Different Varieties Of Grapes Research Articles

Qualitative And Quantitative Analysis Of Organic Acids In Georgian Wine Lees By LCMS/ MS Method

In the XXI century, the interest and demand for natural compounds have increased significantly, compared to the previous period,especially for those natural compounds that have antioxidant, antimicrobial, and anti-inflammatory properties. Accordingly, organic acids arenoteworthy in this direction since studies have confirmed some organic acids' antioxidant, antimicrobial, and anti-inflammatory effects. It is known thatwine from vine products is one of the rich sources of organic acids. Therefore, the waste products of wine production - including wine lees areinteresting from this point of view. Winemaking is one of the most successful directions of agriculture in Georgia. Many waste products, such as grapepomace, grape seed, and wine lees, accompany wine production. It was the reason to use the waste product - wine lees- to study organic acids.Hence, the research aims to assess the potential of using a currently wasted winery product - Georgian wine lees as a source of biologically activeingredients. The objective of the current study was to identify the biologically active substances (organic acids) in the waste product of winemaking -wine lees obtained from widely distributed grape varieties in Georgia and to determine their quantitative content. By the LC-MS/MS method, weidentified organic acids in 6 samples of wine lees made from different varieties of Georgian grapes (Saperavi, Kisi, Rkatsiteli) and with differenttechnologies (traditional Kakhetian, factory conditions) and determined three main organic acids (tartaric acid, lactic acid, and citric acid) quantitatively.The results of the current research showed that the grape variety and the winemaking technology affect the qualitative and quantitative content oforganic acids in the wine; in particular, three organic acids were found in the Saferavi wine made by the factory method, and 2 organic acids in thewine made by the traditional Kakhetian (Georgia) method. Organic acid's quantitative content is also different. Also, the content of organic acids in thewine obtained from different varieties of grapes is different. The research showed that the quantitative content of organic acids in Kisi wine Lees ishigher than the other studied varieties. However, the content of organic acids in all three types of wine is significant. The study results support thepotential of using a currently wasted product - Georgian Wine Lees - as a source of biologically active ingredients.

Growth Performance of Different Varieties of Grapes in Karnataka

The study throws light on the growth performance of different varieties of grape cultivation in the state of Karnataka across its districts and divisions. The state produces majorly four varieties of grapes, namely Bengaluru Blue, Anab-e-Shahi, seedless varieties and miscellaneous varieties. The area and production of all varieties of grapes observed positive and significant growth during the study period. The results revealed that the growth was positively significant in the area (7.23 per cent per annum), production (7.96 per cent per annum) and productivity (0.67 per cent per annum). The growth rate was highest in the case of the Belagavi division, followed by the Kalaburagi division. The highest rate of increase in the area and productivity of grapes was recorded in the case of the Chikkaballapura district. The values of instability indices for the area (6.73), production (13.72) and productivity (7.49) were comparatively lower, indicating their stability in the state. Further, the instability analysis indicated that the area and productivity of grapes in the Mysuru division were more unstable than in other state divisions.

Detection of Pesticide Residue Level in Grape Using Hyperspectral Imaging with Machine Learning.

Rapid and accurate detection of pesticide residue levels can help to prevent the harm of pesticide residue. This study used visible/near-infrared (Vis-NIR) (376–1044 nm) and near-infrared (NIR) (915–1699 nm) hyperspectral imaging systems (HISs) to detect the level of pesticide residues. Three different varieties of grapes were sprayed with four levels of pesticides. Logistic regression (LR), support vector machine (SVM), random forest (RF), convolutional neural network (CNN), and residual neural network (ResNet) models were used to build classification models for pesticide residue levels. The saliency maps of CNN and ResNet were conducted to visualize the contribution of wavelengths. Overall, the results of NIR spectra performed better than those of Vis-NIR spectra. For Vis-NIR spectra, the best model was ResNet, with the accuracy of over 93%. For NIR spectra, LR was the best, with the accuracy of over 97%, but SVM, CNN, and ResNet also showed closed and fine results. The saliency map of CNN and ResNet presented similar and closed ranges of crucial wavelengths. Overall results indicated deep learning performed better than conventional machine learning. The study showed that the use of hyperspectral imaging technology combined with machine learning can effectively detect the level of pesticide residues in grapes.

