Trans-resveratrol Content Research Articles

Investigation of some physiological and chemical changes in shoots and leaves caused by UV-C radiation as an abiotic stress source in grapevine cuttings

In this study, UV-C was applied to the cuttings of Cabernet Sauvignon and Cabernet Franc cv.’s at three different durations to simulate abiotic stress, with subsequent monitoring of resultant changes upon the formation of at least six leaves. In both grape varieties, total phenolic compounds and antioxidant capacity in leaves reached the highest levels after 60 min of UV-C treatment. Trans-resveratrol content reached its highest level with an increase of 157 %. The activity of superoxide dismutase enzyme reached its highest level with an increase of 630 %, especially in Cabernet Franc. Total chlorophyll, chlorophyll a, chlorophyll b contents reached their highest levels after 60 min of UV-C treatment. UV-C treatments did not affect shoot number. However, parameters such as fresh and dry shoot weight, shoot length, fresh and dry root weight reached their highest levels after 45 min of UV-C stress. In correlation analysis, the highest correlation was found between trans-resveratrol and chlorophyll b. In principal component analysis, 6 min of UV-C stress had the highest loading on component 1 and 45 min of UV-C stress had the highest loading on component 2. These results suggest that UV-C treatment may be a potential method to improve grape quality and plant health by inducing important physiological responses in grapevines. This is the first study to investigate the effects of UV-C treatment on grapevine cuttings.

Comparative Study of the Stilbenes and Other Phenolic Compounds in Cabernet Sauvignon Wines Obtained from Two Different Vinifications: Traditional and Co-Inoculation

From grape cultivation to ripening and harvest timing to processing, each step of the winemaking process can be a critical point when it comes to wine quality and phenolic composition. In this study, the influence of winemaking technology on resveratrol and quercetin content, as well as other polyphenolic compounds, was investigated. Resveratrol is a non-flavonoid polyphenolic stilbene synthesized by grape skin when damaged by infectious diseases or ionizing radiation. Quercetin is a phenol found in grape skins and stems and is produced to protect grapes from UV light damage. Trans-resveratrol and quercetin are known to act as antioxidants, reduce the risk of atherosclerosis and type 2 diabetes, inhibit the growth of cancer cells, and prevent the release of allergic and inflammatory molecules. However, the question was whether red wine could be enriched with these phenols using a co-inoculation winemaking technology. The main new idea was to completely replace the cold maceration process with maceration with the addition of wild yeast (Torulaspora delbrueckii, Td). Maceration with the addition of wild yeast (Td) offers the following advantages over traditional cold maceration: (1) higher concentrations of trans-resveratrol (>35–40%) and quercetin (>35–40%) in the final wine, (2) the new wine has a higher potential for human health, (3) the wine has better aroma and stability due to the higher mannoprotein content, and (4) better energy efficiency in the production process. The study of stability during storage and aging also included derivatives of benzoic acid and hydroxycinnamic acid, piceid, catechin, naringenin, rutin, kaempherol, hesperetin, and anthocyanins. This study found that younger wines had higher phenolic content, while storage of the wine resulted in a decrease in total phenolic content, especially monomeric stilbenes and quercetin. This study represents a small part of the investigation of the influence of non-Saccharomyces yeasts on the phenolic profile of wine, which still requires extensive research with practical application. In addition, non-Saccharomyces yeasts such as Kluyveromyces thermotolerans, Candida stellata, and Metschnikowia pulcherrima could also be used in future studies.

Increase in plasma resveratrol levels and in acid-resistant proteins in the acquired enamel pellicle after use of resveratrol-containing orodispersible tablets

