Feteasca Regala Research Articles

Antimicrobial Activity of Grape Pomace Extracts Against Different Species of Microorganisms

Abstract The food sector has become interested in grape pomace for its numerous health benefits and high concentration of bioactive chemicals. In this study, the antibacterial properties of grape pomace obtained from by-products of white and blue grapes were investigated. The aim of our study was antimicrobial activity of grape pomace extracts from blue varieties (Alibernet, Dornfelder, Cabernet Sauvignon), and white varieties (Blaufränkisch, Sauvignon Blanc, Welschriesling, Weisser Riesling, Irsai Oliver, Pinot Blanc, Palava, Müller-Thurgau, Grűner Veltliner, and Feteasca Regala). The antimicrobial activity of grape pomace extracts was evaluated against nine microorganisms Gram-positive, Gram-negative bacteria and yeasts with disc diffusion method. The best antimicrobial activity of blue grape pomace extract was found against Bacillus subtilis. White varieties Sauvignon Blanc, Welschriesling, Weisser Riesling, Irsai Oliver, Pinot Blanc pomace extracts were the most effective ones against B. subtilis and Müller-Thurgau grape pomace extract was the most effective one against C. koseri and Grűner Veltliner and Feteasca Regala against B. subtilis. The most sensitive bacteria were B. subtilis.

OBTAINING ACTIVE DRY YEASTS BIOMASS FOR THE PRODUCTION OF PIETROASA WINES

Consumers are increasingly demanding traditional beverages such as wines that are obtained through innovative technologies and that use indigenous yeasts to preserve the concept of `terroir`. The paper presents the study performed for the exploitation the microbial diversity in the Pietroasa wine region in Romania and to obtain autochthones yeasts biomass. Yeasts were isolated from grapes and must from Feteasca regala FR) and Cabernet Sauvignon (CS) varieties cultivated at the Pietroasa Viticulture and Vinification Research and Development Station. Five yeast isolates were selected and identified by the MALDI-TOF, these belonging to the S. cerevisiae and non-Saccharomyces genera. By using these yeast isolates, active dry biomass was obtained through fermentation on a substrate based on sterilised diluted must (from the Feteasca regala and Cabernet Sauvignon varieties), synthetic sterilised media, followed by freeze-drying. Subsequently, the active dry biomass was used to obtain wines, using two types of nutrients: ET (Energyvin Thiols) and NO (Nutristart® ORG). All studied yeast isolates showed a promising potential for obtaining white wine from Feteasca regala grapes and rosé wine from the Cabernet Sauvignon grapes variety.

Highlighting the Terroir Influence on the Aromatic Profile of Two Romanian White Wines

Climate conditions clearly influence the concentration of important substances in grapes, generating chemical reactions that will determine the final wine aromas. Three different regions were chosen to cover the most important viticultural areas from Romania. The aim of this study was to highlight, for the first time, the volatile profile for two Romanian white wines, Feteasca regala and Feteasca alba, from three different vineyards (Silagiu, Aiud, and Sarica Niculițel). The results showed that wine’s aromatic profile was directly proportional with the area of origin for the grapes, directly correlated to the climate. The obtained values for alcohols, esters, aldehydes, and terpenoid compounds were also related to the oenoclimatic aptitude index, a significant accumulation of aroma compounds being observed mainly for the Feteasca regala wine. A total of 17 superior alcohols were evidenced within the two types of wines, among them, 2-phenyl ethanol being distinguished by its higher level in all samples, varying from 7692 up to 11,783 µg/L. Together with some aromatic esters, it offers one of the most pleasant aromas, resembling rose flavour. Of all the acids found in wines, the succinic acid has the most intense flavour, tasting somehow bitter and salty, imprinting to wine a certain “juiciness” and “vinosity”. Diethyl succinate was one of the main esters in all six samples, with concentrations from 777 up to 1200 µg/L. Also, two terpenoid compounds and two aldehydes were found in all samples. The data obtained from PCA evaluation suggested that there is a significant variance among wine varieties. Nevertheless, hierarchical clustering was applied to explain the relationship between the six samples of wines, the smallest clusters that included Silagiu and Aiud winegrowing regions suggesting an increased similarity of the compositional profile.

