Wine Research Articles

High Growing Season Temperatures Limit Winter Recovery of Grapevines from Xylella fastidiosa Infection - Implications for Epidemiology in Hot Climates.

Management of widespread plant pathogens is challenging as climatic differences among crop-growing regions may alter key aspects of pathogen spread and disease severity. Xylella fastidiosa is a xylem-limited bacterial pathogen that is transmitted by xylem sap-feeding insects. Geographic distribution of X. fastidiosa is limited by winter climate, and vines infected with X. fastidiosa can recover from infection when held at cold temperatures. California has a long history of research on Pierce's disease and significant geographic and climatic diversity among grape-growing regions. This background in combination with experimental disease studies under controlled temperature conditions can inform risk assessment for X. fastidiosa spread and epidemic severity across different regions and under changing climate conditions. California's grape-growing regions have considerable differences in summer and winter climate. In northern and coastal regions, summers are mild and winters are cool, conditions which favor winter recovery of infected vines. In contrast, in inland and southern areas, summers are hot and winters mild, reducing likelihood of winter recovery. Here, winter recovery of three table grape cultivars (Flame, Scarlet Royal, and Thompson Seedless) and three wine grape cultivars (Sauvignon Blanc, Cabernet Sauvignon, and Zinfandel) were evaluated under temperature conditions representative of the San Joaquin Valley, an area with hot summers and mild winters that has been severely impacted by Pierce's disease and contains a large portion of California grape production. Mechanically inoculated vines were held in the greenhouse under one of three warming treatments to represent different seasonal inoculation dates prior to being moved into a cold chamber. Winter recovery under all treatments was generally limited but with some cultivar variation. Given hot summer temperatures of many grape-growing regions worldwide, as well as increasing global temperatures overall, winter recovery of grapevines should not be considered a key factor limiting X. fastidiosa spread and epidemic severity in the majority of cases.

Study of polyphenolic compounds in wines and different parts of the grapevine

ABSTRACT This paper describes research conducted on the polyphenolic compounds found in wine and different parts of the grapevine. The research consisted of two experiments. In the first, extracts of polyphenols from the leaves, stems, skins and seeds were measured. In the second, these parts were macerated and left in the must during fermentation. For this experiment, the Souvignier gris wine grape variety was used. In both cases, 33 polyphenolic compounds were measured. These measurements were made using the liquid chromatography–mass spectrometry (LC-MS) method. Based on the results, the individual concentrations of all the polyphenolic compounds in different parts of the plant were measured. Addition of the individual parts of the grapevine to the must during fermentation was shown to increase the concentration of the individual polyphenols in the wine. It is therefore important not to forget the importance of the stems and the maceration of the grapes during the winemaking process.

Vineyard soil texture and pH effects on Meloidogyne hapla and Mesocriconema xenoplax

AbstractNorthern root‐knot nematode (Meloidogyne hapla) and ring nematode (Mesocriconema xenoplax) are the most prevalent plant‐parasitic nematodes of wine grapes in the Pacific Northwest, but M. hapla is most important in eastern Washington and M. xenoplax in western Oregon. These regions differ edaphically where Washington soils are minimally weathered and alkaline while Oregon soils are highly weathered and acidic. To examine the effect of soil texture and pH on nematode reproduction, an alkaline, sandy loam soil (pH 7.9) from Washington and an acidic loam soil from Oregon (pH 5.4) were modified to the other pH extreme, and to a middle pH of 6.9. Tomatoes were planted into each soil/pH combination, and either 500 M. hapla second‐stage juveniles or M. xenoplax individuals were added to each pot. After 7 weeks, plants were harvested, three roots collected for analysis, remaining roots and leaves dried and weighed, and nematode population densities determined as eggs on roots (M. hapla) and nematodes in soil (M. xenoplax). Soil texture (sandy loam or loam) had no effect on either nematode, but M. hapla reproduction was greater in the lowest pH soil while M. xenoplax was unaffected by soil pH. Mesocriconema xenoplax parasitism reduced root length and root tip number, whereas M. hapla increased root mass in the highest pH Washington soil. Under these experimental conditions, it appears vineyard soil texture in the Pacific Northwest is not a determining factor in population growth of these nematodes, but M. hapla performed better at low pH.