A simple, fast, and direct electrochemical determination of tyramine in Brazilian wines using low-cost electrodes

Biogenic amines are a class of organic compounds formed in foods and beverages by enzymatic reactions or microbial decarboxylation of amino acids. Despite their benefits, in unusual concentrations, they are associated with hypertensive crises, neurological disorders and are precursors of compounds with cancer risk. Their abnormal levels are criteria for food spoilage and food safety. Tyramine is a biogenic amine found mainly in fermented foods as wine. Spoilage in the wine production process can increase tyramine concentration resulting in a harmful product to consumers. A fast, simple, and reliable method of tyramine detection in wine samples is necessary to ensure quality control. As this analyte presents electroactivity, three electrochemical techniques and ten different brands of pencil carbon graphite electrodes were used to explore and optimize its oxidation. Differential pulse voltammetry and square wave voltammetry were efficient electrochemical techniques in the determination of tyramine with excellent linear range and low limit of detection. The method was tested for tyramine determination during the grape fermentation process. There are differences regarding tyramine concentration with different varieties of grapes and during the fermentation steps. The method was validated regarding precision, robustness, specificity, accuracy and provided excellent recovery rates (94.4–106.0%) for Brazilian red wines.

Segmentation of field grape bunches via an improved pyramid scene parsing network

With the continuous expansion of wine grape planting areas, the mechanization and intelligence of grape harvesting have gradually become the future development trend. In order to guide the picking robot to pick grapes more efficiently in the vineyard, this study proposed a grape bunches segmentation method based on Pyramid Scene Parsing Network (PSPNet) deep semantic segmentation network for different varieties of grapes in the natural field environments. To this end, the Convolutional Block Attention Module (CBAM) attention mechanism and the atrous convolution were first embedded in the backbone feature extraction network of the PSPNet model to improve the feature extraction capability. Meanwhile, the proposed model also improved the PSPNet semantic segmentation model by fusing multiple feature layers (with more contextual information) extracted by the backbone network. The improved PSPNet was compared against the original PSPNet on a newly collected grape image dataset, and it was shown that the improved PSPNet model had an Intersection-over-Union (IoU) and Pixel Accuracy (PA) of 87.42% and 95.73%, respectively, implying an improvement of 4.36% and 9.95% over the original PSPNet model. The improved PSPNet was also compared against the state-of-the-art DeepLab-V3+ and U-Net in terms of IoU, PA, computation efficiency and robustness, and showed promising performance. It is concluded that the improved PSPNet can quickly and accurately segment grape bunches of different varieties in the natural field environments, which provides a certain technical basis for intelligent harvesting by grape picking robots. Keywords: grape bunches, semantic segmentation, deep learning, improved PSPNet DOI: 10.25165/j.ijabe.20211406.6903 Citation: Chen S, Song Y Y, Su J Y, Fang Y L, Shen L, Mi Z W, et al. Segmentation of field grape bunches via an improved pyramid scene parsing network. Int J Agric & Biol Eng, 2021; 14(6): 185–194.

Effect of Four Grape Varieties on the Physicochemical and Sensory Properties of Unripe Grape Verjuice

Verjuice is a sour-tasting juice obtained from the mechanical pressing of unripe grapes. The significance of verjuice as food product includes but not limited to its richness in antioxidant compounds, its usage as an alternative to lemon and vinegar, and also its production which can reduce the losses of lower quality grapes and waste from grape thinning. In this study, a survey for the common Lebanese traditional preparation methods for verjuice was done and physicochemical properties of four Lebanese verjuice varieties Tfayfihi, Baytamoni, Black, and Obeideh along with their sensory evaluation by consumers were studied. Results showed that “Black” grape verjuice has the highest density (1.01 ± 0.003 g/L), titratable acidity (4.51 g/L ± 0.03), total soluble solids (5.38°Brix ± 0.3), and polyphenol content (676.1 mg/L ± 6.8); verjuice processed from the Baytamoni grape variety has the highest browning index (0.432 ± 0.002) and color intensity (1.18 ± 0.007); “Obeideh” grape verjuice has the highest pH (2.55 ± 0.006); and “Tfayfihi” grape verjuice has the highest radical scavenging potential (91.76% ± 0.43) and moisture content (95.85% ± 0.19). Both “Tfayfihi” and “Black” grape verjuice has the highest total suspended solids (40 g/L ± 1.3 and 40 g/L ± 2.9, respectively) among all studied verjuice. There is no difference in taste between the four verjuice varieties which we studied, but there is a color preference for the “Tfayfihi” verjuice. The use of different varieties of grapes in the processing of verjuice affects the physicochemical and sensory properties and results in selection of grape varieties being favorable in the processing of verjuice with respect to factors such as polyphenol content and color of the final product.

