Search

This study aimed to evaluate bioactive properties of Teran red wine by-products (grape skins, seeds, and wine lees) from six vinification treatments, including a control (7-day standard maceration). Pre-fermentative cryomaceration (8 °C; 48 h) and hot maceration (50 °C; 48 h), followed by the 13-day (CS15; C15; H15) and 28-day (C30; H30) period, considering fermentation/maceration and extended post-fermentative maceration, were conducted. In CS15, the saignée procedure was applied before fermentation/maceration. After maceration, the separation of by-products was performed, followed by lyophilization and solid–liquid extraction. Then, individual phenols were analyzed using high-performance liquid chromatography (HPLC), and total phenolic content (TPC) and antioxidant activity (FRAP) were analyzed using UV/Vis spectrophotometry. The results showed grape skins and wine lees in all treatments had significantly increased TPC and FRAP values compared to the control. The highest concentration of total phenols (HPLC) in grape skins was found in CS15, at 978.54 mg/100 g DW. In wine lees, the highest concentration of total phenols was detected in the 30-day maceration treatments, at 582.04 mg/100 g DW in C30, and 595.83 mg/100 g DW in H30, despite the pre-fermentative procedure. In grape seeds, the highest concentration of total phenols was found in the control (K7), at 432.42 mg/100 g DW. Pre-fermentative heating together with extended 30-day maceration (H30) strongly reduced the total levels of phenols (HPLC and TPC) in grape seed samples. The findings implied an evident impact of pre- and post-fermentative technologies on phenols and antioxidant activity in wine by-products of cv. Teran (Vitis vinifera L.). [ABSTRACT FROM AUTHOR]

Featured Application: Featured Application: This study provides a comprehensive analysis of the impact of various vinification techniques, including prolonged maceration, pre-fermentation heating, and barrel aging, on the volatile aroma profile and sensory characteristics of Teran red wine. Teran (Vitis vinifera L.) is the most widespread red autochthonous variety in Istria, traditionally grown in the north Adriatic area, including the Croatian Istria viticultural subregion. As a key grapevine variety in viticulture across these regions, understanding the impact of the investigated techniques is crucial for enhancing its unique characteristics and market value. These insights can be directly applied by winemakers to optimize and tailor wine production processes, enhancing desirable aroma attributes and sensory qualities to meet specific market demands. The findings offer practical guidelines for producing wines with distinct and appealing aromatic profiles, aiding in product differentiation and improving overall wine quality. This study investigates the effect of prolonged maceration, pre-fermentation heating, and barrel aging on the volatile aroma profile and sensory characteristics of Teran wine. The vinification processes included a control treatment (7-day maceration, TM7-Y; Y—young wine), 10-day maceration (TM10-Y), 21-day post-fermentation maceration (TM21-Y), and 48-h pre-fermentation heating at 45 °C followed by 8-day maceration (TPHT-Y). All wines were then aged in oak barrels for six months, resulting in TM7-A, TM10-A, TM21-A, and TPHT-A wines (A—aged wine). Volatile compounds were extracted using headspace solid-phase microextraction (HS-SPME) and analyzed by gas chromatography/mass spectrometry (GC/MS), while sensory profiles were evaluated using quantitative descriptive analysis (QDA). TPHT-Y and TM21-Y treatments reduced several groups of free volatile compounds while enhancing sensory properties, with TM21-Y wines notably exhibiting pronounced dried fruit notes, likely due to high β-damascenone concentrations. Conversely, TM10-Y and TM7-Y treatments resulted in significantly higher concentrations of the most volatile aroma compounds. Aging in oak barrels significantly increased the levels of particular free volatile compounds like C13-norisoprenoids, volatile phenols, furans, and lactones. It also enhanced sensory quality, with fruity aromas prominent across all treatments, and TM21-A and TPHT-A wines showing strong dried fruit, jam, and liqueur notes. This study offers valuable insights into tailoring wine aromas and sensory attributes through specific vinification techniques, contributing to a more refined approach to optimizing wine production. In conclusion, the findings highlight the importance of maceration and aging techniques in developing complex and desirable wine profiles, offering practical guidance for improving Teran wine quality. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the impact of early leaf removal (ELR) and cluster thinning (CT) on the phenolic composition of cv. Teran berries and wines, and the sensory profile of wines at 6 and 24 months after fermentation. Although only ELR increased the concentration of total anthocyanins in the berries as compared to the untreated control (UC), both ELR and CT had higher concentration of total anthocyanins and greater colour intensity in the resultant wines than the UC. Similar effects were obtained with total phenolics in the berries and the wines; while CT obtained higher concentration of total phenolics in the berries than UC only in one season, same treatment obtained higher concentration of total phenolics in the wine in both seasons as compared to UC. Only minor sensory differences in wines were obtained at the age of 6 months, while treatments were highly discriminated 24 months after fermentation, when both ELR and CT wines had more enhanced fruitiness, aromatic intensity, complexity, body, balance and wine overall quality than UC. The obtained results indicate that adequate wine aging period is needed for a relevant assessment of the impact of vineyard management practices on wine sensory characteristics.