ObjectiveThis study evaluated the effect of administration of trans-resveratrol-containing orodispersible tablets on the protein composition of the AEP and on blood plasma trans-resveratrol concentrations. MethodsTen volunteers participated in two crossover double-blind phases. In each phase, after dental prophylaxis, they received a trans-resveratrol (15 mg) orodispersible tablet, or a placebo tablet (without actives). The AEP formed after 120 min was collected with electrode filter papers soaked in 3 % citric acid. Blood samples were collected 30, 45, 60 and 120 min after the use of the tablet. After protein extraction, AEP samples were analyzed by shotgun labelfree quantitative proteomics and plasma samples were analyzed by high-performance liquid chromatography (HPLC). ResultsEight hundred and two proteins were identified in the AEP. Among them, 336 and 213 were unique to the trans-resveratrol and control groups, respectively, while 253 were common to both groups. Proteins with important functions in the AEP had increased expression in the trans-resveratroltreated group, such as neutrophil defensins, S100 protein isoforms, lysozyme C, cystatin-D, mucin-7, alphaamylase, albumin, haptoglobin and statherin. Trans-resveratrol was detected in the plasma at all the times evaluated, with the peak at 30 min. ConclusionsThe administration of trans-resveratrol in sublingual orodispersible tablets was effective both to increase the bioavailability of the polyphenol and the expression of antibacterial and acid-resistant proteins in the AEP, which might benefit oral and general health.

Hot-air drying and degradation kinetics of bioactive compounds of gilaburu (Viburnum opulus L.) fruit

This study aims to determine whether drying is a suitable preservation method for gilaburu fruit and the changes in the bioactive components of gilaburu fruit (Viburnum opulus L.) at the end of the drying process. In this study, gilaburu fruits were dried in a cabinet dryer at different temperatures (50?C, 60?C, and 70?C). The analyses of trans-resveratrol, water-soluble vitamins, organic acids, and phenolic compounds were made using the HPLC method, while total phenolic contents and antioxidant activity were spectrophotometric. As a result of drying of gilaburu fruit at 50?C, 6 ?C, and 70?C, the highest component loss was observed at 70?C. Losses of 73.64% and 84.08%, respectively, were detected in the total phenolic substance and antioxidant capacity content of gilaburu fruit after drying at 70?C. While the trans-resveratrol content was 1.26?0.05 (g/100 g dry weight (DW)) in fresh fruit, it reduced to 0.31?0.03, 0.30?0.01 and 0.21?0.01 after drying at 50?C, 60?C and 7 ?C, respectively. In terms of vitamins, the highest loss was seen in niacin. The contents of ascorbic acid, pyridoxine, niacin and thiamine contents of fresh gilaburu fruit decreased after drying at 50?C, 60?C and 70?C. In addition, drying kinetics of water-soluble vitamins, total phenolic contents, antioxidant activity, and trans-resveratrol were modeled. The Page model best described the drying behavior of fruits at 70?C, and the parabolic model at both 50?C and 60?C. Thermal degradation of water-soluble vitamins, total phenolic contents, antioxidant activity, and trans-resveratrol were fitted in the first-order kinetic model.

Effect of the grape thinning on the content of trans-resveratrol in some Syrah clones

Wine is a product obtained through fermentation process, the trans-resveratrol is a polyphenol derived from grapes and a natural antioxidant that passes into wine. The trans-resveratrol is a rare compound with the highest content in the red wine and a positive physiological effect on human organism. The present study was conducted in three years period from 2020 until 2022 at the Agricultural university-Plovdiv experimental vineyard, located near the village of Brestnik. Four Syrah wine variety clones were included and eight experimental wines have been made during the experimental period. In all tested wines, the presence of trans-resveratrol was detected but its amount was higher in clone 524 (V4) with non-reduced yield (3.35, 4.36, 7.02 mg/L), and in clone 100 (V5) with reduced yield (5.24, 3.75, 7.23 mg/L). Reducing the bunch numbers at the “pea size” stage did not significantly influence the content of trans-resveratrol. The wine antioxidant properties were directly affected by the clone and the grape harvest and was under the terroir influence. In today's conditions of overproduction and increased competition, the results of this study provide a valuable economic information and expand the portfolio of wineries. Keywords: clones, Syrah, red wine, resveratrol, bunch thinning, canopy management

