(1) Background: Solid phase microextraction (SPME)-Arrow is a new extraction technology recently employed in the analysis of volatiles in food materials. Grape volatile organic compounds (VOC) have a ...crucial role in the winemaking industry due to their sensory characteristics of wine.; (2) Methods: Box-Behnken experimental design and response surface methodology were used to optimise SPME-Arrow conditions (extraction temperature, incubation time, exposure time, desorption time). Analyzed VOCs were free VOCs directly from grape skins and bound VOCs released from grape skins by acid hydrolysis.; (3) Results: The most significant factors were extraction temperature and exposure time for both free and bound VOCs. For both factors, an increase in their values positively affected the extraction efficiency for almost all classes of VOCs. For free VOCs, the optimum extraction conditions are: extraction temperature 60 °C, incubation time 20 min, exposure time 49 min, and desorption time 7 min, while for the bound VOCs are: extraction temperature 60 °C, incubation time 20 min, exposure time 60 min, desorption time 7 min.; (4) Conclusions: Application of the optimized method provides a powerful tool in the analysis of major classes of volatile organic compounds from grape skins, which can be applied to a large number of samples.
Since changes in temperature and precipitation have different effects on (a) all developmental stages of grapevines in most of the wine regions worldwide (i.e., on their phenological characteristics) ...and (b) different varieties, a comprehensive database of bioclimatic indices has been calculated and analysed for Croatian wine producing regions. The database consists of the average growing season temperature, growing degree‐days, Huglin index, dryness index and cool night index that are based on all available meteorological measurements as well as the outputs of regional climate models (RCMs) from the EURO‐CORDEX database. The horizontal grid spacing of 0.11° from the RCM ensembles enabled a fine‐scale determination of bioclimatic indices for the present and future climate in Croatia. In addition, statistical analyses (standard statistical parameters and Bayesian method) were carried out to examine trends in sugar content, total acidity and date of harvest. Calculations were performed for the present and future climate on the basis of data from seven selected vineyards/wineries and four varieties (‘Graševina’, ‘Plavac mali’, ‘Chardonnay’ and ‘Merlot’). The results show whether the part of Croatia that is suitable for grape cultivation in the present climate will continue to be favourable in the future within the Mediterranean area. In general, projections suggest further warming and drying of the climate in Croatia and an earlier harvest, with some variations among varieties that show latitude dependence. Projections for the future climate also suggest that the existing viticultural zoning will be much less adequate for the Croatian territory because it reduces the economically sustainable production of wine in certain areas.
Spatial distributions of temperature‐based bioclimatic indices (e.g., growing degree‐days GDD) for high‐end climate change scenarios are pointing to further warming in the period 2041–2070. Differences between the two periods P2 (2041–2070) and P0 (1971–2000) clearly show that some indices in certain regions will likely cross into higher (warmer) classes within the index scale. All grape varieties examined indicated an increase in the number of earlier harvests and a reduction in the number of later harvests, regardless of location.
The biochemical response and gene expression in different grapevine cultivars to water deficit are still not well understood. In this study, we investigated the performance of four traditional ...Croatian Vitis vinifera L. cultivars (‘Plavac mali crni’, ‘Istrian Malvasia’, ‘Graševina’, and ‘Tribidrag’), and one wild (Vitis vinifera subsp. sylvestris) genotype exposed to water deficit (WD) for nine days under semi-controlled conditions in the greenhouse. Sampling for biochemical and gene expression analyses was performed at days six and nine from the beginning of WD treatment. The WD affected the accumulation of metabolites with a significant increase in abscisic acid (ABA), salicylic acid (SA), and proline in the leaves of the stressed genotypes when the WD continued for nine days. Lipid peroxidation (MDA) was not significantly different from that of the control plants after six days of WD, whereas it was significantly lower (297.40 nmol/g dw) in the stressed plants after nine days. The cultivar ‘Istrian Malvasia’ responded rapidly to the WD and showed the highest and earliest increase in ABA levels (1.16 ng mg−1 dw, i.e., 3.4-fold increase compared to control). ‘Graševina’ differed significantly from the other genotypes in SA content at both time points analyzed (six and nine days, 47.26 and 49.63 ng mg−1 dw, respectively). Proline level increased significantly under WD (up to 5-fold at day nine), and proline variation was not genotype driven. The expression of aquaporin genes (TIP2;1 and PIP2;1) was down-regulated in all genotypes, coinciding with the accumulation of ABA. The gene NCED1 (9-cis-epoxycarotenoid dioxygenase) related to ABA was up-regulated in all genotypes under stress conditions and served as a reliable marker of drought stress. This work suggests that the stress response in metabolite synthesis and accumulation is complex, treatment- and genotype-dependent.
