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Grape marc seeds contain large amounts of different polyphenolic compounds so they can be used for the recovery of these classes of compounds. A new green extraction method for the recovery of phenols from the grape seeds was developed. To provide a high quality extract sourced from natural product by using enzymes as alternative solvents and spending less energy, it is impeccable to call this method 'green'. Furthermore, this method was optimized by finding out which conditions provide the best possible results and achieving the maximum recovery of polyphenols from grape seeds. The optimization of the enzyme-assisted extraction of phenols was conducted using the commercially available oenological enzyme preparations with respect to the enzyme dosage, temperature, extraction time, pH value and enzyme preparation by applying the response surface methodology. Optimal conditions were determined using the enzyme preparation Lallzyme EX-V, at the extraction temperature of 48 °C, extraction time of 2 h and 43 min, pH 3.5 and enzyme dosage of 20.00 mg g. The new optimized extraction method is less expensive, simple, fast, precise and selective for the recovery of simple phenols (monomeric and dimeric form) and since it is based on the environmentally friendly extraction solvent it may provide a valuable alternative to the conventional extraction methods. The obtained extracts can be used for the application in pharmaceutical, food and cosmetic industry. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

(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. [ABSTRACT FROM AUTHOR]

Grapes are rich in primary and secondary metabolites. Among the secondary metabolites, polyphenolic compounds are the most abundant in grape berries. Besides their important impacts on grape and wine quality, this class of compounds has beneficial effects on human health. Due to their antioxidant activity, polyphenols and phenolic acids can act as anti-inflammatory and anticancerogenic agents, and can modulate the immune system. In grape berries, polyphenols and phenolic acids can be located in the pericarp and seeds, but distribution differs considerably among these tissues. Although some classes of polyphenols and phenolic acids are under strict genetic control, the final content is highly influenced by environmental factors, such as climate, soil, vineyard, and management. This review aims to present the main classes of polyphenolic compounds and phenolic acids in different berry tissues and grape varieties and special emphasis on their beneficial effect on human health. [ABSTRACT FROM AUTHOR]

Abstract: Due to the short period of the grape fresh samples availability and their very complex analysis, appropriate grape samples storage is mandatory. In this study, samples were analyzed immediately after harvest and after storage at −20 °C. Frozen samples were thawed as follows: at the room temperature, in the microwave oven, in the refrigerator, and the skin was pulled off from the frozen grape berries. The freezing had a positive effect on the contents of anthocyanins and flavonol glycosides. These compounds are contained in cell vacuoles thus membrane degradation, throughout the freezing process, could enhance their extractability. The freezing had a negative effect on the content of the other polyphenols which can be bound to the cell wall. Among examined thawing methods, the most appropriate method was the peeling grape berry skin from the frozen berries samples with the receptacle. Suitable alternative to the aforementioned method could be the microwave thawing. Practical application: One of the most important groups of compounds contained in grape berries are polyphenolic compounds. These compounds significantly affect the quality of grapes and wine. They also have a positive impact on human health. Most of the grapes are being processed into wine, but it also has many other uses. Besides the table grapes, raisins, juices, jams, and wine distillates, currently, various cosmetic and pharmaceutical preparations made from grapes whose functioning is based on the effects of polyphenols are encounter on the market. Given the short period of availability of fresh grape samples and complex procedure of their analysis and processing, samples must be stored in an appropriate manner. This study reported the effect of freezing and applied thawing method on retentions of polyphenolics in grapes. The information obtained by this study is essential for the development of specific applications of the grape berries skins. [ABSTRACT FROM AUTHOR]

The population of Croatian autochthonous cultivars has a high degree of infection with economically important viruses, so it is necessary to carry out the elimination of the viruses in some cultivars to obtain healthy planting material. In this research, we tested in vitro meristem culture establishment on 18 autochthonous cultivars with different viral infections and the possibility of GLRaV-3 elimination through in vitro meristem culture. Plant material was sampled in a vineyard in two phenological stages, 10 days before flowering and 10 days after flowering of the grapevine. Apical meristem explants (1 mm) were placed into the MS culture medium supplemented with 0.5 mg/L benzyl adenine (BA) and 0.05 mg/L indol-3-acetic acid (IAA), and their survival, regeneration, and rooting were monitored. The results showed that the cultivar and the growth phase have a significant impact on the success of in vitro culture. In all cultivars studied higher success of in vitro culture establishment parameters (survival, regeneration, and rooting) was obtained in the case of explants sampled after flowering, with the exception of one cultivar for explants survival. Contrary to expectations, genotypes infected with three viruses (GLRaV-1, GLRaV-3, and GFLV) showed better results than genotypes infected with one or two viruses. The results showed successful in vitro establishment of Croatian autochthonous cultivar and GRLaV-3 elimination in one cultivar. However, due to the significant effect of cultivar, for routine application of this in vitro protocol on more than 100 autochthonous cultivars in need of sanitation, further studies should be conducted. [ABSTRACT FROM AUTHOR]