English

Phenolic compounds are important indicators of grape berry and wine quality. They also have many important effects on human health. Biotic and abiotic plant stressors are the factors that affect the composition and amounts of metabolites dramatically. Although wounding is one of these stressors, little is known about its effect on the accumulation and biosynthesis of the entire phenolic profile. This study aimed to identify the effects of human-made wounding to grapevine leaves on the accumulation of grape berry metabolites in cv. ‘Cabernet Sauvignon’ grapevines. Ten combinations of different wounding timing and treatment methods were applied to 20 years old grapevine plants. The data suggests that wounding treatments have the potential to diversify the phenolic compound profile and can be utilized for their management compared to the control group. Specifically, the E15 treatment accelerated MITSS/TA by 39.83% and increased the content of trans-resveratrol by 35.78% compared to the Control. On the other hand, the E10+W5+E3 treatment resulted in a regression in maturity parameters. The wounding treatment E10+W5 increased the total phenolics by 13.74%, total anthocyanin contents by 20.48%, and transresveratrol content by 93.05%. Additionally, the E5+W3 treatment demonstrated a significant increase of 19.65% in syringic acid and 21.89% in vanillic acid contents. Although the control application for antioxidant activity reached its peak value, it decreased in the E15+W5 treatment. As a result, it was determined that the responses given to the treatments were quite diverse. Nevertheless, they also found it applicable to manage berry maturity and quality indicators. Early wounding treatments accelerate maturity, and treatments performed more recently at harvest stop berry sugar accumulation. While late treatments increase the total phenolics, the responses of the phenolic compounds profile differ

EVOLUTION OF CIS AND TRANS-RESVERATROL IN WINES OBTAINED THROUGH INOCULATION WITH ACTIVE DRY YEAST AT PIETROASA VINEYARD

This paper presents the results of the testing during the winemaking process using commercial active dry yeasts (CADY) in parallel with yeast biomass produced starting from yeasts isolated from Pietroasa area (Romania) (PAY). PAYs were obtained based on autochthonous yeasts isolated from Busuioacă de Bohotin (BB) and Tămâioasa Românească (TR) grape varieties. Two variants of must for each grape variety were taken in study, i.e. obtained from early harvested grapes (TRD and BBD) and from late harvested grapes (TRS and BBS). Winemaking experiments were carried out with 7 types of commercial yeasts and two types of commercial nutrients. The alcoholic concentration of the experimental wines varied from 11.8 % for WTRD to 18.4% for WBBD. The WBBD & S samples showed a higher average trans-resveratrol content (1.716 and 1.555 mg/L, respectively) compared to the WTRD & S wine samples (0.590 and 1.365 mg/L, respectively). The variation in the cis-resveratrol content between the experimental variants produced with PAY was not significant.

Fruit Extract, Rich in Polyphenols and Flavonoids, Modifies the Expression of DNMT and HDAC Genes Involved in Epigenetic Processes.

Recently, the field of epigenetics has been intensively studied in relation to nutrition. In our study, the gene expression patterns of histone deacetylases (HDACs), which regulate the stability of histone proteins, and DNA methyltransferases (DNMTs), which regulate DNA methylation, were determined in mice. The animals were fed a human-equivalent dose of the aqueous extract of fruit seeds and peels, which is rich in flavonoids and polyphenols, for 28 days and then exposed to the carcinogen 7,12-dimethylbenz(a)anthracene (DMBA). The concentrations of trans-resveratrol and trans-piceid were determined in the consumed extract by HPLC and were 1.74 mg/L (SD 0.13 mg/L) and 2.37 mg/L (SD 0.32 mg/L), respectively, which corresponds to the consumption of 0.2-1 L of red wine, the main dietary source of resveratrol, in humans daily. Subsequently, 24 h after DMBA exposure, the expression patterns of the HDAC and DNMT genes in the liver and kidneys were determined by qRT-PCR. The DMBA-induced expression of the tested genes HDAC1, HDAC2, DNMT1, DNMT3A and DNMT3B was reduced in most cases by the extract. It has already been shown that inhibition of the DNMT and HDAC genes may delay cancer development and tumour progression. We hypothesise that the extract studied may exert chemopreventive effects.

