Spontaneous fermentation of Maraština wines: The correlation between autochthonous mycobiota and phenolic compounds

Understanding fungal community dynamics during fermentation is important for assessing their influence on wine's phenolic content. The present study represents the first effort to explore the correlation between the autochthonous mycobiota of Maraština grapes collected from Dalmatian winegrowing sub-regions in Croatia and the phenolic composition, as well as the physicochemical parameters of wines produced through spontaneous fermentation. The metataxonomic approach revealed Metschnikowia pulcherrima, Metschnikowia fructicola and Hanseniaspora uvarum as the core mycobiota detected at the initial phase of fermentation. By contrast, Saccharomyces cerevisiae took over the dominance starting from the middle stage of fermentation. The wine's phenolic compounds were revealed by high-performance liquid chromatography, with tyrosol being the most abundant. Rhodotorula babjevae and Botrytis cinerea showed a positive correlation with p-hydroxybenzoic acid, gentisic acid, caffeic acid and cinnamic acid, while demonstrating a negative correlation with protocatechuic acid and chlorogenic acid. Heterophoma novae-verbascicola exhibited the opposite behaviour regarding the same phenolic compounds. The concentration of lactic acid was positively correlated with B. cinerea and negatively correlated with Het. novae-verbascicola. These findings serve as a foundation for in-depth investigations into the role of autochthonous grape mycobiota in phenolic transformation during spontaneous fermentation, potentially leading to the production of high-quality wines with unique terroir characteristics. Future studies should aim to explore the specific role played by individual yeast isolates in the formation of phenolic compounds.

Applying Different Vinification Techniques in Teran Red Wine Production: Impact on Bioactive Compounds and Sensory Attributes

Six different vinification treatments, including a control treatment (7-day standard maceration) (K7), were performed to study the effects of non-standard techniques on bioactive compounds and sensory attributes of Teran red wine. Pre-fermentative mash cooling (8 °C; 48 h) and heating (50 °C; 48 h) followed by prolonged post-fermentative maceration of 13 days (C15;H15) or 28 days (C30;H30) were applied. In another treatment, after cooling, saignée was performed followed by 13-day prolonged maceration (CS15). Wine phenols and vitamins were analyzed by HPLC-DAD-FLD, minerals by ICP-OES, and sensory analysis was performed using the QDA and 100-point O.I.V./U.I.O.E. methods. Obtained results showed total phenolic concentration was the highest in the H30 treatment. The concentration of anthocyanins, flavan-3-ols and phenolic acids was significantly higher in wines of all vinification techniques compared to the control. Stilbene content was highly affected by pre-fermentative heating. Treatments CS15, H15, C30 and H30 resulted in the highest scores by both the QDA and 100-point sensory methods. The obtained results suggest that advanced non-standard vinification techniques have a significant impact on Teran wine by enhancing its composition of bioactive compounds and improving its sensory profile, which gives it an additional market value. Furthermore, a comprehensive comparison of such techniques applied simultaneously in one study is of substantial importance for additional research in wine production.

Effect of Sequential Fermentation with Lachancea thermotolerans/S. cerevisiae on Aromatic and Flavonoid Profiles of Plavac Mali Wine

In this study, the effects of sequential fermentation of Lachancea thermotolerans/S. cerevisiae on the production of Plavac Mali wines were investigated in comparison with the commonly used inoculation of the commercial Saccharomyces cerevisiae strain and spontaneous fermentation. A total of 113 aroma compounds and 35 polyphenolic compounds were analyzed. Sequential inoculation resulted in a decrease in alcohol content and pH (up to 0.3% v/v and 0.12 units, respectively) and an increase in total acidity (0.6 g/L, expressed as tartaric acid). The wines produced by spontaneous fermentation exhibited the greatest diversity of volatile compounds and the highest concentration of C13 norisoprenoids, lactones, and other compounds. These wines exhibited maximum hydroxycinnamic acids, prodelphinidin monomer units, epigallocatechin, B1, B3, and B4 dimers, and total flavan-3-ols. Sequential inoculation decreased the content of the aromas and polyphenols in the wines. The practical significance of this procedure lies in the selective effect on aroma compounds, the decrease in green aromas, undetectable volatile phenols, and the decrease in bitter and astringent compounds such as gallic acid, flavan-3-ol monomers (catechin and epicatechin), and dimers (B1, B2, B3, and B4). This work demonstrates the potential of sequential and spontaneous fermentation to improve the aromatic characteristics and overall quality of Plavac Mali wines.