Analytical Characterization and Sensory Analysis of Distillates of Different Varieties of Grapes Aged by an Accelerated Method.

The wine spirits used for the elaboration of Brandy de Jerez are mainly obtained from wines produced from the Airén type of grape, which comes from the vineyards located in the region of La Mancha (Central Spain). This entails a limitation when achieving a product classified as “protected geographic designation”. For that purpose, it is necessary that the grape used for the wine spirit comes from the area and not from Castile la Mancha, as has happened until now. Due to this fact, it is necessary to search for a possible alternative grape variety which allows the produced brandy to be eligible for a “protected geographic designation”. For that purpose, an accelerated ageing process has been implemented with a method previously optimized to distillates obtained from wines from different varieties of grapes (Airén, Colombard, Corredera, Doradilla, Garrido Fino, Jaén blanco, Moscatel de Alejandría, Palomino Fino, Ugni Blanc, and Zalema) grown in the Jerez Area. They were evaluated, both from the analytical and sensory points of view. The distillates made from Jaén Blanco and Zalema have properties that make them interesting for future development and incorporation into oenological practice.

Development of viticulture in the north-eastern forest-steppe region of Ukraine through the prism of the ecological approach

The purpose of this article is to determine ecological aspects of grapes quality grown on a private plot in the village of Vysokyi, Kharkiv district, Kharkiv region. Main material. The article analyzes the issues of safe and ecological cultivation of grapes in the North-Eastern foreststeppe region of Ukraine as one of the most important indicators for successful and rational cultivation of grapes. This thus ensures crop productivity, drawing a???? ention to the need to intensify research and practical activities for grapes cultivation. The study of viticulture’s optimization shows that it is necessary to have a clear and complete picture of the ecological potential of the territory to increase the productivity of plantations. For this reason a comprehensive method of studying grapes and related plants is required. Useful properties of such a valuable crop as grapes will be manifested if it is environmentally safe for the human body. It should be added that the ecological value of grapes as a crop is due to the fact that it does not deplete the soil and does not suppress other plants. Proper farming techniques, when cultivating soils, do not lead to their signifi cant erosion. Grapes can also be used on soils that are less suitable for other crops in terms of their mechanical and organic composition. All this is complemented by the fact that grape plantations can exist in specifi c areas for a long time without negative manifestations. Grapes are a unique product in their composition and, therefore - extremely useful. The quality of plants is an urgent problem for specialists in various fi elds of research from soil scientists to nutritionists. People have been studying plants for a long time, solving various problems. Conclusions. 10 diff erent varieties of grapes (and grape seeds) have been analysed in the course of study as well as soil samples from the area of cultivation to determine the concentration of heavy metals (Zn, Cu, Cd, Cr, Pb) and nitrates. It has been determined that concentrations of heavy metals do not exceed the normative indicators in berries and stones in any of the grape varieties. An important task is to analyse in detail the suitability of the territory of Kharkiv region for growing grapes in the natural environment. Beneficial properties of grapes will be manifested if they are environmentally safe for the human body.

Cluster approach to development of wine and gastronomy tourism in Volgograd region

This article discusses the possibilities of grape growing and wine production industry in the Volgograd region development to increase the tourist attractiveness of the region. The article describes the soil and climate, historical, agricultural and technological and social and economic prerequisites for development of this branch. It was suggested to use the cluster approach, joining efforts of grape growers and wine producers, as well as scientific and educational, tourist and hospitability enterprises of the Volgograd region for rendering tourist and recreation services for the local residents, Russian and foreign guests of the city within the educational and production project of the Volgograd state agricultural university “Innovative village “Gornaya Polyana”. The originality of suggestions is that the “Gornaya Polyana” is the unique educational, scientific and production center that not only provides the tourists with information on history, local traditions, technology and culture of alcohol drinking, but also suggests them tasting different varieties of grape and wine, working on vinelands, participating in wine festivals and thematic festivals; visiting and taking part in special exhibitions and meetings, workshop sessions and educational programs, joining the abilities of agricultural, wine, gastronomical, ethnographic, educational events and business tourism. The project suggests creating of the recreation and service areas such as: park area, pond, bath house at the water basin shore, recreation services, including the wine therapy and wine cosmetology; production and workshops, including wine production, willow weaving; leisure activities and services, accommodation means and other.The results of investigation should be used for solving the social and economic problems in the region due to development of non-agricultural activities at the rural area, such as: wine, gastronomical and ethnographical tourism.