Changes in anthocyanin pigments, trans-resveratrol, and colorimetric characteristics of Fondillón wine and other “Monastrell” wines during the aging period

The studied red wines, which are Fondillón, reserva, crianza, and young, are prepared from exclusive “Monastrell” grapes, and protected under the Alicante Denomination of Origin (Alicante, Spain). The objectives of the present study were (i) to show the effect of aging period on the amount of anthocyanin pigments, trans-resveratrol, and the colorimetric characteristics (color intensity, color density, and tonality) of Fondillón and other Monastrell wines (young, crianza, and reserva) which have different aging periods, and (ii) to propose a new traceability method for the determination of the Fondillón originality. Identification of anthocyanin compounds and determination of trans-resveratrol content were performed using LC–MS/MS. Correlation analysis was performed among anthocyanin compounds and color parameters. A sharp decrease in the anthocyanins content was observed in Fondillón wine. Besides, statistically significant changes were found in all colorimetric parameters between young and Fondillón samples. A significant change from red hue to brick red/yellow hue was observed between the colors of young and Fondillón wines, respectively. A significant decrease in the content of trans-resveratrol was also observed as a result of the aging period of these “Monastrell” wines. In this study, anthocyanin compounds of Fondillón wine were identified for the first time and their effects on the colorimetric parameters of the wine were revealed. Consequently, the authenticity of Fondillón wines can be determined by monitoring of anthocyanin compounds and trans-resveratrol.

Holistic understanding of the response of grapevines to foliar application of seaweed extracts.

Viticulture is highly dependent on phytochemicals to maintain good vineyard health. However, to reduce their accumulation in the environment, green regulations are driving the development of eco-friendly strategies. In this respect, seaweeds have proven to be one of the marine resources with the highest potential as plant protective agents, representing an environmentally-friendly alternative approach for sustainable wine production. The current work follows an interdisciplinary framework to evaluate the capacity of Ulva ohnoi and Rugulopteryx okamurae seaweeds to induce defense mechanisms in grapevine plants. To our knowledge, this is the first study to evaluate Rugulopteryx okamurae as a biostimulator . This macroalgae is relevant since it is an invasive species on the Atlantic and Mediterranean coast causing incalculable economic and environmental burdens. Four extracts (UL1, UL2, RU1 and RU2 developed from Ulva and Rugulopteryx, respectively) were foliar applied to Tempranillo plants cultivated under greenhouse conditions. UL1 and RU2 stood out for their capacity to induce defense genes, such as a PR10, PAL, STS48 and GST1, mainly 24 hours after the first application. The increased expression level of these genes agreed with i) an increase in trans-piceid and trans-resveratrol content, mainly in the RU2 treated leaves, and, ii) an increase in jasmonic acid and decrease in salicylic acid. Moreover, an induction of the activity of the antioxidant enzymes was observed at the end of the experiment, with an increase in superoxide dismutase and catalase in the RU2-treated leaves in particular. Interestingly, while foliar fungal diversity was not influenced by the treatments, alga extract amendment modified fungal composition, RU2 application enriching the content of various groups known for their biocontrol activity. Overall, the results evidenced the capacity of Rugulopteryx okamurae for grapevine biostimulation, inducing the activation of several secondary metabolite pathways and promoting the abundance of beneficial microbiota involved in grapevine protection. While further studies are needed to unravel the bioactive compound(s) involved, including conducting field experiments etc., the current findings are the first steps towards the inclusion of Rugulopteryx okamurae in a circular scheme that would reduce its accumulation on the coast and benefit the viticulture sector at the same time.

Evolution of Physicochemical Properties and Phenolic Maturity of Vilana, Vidiano, Kotsifali and Mandilari Wine Grape Cultivars (Vitis vinifera L.) during Ripening.

Determining the optimum harvest time is a significant factor affecting the quality of the grapes and the wine. Monitoring the evolution of grapes' physicochemical properties and phenolic maturity during ripening could be a valuable tool for determining the optimum harvest time. In this study, the total phenolic content, antioxidant activity, flavonols, flavanols, anthocyanins and resveratrol content were determined during the last weeks of ripening for the white cultivars Vilana and Vidiano, as well as for the red cultivars Kotsifali and Mandilari (Vitis vinifera L.). According to the results, an early harvest for the white cultivars and a late harvest for the red cultivars may increase the total phenolics and trans-resveratrol content in grapes and wine. An early harvest would be desirable to maintain high flavanols content and high levels of antioxidant activity in the grapes' skin and seeds. Conversely, a late harvest for the red cultivars may be desirable to increase the total flavonols and anthocyanin content in grapes and wines.

First investigation on polyphenols and glycosidic aroma precursors in a spontaneous colour mutant of 'Glera', the principal grape variety of Prosecco sparkling wine.

