Commercial sparkling wine production represents a relatively low but important part of the Croatian wine production, especially in the Zagreb county. This study presents the results of volatile aroma compounds profile and organic acid composition of commercial sparkling wine samples from three vine-growing regions in Zagreb county. In total, 174 volatile aroma compounds were identified, separated between their chemical classes (aldehydes, higher alcohols, volatile phenols, terpenes, C13-norisoprenoids, lactones, esters, fatty acids, sulfur compounds, other compounds, other alcohols). Higher alcohols such as phenylethyl and isoamyl alcohol as well as 2-methyl-1-butanol, and esters such as diethyl succinate, ethyl hydrogensuccinate, and ethyl lactate had the strongest impact on the volatile compounds profile of Zagreb county sparkling wine. The presence of diethyl glutarate and diethyl malonate, compounds whose concentrations are influenced by yeast autolysis or caused by chemical esterification during the ageing process, was also noted. The influence of every single volatile aroma compound was evaluated by discriminant analysis using forward stepwise model. The volatile profiles of traditional sparkling wines from Croatia were presented for the first time. It is hoped the results will contribute to better understanding the quality potential and to evaluate possible differences on the bases of detected aroma concentrations and multivariate analysis.

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NMR is a swift and highly reproducible spectrometric technique that makes it possible to obtain spectra containing a lot of information about the sample analyzed. This approach helps major components be described in complex mixtures such as wine in just one analysis. Analysis of wine metabolites is very often used to understand the impact of geographical origin or variety on wine quality. NMR is often used for tracing the geographical origin of wine. Research on NMR metabolic effects of geographical origin is of great importance as the high added value of wines results from compliance with state legislation on the protected denomination of origin (PDO) and protected geographical indication (PGI) for the administration of the appellation of wines. A review of NMR with emphasis on SNIF-NMR in the analysis of wine authenticity is given. SNIF-NMR remains a method of choice for the detection of wine chaptalization as it is the only approach which provides position-specific information on the origin of sugar in wine. However, the sample preparation step, which lacks major improvements since its conception, is strenuous and expensive, and suffers from drawbacks in terms of low sample throughput. Mainstream 1D and 2D NMR experiments provide a fast and affordable way to authenticate wine based on the geographical origin, vintage, and variety discrimination, and include a simple and non-destructive sample preparation step. With this approach, spectral data processing often represents a crucial step of the analysis. With properly performed NMR experiments good to excellent differentiation of wines from different vintages, regions, and varieties was achieved recently.

Even though Saccharomyces cerevisiae starter cultures are still largely used nowadays, the non-Saccharomyces contribution is re-evaluated, showing positive enological characteristics. Among them, Lachancea thermotolerans is one of the key yeast species that are desired for their contribution to wine sensory characteristics. The main goal of this work was to explore the impact of L. thermotolerans commercial yeast strain used in sequential inoculation with S. cerevisiae commercial yeast on the main enological parameters and volatile aroma profile of Trnjak, Babić, Blatina, and Frankovka red wines and compare it with wines produced by the use of S. cerevisiae commercial yeast strain. In all sequential fermented wines, lactic acid concentrations were significantly higher, ranging from 0.20 mg/L in Trnjak up to 0.92 mg/L in Frankovka wines, while reducing alcohol levels from 0.1% v/v in Trnjak up to 0.9% v/v in Frankovka wines. Among volatile compounds, a significant increase of ethyl lactate and isobutyl acetate, geraniol, and geranyl acetate was detected in all wines made by use of L. thermotolerans. In Babić wines, the strongest influence of sequential fermentation was connected with higher total terpenes and total ester concentrations, while Trnjak sequentially fermented wines stood up with higher total aldehyde, volatile phenol, and total lactone concentrations. Control wines, regardless of variety, stood up with higher concentrations of total higher alcohols, especially isoamyl alcohol. The present work contributed to a better understanding of the fermentation possibilities of selected non-Saccharomyces strains in the overall red wine quality modeling.

Aroma profiles and phenolic components of white wines made from ’Pošip’ and ’Škrlet’ (Vitis vinifera L.) both native Croatian, non-aromatic grape varieties enhances the knowledge about these varieties, prepared without maceration (control) and subjected to the pre-fermentative cold maceration (CM). Individual phenolic compounds in wines were determined by high-performance liquid chromatography (HPLC) system, while total phenolics and flavan-3-ols in wines were determined by spectrophotometric methods. CM had the significant impact on the total phenolic and flavan-3-ols composition of ’Škrlet’ wine. The significant increase of some individual phenolic compounds was observed in ’Pošip’ wine. Volatile aroma compounds in wines were determined by gas chromatography (GC) with the previous extraction on the solid phase micro extraction (SPME). The primary aroma compounds, i.e. terpenes were under the significant influence of CM process in ’Škrlet’ wine. Aroma profiles, based on the content of 24 specific compounds, grouped in eight aroma series that contribute to wine odor were developed. CM significantly increased five aroma series in ’Škrlet’ wine and only three in ’Pošip’ wine.

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In Croatian viticultural sub-region of Middle and South Dalmatia, several high-quality white wines, mainly using the native grape varieties, are being produced and one of them is Vugava from the island of Vis. The aim of this two-year study was to investigate the effect of cold maceration conditions on aromatic and sensory properties of Vugava wines in comparison to the control wine produced without maceration. The GC/MS method was used for the determination of higher alcohols, methanol, ethyl acetate, and acetaldehyde concentrations. Aromatic profile was obtained by odor activity values and sensory evaluation. The significant difference in concentrations of total higher alcohols and isoamyl alcohol was determined in both vintages unlike the differences in basic wine composition. There was no visible difference or significant increase of methanol and ethyl acetate concentration what is positive from the health and sensory point of view. Sensory evaluation of Vugava wines showed that treatment of cold maceration (20 h/10 °C) resulted in increased complexity and better rated wine.

The maceration process is one of the indispensable winemaking steps in red wine production that has a marked impact on phenolic compound extraction and can strongly influence the color and gustatory quality. Seed removal can have a substantial impact on the intensity of bitterness and astringency which are mainly influenced by the presence of flavanols. The main aim of this study was to investigate the influence of seed removal and extraction time on the phenolic composition, color parameters, and organoleptic properties of Plavac mali wines produced from the grapes from the Pelješac Peninsula. The achieved results showed that the control wines differ in terms of their highest content of total anthocyanins in both years and total flavonols in one year of investigation, while prolonged maceration without seeds decreases the concentration of phenolic acids as well as that of flavan-3-ols. A prolonged extraction time influenced the color intensity and tonality, moving it towards more yellow pigments. These changes could possibly be explained by the pronounced interaction between phenolic compounds and the formation of the new ones. Interestingly, seed removal probably diminished that change because the potential absorption of the anthocyanins by grape seeds and tannins were excluded. The highest quality was sensory defined in wines produced by prolonged maceration without seeds.