Rapid Determination of Wine Grape Maturity Level from pH, Titratable Acidity, and Sugar Content Using Non-Destructive In Situ Infrared Spectroscopy and Multi-Head Attention Convolutional Neural Networks.

In the pursuit of enhancing the wine production process through the utilization of new technologies in viticulture, this study presents a novel approach for the rapid assessment of wine grape maturity levels using non-destructive, in situ infrared spectroscopy and artificial intelligence techniques. Building upon our previous work focused on estimating sugar content (∘Brix) from the visible and near-infrared (VNIR) and short-wave infrared (SWIR) regions, this research expands its scope to encompass pH and titratable acidity, critical parameters determining the grape maturity degree, and in turn, wine quality, offering a more representative estimation pathway. Data were collected from four grape varieties-Chardonnay, Malagouzia, Sauvignon Blanc, and Syrah-during the 2023 harvest and pre-harvest phenological stages in the vineyards of Ktima Gerovassiliou, northern Greece. A comprehensive spectral library was developed, covering the VNIR-SWIR spectrum (350-2500 nm), with measurements performed in situ. Ground truth data for pH, titratable acidity, and sugar content were obtained using conventional laboratory methods: total soluble solids (TSS) (∘Brix) by refractometry, titratable acidity by titration (expressed as mg tartaric acid per liter of must) and pH by a pH meter, analyzed at different maturation stages in the must samples. The maturity indicators were predicted from the point hyperspectral data by employing machine learning algorithms, including Partial Least Squares regression (PLS), Random Forest regression (RF), Support Vector Regression (SVR), and Convolutional Neural Networks (CNN), in conjunction with various pre-processing techniques. Multi-output models were also considered to simultaneously predict all three indicators to exploit their intercorrelations. A novel multi-input-multi-output CNN model was also proposed, incorporating a multi-head attention mechanism and enabling the identification of the spectral regions it focuses on, and thus having a higher interpretability degree. Our results indicate high accuracy in the estimation of sugar content, pH, and titratable acidity, with the best models yielding mean R2 values of 0.84, 0.76, and 0.79, respectively, across all properties. The multi-output models did not improve the prediction results compared to the best single-output models, and the proposed CNN model was on par with the next best model. The interpretability analysis highlighted that the CNN model focused on spectral regions associated with the presence of sugars (i.e., glucose and fructose) and of the carboxylic acid group. This study underscores the potential of portable spectrometry for real-time, non-destructive assessments of wine grape maturity, thereby providing valuable tools for informed decision making in the wine production industry. By integrating pH and titratable acidity into the analysis, our approach offers a holistic view of grape quality, facilitating more comprehensive and efficient viticultural practices.

The Interactions between Two Fungal Endophytes Epicoccum layuense R2-21 and Alternaria alternata XHYN2 and Grapevines (Vitis vinifera) with De Novo Established Symbionts under Aseptic Conditions.

In this study, we focused on grapevine-endophyte interactions and reprogrammed secondary metabolism in the host plant due to defense against the colonization of endophytes. Thus, the transcriptional responses of tissue cultured grapevine seedlings (Vitis vinifera L. cv.: Cabernet Sauvignon) to two fungal endophytes Epicoccum layuense R2-21 (Epi R2-21) and Alternaria alternata XHYN2 (Alt XHYN2) at three different time points (6 h, 6 d, 15 d) were analyzed. As expected, a total of 5748 and 5817 differentially expressed genes (DEGs) were separately initiated in Epi R2-21 and Alt XHYN2 symbiotic tissue cultured seedlings compared to no endophyte treatment. The up-regulated DEGs at all time points in Epi R2-21- or Alt XHYN2-treated seedlings were mainly enriched in the flavonoid biosynthesis, phenylpropanoid biosynthesis, phenylalanine metabolism, stilbenoid, diarylheptanoid and gingerol biosynthesis, and circadian rhythm-plant pathways. In addition, the up-regulated DEGs at all sampling times in Alt XHYN2-treated tissue cultured seedlings were enriched in the plant-pathogen interaction pathway, but appeared in Epi R2-21 symbiotic seedlings only after 15 d of treatment. The down-regulated DEGs were not enriched in any KEGG pathways after 6 h inoculation for Epi R2-21 and Alt XHYN2 treatments, but were enriched mainly in photosynthesis-antenna proteins and plant hormone signal transduction pathways at other sampling times. At three different time points, a total of 51 DEGs (all up-regulated, 1.33-10.41-fold) were involved in secondary metabolism, and 22 DEGs (all up-regulated, 1.01-8.40-fold) were involved in defense responses in endophytic fungi symbiotic tissue cultured seedlings. The protein-protein interaction (PPI) network demonstrated that genes encoding CHS (VIT_10s0042g00920, VIT_14s0068g00920, and VIT_16s0100g00910) and the VIT_11s0065g00350 gene encoding CYP73A mediated the defense responses, and might induce more defense-associated metabolites. These results illustrated the activation of stress-associated secondary metabolism in the host grapevine during the establishment of fungi-plant endophytism. This work provides avenues for reshaping the qualities and characteristics of wine grapes utilizing specific endophytes and better understanding plant-microbe interactions.