Somatic mutations in Vitis spp. are relatively frequent and can generate new agronomically interesting phenotypes. We report the discovery, genetic and chemical characterization of 'Glera rosa', a mutant for the berry skin colour of 'Glera', the main white cultivar used to produce Prosecco wine. We ascertained the relationship between the skin colour of 'Glera rosa' and the polymorphisms in the Myb-gene transcription factors involved in polyphenol biosynthesis. We established that VvMybA1 was homozygous (VvMybA1a/VvMybA1a) in 'Glera' but heterozygous (VvmybA1a/VvmybA1b) in the 'Glera rosa' mutant. We verified that the VvMybA1a non-functional allele contained Grapevine Retrotransposon 1 (Gret1), while in the VvmybA1b allele Gret1 was missing, and the gene function was partially restored. The effects of mutation on 'Glera rosa' grape metabolites were studied by high-resolution mass spectrometry and gas chromatography/mass spectrometry analysis. Fifteen anthocyanins and five unique flavonols were found in the 'Glera rosa' mutant. The mutation also increased the contents of trans-resveratrol and its derivatives (i.e., piceatannol, E-ε-viniferin, cis- and trans-piceid) and of some flavonols in grape. Finally, the mutation did not significantly affect the typical aroma precursors of Glera grape such as glycosidic monoterpenes, norisoprenoids and benzenoids. 'Glera rosa' could be an interesting genetic source for the wine industry to produce Prosecco DOC rosé typology (made by adding up to 15% of 'Pinot Noir'), which was introduced to the market in 2020 with a worldwide massive success. © 2022 Society of Chemical Industry.

Ecogeographic Conditions Dramatically Affect Trans-Resveratrol and Other Major Phenolics' Levels in Wine at a Semi-Arid Area.

Grapevines are susceptible and responsive to their surrounding environment. Factors such as climate region and terroir are known to affect polyphenolic compounds in wine and therefore, its quality. The uniqueness of the terroir in Israel is the variety of soil types and the climatic conditions, ranging from Mediterranean to arid climates. Thus, understanding the effects of climate on grapevine performance in Israel may be a test case for the effect of climate change on grapevine at other areas in the future. First, we present a preliminary survey (2012–2014) in different climate zones and terroirs, which showed that trans-resveratrol concentrations in Merlot and Shiraz were high, while those of Cabernet Sauvignon were significantly lower. A further comprehensive countrywide survey (2016) of Merlot wines from 62 vineyards (53 wineries) compared several phenolic compounds’ concentrations between five areas of different climate and terroir. Results show a connection between trans-resveratrol concentrations, variety, and terroir properties. Furthermore, we show that trans-resveratrol concentrations are strongly correlated to humidity levels at springtime, precipitation, and soil permeability. This work can be considered a glimpse into the possible alterations of wine composition in currently moderate-climate wine-growing areas.

Study of the possibility of obtaining quality wines from grapes of the Central Black Earth Region

Currently, import substitution, the presence of domestic quality products on the market, including alcoholic beverages, is an urgent direction in the food industry The technical grape variety "Isabella" is one of the most widespread in the Central Black Earth Region (CBER). The purpose of the work is to popularize the culture of wine consumption and saturate the food market of the CBER with high-quality wine materials and finished products. Objects of research were: five samples of the technical grape variety "Isabella" grown in different territories of the Voronezh, Belgorod, Lipetsk regions of the CBER: five samples of wine prepared from the above raw materials by the «red» method. When collecting grape raw materials, they were guided by the conditions of sugar content and acidity. The processing of grapes, the production of wine materials and finished wine was carried out according to the technological scheme for red table wine. As a result, the possibility of using the technical grape variety "Isabella" grown in the CBER is shown. The conditions of all five samples of grapes corresponded to the standards adopted in the wine production. According to the basic physico-chemical parameters, the obtained wine samples corresponded to the standards adopted for ordinary red semi-sweet wines. The evaluation of wine samples according to the indicator "Quantitative determination of trans-resveratrol" revealed a sample containing trans-resveratrol - a sample of wine № 4 obtained from grapes of the variety "Isabella" growing in the Lipetsk region, the city of Gryazi, Gryazinsky district. The content of trans-resveratrol in it was 0.143 mg/dm3. Resveratrol, having antioxidant activity, is of the greatest interest among biomolecules with nutraceutical properties in red wine. The separation and identification of trans-resveratrol was carried out using high-performance liquid chromatography (HPLC) coupled with a detector on a diode matrix (DAD-3000 model, Thermo Scientific). The calibration curve was constructed using a standard sample at increasing concentrations. Further development of research are: to develop the technology of terroir wine, which differs from other wines produced in other geographical latitudes with appearance, taste, aroma, which will be formed due to the influence of external factors.

