Ochratoxin A: an improvement clean-up and HPLC method used to investigate wine and grape juice on the Polish market.

A routine method appropriate for the determination of ochratoxin A (OTA) in wine, grape juice and grape juice drinks was described, and the occurrence of the mycotoxin was investigated in the most popular red wines, grape juice and grape juice drinks available on the Polish market. After clean-up on immunoaffinity column, samples were analysed by RP-HPLC using a fluorescence detector at 330 and 460 nm. The average OTA recoveries from spiked blank wine samples varied from 60 to 82%, and RSD% ranged from 5 to 14%. The OTA recovery for spiked grape juice and grape juice drinks were 80-100%, but the RSD% was between 7 and 10%. The limit of detection and limit of quantitation for all sample types were 0.5 and 2.0 ng l(-1), respectively. Fifty-three samples of red wine and seven samples of grape juice and grape drinks were assessed by means of this analytical procedure. OTA was detected in most wine samples (92%); its concentrations ranged from 2.2 to 6710 ng l(-1). In all grape juice and drink samples, OTA levels ranged from 1.6 to 64.7 ng l(-1).     

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     

Occurrence of ochratoxin A in wine and grape juice marketed in Rio de Janeiro, Brazil.

Ochratoxin A (OA) is receiving attention world-wide because of the hazard it poses to human health. The aim was to test the distribution of OA in grape juice, pulps of frozen grapes, and national and imported table wine obtained from markets in Rio de Janeiro, Brazil. Analytical methodology using immunoaffinity column for OA extraction and clean-up with a final separation on a reversed-phase (C(18)) column and fluorescence detection in high-performance liquid chromatography showed a detection limit of 21 ng l(-1). The mean recovery was 91% for red wines and 82% for white wines; while the mean recoveries for juices and pulps of frozen grapes were 91.6 and 88%, respectively. Of 64 samples of grape juice and frozen pulps, 25% were positive for OA, being the mean content of 37 ng l(-1) with a maximum concentration of 100 ng l(-1). In wines, the mean concentration detected in 80 samples analysed was 34.4 ng l(-1) with 28.75% of positive samples. Red wines showed the highest percentages and levels of contaminated samples: 38% and 37 ng l(-1), respectively. The white wine contained levels above 26 ng l(-1) in 17.75% of the analysed samples. The levels of contamination detected in red wine sold in Río de Janeiro were not enough to surpass the virtually safe dose established as 5 n g kg(-1) body weight of daily intake.     

Detoxification of Ochratoxin A by pulsed light in grape juice and evaluation of its degradation products and safety

Pulsed light (PL) was used to remove Ochratoxin A (OTA) from clear grape juice in this study. Firstly, the factors of OTA degraded by PL were explored, and the OTA degradation rate was 95.29% after optimization by response surface methodology. Dose-response curves were most suitable for kinetic fitting of OTA degradation by PL treatment (R² = 0.9937). Besides, results showed that pH value, soluble solids content and total organic acid content did not change significantly, little changes in color difference (ΔE < 3), while the content of monomer phenol decreased (12.81%–30.95%) with increased PL application time. The contents of alcohols, esters and aldehydes significantly decreased in aroma components, while the contents of ketones and acids significantly increased, alkanes were not affected. Results of animal experiments showed that PL treatment greatly alleviated the toxic effects of high dose OTA on mice. LC-MS/MS also showed that OTA produced non-toxic OTα and phenylalanine when treated with PL.     

Mousy off-flavour production in grape juice and wine by Dekkera and Brettanomyces yeasts

The ability of four known species of Dekkera and Brettanomyces yeasts to produce mousy off-flavour in grape juice and wine was investigated for the first time. Using a sensory assessment technique the twelve type strains of Dekkera and Brettanomyces , representing four species, were found to grow and to be capable of producing mousy off-flavour in a grape juice medium; however, differences between strains were apparent. Four strains representing the two species of Dekkera (D. bruxellensis and D. anomala ) known to be associated with the spoilage of wine and other fermented beverages were further investigated for mousy off-flavour production in a red and white wine supplemented with nutrients. D. anomala and only one of the three D. bruxellensis strains tested grew in both wines and generally produced a moderate level of off-flavour, whereas the remaining two strains of D. bruxellensis , despite slowly losing viability (10- to 100-fold) over the 52–55 day period, produced detectable off-flavour. This work demonstrates the general ability of Dekkera and Brettanomyces yeasts to produce mousy off-flavour and confirms the importance of these yeasts for off-flavour production in grape juice and wine.     

