## 1 Introduction  
Wine is the most traditional and popular alcoholic beverage consumed worldwide. A highly competitive market and consumer expectations force wineries to produce quality wines. Wine quality is determined by various factors, such as the type of grape varieties, geographical, climatic and pedological factors, viticultural practices, winemaking techniques, and aging conditions. Wine quality evaluation is based on both chemical and sensory analyses. The sensory characteristics of wines are significantly influenced by the phenolic profile, which is often used to evaluate the quality and authenticity of wines [1, 2]. Phenolic compounds are a diverse group of highly bioactive substances found in grapes and wine that can be formed and altered during the winemaking process. They are essential for color, flavor, and taste attributes, such as mouthfeel and astringency of wines, especially red wines. The most important phenolic compounds in red wines include anthocyanins and their derivatives, which give the wine its color, flavonoids, which are involved in the copignmentation process, and tannins, which are responsible for mouthfeel and astringency. Polymeric pigments, a heterogeneous group of anthocyanin-tannin reaction products, are usually formed during vinification [3]. The technological process to which the grapes are subjected has a significant impact on the phenolic content and composition of the wines. Since red wines are in contact with all parts of the grapes during macceration, they have a higher polyphenol concentration than white wines, whose polyphenol content comes mainly from the pulp [4]. During grape treatment and ripening, numerous chemical changes can take place, creating new compounds and/or degrading others. These changes can affect the polyphenolic profiles of wines. The phenolic composition of wines, which determines their organoleptic properties and provides information about their primary characteristics, can be used as a fingerprint to distinguish them according to their origin in terms of region, grape variety, and vintage [2]. The phenolic compounds most commonly used to evaluate wine quality and authenticity include phenolic acids, flavonoids, tannins, and stilbenes [1]. Polyphenols are not only closely related to wine quality but have also been shown to have health-promoting properties. Numerous studies have shown that moderate consumption of wine, especially red wine, is healthy as it protects against various chronic diseases such as cardiovascular and neurological disorders, metabolic syndrome, cognitive disorders, depression, and some cancers [4; 5; 6; 7]. The positive role of red wine in oxidative stress [8] and in promoting desirable gut bacteria leading to a healthier human body system has also been highlighted [9; 10]. Viticulture has a long tradition in Croatia, and there are an estimated 140 autochthonous grape varieties. Although the area under cultivation of foreign varieties has steadily increased over the last 50 years, 14 of the 30 most important varieties in Croatia are still indigenous [11]. Due to the geographical position of Croatia, the continental climate in the eastern and central parts of the country meets the Mediterranean climate in the southern, coastal areas [12]. In this context, Croatia is divided into four wine-growing regions [13]. The importance of determining the authenticity and commercial value of a wine, often related to its geographical origin, is recognized in Croatia, where viticulture and wine production play a significant economic role [12]. In the last two decades, several studies have been conducted to investigate the polyphenolic composition of Croatian wines. [PERSON] et al. [14] analyzed fifteen individual polyphenols in twelve Croatian wines from the 2002 vintage, and the wines from the Dalmatia wine region with a Mediterranean climate were the richest in polyphenols and contained the highest levels of gallic acid, quercetin, and myricetin. This was also confirmed in a study by [PERSON] et al. [15].