Minor varieties represent a significant part of the grapevine germplasm (Vitis vinifera L. subsp. vinifera) in Croatia. During the long history of grape cultivation in insular, coastal and continental Croatia, numerous local varieties were cultivated, many of which are still used today. There are also several populations of wild grapevine (Vitis vinifera subsp. sylvestris Hegi Gmel) that have survived until the present in natural sites. Here, we developed a single primer enrichment technology (SPET) panel consisting of 61,308 probes for targeted sequencing of the V. vinifera gene space. In doing so, we examined a total of 28,092 gene models, 88.2% of all predicted genes, interrogating an average of 19 Mb nucleotides per individual genome, which corresponds to 4% of the haploid genome length. This is the first time that SPET-based sequencing has been applied to Croatian grapevine germplasm to generate multilocus genotype data of 126 cultivated accessions and 50 wild specimens. We identified 531,900 variants sites, 208,802 of which reside in coding sequences, 140,836 in introns, 118,416 in UTRs, and 63,424 in the nearby intergenic space that revealed the presence of 33 clonally propagated specimens representing both synonymies and clones within local varieties (22) as well as synonymies between local and international varieties (11), mostly from neighbouring countries. To investigate possible contribution of wild grapevine (Vitis vinifera subsp. sylvestris Hegi Gmel) to the development of present cultivars, four wild grapevine populations were included. None of the cultivated varieties showed close kinship with local wild specimens. This study opens new possibilities for studying the genetic diversity of Croatian grapevine germplasm and provides additional information with respect to SSR genotyping and phenotyping. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the effects of cluster thinning and severe shoot trimming on berry and wine composition and wine sensory characteristics of Merlot variety, in the context of climate change challenges related to grapevine ripening and the corresponding high alcohol content in wine. In two seasons, two different crop sizes were obtained via cluster thinning and combined in a two-factorial design with severe shoot trimming (SST) and its respective high canopy control (HC). In both seasons, cluster thinning (CT) resulted in higher Brix in grape juice and higher alcohol in wine than full crop size (FC), whereas SST obtained lower values than HC. Total anthocyanins and phenolics in wine were increased by CT, whereas SST had no any significant effect on wine's phenolic content. Several sensory characteristics of wine were positively affected by CT in both seasons, including aroma intensity, wine body and overall wine quality, whereas SST wines were in one season characterized by increased perception of vegetal aroma, acidity and bitterness, and decreased perception of body, persistency and taste balance. Our results demonstrate that practices which affect the leaf area to fruit ratio have a major impact on wine sensorial characteristics, concluding that their choice should be based on the desired wine style. [ABSTRACT FROM AUTHOR]

As for grapevine, there are many genetic resources in the Balkan region that have not yet been evaluated at the molecular level. Conventional molecular markers used for genotyping of grapevines have been largely replaced in recent years by HTS techniques that have dramatically expanded the possibilities for identifying allelic variations used in the application for genotyping by multiplexing. Multigene panels can be easily performed with gene-specific target enrichment probes. In this project we developed probes to capture information on key sites in the grapevine nuclear genome: 2271 highly variable SNP loci, 943 sites of the sex locus, 96 GAl1 loci associated with berry traits and phenology, 51 loci associated with resistance, 59 random loci, 312 MYB loci associated with color, and 47 TFL1 loci associated with flowering and phenology. For each polymorphic site, a 120-mer probe was designed with the expected variant in the central position. The panel was designed to genotype most of the diversity in grapevine from Balkan region (370 Vitis vinifera genotypes; 124 from Slovenia, 28 from Serbia, 76 from Croatia, 16 from Montenegro, 55 from BIH, 6 from Macedonia, 26 from Greece, 39 from Albania) and 23 V. vinifera references from France and 27 Vitis sp. species. The obtained data will allow to determine the exact calling of the variants for the evaluation of Balkan grapevines: their true-to-typness, important traits and kinships in the grapevine gene-pool. For the same group of samples, we performed whole-genome shotgun sequencing to detect DNA variation in chloroplasts and performed sequence alignment and phylogenetic analyses. Analyses were performed at inter- and intra-specific levels to improve previous phylogenetic work that was limited in taxonomic scope or marker choice (Peros et al. 2011, Wan et al. 2013, Trondle et al. 2010, Lozsa et al. 2015) and to improve parental analysis, particularly of grapevine varieties from the Balkans (Stajner et al. 2015), using maternally inherited chloroplast variation. Using low coverage DNA-seq, we were able to sequence a grapevine genome with an average coverage of 0.17, while the chloroplast genome reached up to 60-fold coverage, which was high enough to determine reliable SNPs. [ABSTRACT FROM AUTHOR]