PHYSICAL AND CHEMICAL PROPERTIES OF THE JUJUBE FRUITS AT DIFFERENT MATURATION STAGES

The effects of maturation stages on some physical and chemical properties of the jujube fruits were investigated. The maturation stages of the jujube fruits were described as green, yellow, half-red and red maturation. The physical properties and chemical composition of the jujube fruit significantly changed depending on the maturation stage. The size and weight of the jujube fruits increased, and the peel color changed from green to red with the maturation. The content of water-soluble vitamins, trans-resveratrol, total phenolic content and antioxidant capacity of the jujube fruits decreased during the maturation. The trans-resveratrol content of the jujube fruits was investigated for the first time and no trans-resveratrol content could be detected at red maturation stage. The major organic acid and sugar at the red maturation stage were found to be malic acid and sucrose, respectively. The phenolic composition also changed, but these changes showed unstable trend during the maturation. The major phenolic compound was catechin at the green maturation stage, whereas chlorogenic acid dominated at the red maturation stage. The jujube fruit is rich in minerals especially potassium and no changes in the mineral contents except for copper was observed between green and red maturation stages.

Study on Kinetics of Trans-Resveratrol, Total Phenolic Content, and Antioxidant Activity Increase in Vine Waste during Post-Pruning Storage

There is increasing evidence surrounding the health benefits of E-resveratrol; this has triggered interest in stilbenoids in grapes, wine, and by-products. On the one hand, there is an enormous amount of underutilized vine waste, rich in bioactive substances during wine production. On the other hand, there is a growing demand for promising phytochemicals, for dietary and pharmaceutical purposes. Vine shoots are promising sources of stilbenoids; they have economic potential because they are sources of high-value phytochemicals. Recent studies have shown that, due to biosynthesis pathway genes, especially STS (forming trans-resveratrol), which is abundant during storage periods of vine shoots—trans-resveratrol accumulates up to 40-fold. The objective of this research was to determine the most economical part of vine waste to be exploited, and to study the kinetics of resveratrol increase in a 90-day period, to determine the optimal storage period to reach a maximum trans-resveratrol content. Total phenolic content (TPC) and antioxidant activity (AA) were studied to determine possible correlations. In Fetească Neagră vine shoot varieties stored at laboratory temperatures, trans-resveratrol content increased to a maximum (2712.86 mg/kg D.W.) at day 70, and then slightly decreased until day 90. TPC remained constant and there was a slight increase in AA. Vine shoots contained the largest amounts of trans-resveratrol (1658.22 mg/kg D.W.), followed by tendrils (169.92 mg/kg D.W.), and leaves (43.54 mg/kg D.W.).

Near-harvest application of methyl jasmonate affected phenolic content and antioxidant properties in "Thompson Seedless" grape.

The influence of methyl jasmonate (MJ) preharvest treatment was investigated on some polyphenols and antioxidant systems in the “Thompson Seedless” table grape. The clusters were sprayed in the vineyard 2 days before harvest with 0, 1, 5, and 10 mM MJ. After picking, berries were stored for 6 days at 15°C, simulating marketing conditions. Total phenols and flavonoids were affected by MJ treatment, especially at 10 mM concentration, whereas total tannins were found to be unchanged. Antioxidant activity of the treated skin was noticeably higher compared with the control, together with PAL and POD activity. Although MJ had little effect on catechin and epicatechin, the levels of quercetin and rutin were noticeable. In addition, 5 and 10 mM MJ exerted a pronounced effect on transresveratrol content. These data showed that a single preharvest application close to the harvest time could be an effective treatment to promote the antioxidant properties of the grape.