Phytochemical and Antioxidant Profile of Different Varieties of Grape from the Small Carpathians Wine Region of Slovakia

The aims of the present study was to determine antioxidant profile (antioxidant activity, total polyphenol, phenolic acid, flavonoid and in red varieties also anthocyanin content) as well as a content of phytochemicals (crude protein, ash, reducing sugars and ascorbic acid content) in four red grape varieties (‘Alibernet’, ‘Dornfelder’, ‘Cabernet Sauvignon’, ‘Blaufrankisch’) and nine white varieties (‘Sauvignon Blanc’, ‘Welschriesling’, ‘Weisser Riesling’, ‘Irsai Oliver’, ‘Pinot Blanc’, ‘Palava’, ‘Muller-Thurgau’, ‘Grűner Veltliner’, ‘Feteasca Regala’) produced in the Small Carpathians wine region of Slovakia. The antioxidant activity was the highest in ‘Alibernet’ tested by both methods (0.52 ± 0.02 and 23.61 ± 0.09 mg TEAC/g fresh matter; TEAC—Trolox equivalent antioxidant activity), and in ‘Pinot Blanc’ by DPPH and ‘Irsai Oliver’ by phosphomolybdenum methods (0.41 ± 0.01 and 21.55 ± 0.03 mg TEAC/g fresh matter). The highest content of total polyphenol was detected in ‘Alibernet’ and ‘Grűner Veltliner’ (3.53 ± 0.42 mg GAE/g and 1.06 ± 0.05 mg GAE/g; GAE—gallic acid equivalent), respectively. The highest total flavonoid content was found in ‘Alibernet’ and ‘Irsai Oliver’ (1.37 ± 0.01 mg QE/g and 0.35 ± 0.01 mg QE/g; QE—quercetin equivalent) and the highest total phenolic acid content in ‘Alibernet’ and ‘Grűner Veltliner’ samples (1.77 ± 0.03 mg CAE/g and 0.50 ± 0.01 mg CAE/g; CAE—caffeic acid equivalent). The highest level of total anthocyanin was determined in ‘Alibernet’ (5.79 ± 0.24 mg/g fresh matter) in comparison with other tested red varieties. The obtained results confirmed that the grape is a good source of phytochemicals.

Effect of weather conditions on the development of grape oidium in the steppe zone of the lower Volga region

The peculiarities of the oidium spread in the steppe zone of the Lower Volga region were studied on 33 grape varieties taking into account the weather conditions of this region. It has been shown that two of seven years of research were characterized by oidium epidhytotics, two years - by the disease of  medium severity, and three years  - by the mild case. The most favorable weather conditions for the disease development are identified. A macroscopic study of oidium spread has shown that different varieties of grape  have different resistance to the causative agent of the disease. The following groups of varieties were identified: unstable – Zhemchug Saba, MadLen Anzhevin, Shasla belaya; medium resistant - Aleshenkin, Bulgaria, Victoria, Ukrainka, Tsvetochniy; tolerant - Bianca; Kishmish Mirazh, Levokumsky ustoichivyi, Muscat letniy; highly resistant - Augustine, Arcadia, Vostorg, Vostorg Idealniy, Vostorg krasniy, Vostorg cherniy, GF 14-75, Kantemirovsky, Kobzar, Korinka Russkaya, Lucy Belaya, Pamyati  Negrulya, European Pleven, Smuglyanka Moldavskaya, Talisman, Ezop; very highly resistant - Bako cherniy, Kishmish Hungarian, Lediya, Nectarniy, Severniy Plechistic. For industrial cultivation in the steppe zone of the Lower Volga region, varieties characterized by increased oidium resistance are recommended.

