that are the descendants of V. riparia were also very high. The cultivated European type (V. vinifera) cultivars and their hybrids with V. labrusca had relatively low levels of extractable resveratrol in berry skin and seed, and the extractable amounts of resveratrol in berry skin and seeds were, with a few exceptions, <2 microg g(-1) of skin or seed FW. Extractable amounts of resveratrol in berry skin and seeds were closely related with fruit traits or purpose of uses and climate. Significantly higher extractable amounts of resveratrol in berry skin were found in seeded cultivars than in seedless ones, in both berry skin and seeds in winemaking grapes than in table grapes, and in red grapes than in green ones. Moreover, rainfall during fruit development resulted in higher extractable amounts of resveratrol in berry skin, whereas resveratrol synthesis and accumulation in grape seeds were not related to climate change.  相似文献   

18.
Occurrence of resveratrol in edible peanuts   总被引：11，自引：0，他引：11  
Resveratrol has been associated with reduced cardiovascular disease and reduced cancer risk. This phytoalexin has been reported in a number of plant species, including grapes, and may be one of the compounds responsible for the health benefits of red wine. Analytical methods for measuring resveratrol in wine and peanuts were adapted to isolate, identify, and quantify resveratrol in several cultivars of peanuts. Aqueous ethanol (80% v/v) extracts from peanuts without seed coats were purified over alumina/silica gel columns and analyzed by reversed phase HPLC using a C-18 column. Peanuts from each market type, Virginia, runner, and Spanish, produced in four different locations contained from 0.03 to 0.14 microg of resveratrol/g. Seed coats from runner and Virginia types contained approximately 0.65 microg/g of seed coat, which is equivalent to <0.04 microg/seed. Quantitative analysis of 15 cultivars representing 3 peanut market types, which had been cold stored for up to 3 years, indicated a range of 0.02-1.79 microg/g of peanut compared to 0.6-8.0 microg/mL in red wines.  相似文献   

19.
Captan and its metabolite tetrahydrophthalimide (THPI) were determined in grapes, must, and wine by GC-ITMS. Pesticides were extracted with acetone/petroleum ether (50:50 v/v). Because of the high selectivity of the ITMS detector, no interferent was found and cleanup was not necessary. Recoveries from fortified grapes, must, and wines ranged between 90 and 113% with a maximum coefficient of variation of 11%. Limits of quantitation were 0.01 mg/kg for both compounds. In model systems, captan and its metabolites, THPI, cis-4-cyclohexene-1,2-dicarboxylic acid, and 1,2,3,6-tetrahydrophthalamic acid, were determined by HPLC. The degradation of captan during winemaking was studied. Captan degraded in must, giving 100% THPI, and at the end of fermentation, only THPI was found in wine. The degradation of captan to THPI was due to the acidity in must and wine. This metabolite was present at low levels on grapes, and, unlike captan, it had no negative effect on the fermentative process. Model systems showed that the mechanism of disappearance of captan in grapes was due to photodegradation and codistillation.  相似文献   

20.
Dietary resveratrol (3,4',5-trihydroxystilbene) has been implicated in the health benefits associated with grapes and red wine, more specifically with potential benefits for metabolic syndrome, energy use, and increased endurance. Levels of trans-resveratrol and its glucoside, trans-piceid, were determined in 19 top selling commercially available cocoa-containing and chocolate products from the U.S. market. Amounts of trans-resveratrol and trans-piceid were closely correlated with the amount of nonfat cocoa solids (NFCS) in the cocoa-containing products. Among these products, trans-resveratrol levels were highest in cocoa powders (1.85 +/- 0.43 microg/g), followed by unsweetened baking chocolates (1.24 +/- 0.22), semisweet chocolate baking chips (0.52 +/- 0.14), dark chocolates (0.35 +/- 0.08), milk chocolates (0.10 +/- 0.05), and chocolate syrups (0.09 +/- 0.02). These cocoa-containing and chocolate products have about 3-5 times more trans-piceid than trans-resveratrol. Levels of trans-piceid were highest in the cocoa powders (7.14 +/- 0.80 microg/g), followed by unsweetened baking chocolates (4.04 +/- 0.14), semisweet chocolate baking chips (2.01 +/- 0.18), dark chocolates (1.82 +/- 0.36), milk chocolates (0.44 +/- 0.06), and chocolate syrups (0.35 +/- 0.06). On an equal weight basis, cocoa powder had about half as much trans-resveratrol as the average California red wine. On a per serving basis, cocoa-containing and chocolate products had less trans-resveratrol than red wine and grape juice but more than roasted peanuts. Overall, these cocoa-containing and chocolate products rank second after red wines and grape juice in foods with the highest levels of total trans-resveratrol in the diet.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号