Ochratoxin A in grape pekmez (grape molasses) consumed in Turkey

In this study, ochratoxin A (OTA) in 55 home-made, 20 commercial and 7 organic grape pekmez (grape molasses) produced in Turkey was investigated. OTA was detected in 73% of home-made pekmez samples, in 35% of commercial pekmez samples and in 71% of organic pekmez samples. Eleven per cent of the samples had OTA levels higher than 10 µg/l. The highest OTA level (31 µg/l) was detected in organic pekmez. The maximum OTA levels were 15 µg/l and 12 µg/l in home-made and commercial pekmez samples, respectively. Mean OTA levels were 3.5 µg/l, 1.4 µg/l and 9.2 µg/l in home-made, commercial and organic pekmez samples, respectively. Organic pekmez samples and home-made pekmez samples had higher OTA contamination than commercial pekmez samples. Results confirm OTA contamination in grape pekmez samples, indicating that the OTA level in grape pekmez could be a potential risk for consumers.     

Ochratoxin A in cocoa and chocolate sampled in Canada

In order to determine the levels of ochratoxin A (OTA) in cocoa and cocoa products available in Canada, a previously published analytical method, with minor modifications to the extraction and immunoaffinity clean-up and inclusion of an evaporation step, was initially used (Method I). To improve the low method recoveries (46-61%), 40% methanol was then included in the aqueous sodium bicarbonate extraction solvent (pH 7.8) (Method II). Clean-up was on an Ochratest? immunoaffinity column and OTA was determined by liquid chromatography (LC) with fluorescence detection. Recoveries of OTA from spiked cocoa powder (0.5 and 5 ng g(-1)) were 75-84%; while recoveries from chocolate were 93-94%. The optimized method was sensitive (limit of quantification (LOQ) = 0.07-0.08 ng g(-1)), accurate (recovery = 75-94%) and precise (coefficient of variation (CV) < 5%). It is applicable to cocoa and chocolate. Analysis of 32 samples of cocoa powder (16 alkalized and 16 natural) for OTA showed an incidence of 100%, with concentrations ranging from 0.25 to 7.8 ng g(-1); in six samples the OTA level exceeded 2 ng g(-1), the previously considered European Union limit for cocoa. The frequency of detection of OTA in 28 chocolate samples (21 dark or baking chocolate and seven milk chocolate) was also 100% with concentrations ranging from 0.05 to 1.4 ng g(-1); one sample had a level higher than the previously considered European Union limit for chocolate (1 ng g(-1)).     

Gas chromatographic determination of diethylene glycol in wine, grape juice and grape-juice concentrates

A gas chromatographic method for the quantitative determination of diethylene glycol in wine, red and white grape juice, and red and white grape juice concentrates is described. The method includes continuous extraction of the diethylene glycol with ethyl acetate by the aid of a rotation perforator. Using the new generation of chemically bonded stationary phases on fused silica together with an appropriate modern cold on-column injection system coupled with an autoanalyzer and a retention gap, the GLC analysis is shown to provide adequate information for quality control purposes. Linearity, precision and recovery with the described procedure were investigated. The precision of the method was studied using a sample containing approximately 65 mg/l diethylene glycol. Twelve separate determinations were performed by the described method; the coefficient of variation was 3.9%. The detection limit of our method is 5 mg/l diethylene glycol both for wine, grape juice and grape juice concentrates. Recovery data are based on wine, grape juice and grape juice concentrates fortified with diethylene glycol at different levels. The ranges of concentration used in this study were 10 mg/l to 10 g/l for wine and 10 mg/l to 100 mg/l for grape juice and grape juice concentrate. The average recovery of diethylene glycol for wine at all concentrations tested was 98.8%; coefficients of variation were between 1.6 and 8.0%. Recoveries of diethylene glycol added to grape juice at the level of 10 mg/l to 100 mg/l were 96% to 109%.     