Enhancing humification and microbial interactions during co-composting of pig manure and wine grape pomace: The role of biochar and Fe2O3

Phenol-rich wine grape pomace (WGP) improves the conversion of pig manure (PM) into humic acid (HA) during composting. However, the impact of using combinations of Fe2O3 and biochar known to promote compost maturation remains uncertain. This research explored the individual and combined influence of biochar and Fe2O3 during the co-composting of PM and WGP. The findings revealed that Fe2O3 boosts microbial network symbiosis (3233 links), augments the HA yield to 3.38 by promoting polysaccharide C–O stretching, and improves the germination index to 124.82 %. Limited microbial interactions, increased by biochar, resulted in a lower HA yield (2.50). However, the combination weakened the stretching of aromatics and quinones, which contribute to the formation of HA, resulting in reduced the humification to 2.73. In addition, Bacillus and Actinomadura were identified as pivotal factors affecting HA content. This study highlights Fe2O3 and biochar's roles in phenol-rich compost humification, but combined use reduces efficacy.

Reducing cluster rots in Michigan wine grapes using combined pathogen and vinegar fly control

Cluster rots pose a significant threat to the wine grape industry, leading to substantial economic losses. This study aimed to determine the performance of multiple treatments targeting cluster rot pathogens and their insect vectors over three years in southwest Michigan. Grape clusters were rated for disease incidence and severity, insects were collected and identified, and pesticide residues were measured on harvested clusters. In 2020, disease incidence decreased significantly when BLAD was applied in combination with the insecticides spinetoram, imidacloprid with beta-cyfluthrin, or zeta-cypermethrin. Similarly, in 2021, clusters treated with cyprodinil plus fludioxonil mixed with insecticides cyclaniliprole, spinosad, zeta-cypermethrin, or imidacloprid plus beta-cyfluthrin significantly reduced disease incidence compared to fungicide alone. Notably, in 2022, treating clusters solely with an insecticide significantly lowered disease incidence compared to treating with only a fungicide. Disease incidence and severity were positively correlated with the number of Drosophila larvae or the adults emerging from clusters collected in the trial. The relationship between disease and insect incidence were significant in 2021 and 2022, highlighting the importance of controlling insect vectors to manage rots. Through chemical residue testing, we identified pesticide programs that resulted in lower pesticide residues on the grapes. Programs that incorporate organic insecticides or sterilants had statistically lower residues than programs with conventional products. Our findings highlight the effectiveness of incorporating insecticides into late-season IPM programs for reducing cluster rots in wine grapes as managing insect vectors mitigate the impact of cluster rots on grape production.

Destructive and non-destructive early detection of postharvest noble rot (Botrytis cinerea) in wine grapes aimed at producing high-quality wines.

Botrytis cinerea (Bc) is the causative agent of gray mold disease in wine grape bunches. Under particular climatic and edaphic conditions, typical of some wine regions, the grapes infected by this fungus can develop noble rot, the basic phenomenon for the production of sweet botrytized wines or some high-quality dry wines, such as Amarone. The possibility of early detection of noble rot on plants and at postharvest is an interesting option for managing botrytized wines. The present work aimed at early detection of noble rot and monitoring its development, at postharvest, on Trebbiano wine grapes by means of destructive and non-destructive analytical approaches (e.g., electronic nose and near-infrared spectroscopy). The development of Bc led to substantial modifications in grape composition, including dehydration, biosynthesis, and accumulation of different compounds due to Bc metabolism, grape stress responses, or both. However, these modifications are appreciable, notably at advanced stages of infection. Consequently, a specific focus was to monitor the infection in the first 72 h post inoculation for testing, potentially through non-destructive technologies, and to identify the real early stages of Bc development. The destructive chemical analyses performed over the 16 monitored days confirmed what is widely reported in the literature regarding the metabolic/compositional changes that occur following the development of Bc. Moreover, non-destructive technologies allowed us to identify the evolution of Bc, even at early stages of its presence. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Using Remote and Proximal Sensing Data and Vine Vigor Parameters for Non-Destructive and Rapid Prediction of Grape Quality