Determination of hydroxytyrosol produced by winemaking yeasts during alcoholic fermentation using a validated UHPLC–HRMS method

Hydroxytyrosol (HT) is a phenolic compound of recognized bioactivity that has been described in wines but little is known about its origin. This work demonstrates that yeast involved in wine making, i.e. Saccharomyces cerevisiae strains and the non-Saccharomyces Torulaspora delbrueckii, can synthesise HT, as this compound was identified in the intracellular media of three strains by means of a developed and validated UHPLC–HRMS method with LOQ and LOD of 0.108 and 0.035ngmL−1 respectively. Controlled fermentations were performed with different varieties of grapes (Corredera, Moscatel, Chardonnay, Palomino fino, Sauvignon Blanc, Vijiriega, and Tempranillo) and synthetic must. The Saccharomyces cerevisiae strain QA23 was the most efficient producer of HT from tested yeasts. On the other hand, the grape variety influences HT wine concentrations. Furthermore, the maximum concentration of HT is reached between the fourth and sixth day of fermentation. This work reveals that yeasts have a great potential for the production of HT.

Production of White Wine from Grapes Using Sacharomyces cervisiae

Wine is an alcoholic beverage often made of fermented grape juice. The natural chemical balance of grapes is such that they can ferment without the addition of sugars, acids, enzymes or other nutrients. Wine is produced by fermenting crushed grapes using various types of yeast which consume the sugars found in the grapes and convert them into alcohol. Different varieties of grapes and strains of yeasts are used depending on the types of wine being produced. Although other fruits such as apples and berries can also be fermented, the resultant wines are normally named after the fruit from which they are produced (for example, apple wine or elderberry wine) and are generically known as fruit wine or country wine. Wine is an undistilled product obtained after normal alcoholic fermentation of grapes by yeast. Wine is basically the transformation of sugars of grapes by yeast under anaerobic conditions in to ethanol, co2, and small amounts of byproducts like D-Glucose, D-fructose. In our project, for the extraction of juice grapes must be stemed, cleaned, and crushed and then sodium or potassium metabiosulphate is added to check undesirable organisms. The crushed grape is called must. Fermentation is carried out by adding 2–5% of wine yeast namely sacharomyces cervisiae, anaerobic conditions favors the alcoholic fermentation liberating ethanol, co2. Main aim of this work is to produce white wine from grapes. A detailed study on grapes and different methods to produce wine is also reported. By analysis of wine, we reported the percentage purity, alcohol percentage in produced wine and different compound compositions.

Array of biosensors for discrimination of grapes according to grape variety, vintage and ripeness

A bioelectronic tongue based on nanostructured biosensors specific for the simultaneous detection of sugars and phenols has been developed. The array combined oxidases and dehydrogenases immobilized on a lipidic layer prepared using the Langmuir-Blodgett technique where Glucose oxidase, d-Fructose dehydrogenase, Tyrosinase or Laccase were imbibed. A phthalocyanine was co-immobilized in the sensing layer and used as electron mediator. The array thus formed has been used to analyze grapes and provides global information about the samples while providing specific information about their phenolic and their sugar content. Using Principal Component Analysis (PCA) the array of voltammetric biosensors has been successfully used to discriminate musts prepared from different varieties of grapes (Tempranillo, Garnacha, Cabernet-Sauvignon, Prieto Picudo and Mencía). Differences could be also detected between grapes of the same variety and cultivar harvested in two successive vintages (2012 and 2013).Moreover, the ripening of grapes could be monitored from veraison to maturity due to the changes in their phenolic and sugar content. Using Partial Least Squares (PLS-1) analysis, excellent correlations have been found between the responses provided by the array of biosensors and classical parameters directly related to phenols (total polyphenol index, TPI) and sugar concentration (degree Brix) measured by chemical methods with correlation coefficients close to 1 and errors close to 0. It is also worthy to notice the good correlations found with parameters associated with the pH and acidity that can be explained by taking into account the influence of the pH in the oxidation potentials of the phenols and in the enzymatic activity.This bioelectronic tongue can assess simultaneously the sugar and the phenolic content of grapes and could be used to monitor the maturity of the fruit and could be adapted easily to field analysis.