Grapevine leaves are photosynthetically the most active green organs providing carbohydrates that are of utmost importance for the regular vine’s metabolism and growth. Moreover, leaves are the ...pioneers of fungal infections caused by B. cinerea, E. necator, and P. viticola. Plant response to these microorganisms mostly depends on the content and composition of phenolic compounds abundantly found in the leaf’s outer tissues (epidermis, cuticle, trichomes). In order to obtain a satisfactory quantity of phenolic compounds, an experiment was conducted towards optimizing a solid–liquid extraction method. Variables were as follows: the type of organic solvent, the sample weight, the extraction temperature, and the extraction time. The optimal conditions were obtained by applying the response surface methodology. Therefore, by using acetonitrile as the organic solvent, conducting a single-step extraction at the temperature of 48 °C during the time period of 2 h and 25 min with a solid-to-solvent ratio of 1:56 g mL−1 (178 mg of leaves powder and 10 mL of extraction solvent) the optimal content of phenolic compounds was obtained. This protocol is reliable, fast, and relatively easy to perform for the determination of the abovementioned compounds.
The
pathogen causes one of the most severe grapevine diseases, namely downy mildew. The response to
involves both visible symptoms and intricate metabolomic alterations, particularly in relation to ...volatile organic compounds, and depends on the degree of resistance of a particular variety. There are numerous native grapevine varieties in Croatia, and they vary in susceptibility to this oomycete. As previously reported, in vitro leaf disc bioassay and polyphenolic compound analysis are complementary methods that can be used to separate native varieties into various resistance classes. This research used the Solid Phase Microextraction-Arrow Gas Chromatography-Mass Spectrometry method to identify the early alterations in the VOCs in the leaves after
inoculation. Based on the absolute peak area of sesquiterpenes, some discrepancies between the sampling terms were noticed. The presence of certain chemical compounds such as humulene, ylangene, and
-farnesene helped distinguish the non-inoculated and inoculated samples. Although specific VOC responses to
infection of native varieties from various resistance classes could not be identified, the response of less susceptible native varieties and resistant controls was associated with an increase in the absolute peak area of several compounds, including geranylacetone,
-ocimene, and (
)-2-hexen-1-ol.
Grape skin contains large amounts of different flavonoids so it can be used for their recovery. Optimization of enzyme-assisted extraction of flavonoids was conducted using oenological enzyme ...preparations with respect to enzyme dosage, temperature, extraction time, pH, and enzyme preparation. Optimal conditions were obtained using enzyme preparation Lallzyme EX-V, at the temperature of 45°C, time of 3 h, pH 2.0, and enzyme dosage of 10.52 mg/g. The new optimized extraction method is less expensive, simple, accurate, and selective for the recovery of simple flavonoids. It is based on an environmentally-friendly extraction solvent which may provide a valuable alternative to conventional methods.