The traditional method for determining wine grape total soluble solid (TSS) is destructive laboratory analysis, which is time consuming and expensive. In this study, we explore the potential of using different predictor variables from various advanced techniques to predict the grape TSS in a non-destructive and rapid way. Calculating Pearson’s correlation coefficient between the vegetation indices (VIs) obtained from UAV multispectral imagery and grape TSS resulted in a strong correlation between OSAVI and grape TSS with a coefficient of 0.64. Additionally, seven machine learning models including ridge regression and lasso regression, k-Nearest neighbor (KNN), support vector regression (SVR), random forest regression (RFR), extreme gradient boosting (XGBoost), and artificial neural network (ANN) are used to build the prediction models. The predictor variables include the unmanned aerial vehicles (UAV) derived VIs, and other ancillary variables including normalized difference vegetation index (NDVI_proximal) and soil electrical conductivity (ECa) measured by proximal sensors, elevation, slope, trunk circumference, and day of the year for each sampling date. When using 23 VIs and other ancillary variables as input variables, the results show that ensemble learning models (RFR, and XGBoost) outperform other regression models when predicting grape TSS, with the average of root mean square error (RMSE) of 1.19 and 1.2 °Brix, and coefficient of determination (R2) of 0.52 and 0.52, respectively, during the 20 times testing process. In addition, this study examines the prediction performance of using optimized soil adjusted vegetation index (OSAVI) or normalized green-blue difference index (NGBDI) as the main input for different machine learning models with other ancillary variables. When using OSAVI-based models, the best prediction model is RFR with an average R2 of 0.51 and RMSE of 1.19 °Brix, respectively. For NGBDI-based model, the RFR model showed the best average result of predicting TSS were a R2 of 0.54 and a RMSE of 1.16 °Brix, respectively. The approach proposed in this study provides an opportunity to grape growers to estimate the whole vineyard grape TSS in a non-destructive way.

Effects of mixed starters of plant- and wine-derived L. plantarum on hawthorn juice fermentation: Physicochemical properties, phenolic and volatile profiles

Lactic acid bacteria (LAB) fermentation is an effective way to improve the nutrition and sensory qualities of hawthorn juice, however the scarcity of LAB strains adapting to the high acidity of hawthorn juice limits its industrial application. In this study, a total of thirty-seven LAB strains belonging to different genera and species were isolated from spontaneously fermented plant and spine grape wine products, and four acid-resistant L. plantarum strains (Lpl.58, Lpl.55, Lpl.69 and Lpl.HY-1) were finally screened according to their viability and fermentation activity in hawthorn juice. The influences of their single and dual-mixed inoculation on the physicochemical properties, antioxidant activity, phenolic compounds and volatile flavor compounds of hawthorn probiotic beverages were subsequently investigated. Compared to single fermentation, mixed fermentation achieved higher fermentation activity, cell viability, and acid production, especially Lpl.69 + Lpl.HY-1, which also exhibited the greatest antioxidant activity. A significant increase of phenolic compounds (e.g. chlorogenic acid, proanthocyanidin B1, proanthocyanidin B2) was observed in Lpl.58 + Lpl.HY-1. Notably, co-inoculating Lpl.69 + Lpl.HY-1 and Lpl.55 + Lpl.HY-1 largely reduced volatile compounds with unpleasant odor (hexanol and hexanal), and increased the levels of desired aroma compounds (alcohols, esters, aldehydes and ketones) compared to single fermentation. The obtained results of this study indicated that screening L. plantarum strains from different acidic matrices and conducting mixed fermentation was a promising approach to produce hawthorn probiotic beverages with high nutrition and aroma complexity.

