套袋对红地球葡萄果皮色素和果实品质的影响

以红地球葡萄为试材,研究了不同栽培条件下套袋对葡萄果皮花青苷、叶绿素含量及果实品质的影响。结果表明,红古地区露地栽培条件下,套袋降低了可溶性固形物、总糖、花青苷、叶绿素含量,增加了可滴定酸含量;临泽地区在设施栽培条件下套白纸袋增加了可溶性固形物、总糖、花青苷含量,降低了可滴定酸、叶绿素含量。套袋对氨基酸含量影响不大,但设施延后栽培的红地球各处理氨基酸含量均高于露地。     

Anthocyanin composition and content of the Vaccinium uliginosum berry

Anthocyanins are polyphenols that are widely distributed in plants, and contribute to the brilliant blue, red or purple colour in leaves, flowers or fruits. Their attractive colours and their abundance in the north-east of China make the berries of Vaccinium uliginosum a new and excellent source of natural pigments. The pigments were extracted from the V. uliginosum berry using 0.5% TFA in ethanol solution, purified by an X-5 resin column and characterised by HPLC–DAD analysis. All of the peak assignments were confirmed by low-resolution electrospray mass spectrometry. The results showed that 11 anthocyanins and 2 flavonols were present in the V. uliginosum berry.     

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.     

Phenolic compounds and antioxidant properties of different grape cultivars grown in China

Skins and seeds of 18 grape cultivars belonging to Oriental and North American Vitis Species/hybrids, and Vitis vinifera were analysed for health beneficial properties. Four phenolic compound parameters (total phenols, flavonoids, flavan-3-ols and anthocyanins) and three antioxidant property parameters (DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging, ABTS [2,2-azino-di-(3-ethylbenzothialozine-sulphonic acid)] radical scavenging and FRAP (ferric reducing antioxidant power)) were measured. Principal component analysis (PCA) was used for this evaluation and results showed that both phenolic compounds and antioxidant properties in the seeds and skins varied among the cultivars investigated. V. vinifera “Cabernet Sauvignon” had the highest values of phenolic compounds and antioxidant properties in seeds followed by Muscadines, while the lowest appeared in the Oriental Vitis species. As expected, these values of the Euro-Asian or Euro-American hybrids fell between the parents. However, far less variation of these values was observed in the skins among different grape cultivars investigated. Interestingly, even the total phenolic contents in the berries of two cultivars are similar, distributions of phenolic compounds in seeds and skins varied greatly among them. Additionally, significant correlations among different antioxidant assays in both seeds and skins were observed. These antioxidant properties were also found highly correlated to the main phenolic compounds.     

Determination of the hormonal growth promoter 17α-methyltestosterone in food-producing animals: Bovine hair analysis by HPLC–MS/MS

This paper describes the development, validation and application of a confirmatory method to detect 17α-methyltestosterone (MT) in bovine hair, to aid in controlling the administration of this growth promoter in meat-producing animals. After cryogenic grinding, MT was removed from the hair matrix using a single step extraction procedure with acetonitrile. Hydroxylamine derivatisation was used to enhance analyte determination with an electrospray ionisation (ESI) source. Determination was carried out using a triple quadrupole liquid chromatography tandem mass spectrometer (LC–MS/MS) in multiple reaction monitoring mode (MRM). The method was validated in accordance with the criteria defined in Commission Decision 2002/657/EC and using deuterated testosterone (T-d₃) as the internal standard. The decision limit (CCα) was 0.07 ng g⁻¹ and the detection capability (CCβ) was 0.12 ng g⁻¹. Repeatability was CV% (7%), within-laboratory reproducibility was CV% (11.0%), and trueness was (87%). Applicability of the method was demonstrated in an animal study. Samples obtained from animal experiments were analyzed and the presence of MT was confirmed.     

Polyphenols,anthocyanins, and trans-resveratrol in red wines from the Hungarian Villány region

Epidemiological data indicate that moderate red wine consumption leads to less coronary heart disease and shows anti-carcinogenic effects. Especially, red wine phenolics have been linked to these effects. Sixty-seven red wines from the Hungarian Villány region, of vintages from 1996 to 2003 were analysed for their polyphenolic and anthocyanin composition by means of RP-HPLC/UV–Vis. Varieties with generally high concentrations of polyphenols are Kékfrankos, Merlot and Zweigelt, while anthocyanin content was highest in Shiraz, Oportó, Kékfrankos and Zweigelt. In agreement with other authors, our results show that trans-resveratrol content is mainly dependent on variety and vintage year. Principal component analysis (PCA) revealed that flavan-3-ols and delphinidin- and petunidin-3-glucosides are mainly responsible for the separation of wines according to polyphenolic composition. We could not discriminate between varieties or wineries based on polyphenol content, but could for vintage years.     