Since grapevine is highly susceptible to various pathogens, enormous amounts of pesticides are applied each season to achieve profitable production. One of the most destructive grapevine diseases is ...downy mildew, and their interaction has been in the spotlight for more than a decade. When it comes to a metabolome level, phenolic compounds are relevant to investigate due to their involvement in the plant immune system and known antifungal properties. Croatian grapevine germplasm is highly heterogeneous due to its long history of cultivation in diversified geographical regions. Since it has been found that native varieties react differently to the infection of
, the intention of this study is to define if the chemical background of the leaves, i.e., polyphenolic composition, is responsible for these dissimilarities. Therefore, the leaves of 17 genotypes, among which 14 were native and 3 were controls, were analyzed using high-performance liquid chromatography (HPLC) in four terms: before inoculation and 24, 48, and 96 h post inoculation (hpi). During this early phase, significant differences were found neither between the terms nor between the non-inoculated and inoculated samples, except for resveratrol-3-
-glucoside. By applying principal component analysis (PCA) using initial leaf polyphenolic composition, varieties of
were clearly separated into three different groups corresponding to their International Organization of Vine and Wine (OIV) classes of susceptibility to
. Results obtained in this research suggest that the initial constitutive polyphenolic composition of the cultivar leaves has a crucial influence on their susceptibility to
, and this finding can be used to improve the success of grapevine breeding programs toward downy mildew resistance.
Grape volatile organic compounds (VOCs) play an important role in the winemaking industry due to their contribution to wine sensory characteristics. Another important role in the winemaking industry ...have the grapevine varieties used in specific regions or countries for wine production. Due to the high variability of grapevine germplasm, grapevine varieties are as classified based on their genetic and geographical origin into genetic-geographic groups (GEN-GEO). The aim of this research was to investigate VOCs in 50 red grapevine varieties belonging to different GEN-GEO groups. The study included varieties from groups C2 (Italy and France), C7 (Croatia), and C8 (Spain and Portugal). The analysis of VOCs was performed by SPME-Arrow-GC/MS directly from grape skins. The analyzed VOCs included aldehydes, ketones, acids, alcohols, monoterpenes, and sesquiterpenes. The most abundant VOCs were aldehydes and alcohols, while the most numerous were sesquiterpenes. The most abundant compounds, aldehydes and alcohols, were found to be (
E
)-2-hexenal, hexenal, (
E
)-2-hexen-1-ol, and 1-hexanol. Using discriminant analysis, the GEN-GEO groups were separated based on their volatile profile. Some of the individual compounds contributing to the discrimination were found in relatively small amounts, such as benzoic acid, (
E,E
)-2,4-hexadienal, 4-pentenal, and nonanoic acid. The groups were also discriminated by their overall volatile profile: group C2 was characterized by a higher content of aldehydes and alcohols, and group C8 was characterized by a higher content of sesquiterpenes and acids. Group C7 was characterized by all low amount of all classes of VOCs.