Utilization of different yield regulation methods of the vine for production of wines of higher designation protected of origin

Grape yield regulation is a method used to improve grape quality parameters. Experiments were carried out in 2021 on the grapevine (Vitis vinifera L.) wine varieties 'Feteasca regala' and 'Sauvignon blanc', focusing on the effect of two different methods of grape yield regulation on its selected parameters and must sugar content. The first method used was cluster thinning, leaving one bunch on the shoot. The next method used was cluster tipping when we removed the terminal part of each bunch. Yield reduction was carried out in the period between pea-sized berry phenophase (BBCH 75) and bunch closure phenophase (BBCH 77). The operations were carried out manually. Cluster thinning did not lead to a statistically significant difference in bunch weight compared to the control in any of the studied varieties. We observed a statistically significant (p <0.05) decrease in the average bunch weight in the variant cluster tipping. The 'Feteasca regala' hectare yield was 32.25% lower in the cluster thinning than the control. The hectare yield in the cluster thinning variant was reduced by 46.61% compared with the control. Cluster thinning variant of the Sauvignon blanc variety had a 19.13% lower yield than the control variant. The cluster tipping variant had a 29.03% lower yield than the control variant. In the case of the cluster thinning method, we observed a greater decrease in grape yield compared to the cluster tipping method. The obtained results indicate that cluster tipping method is preferable to the cluster thinning in terms of the profitability of grape production. The must sugar content was statistically significantly (p <0.05) increased in all the yield reduction variants. The variety 'Feteasca regala' had the highest sugar content of the must in the cluster thinning method, 19.42 kg/hL. The highest sugar content of 'Sauvignon blanc' was 21.33 kg/hL in the variant with cluster tipping. This shows that regulating the grape yield can improve the quality parameters of the grapes. On the other hand, it may lead to a decrease in yield per hectare below the break-even point. The justness and intensity of the method used must be carefully considered.

Grapevine Plants Management Using Natural Extracts and Phytosynthesized Silver Nanoparticles.

Starting from the well-known antimicrobial properties of silver nanoparticles, the goal of this study is to evaluate the influence of two "green" recipes, namely an alcoholic extract of Dryopteris filix-mas (L.) Schott and a dispersion of silver nanoparticles phytosynthesized using the extract on grapevine pathogens. The influence of some grapevine parameters (pith/wood rapport, soluble sugars, starch, total sugars, total water content, length of young shoots, number of grapes) in field experiments was also studied. The study was conducted on four clones (Feteasca alba 97 St., Feteasca neagra 6 St., Feteasca regala 72 St., and Cabernet Sauvignon 131 St.) located in vegetation pots inside a greenhouse. For the phytosynthesis of the silver nanoparticles (AgNPs) we used a scaled-up technology, allowing us to obtain large quantities of nanoparticles-containing solution. The AgNPs analysis by X-ray diffraction and transmission electron microscopy confirmed the synthesis of spherical and quasi-spherical nanoparticles of 17 nm average diameter and 6.72 nm crystallite size. The field experiments registered different responses of the four clones to the treatment, using both the natural extracts and phytosynthesized nanoparticles solution. Both recipes exhibited a protective effect against the Uncinula necator pathogen. For the treatment using phytosynthesized nanoparticles, significant increases in the pith/wood ratio for white wine clones (Feteasca alba 97 St. and Feteasca regala 72 St.) were observed. The biochemical analyses revealed other significant increases of soluble sugars (red wine clones-Feteasca neagra and Cabernet Sauvignon/second year), starch (Feteasca alba and Cabernet Sauvignon in 2021 for both clones), total sugars (Feteasca alba and Feteasca neagra in 2021 for both clones), and of total water content (Feteasca alba and Feteasca neagra in 2021 for both clones), respectively. The applied treatments also led to an increase of young shoots length and grape numbers for all clones as compared to the control (chemical pesticide), which would suggest a potential biostimulant effect of the recipes.