Systematic Bioinformatic Analyses of Nutrigenomic Modifications by Polyphenols Associated with Cardiometabolic Health in Humans-Evidence from Targeted Nutrigenomic Studies

Cardiometabolic disorders are among the leading causes of mortality in the human population. Dietary polyphenols exert beneficial effects on cardiometabolic health in humans. Molecular mechanisms, however, are not completely understood. Aiming to conduct in-depth integrative bioinformatic analyses to elucidate molecular mechanisms underlying the protective effects of polyphenols on cardiometabolic health, we first conducted a systematic literature search to identify human intervention studies with polyphenols that demonstrate improvement of cardiometabolic risk factors in parallel with significant nutrigenomic effects. Applying the predefined inclusion criteria, we identified 58 differentially expressed genes at mRNA level and 5 miRNAs, analyzed in peripheral blood cells with RT-PCR methods. Subsequent integrative bioinformatic analyses demonstrated that polyphenols modulate genes that are mainly involved in the processes such as inflammation, lipid metabolism, and endothelial function. We also identified 37 transcription factors that are involved in the regulation of polyphenol modulated genes, including RELA/NFKB1, STAT1, JUN, or SIRT1. Integrative bioinformatic analysis of mRNA and miRNA-target pathways demonstrated several common enriched pathways that include MAPK signaling pathway, TNF signaling pathway, PI3K-Akt signaling pathway, focal adhesion, or PPAR signaling pathway. These bioinformatic analyses represent a valuable source of information for the identification of molecular mechanisms underlying the beneficial health effects of polyphenols and potential target genes for future nutrigenetic studies.

Early Defoliation Techniques Enhance Yield Components, Grape and Wine Composition of cv. Trnjak (Vitis vinifera L.) in Dalmatian Hinterland Wine Region

Defoliation and cluster thinning are of practical importance in a control of the grapevine source-sink balance, cluster architecture, microclimate and berry composition. Nevertheless, their effectiveness on wine composition is unexplored. In this work, the impacts of preflowering (T1), after berry set (T2), and veraison defoliation (T3) and cluster thinning (T4), on yield components, grape and wine composition of cv. Trnjak are given. Implemented techniques significantly reduced yield and affected grape and wine components in comparison to untreated control (C). Despite lowest number of clusters ensured by cluster thinning, defoliation at veraison had lowest yield. Defoliations improved cluster architecture parameters. Highest berry per se was in preflowering T1 and lowest at veraison T3 defoliation. Berries of T1 had lowest sugar content (19.47 °Brix) while T3 had highest (22.3 °Brix), and the reverse is seen in total acidity highest in T1 (6.12 g/L) and lowest in T3 (5.01 g/L). Wines of early defoliations (T1 and T2) had lowest alcohol and highest anthocyanin concentration. Both techniques applied at veraison produced wines with lower anthocyanins and flavonols than those obtained without any intervention (C). In conclusion, the early defoliations (T1 and T2) improve yield and wine composition of cv. Trnjak in the Mediterranean region of Croatia.

Targeted UPLC-QqQ-MS/MS profiling of phenolic compounds for differentiation of monovarietal wines and corroboration of particular varietal typicity concepts

Targeted ultra-performance liquid chromatography with triple quadrupole mass spectrometric (UPLC-QqQ-MS/MS) profiling of phenolic compounds was utilised for varietal differentiation of 173 wines made from four red and six white grape varieties. Among 58 identified phenols many were found relevant as exclusive or partial discriminators between wines. Successful differentiation models were built by linear discriminant analysis with the percentage of correct classification higher than 95% in all cases, with peonidin 3-(6″-acetyl)-glucoside and taxifolin as the most potent differentiators between red, and cis-piceid between white monovarietal wines. Diverse typical colour attributes among the monovarietal wines were tentatively ascribed to the variations in the composition of monomeric anthocyanins. Plavac mali red wine exhibited the most specific composition, and its most typical samples were distinguished by the abundance in trans-fertaric acid, isorhapontin, phlorizin, quercetin 3-rhamnoside, and myricitrin. Despite positive correlations with particular astringent flavonols, the typical astringency of Plavac mali wine remained unresolved.

Chemical Composition and Biological Activity of Allium cepa L. and Allium × cornutum (Clementi ex Visiani 1842) Methanolic Extracts

Here, we report a comparative study of the phytochemical profile and the biological activity of two onion extracts, namely Allium cepa L. and Allium × cornutum (Clementi ex Visiani 1842), members of the family Amaryllidaceae. The identification of flavonoids and anthocyanins, and their individual quantities, was determined by high-performance liquid chromatography (HPLC). The potency of both extracts to scavenge free radicals was determined by the DPPH (2,2'-diphenyl-1-picrylhydrazyl) radical-scavenging activity and oxygen radical absorbance capacity (ORAC) methods. The DNA protective role was further tested by the single-cell gel electrophoresis (COMET) assay and by Fenton's reagent causing double-strand breaks on the closed circular high copy pUC19 plasmid isolated from Escherichia coli. In the presence of both extracts, a significant decrease in DNA damage was observed, which indicates a protective role of Allium cepa and Allium × cornutum on DNA strand breaks. Additionally, cytotoxicity was tested on glioblastoma and breast cancer cell lines. The results showed that both extracts had antiproliferative effects, but the most prominent decrease in cellular growth was observed in glioblastoma cells.