Information Transfer Among Grape Producers in the Western United States on Pest and Disease Management

Knowledge about how producers subjectively assess and communicate about different information resources can help optimize Agricultural Extension efforts. In particular, how do growers use different information resources when making decisions on pest and disease management? Using pest and disease management in wine grapes ( Vitis vinifera) as a case study, three surveys were conducted among grape producers in the western United States to qualitatively explore resource options ( n = 15), examine the relative importance of the 23 different information resources identified ( n = 63), and investigate the social networks where information is passed within and between regions ( n = 65). Five different informational archetypes emerged, demonstrating different preferences for information resource use, which explained 66% of the variance in survey responses. Personal connections (e.g., discussion with professional network, with field foreman and supervisors, and with an Extension agent) were extremely important to the participants. In the communication network analysis, 65 participants were used to form a 324-actor network with 448 links, which were then subdivided into intra-state networks. The networks show evidence of structures that facilitate information diffusion and cooperation between independent producers. Additionally, even with networks much smaller than the grape producer populations in these states, influential individuals could be identified. These individuals, when targeted by outreach professionals, could assist with information dissemination and facilitate changes in opinion or behaviors in the region. [Formula: see text] The author(s) have dedicated the work to the public domain under the Creative Commons CC0 “No Rights Reserved” license by waiving all of his or her rights to the work worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law, 2024.

Perspectives Towards Collective Action for Pest and Disease Management in Vineyards in the Western United States

An individual grower's response to pests and diseases in their vineyard can have consequences for an entire growing region. Collective action strategies can help align grower responses to achieve better regional disease control. Ways in which we identify, approach, and address manager opinions regarding cooperative management efforts influence the success of collective action strategies. A Q-method survey was conducted to investigate the adoption obstacles of wine grape growers to regionally collective actions for managing pests and diseases. Qualitative information from the western United States ( n = 17 participants) was used to generate 36 statements describing opinions on collective management action and general disease management. A second set of grape producers ( n = 59) was asked to rank these statements relative to each other. Participants perceived that collective management action would be worth the extra associated time or costs. Four prominent archetypal perspectives arose from the Q-method analysis, explaining 66% of the variance in expressed opinions. Archetypes were termed “The Cooperators” (14 of 59), “The Quasi-Individualists” (9 of 59), “The Mid-Level Pragmatists” (8 of 59), and “The Bottom-Line Focused” (5 of 59). These groups were split across the demographic information collected; archetypes explained more variation between responses than demographic information. Overall, participants were likely to agree that cooperation was important, but they were more concerned about their individual vineyard economic and crop health concerns, thus suggesting that if outreach professionals want to increase the likelihood of grape growers participating in collective pest management actions, they should emphasize the individual benefits of participation. [Formula: see text] The author(s) have dedicated the work to the public domain under the Creative Commons CC0 “No Rights Reserved” license by waiving all of his or her rights to the work worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law, 2024.

Spider and harvestmen biodiversity in New Zealand horticultural ecosystems

ABSTRACT Spiders contribute to pest suppression in agroecosystems by direct and non-direct consumption. They provide an ecosystem service which provides economic gains to horticultural growing systems, such as apples, wine grapes, and kiwifruit. Very few studies on spider biodiversity in cropping systems have been completed in New Zealand, and no studies have been published for New Zealand orchard systems. In this study, spiders and harvestmen were sampled from vineyards, apple orchards, and kiwifruit orchards in three New Zealand locations, Waipara, Motueka, and Kerikeri. Spiders were sampled using pitfall traps, sweep netting, active day sampling, and active night sampling. A total of 1359 spiders and 87 Opiliones were caught in this study, from 17 families and 31 species. Sixteen of the 31 (51.6%) species found were introduced, 9 (29%) endemic to New Zealand, two species (6.4%) native to New Zealand, and four (12.9%) unknown. There were five dominant spider families caught (Araneidae, Lycosidae, Theridiidae, Linyphiidae, and Desidae), and of the adults, there were five dominant species: Anoteropsis hilaris, Tenuiphantes tenuis, Cryptachaea veruculata, Cryptachaea blattea, and Steatoda capensis. This study provides the first important step in describing the spider families and species found in three economically important New Zealand horticultural systems.