Effect of added sulphur dioxide levels on the aroma characteristics of wines from Panciu wine region

In the wine-making process, the yeasts form over 20 higher alcohols that improve the sensation of palatine veil for the wine. The amount of higher alcohols is lower for white and rosé wines obtained from clarified musts fermented at moderate temperatures. The formation of higher alcohols is confirmed by the fact that the addition of certain nitrogen compounds to a glucose-containing culture medium leads, after the fermentation, to an increase in the higher alcohol content. Data evaluate by comparison the levels of higher alcohols, esters and aldehydes, important to fermentation process in case of several wines from Panciu region. The wine-making was done by classical methods and by using specific protocols for low content sulphur dioxide. This study is focused to compare wines obtained from two grape varieties produced at industrial level: Feteasca regala vs. Feteasca regala Frizzante and Cabernet Sauvignon rosé vs. Cabernet Sauvignon. The compounds were analyzed by GC-FID method with head-space technique for methanol, 1-propanol, 2-methyl-propanol, 1-butanol, ethyl acetate, ethyl lactate, isoamyl acetate and acetaldehyde. The results showed that in almost every comparative study the levels of aroma compounds are maintained, when compared with the wines with low content of sulphur dioxide. Tuckey test showed that 1-propanol and ethyl acetate register statistically significant differences for Cabernet Sauvignon rosé and for Feteasca regala Frizzante.

Analyse of iPBS lenght polymorphism in selected group of Vitis vinifera, L varieties

Here, the specific natural variability of iPBS (Inter Primer Binding Sites Polymorphism) fingerprints in thirteen varieties of Vitis vinifera, L. was performed. All of the analysed biological material was collected in the vineyard of Sabo vinery for describing of the existing genetic polymorphism. Young leaves from a total of thirteen grapevine varieties were obtained in the in the Small Carpathians wine region of Slovakia, Vrbové. Genetic length polymorphism was studied by iPBS markers. A dendrogram of genetic similarity of generated fingerprints was constucted by UPGMA (Unweighted Pair Group Method with Arithmetic mean) and the Jaccard coefficient of genetic similarity was used for the analyse of 13 Vitis vinifera, L varieties. The generated dendrogram is separated into three major clusters at the genetic dissimilarity of 0.58. Cluster 1 is composed of two red varieties – Alibernet and Cabernet Sauvignon. Cluster 2 was further subdivided into two sub-clusters, where the larger one include all white varieties - Pinot Blanc, Müller-Thurgau, Welschriesling, Irsai Oliver, Grüner Veltliner, Pálava, Weisser Riesling, Sauvignon Blanc and Feteasca Regala. The second subcluster is comprised from two red varieties – Blaufränkisch and Dornfelder. The analysis prooved the the iPBS technique is an effective retrotransposon based markers to evaluate the variability of the genome in the germplasm of Vitis vinifera L. cultivated varieties.

The influence of climatic factors on the aroma compounds of Feteasca Regala wine from three southern regions of Romania

The influence of climatic factors on the aroma compounds of Feteasca Regala wine from three southern regions of Romania

Evaluation by Flash GC Electronic Nose of the Effect of Combinations of Yeasts and Nutrients on the Aromatic Profiles of Feteasca Regala Wines after Two Years of Storage