Multisensor systems based on phthalocyanines for monitoring the quality of grapes

Arrays of phthalocyanine-based sensors with complementary activity have been used to develop voltammetric electronic tongues. Such systems have demonstrated to be useful in enology for the evaluation of quality of wines in different production stages, from grapes to bottles. In this paper, the state of the art of multisensor systems based on phthalocyanines dedicated to the analysis of musts (juices obtained from crushed grapes) is described. Such multisensor systems cover different types of sensors from simple Carbon Paste Electrodes, to sophiticated nanostructured sensors, including Langmuir–Blodgett or Layer by Layer thin films and biomimetic biosensors where phthalocyanines play a crucial role as electron mediator between enzymes and electrodes. In all cases, multisensor systems based on phthalocyanines have been able to discriminate musts prepared from different varieties of grapes. The performance of these systems can be improved by combining non-specific sensors with biosensors containing enzymes selective to phenols. In this case, excellent relationships have been found between the responses provided by the array and the content in phenols and acids provided by traditional chemical analysis.

Integrated, paper-based potentiometric electronic tongue for the analysis of beer and wine

The following manuscript details the stages of construction of a novel paper-based electronic tongue with an integrated Ag/AgCl reference, which can operate using a minimal amount of sample (40 μL). First, we optimized the fabrication procedure of silver electrodes, testing a set of different methodologies (electroless plating, use of silver nanoparticles and commercial silver paints). Later a novel, integrated electronic tongue system was assembled with the use of readily available materials such as paper, wax, lamination sheets, bleach etc. New system was thoroughly characterized and the ion-selective potentiometric sensors presented performance close to theoretical. An electronic tongue, composed of electrodes sensitive to sodium, calcium, ammonia and a cross-sensitive, anion-selective electrode was used to analyze 34 beer samples (12 types, 19 brands). This system was able to discriminate beers from different brands, and types, indicate presence of stabilizers and antioxidants, dyes or even unmalted cereals and carbohydrates added to the fermentation wort. Samples could be classified by type of fermentation (low, high) and system was able to predict pH and in part also alcohol content of tested beers. In the next step sample volume was minimalized by the use of paper sample pads and measurement in flow conditions. In order to test the impact of this advancement a four electrode system, with cross-sensitive (anion-selective, cation-selective, Ca2+/Mg2+, K+/Na+) electrodes was applied for the analysis of 11 types of wine (4 types of grapes, red/white, 3 countries). Proposed matrix was able to group wines produced from different varieties of grapes (Chardonnay, Americanas, Malbec, Merlot) using only 40 μL of sample. Apart from that, storage stability studies were performed using a multimeter, therefore showing that not only fabrication but also detection can be accomplished by means of off-the-shelf components. This manuscript not only describes new paper-based, potentiometric sensors but also according to our knowledge is the first description of an electrochemical paper-based electronic tongue with integrated reference.

An Electrochemical Quartz Crystal Microbalance Multisensor System Based on Phthalocyanine Nanostructured Films: Discrimination of Musts.

An array of electrochemical quartz crystal electrodes (EQCM) modified with nanostructured films based on phthalocyanines was developed and used to discriminate musts prepared from different varieties of grapes. Nanostructured films of iron, nickel and copper phthalocyanines were deposited on Pt/quartz crystals through the Layer by Layer technique by alternating layers of the corresponding phthalocyanine and poly-allylamine hydrochloride. Simultaneous electrochemical and mass measurements were used to study the mass changes accompanying the oxidation of electroactive species present in must samples obtained from six Spanish varieties of grapes (Juan García, Prieto Picudo, Mencía Regadío, Cabernet Sauvignon, Garnacha and Tempranillo). The mass and voltammetric outputs were processed using three-way models. Parallel Factor Analysis (PARAFAC) was successfully used to discriminate the must samples according to their variety. Multi-way partial least squares (N-PLS) evidenced the correlations existing between the voltammetric data and the polyphenolic content measured by chemical methods. Similarly, N-PLS showed a correlation between mass outputs and parameters related to the sugar content. These results demonstrated that electronic tongues based on arrays of EQCM sensors can offer advantages over arrays of mass or voltammetric sensors used separately.