The traditional Croatian grapevine varieties (Vitis vinifera L. subsp. vinifera) represent a significant part of the germplasm of the so-called Balkan grapes. Over time and the rich history of this area, numerous varieties have accumulated and are still grown commercially. There are also several populations of wild grapevine (Vitis vinifera subsp. sylvestris Hegi Gmel) in natural sites in this region. Both methods, morphometric and SSR markers, have previously been used to validate identities and investigate genetic variability of Croatian germplasm, but without a detailed characterization of their genomes. Genotyping-by-sequencing (GBS) is a recent approach to effectively characterize individuals at thousands of variant sites based on next generation sequencing technology. The aim of this study was to use GBS to: (i) define a panel of single nucleotide polymorphisms (SNPs) and determine the identity of Croatian cultivated and wild grapevine accessions, (ii) verify the presence of homonyms and synonyms, (iii) determine the genealogical relationships and the varieties that acted as the main progenitors of the Croatian germplasm, (iv) determine the distance between wild and cultivated accessions. We successfully genotyped 192 grapevine accessions, including 132 cultivated (vinifera) and 60 wild (sylvestris) individuals. Approximately 50,000 genomic intervals in the gene space were analyzed using a targeted sequencing system based on single primer enrichment technology. The filtered DNA reads were aligned to the PN40024 v0 reference genome and more than 500,000 high quality SNPs were identified using the Genome Analysis Toolkit (GATK) software. Twelve synonyms were found within Croatian varieties, while eleven varieties were matched to international varieties, mostly from neighboring countries, indicating historical migration of cultivars. Distance- and model-based cluster analysis showed a clear genetic separation between cultivated varieties and wild accessions but also spotted the presence of rare feral individuals in natural populations of wild grapevines. For the prediction of relatedness, an identity-by-descent (IBD) analysis identified 'Plavac Mali', 'Bombino bianco', 'Bljuzgavac', 'Heunisch weiss' and 'Tribidrag' as varieties with highest numbers of first-degree relationships among the genotypes studied. [ABSTRACT FROM AUTHOR]

Phenolic acids, represented by hydroxycinnamic and hydroxybenzoic acids and their derivatives, are the most abundant phenolic compounds in grape juice and wine of white grapevine cultivars. The effects of fruit zone leaf removal on the concentration of hydroxycinnamic, hydroxybenzoic and organic acids of cv. Istrian Malvasia grape juice and wine are investigated in this study. Fruit zone leaf removal was applied at three different phenological stages: before blooming, at berry set and at veraison. Control treatment without leaf removal was also included. At veraison two intensities of leaf removal were applied. Phenolic and organic acids were identified and quantified using high-performance liquid chromatography. Juice samples from the grapes treated at the stages before blooming and berry set had the lowest concentrations of tartaric acid and the highest concentrations of malic acid, while juices from veraison stage treatments had the lowest concentrations of malic acid and the highest concentrations of tartaric acid. Before blooming treatment significantly lowered the concentration of all hydroxycinnamic and hydroxybenzoic acids in grape juice in comparison with other investigated treatments, which did not affect the concentration of total hydroxycinnamic acids considerably. The concentration of hydroxybenzoic acids in grape juice was lower in veraison treatments in comparison with berry set and control treatments. The concentrations of hydroxycinnamic, hydroxybenzoic and organic acids in wine followed the same trends as observed in grape juice. It is concluded that the concentration of phenolic and organic acids in grape juice and wine of white grapevine cultivars can be managed with the timing of fruit zone leaf removal according to the desired wine style. [ABSTRACT FROM AUTHOR]