Feteasca regala is a semi-aromatic Romanian white grape variety, which can benefit from technological interventions aiming to modulate its aromatic profile. In this study, two specific yeast nutrients, designed to increase the esteric and thiolic aromatic potential, respectively, were added at appropriate times, before or during fermentation. The musts were inoculated with two different strains of yeast, specially selected to favour the formation of an esteric or a thiolic volatile profile. The resulting wines were bottled and analysed two years later by Heracles flash GC electronic nose (from Alpha MOS), which provided a good discrimination of the samples based on the peaks of volatile molecules identified on the two chromatographic columns. The electronic nose showed that, in the aged wines, the influence of the yeast inoculated for fermentation was more evident than the impact of the yeast nutrients added. Using the AroChemBase software module from Alpha MOS, some volatile esters and other compounds were identified, and their importance for the discrimination of the wines and for the aroma profile is discussed. However, because the GC electronic nose can identify only some volatile compounds, but not all, sensory analysis was also applied to evaluate the wine samples, showing that the yeast, as well as the nutrients, have a clear influence on the perceived aromatic profiles. As intended, samples prepared with any of the technological interventions showed different volatile/aromatic profiles than the control wine prepared by natural fermentation and were clearly separated by the electronic nose, even after two years of storage. However, due to the limitations of the chromatographic columns used, the electronic nose could not provide an overall description of the aromatic profile of the produced wines, which is why the expertise of panelists was still needed to evaluate wines.

THE INFLUENCE OF VEGETAL EXTRACTS AND NANOSTRUCTURED MIXTURES ON GRAPEVINE POLLEN GRAINS

Pesticides, plant bio-stimulants and chemical fertilizers used in intensified viticulture affects negatively the viability of the plants pollen causing relevant economic losses to viticulturists. Given these conditions, we aimed to identify the environmentally friendly phytosanitary treatments which does not negatively affect the evolution of pollen grains. The experiment took place in the greenhouse on 120 grapevine plants from the genotypes Feteasca alba 97 St., Feteasca regala 72 St., Feteasca neagra 6 St., Cabernet Sauvignon 131 St., 30 plants/genotype. These have been treated to combat the Plasmopara viticola and Uncinula necator pathogens with pesticides, biological products, plant extract and nanostructured mixture. The studied genotypes reacted differently regarding the evolution of the viability of pollen grains, the average pollen grains size and the total number of pollen grains. The best results have been registered at F. regala 72 St. (the viability was significantly improved at plants treated with plant extract and those with nanostructured mixture and the highest number of pollen grains was recorded at the plants treated with nanostructured mixture).

HPTLC Profile of Phenolic Compounds Presents in Extracts Obtained from Different Varieties of White and Red Grape Pomace

Grape pomace is used in different areas in the food and food supplement, cosmetic, pharmaceutic industries, and for compost or animal food. The chemical composition is different between white and red grapes varieties, depending also on the sort of wine obtained. Grape pomace contains various chemical compounds from the following classes: phenolics, proteins, minerals, lipids. Our goal was to show the HPTLC fingerprint for quality evaluation and total phenol content for the quantitative evaluation of extracts obtained from 4 varieties of grape pomace (Feteasca regala, Riesling, Burgund, Cabernet Sauvignon). The extracts were obtained by UAE and MAE. The HPTLC fingerprints of the extract shown that there are 4 compounds present in all samples: rutin, hyperoside and, chlorogenic and caffeic acids. In all samples was observed the presence of resveratrol. Total phenol content expressed as gallic (GAE) acid equivalents per 100ml extract were between 4.75% and 13.08%.

DETERMINATION OF HEAVY METALS CONCENTRATION IN WINE USING INDUCTIVELY COUPLED PLASMA MASS SPECTROMETRY (ICP-MS)