Optimization of antioxidant extraction and characterization of oil obtained by pressing cold from Vitis labrusca seeds

This study aimed to optimize the extraction solvents for Bordo grape (Vitis labrusca) seeds by response surface methodology regarding to the antioxidant activity (AA) and trans-resveratrol content. Fatty acids (FA) and AA of the oil obtained by pressing cold method were also determined. The extraction optimization was determined by the statistical simplex-centroid mixing scheme, enabling the analysis of solvents effects (water, ethanol and acetone) and their mixtures on the responses. AA was performed by DPPH, ABTS and FRAP methods, and by total phenolic compounds and flavonoids. FA were determined by GC and trans-resveratrol by HPLC. The extracts containing ternary fraction of solvents showed greater AA, increasing about 20 times compared to pure solvent. The composition that showed the best response ranged between 45-48% of water, 14-20% of ethanol and 35-38% of acetone for both grape seeds, with polarity ranged from 0.705 to 0.706. The oil from seeds showed high concentrations of PUFA, particularly linoleic acid. The optimized extraction method improved the use of this residue as a potential antioxidant source for food industry.

Selected phenolics and antioxidant capacities: From Boğazkere (Vitis vinifera L.) grape to pomace and wine

In this research, the amounts of trans-resveratrol, (+)-catechin, (-)- epicatechin, and malvidin-3-glucoside which are among phenolic compounds as well as the total phenolic compound, total anthocyanin, and antioxidant capacity changes were examined in the Boğazkere (Vitis vinifera L.) grape, pomace before press, pomace after press and wine. In all parameters examined, a decrease was seen when proceeding from grape to wine, only (+)- catechin and (-)- epicatechin levels were detected to be higher in the prepress pomace. Total phenolic compound, total anthocyanin, and antioxidant capacity levels were found highest in grape samples, respectively, 8018 mg GAE/kg; 1606 mg/kg; 16.05 μmol troloxl/g with ABTS method; 7.75 μmol trolox/g with DPPH method; 4.78 μmol trolox/g with FRAP method. The highest amount of trans-resveratrol content was obtained from grape berry with 3.57 mg/kg, the highest (+)- catechin content was obtained from the pomace before press sample with 54.66 mg/kg, the highest amount of (-)- epicatechin was obtained from pomace before press sample 20.38 mg/kg and the highest amount of malvidin-3-glucoside amount was determined as 510 mg/kg in grape. According to the results of the research, it was understood that the pomace of the Boğazkere variety, which is one of the grape varieties mostly processed as wine in our country, has a high level of antioxidant capacity and phenolic content.

POTENTIAL OF ROMANIAN VINE WASTES AS A NATURAL RESOURCE OF TRANS-RESVERATROL

The methods for producing natural resveratrol are of big interest due to the numerous health benefits of this substance and its increasing use in functional foods, food supplements and para-pharmaceutical preparations, especially with the recent permission of resveratrol as a novel food ingredient in the European Union (Commission Implementing Decision (EU) 2016/1190). Since annually a large amount of waste is produced in vine pruning, the aim of this study was to evaluate the potential of vine shoots from ten grape varieties (Fetească Albă, Fetească Neagră, Muscat Ottonel, Muscat de Hamburg, Tămâioasă, Coarnă Neagră, Merlot, Cabernet Sauvignon, Fetească Regală and Burgund Mare) from two different locations to be used as a natural source of trans-resveratrol. To reach this goal, two different solvents were explored, two different storage periods, three different time of collecting of samples in two different years. Moreover, a correlation between the type of vine (red or white) and trans-resveratrol content was analyzed. Maceration solvent diethyl-ether:ethanol, 1:4 ratio, showed a higher yield of extraction of trans-resveratrol than methanol 80%. Increasing the storage time by another 6 weeks positively affected the concentration of resveratrol for 5 samples, and for another 7 negatively. The time of collecting the samples had a high influence on the resveratrol content on shoots samples, highlighting the fact that autumn is the optimal time for harvesting. No correlation could be established among the grape varieties (red or white) and the trans-resveratrol content. The highest concentration of resveratrol was recorded for the Fetească Neagră variety – 2367.37 mg/kg. D.W.