Anthocyanin composition and anthocyanin pathway gene expression in grapevine sports differing in berry skin colour

The synthesis of anthocyanins was investigated in six grapevine sports with altered skin colour. Cabernet Sauvignon and Shiraz grapes contained anthocyanin monoglucosides as well as acetylated and coumarylated derivatives, predominantly of malvidin, whereas Pinot Noir grapes contained only anthocyanin monoglucosides. Fruit of some sports arising from varieties with black berries either lacked anthocyanins or had much lower levels than their progenitors. A bud sport of Cabernet Sauvignon (Bronze Cabernet) exhibited a 90% reduction in anthocyanin levels, but an anthocyanin composition similar to that of the normal Cabernet Sauvignon fruit. The fruit of a white-coloured bud sport of Bronze Cabernet did not contain anthocyanins. Coloured berries of sports originating on varieties with white-skinned berries also had lower levels of anthocyanins than black grapes, but like Pinot Noir contained very low levels of acylated anthocyanins. The berries of these sports also varied in the proportions of the different types of 3-monoglucosides they contained. The results suggest that control of 3-monoglucoside synthesis and modification vary in the sports. The expression of six genes from the flavonoid biosynthetic pathway was determined. Some genes were expressed in all grapes, even where little or no anthocyanins accumulated, but expression of the gene encoding a UDP glucose-flavonoid 3-o-glucosyl transferase (UFGT) was only detected in coloured grapes that synthesised anthocyanins. Southern and northern analysis of the white grapes indicated that the UFGT gene was present but was not expressed. Thus the lack of anthocyanins in white-skinned varieties or sports correlates with a lack of expression of the UFGT gene, although the expression of some other flavonoid pathway genes was also decreased.     

Interaction mechanisms between caffeine and polyphenols in infusions of Camellia sinensis leaves

Black tea infusions of Camellia sinensis leaves were studied for the influence of water composition, especially calcium content, on the amount of extracted organic matter and on the interactions between caffeine and polyphenols. The higher the calcium content, the lower the extraction of caffeine and polyphenols in acidic media. In alkaline media, besides the calcium effect, polyphenols are oxidized. Caffeine NMR chemical shifts varied depending on the water used showing modified interactions. Using model solutions, polyphenols seem to be responsible for these changes in the case of ultra pure water, but in the case of alkaline solutions, the data in model solutions are different from tea infusions implying that other compounds should interact. Moreover, epigallocatechin gallate (EGCg) and epigallocatechin are the polyphenols interacting most strongly with caffeine in infusions and not EGCg and epicatechin gallate as thought before.     

An improved analytical method for determination of trans-resveratrol and related stilbenes in grape skin by QuEChERS coupled with HPLC-PDA-MS

Grape is a popular fruit crop that generates about one-fourth of total weight as pomace during winemaking and commercial juice production. However, a significant amount of resveratrol and related stilbenes is present in grape skin, and their effective isolation enables the production of functional foods. Herein, an improved analytical method for the determination of trans-resveratrol and related stilbenes in grape skin waste by QuEChERS method coupled with a high-performance liquid chromatograph-photodiode array detector-mass spectrometer was developed. By employing a Gemini C18 column and a mobile phase of acetic acid in water (pH 3.6) and acetonitrile, a total of five resveratrol and related stilbenes could be separated within 15 min with a flow rate of 0.8 mL min⁻¹ and detection wavelength at 306 nm. The optimised QuEChERS conditions were 10 mL of acetonitrile, 1 mL of grape skin extract and 900 mg of magnesium sulphate plus 25 mg of primary secondary amine. Principal component analysis by two principal components (74.18%, 25.82%) could well describe the trans-resveratrol recovery at different QuEChERS conditions. A mean recovery, as well as coefficient of variation (CV, %) of repeatability and intermediate precision, ranged from 96.6% to 104.4%, 1.96% to 3.10% and 1.68% to 4.27%, respectively, conforming to the regulation set by Taiwan Food and Drug Administration. Quantitation revealed cis-piceid to be present in largest amount (2.616 μg mL⁻¹), followed by trans-piceid (1.027 μg mL⁻¹), trans-resveratrol (0.967 μg mL⁻¹), ε-viniferin (0.660 μg mL⁻¹) and cis-resveratrol (0.183 μg mL⁻¹) in grape skin extract, with their corresponding contents in dried grape skin being 4.185, 1.643, 1.539, 1.056 and 0.293 μg g⁻¹, respectively.     

Anthocyanin composition and extractability in berry skin and wine of Vitis vinifera L. cv. Aglianico

BACKGROUND: The present article reports the anthocyanin content in the berry skin and wine of the Italian red grape cultivar Aglianico (clone VCR11 grafted onto 1103 Paulsen), one of the most ancient vines and famous for its deep‐red colour. Anthocyanins were extracted from frozen berry skin in an acidified methanol solution. The extraction mixtures, monitored for 120 h, were analysed by high‐performance liquid chromatography. RESULTS: The extraction from berry skin of delphinidin, petunidin and malvidin appeared to be a time‐independent process, whereas the concentration of peonidin increased linearly with time. Peonidin‐O‐acetyl‐glucoside was transferred from skin more slowly than petunidin‐O‐acetyl‐glucoside and malvidin‐O‐acetyl‐glucoside. The anthocyanin composition of the resulting wine showed that the total anthocyanin content was about one‐tenth of the corresponding berry skin content. The ratio acetyl/coumaroyl anthocyanins in the wine was sharply higher than the value in berry skin (0.85 and 0.10, respectively), indicating an enrichment of acetyl derivatives in the wine. CONCLUSION: Levels of single anthocyanins in wine were not always correlated with those detected in grapes, as they were affected by winemaking. The high values of some anthocyanins in Aglianico wine could ameliorate its quality, increasing the chromatic properties, aging stability and product acceptance. Copyright © 2011 Society of Chemical Industry     