The determination of metals in different type of wines is of high importance for the nutritional, as well as toxic effects of these elements. The main purpose of this research is to determine the concentration of Cu, Fe, Mn, Cd, Zn and Pb in wine. The analyzed samples were wine samples obtained under micro-vinification conditions and from grapevine cultivars for the white wines (Feteasca Alba, Feteasca Regala, Babeasca Gri, Sarba) and for the red wines (Merlot, Feteasca Neagră, Cabernet Sauvignon). The highest concentrations were obtained in the cultivars of grapevine for the red wines (49.86 ± 1.32 μg/L Pb) recorded by the Feteasca Neagra cultivar and (0.23 ± 0.01 μg/L Cd) for the Merlot cultivar. In the case of Cu, Zn, Fe and Mn, the highest concentrations were recorded by the vines for white wines (532.48 ± 13.79 μg/L Cu, 1845.23 ± 32.58 μg/L Zn, 1654.98 ± 26.68 μg/L Fe, 221.32 ± 17.49 μg/L Mn) in comparison to the cultivars of vines for red wines. The conclusions obtained from the analysis of heavy metals in wines through ICP-MS are as follows: grapevine cultivars for red wine recorded the highest concentrations of Cd and Pb and the grapevine cultivars for white wines recorded the highest concentrations of Cu, Zn, Fe and Mn.Wine samples do not have a metal ion concentration higher than the maximum concentration allowed by law.The storage temperature does not affect the concentration of heavy metals, dry wine has a higher concentration of heavy metals in its composition.

Optimization of High-Pressure Extraction Process of Antioxidant Compounds from Feteasca regala Leaves Using Response Surface Methodology.

Circular economy principles are based on the use of by-products from one operation as the raw materials in another. The aim of this work is to obtain extracts with high antioxidant capacity and resveratrol content for the superior capitalization of the biomass of Feteasca regala leaves obtained during vineyard horticultural operations in spring. In order to obtain a high-quality extract at an industrial level, an optimal extraction process is needed. Central composite design (CCD) was used for the experiment design, which contained three independent variables: the ratio of extraction solvent to solid matter, temperature (°C) and time (minutes). The evaluation of extracts was done by measuring the total antioxidant capacity of the extracts using photo-chemiluminescent techniques, and the resveratrol content using liquid chromatography. Process optimization was done using response surface methodology (RSM). Minitab software version 17.0 was used for the design of experiments and data analysis. Regression analysis showed that the model predicts 87.5% of the variation for resveratrol and 96% for total antioxidant capacity (TAC). The temperature had the biggest influence on the extraction yield. The optimal operational conditions for the extraction method applied had the following conditions: ratio e/m 2.92; 43.23 °C and 55.4 min. A maximum value of 34,623 µg ascorbic acid equivalent (AAE) /mL total antioxidant capacity and 182.4 µg/mL resveratrol content were obtained when the optimal extraction parameters where used. The values obtained in experiments proved that by using RSM an accurate model can be obtained for extraction of Feteasca regala leaves.

Expression of Specific Class I Chitinase mRNA Levels in Different Grape Varieties and Their Antimicrobial Activity

The aim of this study was to compare the natural variability of the expression of class I chitinase gene in grapes of Vitis vinifera L. varieties as well as investigate their antimicrobial activity. Further, the effect of antimicrobial activity in chitinase expression was analyzed. Matured berries of thirteen grape varieties were used in the study—Alibernet, Dornfelder, Cabernet Sauvignon, Blaufränkisch, Sauvignon Blanc, Welschriesling, Weisser Riesling, Irsai Oliver, Pinot Blanc, Pálava, Müller-Thurgau, Grűner Veltliner, and Feteasca Regala, grown in the Small Carpathians wine region of Slovakia, Vrbové. Chitinase I gene expression was found to be similar in most of the analyzed varieties with the except of two varieties, where the expression of chitinase I was significantly higher—Pinot Blanc and Savignon Blanc. By comparing the varieties between the lowest and highest expression fold change, they were statistically different in the level of its chitinase I gene expression. Grape pomace extracts of analyzed Vitis vinifera L. were effective against Gram-positive, Gram-negative bacteria and yeasts, but a weak correlation tendency was found between chitinase I gene expression and antimicrobial activity, only against Staphylococcus aureus subsp. aureus, Candida albicans, and Candida glabrata.