Ochratoxin A in wines,musts and grape juices from Spain

A survey on the occurrence of ochratoxin A (OTA) in 240 grape‐based beverages was carried out. Red and white wines from four different Spanish Designations of Origin (n = 160), musts (n = 20), grape juices (n = 10), ordinary wines (n = 20), special wines (Malaga, muscatel, sherry, vermouth, etc) (n = 20) and sparkling wines (n = 10) were assayed for OTA content using immunoaffinity column clean‐up and high‐performance liquid chromatography with fluorimetric detection (detection limit 0.05 µg l^?1). Forty‐three (17.9%) of the samples tested contained detectable levels of OTA. The overall mean OTA concentration in red and white wines of Designations of Origin was 0.30 and 0.18 µg l^?1 respectively (ranges 0.05–3.19 and 0.05–1.13 µg l^?1 respectively). The percentage of wine samples with detectable amounts of OTA was higher for red (18.3%) than for white (10%) wines. OTA was also found in two of 10 red ordinary wines (0.68 and 4.24 µg l^?1), whereas none of 10 white ordinary wines contained OTA. The mean OTA amount detected in sparkling wines was 0.44 µg l^?1 (range 0.14–0.71 µg l^?1). Two of 20 must samples contained OTA at low levels (0.08 and 0.18 µg l^?1), while none of 10 grape juice samples contained OTA. Highest amounts of OTA were found in special wines (45%), with a maximum of 15.25 µg l^?1 in a muscatel sample. Copyright © 2004 Society of Chemical Industry     

果胶酶提高葡萄出汁率及色泽的影响

研究用果胶酶提高葡萄出汁率的方法及果胶酶对葡萄汁色泽的影响.通过单因素与正交试验分析酶添加量、酶解温度和酶解时间对葡萄出汁率的影响,结果表明：最佳工艺条件为：果胶酶用量0.1 mL/kg,酶解温度55℃,酶解时间50 min.     

The metabolic fate of red wine and grape juice polyphenols in humans assessed by metabolomics

The metabolic impact of polyphenol‐rich red wine and grape juice consumption in humans was studied using a metabolomics approach. Fifty‐eight men and women participated in a placebo‐controlled, double‐crossover study in which they consumed during a period of 4 wk, either a polyphenol‐rich 2:1 dry mix of red wine and red grape juice extracts (MIX) or only a grape juice extract (GJX). Twenty‐four‐hour urine samples were collected after each intervention. ¹H NMR spectroscopy was applied for global metabolite profiling, while GC‐MS was used for focused profiling of urinary phenolic acids. Urine metabolic profiles after intake of both polyphenol‐rich extracts were significantly differentiated from placebo using multilevel partial least squares discriminant analysis. A significant 35% increase in hippuric acid excretion (p<0.001) in urine was measured after the MIX consumption as) or only a red grape juice dry extract (GJX). 24‐h urine samples were collected after each intervention. 1H‐NMR spectroscopy was applied for global metabolite profiling, while gas chromatography‐mass spectrometry (GC‐MS) was used for focused profiling of urinary phenolic acids. Urine metabolic profiles after intake of both polyphenol‐rich extracts were significantly differentiated from placebo using multilevel partial least squares discriminant analysis (ML‐PLS‐DA). A significant 35% increase in hippuric acid excretion (p<0.001) in urine was measured after the MIX consumption compared with placebo, whereas no change was found after GJX consumption. GC‐MS‐based metabolomics of urine allowed identification of 18 different phenolic acids, which were significantly elevated following intake of either extract. Syringic acid, 3‐ and 4‐hydroxyhippuric acid and 4‐hydroxymandelic acid were the strongest urinary markers for both extracts. MIX and GJX consumption had a slightly different effect on the excreted phenolic acid profile and on endogenous metabolite excretion, possibly reflecting their different polyphenol composition.     

加州葡萄与葡萄酒

加州位于美国西南部,是沿太平洋东海岸的一片狭长地带。四周为连绵不断的山脉,中央为谷地,具有夏干、冬湿的独特气候特点。这里不仅拥有美丽的海滩、迷人的景色、和煦的阳光,还是美国最重要的葡萄和葡萄酒产地。加州是美国最大的葡萄酒产区,无论是产量还是产值都占美国葡萄酒业     

Relationship between pectin methylesterase activity and the formation of methanol in Concord grape juice and wine

Pectin methylesterase (PME) activity in grapes was studied. Concord grape PME has optimum activity at pH 7·5 and the activity was the highest among several grape varieties tested. PME activity in Concord grapes increased continuously throughout the maturation period and reached a maximum at harvest. Consequently, this reflected the large amount of methanol formation during wine fermentation.     