Evaluation of the ‘Leányka’ (‘Fetească Albă’) white wine grape variety’s qualitative and quantitative parameters in the context of different bud loads

Abstract Wine is a product of human creativity, culture, and nature, and therefore it is an intriguing subject for scientific research and admiration. Among its many kinds, white wine stands out oenologically because of its diverse flavours, aromatic attributes, and capacity to mature. In this experiment, we established 3 different bud load levels (25%, 50%, and 75%) on the well-known white wine grape variety ‘Fetească Albă’. The sugar content significantly increased in the 50% and 76% groups, whereas there were no significant changes regarding titratable acid content, must quantity, and cluster weight.

A highly efficient strategy for simultaneous analysis of eleven monomeric hydroxylated-stilbenes in grape wines and juices by a salting-out assisted liquid-liquid (SALLE) extraction combined with a high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS).

Wine and grape juice are known to have hydroxylated stilbenes, a group of phytoalexins, health-promoting compounds. The determination of stilbene species in wine and grape juices remains a challenging task. Here, we propose an efficient strategy for the simultaneous determination of eleven hydroxylated stilbenes in grape wines and grape juice by a SALLE in conjunction with an HPLC-ESI-MS/MS. SALLE and HPLC-MS/MS conditions were optimized. The proposed method was validated and found to be a simple, sensitive, and reliable measure for the determination of the stilbene species in wine and grape juice. The SALLE was fast and efficient, taking only 10min. The HPLC-MS/MS was able to quickly separate and quantitate the eleven stilbenes (9min running). This method was successfully applied to determine the contents of stilbene species in commercial wine and grape juice in Korea. This method is advantageous in reduced sample preparation time, low labor, and cost efficiency.

Safety evaluation of the food enzyme endo-polygalacturonase from the non-genetically modified Aspergillus tubingensis strain MUCL 55013.

The food enzyme endo-polygalacturonase ((1→4)-α-d-galacturonan glycanohydrolase (endo-cleaving); EC 3.2.1.15)) is produced with the non-genetically modified Aspergillus tubingensis strain MUCL 55013 by Soufflet Biotechnologies. The food enzyme is free from viable cells of the production organism. It is intended to be used in 10 food manufacturing processes: processing of fruits and vegetables for the production of juices, other fruit and vegetable products, wine, distilled spirits from wine, alcoholic beverages other than grape wine; processing of plant-derived products for the production of refined and unrefined sugar, edible oils from plants, green coffee beans by demucilation, coffee extracts and tea and other herbal and fruit infusions. Since residual amounts of total organic solids (TOS) are removed in three processes, dietary exposure was calculated only for the remaining seven food manufacturing processes. Exposure was estimated to be up to 7.834 mg TOS/kg body weight (bw) per day in European populations. Genotoxicity tests did not indicate a safety concern. The systemic toxicity was assessed by a repeated dose 90-day oral toxicity study in rats. The Panel identified a no observed adverse effect level of 2,097 mg TOS/kg bw per day, the highest dose tested, resulting in a margin of exposure of at least 268. A search for the similarity of the amino acid sequence of the food enzyme to known allergens found 14 matches, one of which was to a food allergen. The Panel considered that the risk of allergic reactions upon dietary exposure to this food enzyme cannot be excluded, in particular for individuals sensitised to papaya, but that the risk will not exceed that of consumption of papaya. In addition, oral allergy reactions cannot be excluded in pollen-sensitised individuals. Based on the data provided, the Panel concluded that this food enzyme does not give rise to safety concerns, under the intended conditions of use.

Direct microwave treatment enhances antioxidant and antibacterial properties of the seed extracts of Kékfrankos grapes

The Kékfrankos is the most frequently cultivated wine grape in Hungary, with a significant national and regional impact, resulting in considerable amounts of byproducts (e.g. pomace, seeds). To the best of our knowledge no research has been conducted on the antioxidant and antibacterial properties of its seed extracts (GSE). A novel apporach of applying direct microwave treatment on grape seeds was implemented for the first time to enhance antioxidant and antimicrobial properties of GSE. Antioxidant properties were assayed using the DPPH (2,2-diphenyl-1-picrylhydrazyl), FRAP (Ferric Reducing Antioxidant Power) and TPC (Folin-Ciocâlteu's Total Polyphenol Content) methods. Profile and content of polyphenols was studied using high-performance liquid chromatography/tandem mass spectrometry and matrix-assisted laser desorption/ionization mass spectrometry. Antibacterial properties were evaluated using Gram-positive Staphylococcus aureus (SA), methicillin-resistant Staphylococcus aureus (ST239) (MRSA) and Gram-negative Escherichia coli (EC) bacteria strains. Results proved that the mild direct microwave treatment of grape seeds significantly increased total polyphenol, (+)-catechin, (−)-epicatechin as well as antioxidant capacity levels by 20–30 % compared to untreated samples and resulted the best antibacterial properties based on bacterial growth curves (SA and MRSA: 0.015625 mg/mL, EC: 0.25 mg/mL). Results justify the importance of further pharmacological investigations on Kékfrankos grape seed extracts and that the direct microwave treatment of grape seeds is an innovative approach for the fast and cost efficient improvement of the antibacterial properties of grape seed extracts.