Phenolic composition and antioxidant activity of red, rosé and white wines originating from Romanian grape cultivars

The objective of this work was to study the phenolic profile and composition in relation to antioxidant activity of fifteen samples of commercial red, rosé and white wines originating from six native grape varieties and produced in important wine regions from Romania. The profile and quantification of major phenolic compounds were performed by direct injection of wines in the LC-MS system, using DAD and ESI (+) MS techniques, in parallel with the total phenolic content (TPC) measured by spectrometry and the free radical scavenging activity, against 2,2-diphenyl-1-picrylhydrazyl (DPPH). There were identified 38 polyphenols in wines, including 3 flavan-3-ols, 17 flavonols, 12 anthocyanins and 6 stilbenes. The red wines had significant higher phenolic content and antioxidant capacity, followed by rosé and white wines. The richest phenolic content and antioxidant activity was obtained for ‘Feteasca Neagra’ (Tohani) among red wines and for ‘Feteasca Regala’ (Jidvei) among white wines. TPC values were positively correlated with the antioxidant capacity in all white wines and only for the red ‘Feteasca Neagra’ assortment, while for the ‘Babeasca Neagra’ assortment negative correlations were obtained. From the 38 variables, flavan-3-ols have exerted the greatest influence on wine differentiation, based on their colour (red, rosé and white). The study also revealed significant differences between cultivars, both qualitative and quantitative, in terms of their polyphenolic composition, that could be important in the cultivar authentication of wines from these varieties.

Grapevine Trunk Diseases Management in Vineyards from Central Transylvania

Grapevine trunk diseases (GTD) are among the most important diseases reported in vineyards in central Transylvania. On average, up to 5% of the vineyards are affected by the GTD although there are also vineyards where the incidence of the attack exceeds 15%. Recent studies show that the importance of pathogens in wood is so great that they are considered limiting factors that affect the stability of the world’s vineyards. The main objective of this study is to develop new sustainable management alternatives for the GTD control. For this purpose, an agroecological variant including prophylactic and cultural measures and two treatments with biofungicides based on: Trichoderma atroviride strain 8, Trichoderma atroviride strain B11 and Trichoderma harzianum, were tested. The frequency of the attack of the main four GTD diseases (Esca complex, Phomopsis dieback, Eutypa dieback and Crown gall) on the SCDVV Blaj homologated grapevine varieties, ‘Astra’, ‘Amurg’, ‘Brumariu’, ‘Blasius’ ‘Radames’, ‘Rubin’ and ‘Selena’, was assessed showing that these had a lower frequency of the symptoms compared with the widely cultivated variety ‘Feteasca regala’. Also the effect of training system (Classical versus semi-high Guyot) on GTD is presented. The classical system had decreased the frequency of crown gall and Phomopsis dieback, and the semi-high Guyot system had decreased Eutypa dieback’s frequency, indicating that the training system is an important tool of the agroecological system in maintaing the health of grapevine. Biofungicides tested help reduce the symptoms of GTD, but not enough to help reduce the premature death of grapevine.

Influence of Glutathione and Ascorbic Acid Treatments during Vinification of Feteasca Regala Variety and Their Antioxidant Effect on Volatile Profile.

Volatile profiles were determined for white wines of Feteasca regala variety produced from musts in which the antioxidants glutathione and ascorbic acid were added in different proportions before inception of alcoholic fermentation. Treatments with these antioxidants affect some volatile compound evolution and positively influence the wine volatile profile. After one year of storage in bottles with and without carbon dioxide protection the volatile profiles of the wines were assessed by using a Fast GC Alpha MOS Heracles e-Nose by applying a DFA multivariate statistical method and AroChemBase database for compound identification. The analyses showed that some higher alcohols, such as 2-phenylethanol and 2-methyl-1-butanol were in lower concentrations in wines treated with reduced glutathione, while the main ethyl fatty acid esters, such as ethyl butanoate, ethyl hexanoate, ethyl octanoate, and ethyl decanoate were better preserved when higher concentrations of any of the antioxidants were added in must. On the other hand, it was observed that some other volatile compounds were not affected by these applied treatments.