葡萄与葡萄酒中的白藜芦醇

前 言白藜芦醇（Resveratrol，简称Res），化学名称为3,4′,5－三羟基1,2－二苯基乙烯（3,4′,5－Trihydroxysilbene）具有顺式与反式两种结构，是一种酚类化合物。经研究表明白藜芦醇具有一定的保健功能，特别对心血管疾病很有效，是目前世界关注的一个热点，它具有以下特点：（1）抗氧化、抗自由基作用；（2）对心血管疾病的防治作用。目前人们已在多种植物中发现有白藜芦醇，如花生、桑椹、虎仗、葡萄等，葡萄酒中含有一定量的白藜芦醇，尤其在红葡萄酒中含量较高，也就是造成法国人“PARADOX”的原因。由于白藜芦醇含量很少，不能…     

红提葡萄与酿酒葡萄复合果酒发酵工艺优化

该研究以新疆红提葡萄为主要原料,加入酿酒葡萄（宝石解百纳、赤霞珠）后制备红提葡萄与酿酒葡萄复合果酒,探讨最佳酿酒葡萄种类,并通过单因素及响应面试验探寻红提葡萄与酿酒葡萄复合果酒的最佳发酵工艺参数。结果表明,最佳酿酒葡萄为赤霞珠,红提葡萄与赤霞珠的质量比为4∶1;最佳发酵工艺条件为发酵温度20 ℃,初始pH值4.4,初始糖浓度28 °Bx。在此优化条件下,发酵所得红提葡萄与酿酒葡萄复合果酒的感官评分为95分,酒精度为8%vol,残糖量为13 °Bx,其色泽透亮,口感酸甜,果香浓郁,典型性明显,其理化指标及微生物指标均符合国家相关标准。     

品丽珠--古老的贵族酿酒品种

1 品种来源与别名品丽珠（Cabernet franc）同赤霞珠（Cabernet-Sauvignon）一样具有相同来源，即法国波尔多地区（Bordeaux）。但不要忽视它的第二故乡——法国卢瓦尔河谷地区（Vallede la Loire），在那里被称作“维龙”或“维龙人”（Vron, Vronais），这一称谓得名于法国西北边的维龙小镇。维龙位于席侬（Chinon）与卢瓦河-维埃讷河交汇处。它的别名首次出现在涅夫勒（Nivre）和德塞夫勒（Deux-Svres）地区。在布尔格耶（Bourgueil）如同席侬一样被称为布列塔尼亚人（Breton）或布列塔尼亚苗（Plant Breton）。按照当地传统，由…     

高效液相色谱法测定酒中的赭曲霉毒素A

研究了单克隆免疫亲和柱-高效液相色谱法测定酒中赭曲霉毒素A的方法。脱气后的酒类样品用1%PEG和5%NaHCO3的水溶液稀释,然后通过Ochra Test免疫亲和柱净化,净化液经Hypersil BDS C18柱反相色谱柱分离、荧光检测器检测、外标法定量。对添加不同含量的赭曲霉毒素A进行6次反复实验,得其平均回收率为92.8%-99.5%,RSD%〈10,最低检测限为0.04ng/mL,线性范围为0.1-10ng/mL。     

A treatment of grape wine distillation heads

The development of a procedure to eliminate sulphur dioxide, acetaldehyde, acetals, and ethyl acetate from grape wine distillation heads is reported. This process, designed for use in a modified pot still, involves inert gas sparging of the diluted and acidified heads held at reflux until an acceptable concentration of acetaldehyde has been reached. The solution is basified and distilled, giving a treated product which, as shown by sensory evaluation, can be as good as high-quality fortifying spirit. The ethanol recovery in this process is greater than that obtained by a comparable fractional distillation of heads.     

阿根廷葡萄与葡萄酒业

阿根廷是南美洲最大的葡萄酒生产国，也是世界第5大葡萄酒生产国和第6大葡萄酒消费国。但是直到最近5年，阿根廷葡萄酒才逐渐被世界所了解。阿根廷与智利之间隔着安第斯山脉，西面是智利葡萄酒产区，东面是阿根廷葡萄酒产区。正所谓“十里不同风和雨”，智利主要受海岸影响，而