Comparison of the yeast microbiota of different varieties of cool-climate grapes by PCR-RAPD

The yeast microbiota occurring on different varieties of grapes grown in cool-climate is not completely researched. Therefore, its identification is important to research. On the other hand, yeasts occurring in these fruits can be potentially used as starter cultures to obtain particularly demanded features in the production of wine. In addition, rapid methods for yeast identification allow to eliminate the contamination with pathogenic yeasts, which could cause the loss of wine production. The aim of the study was to isolate and identify the yeasts occurring on the surface of the different varieties of white and red grapes, grown in cool-climate of Poland. Also, the aim was to compare the qualitative and quantitative composition of yeasts on the tested grapes. The 84 cultures of yeasts were isolated, that were initially macroscopic and microscopic analyzed and the purity of cultures was rated on the WL medium. Identification of yeasts by PCR-RAPD was carried using the M13 primer. In the PCR-RFLP method ITS1 and ITS4 primers, as well as restriction enzymes HhaI, HinfI, HaeIII, were used. Preliminary identification of yeasts by standard methods produced results very different from the results obtained by molecular methods. Among the isolated microorganisms yeasts were dominating, but bacteria and molds were also present. Using the PCR-RAPD method most strains of yeasts were identified. Yeast microflora of different varieties of white and red grapes was very similar as the same species of yeasts were identified. Yeasts of the genus Saccharomyces were present in all varieties of grapes. The Rhodotorula mucilaginosa, Saccharomyces cerevisiae, Metschnikowia pulcherrima, Rhodotorula minuta, Pichia kluyveri, Hanseniaspora uvarum and Rhodotorula mucilaginosa were identified by PCR-RAPD. 4 of the 33 tested strains of yeasts were identified by PCR-RFLP. By PCR-RAPD only Hanseniaspora uvarum was identified. The quantity and quality of microorganisms living on the surface of grape fruits is very important for the process of winemaking. Yeasts influence the course of alcoholic fermentation, the flavor, aroma, and thus the quality of the produced wine. To a large extent their presence depends on the condition of the surface of the fruit. Many researchers reported significant differences between yeast microflora in grapes of Mediterranean and cool-climate vineyards. As they are expected to affect the final wine properties precise researching of the microflora of cool-climate grapes may lead to the isolation of new species of yeasts and thus the wines with unique characteristics can be obtained.

Exploitation of the non-Saccharomyces yeast Starmerella bacillaris (synonym Candida zemplinina) in wine fermentation: Physiological and molecular characterizations

Nowadays, the use of non-Saccharomyces yeasts in combination with Saccharomyces cerevisiae is a state-of-the-art strategy to improve complexity and enhance the analytical composition of the wines. This application has stimulated the interest of understanding how the non-Saccharomyces yeasts can contribute to the quality of the wines. The study presented here explores the potential use of Starmerella bacillaris (synonym Candida zemplinina) under winemaking conditions. Physiological and genetic characterizations of sixty-three isolates of Starm. bacillaris, previously isolated from four different varieties of grapes, were carried out. Both analyses revealed a low level of diversity between the isolates of Starm. bacillaris, while the fermentation trials in laboratory scale demonstrated the good enological performance of this species. The strong fructophilic character of this species and its ability to produce low quantities of ethanol and acetic acid and high amounts of glycerol were confirmed. The results, presented here, demonstrated a potential application of this non-Saccharomyces species in mixed wine fermentations with S. cerevisiae.

Phenolic compounds, organic acids and antioxidant activity of grape juices produced from new Brazilian varieties planted in the Northeast Region of Brazil

The phenolic compounds, organic acids and the antioxidant activity were determined for grape juice samples from new Brazilian varieties grown in the Sub-middle São Francisco Valley in the Northeast Region of Brazil. The results showed that the Brazilian grape juices have high antioxidant activity, which was significantly correlated with the phenolic compounds catechin, epicatechin gallate, procyanidin B1, rutin, gallic acid, caffeic acid, p-coumaric acid, pelargonidin-3-glucoside, cyanidin-3-glucoside, cyaniding-3,5-diglucoside and delphinidin-3-glucoside. The produced juice samples showed higher concentrations of trans-resveratrol than those observed in juices made from different varieties of grapes from traditional growing regions. Organic acids concentrations were similar to those of juices produced from other classical varieties. It was demonstrated that it is possible to prepare juices from grapes of new varieties grown in the Northeast of Brazil containing a high content of bioactive compounds and typical characteristics of the tropical viticulture practised in the Sub-middle São Francisco Valley.