Microbiota of different wine grape berries

The wine grape berries share a complex microbial ecology including filamentous fungi, yeasts and bacteria. The microbiota reveals different physiological characteristics and depends on the grape ripening stage and the availability of nutrients with different effect on wine production. The microbiota of grape berries (n = 12) was isolated and identified in the present study. The samples were collected in September 2018. Grape berries were obtained from Vrbovo vineyard located in Slovakia. The grape berries investigated belonged to Blue Frankish, Cabernet Sauvignon, Chardonnay, Dornfelder, Feteasca regala, Green Veltliner, Irsai Oliver, Mūller Thurgau, Pálava, Pinot Blanc, Rhinriesling and Welschriesling varieties. The microorganisms were cultivated on Malt extract agar (MEA) at 25 °C for five days in aerobically for microscopic filamentous fungi and Tryptone Soya agar (TSA) at 37 °C for 24 – 48 h aerobically for bacteria and yeasts. Total bacterial counts on different wine grape berries ranged from 2.57 ±0.09 in Chardonnay to 4.39 ±0.21 log CFU.g-1 in Pálava. Microscopic filamentous fungi count ranged from 1.18 ±0.03 in Blue Frankish to 2.60 ±0.17 log CFU.g-1 in Welschriesling. MALDI-TOF MS Biotyper mass spectrometry was used for identification of microorganisms (bacteria and yeasts) and microscopic filamentous fungi with manuals. The most identified microscopic fungal species was Alternaria sp., for yeasts Issatchenkia orientalis and Leuconostoc mesenteroides subsp. mesenteroides for bacteria.

Yield, berry quality and physiological response of grapevine to foliar humic acid application

ABSTRACT Environmentally friendly grape growing is an important objective of modern viticulture. The aim of the study was to examine the response of two grapevine Vitis vinifera L. cultivars to humic acids (HA) foliar application as biostimulant in order to provide sustainable viticultural practices for farmers. The experiment was carried out under field conditions and repeated in two consecutive years. In order to evaluate the effect of humic acids application, the grapevines were treated with three concentrations: 30 ml.L-1 (HAT1), 40 ml∙L-1 (HAT2) and 50 ml∙L-1 (HAT3). The grapevines were represented by two grape varieties: cv. Feteasca Regala (cv. FR) and cv. Riesling Italian (cv. RI). Foliar sprays with humic acid derived from vermicompost at a concentration of 50 ml∙L-1 induced a significant increase in the total leaf area, yield and total soluble solids. For several measurements performed in plants we found no significant difference between grapevines treated with HAT2 and those with HAT3. The experimental results in the present study confirm that foliar application with humic acid may improve growth, yield, and berry quality attributes of grapevine.

Application of SERS technique in white wines discrimination

The wine discrimination potential of surface-enhanced Raman scattering (SERS) technique is reported. For this purpose, a set of 30 wines from three Romanian regions (Transylvania, Banat, Moldova) comprising two varieties, Sauvignon Blanc and Feteasca Regala from 2011-2015 vintages, was investigated. Additionally four French wine samples from Sauvignon Blanc and Chardonnay varieties, produced in 2015 were included in the study. The vine variety differentiation (Feteasca Regala versus Sauvignon Blanc) was achieved with a percentage of 90.3% while for the geographical origin differentiation among investigated Romanian areas a percentage of 83.3% was obtained. Additionally, the separation of French samples from Romanian ones was realized in a percentage of 100% in both, initial and cross-validation procedure. For vintage discrimination, the method proved to be less sensitive allowing only the differentiation of 2012 vintage from the other investigated vintages. In this case, the obtained percentages were 90% for initial classification and 83.3% in cross-validation.