Phenolic compounds and antioxidant activity of seed and skin extracts of red grape (Vitis vinifera and Vitis labrusca) pomace from Brazilian winemaking

The phenolic compounds content and antioxidant activity of seed and skin of pomace from the vinification of grape varieties widely produced in Brazil were investigated with a view to their exploitation as a potential source of natural antioxidants. There was a greater concentration of phenolic compounds in the seeds (2128 to 16,518 mg of catechin equivalents (CE)/100 g) than in the skins (660 to 1839 mg CE/100 g). The highest antioxidant activity values determined as DPPH radical-scavenging ability and ferric reducing-antioxidant power (FRAP) were found for the seeds of the Pinot Noir variety (16,925 ??mol Trolox equivalents (TE)/100 g and 21,492 ??mol Fe²⁺/100 g, respectively) and in the skin extracts of the Isabel variety (3640 ??mol TE/100 g and 4362 ??mol Fe²⁺/100 g, respectively). The skin of Cabernet Sauvignon and Primitivo varieties had the highest contents of anthocyanins (935 and 832 mg/100 g, respectively). The grape seed extracts were rich in oligomeric and polymeric flavanols. The data suggested that grape seed and skin extracts may be exploited as antioxidant agents.     

越橘提取物中花青素分析及其体外抗氧化活性

研究越橘提取物中花青素的组成与含量及其体外抗氧化活性。实验采用高效液相色谱与质谱联用法对越橘提取物中的花青素组成进行鉴定,并以矢车菊素-3-O-葡萄糖苷为标准品测定了花青素的含量。以V_C为对照,测定越橘提取物对DPPH自由基、ABTS自由基、羟基自由基的清除能力和还原力。结果表明,越橘提取物中含有14种花青素,包括飞燕草素、矢车菊素、矮牵牛素、芍药素和锦葵素类;越橘提取物中花青素的总含量为408.74 μg/mg,其中,矢车菊素类花青素含量最高,为159.93 μg/mg,占总含量的39.12%;体外抗氧化实验表明,越橘提取物的DPPH自由基清除能力、ABTS自由基清除能力和羟基自由基清除能力的IC₅₀分别为26.16、13.07、1.91 mg/mL,还原力在浓度为250 μg/mL时达到0.617。本研究为越橘的开发利用提供一定理论与数据基础。     

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     

Berry skin thickness as main texture parameter to predict anthocyanin extractability in winegrapes

Red grapes are the only source of anthocyanins in wines and therefore the assessment of their extractability is important for wine quality. To date, a mathematical equation relating skin mechanical properties and anthocyanin extractability has never been performed for different ripening stages and vineyards located in a given production area. The main aim of this work was to assess anthocyanin extractability attempting to its relation with skin textural parameters. Morphological parameters, skin texture characteristics, total anthocyanin contents and extractability percentages were determined in Mencía grape berries (Vitis vinifera L.) from several vineyards and calibrated according to their density at three amounts of soluble solids. Skin mechanical properties were measured by Texture Analysis; a rapid and low-cost analytical technique. In most vineyards, an increasing tendency of texture parameter values was observed with the ripening stage but the differences were not statistically significant. The accumulation of anthocyanins in berry skin usually increased with the ripening stage. Anthocyanin extractability was no influenced by ripening stages for each vineyard studied. The study allowed to establish a skin texture parameter as predictor of anthocyanin extractability for a given production area. Thinner skins seem to be characterized by a greater release of red pigments.     

Changes in polyphenol and polysaccharide content of grape seed extract and grape pomace after enzymatic treatment

Grape seed extract and grape pomace are rich sources of polyphenols. The aim of this study was to evaluate the release of polyphenols, the solubilisation of carbohydrate, and the antioxidant capacity of these grape by-products after enzymatic reaction with carbohydrases (cellulolytic and pectinolytic activities) and tannase for 24 h. The use of tannase in these by-products, and pectinase in grape pomace changed the galloylated form of catechin to its free form, releasing gallic acid and increasing the antioxidant activity. In grape pomace, cellulase treatment was not efficient for phenolic release and antioxidant activity improvement. The addition of carbohydrases to grape pomace, either alone or in combination, degraded the cell wall polysaccharides, increasing the content of monosaccharides. These results provide relevant data about the potential of pectinase, tannase and combinations of enzymes on the release of polyphenols and monosaccharides from grape by-products, improving the antioxidant capacity and the nutritional value.