EVALUATION OF VITICULTURE AND WINEMAKING REGIONS OF CRIMEA IN ACCORDANCE WITH CLIMATIC FACTORS, AND THEIR INFLUENCE ON THE QUALITY CHARACTERISTICS OF GRAPES

A grape plant is capable to adapt, grow and produce crops in different environmental conditions. At the same time, agro-climatic conditions of grape growing area have a significant effect on the product quality. Environmental climatic conditions of Crimea contribute to cultivating grapes from very early to late ripening varieties. Diverse range of abiotic conditions allows choosing an optimal terroir for the formation of necessary grape conditions depending on the application target. Significant spatial climate variability within the region makes it possible to evaluate the impact of environmental factors on biosynthetic and accumulative properties of grapes.
 The purpose is to study changes in the profile of carbohydrate-acid complex of wine grape varieties under the influence of agro-ecological growing conditions.
 Materials and methods. Study objects were white and red grape varieties growing in various viticulture and winemaking regions of Crimea. A research for grape plant response to the variability of environmental factors basing on a long-term comparative study of chemical composition of its fruits, determining the varietal biochemical identity and technological properties in a particular region, was carried out.
 Results and conclusion. As a research result, the cumulative effect of agro-ecological factors on the accumulation of components of carbohydrate-acid grape complex was established, and in particular years it was possible to identify the dependence between their quantitative content and individual environmental factors. Accumulation of the mass concentration of sugars in grape berry directly correlated with the Huglin index value (r = 0.7). With regard to the mass concentration of titratable acids, an inverse correlation was revealed with the Winkler index value (r = -0.59). A comparative analysis of the results shows that one grape variety grown under different climatic conditions may show different ability to synthesize the components of carbohydrate-acid complexes, determining its suitability for various output production. There is a direct correlation of the mass concentration of sugars on the average air temperature for the last month before harvest (r=0.70) within the variety.

Wine tourism – a chance for the development of rural regions: A case study from Eastern Poland

European wine tourism has long been carried out in the traditional wine areas of France, Portugal or Germany. In the countries of Central Europe, these traditions also occur, but they have a more local meaning. The article presents one of the wine regions in Eastern Poland – the Lesser Poland Gorge of the Vistula River, where the development of small wineries has been observed for several years. The article’s primary goal is to present vineyards in the Lesser Poland Gorge of the Vistula River concerning the possibilities of development of wine tourism and its impact on the region’s functioning. It seems that the concept of “terroir” can be used by local winemakers to identify the particularities of wines from vineyards. This can be an excellent contribution to the development of wine tourism, considering that nowadays, tourists search for authentic experiences. The production of local grape wine and its promotion may be the basis for rebuilding the region’s wine production tradition, as well as contributing to the region’s development.

Using abandoned unripe grape resources to solve the low-acid problem in the northwest wine region of China

Low acid is the main defect in the northwest wine region of China in recent years. The fermentation of unripe grape (UG) and wine grapes with low acid contents was carried out. Compared with control group (CK), the addition of UG addressed the core flaw that low acid grape bring to wine firstly, it significantly increased titratable acid, tartaric acid and malic acid while significantly decreasing alcohol and volatile acids in wine. Secondly, UG significantly improved wine color, the color parameters a*, b*, C* and L* were significantly increased to different degrees. At the same time, the addition of UG significantly improves other qualities of wine, including the phenolic substances and antioxidant capacity of wine. In addition, adding UGJ2% significantly improved the sensory quality, and pleasant volatile substances such as phenethyl alcohol, ethyl hexanoate, ethyl butyrate and isoamyl acetate were significantly increased, giving the wine more prominent floral and fruity aromas.