Polyphenols are secondary plant metabolites and important organic compounds present in grapes, must and wine. The importance of polyphenolic compounds present in grapes is mainly related to the ...quality of the wine. Those compounds affect the colour, taste, astringency, bitterness, and potential of wine aging. Therefore, the aim of this research was to determine and compare quantitative and qualitative changes in low molecular weight polyphenol content of 11 red grapevine varieties during ripening. Samples were collected periodically from the beginning of verasion to the technological maturity. The polyphenolic compounds were analysed with high performance liquid chromatography (HPLC) with prior lyophilization and extraction. Based on the obtained results, changes in the composition and content of researched groups of polyphenolic compounds during maturation were determined. Keywords: grape berry, red grapevine varieties, polyphenolic compounds, liquid chromatography Polifenoli su sekundarni biljni metaboliti te vazni organski spojevi prisutni u grozdu, mostu i vinu. Vaznost polifenolnih spojeva prisutnih u grozdu uglavnom je vezana uz kakvocu vina obzirom da utjecu na boju, okus, astringenciju, gorcinu te potencijal starenja vina. Cilj ovog rada je utvrditi i usporediti kvantitativne i kvalitativne promjene sadrzaja polifenola male molekulske mase u kozici grozda 11 crnih sorata vinove loze tijekom dozrijevanja grozda. Uzorci su prikupljani periodicno od pocetka sare do tehnoloske zrelosti. Sadrzaj polifenola u kozici boba utvrden je tekucinskom kromatografijom visoke djelotvornosti (HPLC) uz prethodnu liofilizaciju i ekstrakciju. Temeljem dobivenih rezultata utvrdene su promjene sastava i sadrzaja pojedinih grupa polifenolnih spojeva tijekom dozrijevanja. Kljucne rijeci: boba grozda, crne sorte, polifenolni spojevi, tekucinska kromatografija Polyphenols are secondary plant metabolites and important organic compounds present in grapes, must and wine. The importance of polyphenolic compounds in grapes is mainly related to the quality of the wine. Those compounds affect the colour, taste, astringency, bitterness, and potential of wine aging. Recently, due to numerous research of the polyphenolic composition of grapes, their nutritional value as well as many positive effects on human health have been recognized. Their beneficial effect on the organism derives from antioxidant capabilities, chelating activity, and inactivation of certain enzymes that are attributed to antitumor, antimicrobial, antiallergic, neuroprotective, anti-inflammatory and many other properties. A large group of polyphenolic compounds such as phenolic acids (hydroxycinnamic and hydroxybenzoic acid), flavonoid stilbenes (anthocyanins, flavonols and flavan-3-ols) have been found in grape berry. The largest proportion of polyphenolic compounds in grape berries is contained in the seeds, then skin and pulp. Phenolic compounds are particularly important in red grape wine production technology, because they greatly affect the colour and the characteristic taste of wine. Therefore, the aim of this study is to determine the changes that occur in the polyphenol profile (hydroxycinnamic acids, anthocyanins, flavonols, flavan-3-ols) of 11 red grape varieties during ripening. The research was set up in a vineyard at the location of experimental station Jazbina, viticultural region Sredisnja bregovita Hrvatska, subregion Prigorje - Bilogora and vineyard area Zagreb. Samples were collected periodically, from the beginning of the verasion to technological maturity. They were adequately stored, lyophilized, and subjected to extraction. The obtained extracts were analysed with high performance liquid chromatography. Based on the obtained results, anthocyanins are the most common polyphenol compounds in the skin of the investigated varieties, followed by flavanol glycosides, flavanol-3-ols and hydroxymethyl acids. The mass fraction of anthocyanin and flavonol glycosides in berry skin increases from the beginning of the verasion to the technological maturity, while the mass fraction of flavan-3-ols, hydroxycinnamic acids and flavonol glycosides decreases by technological maturity.
Polyphenols are organic compounds that can be found in food, especially in fruits, vegetables, and their products. It was shown that their presence significantly affects the properties of food ...products and that the consumption of food rich in phenolic compounds has a beneficial effect on human health. The subjects of this research were polyphenols: anthocyanins, flavonols, and flavan-3-ols in the skin of grapevine variety Regent. Polyphenols from grape skins were extracted via microwave-assisted extraction (MAE) and matrix solid-phase dispersion (MSPD) as unconventional and green techniques. Therefore, the main aim of this work was to optimize the conditions for the extraction of polyphenolic compounds from grape skin using MAE and MSPD. The extracts were analyzed using high-performance liquid chromatography with a diode array detector and fluorescence detector. Analyses showed that MAE was a very effective method for extracting polyphenolic compounds from grape skin with 10 mL of 60% ethanol for 5 min at 40 °C. The best results for the MSPD extraction of polyphenolic compounds from grape skin were obtained with phenyl as an MSPD sorbent with 10 mL of acetonitrile:water 50:50 v/v as an elution solvent. This scientific research can be used for the better use of grapes as a basis for obtaining flavonoids for commercial purposes.
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