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Antocijani su pigmenti crvene boje smješteni uglavnom u kožici bobice crvenog grožđa te pridonose boji crvenih vina. Njihova koncentracija u vinima ovisi o: sorti, području uzgoja, tehnikama vinifikacije. Najzastupljeniji antocijan u vinima proizvedenim od grožđa Vitis vinifera L. je u pravilu malvidin-3- monoglukozid. Utjecaj na ekstrakciju i degradaciju antocijana mogu imati i Saccharomyces cerevisiae kvasci. Identifikacija antocijana u vinima Teran i Cabernet sauvignon berbe 2009. provedena je tehnikom tekućinske kromatografije visoke djelotvornosti. Istraživan je utjecaj tri komercijalna Saccharomyces cerevisiae kvasca (Uvaferm BDX, D254 i Fermol Premier Cru) na koncentraciju antocijana. Rezultati istraživanja pokazali su da kvasci Uvaferm BDX i D254 ekstrahiraju više aciliranih i neaciliranih antocijana., Anthocyanins are red, blue and purple pigments located mainly in the skin of red grape berries and contribute to the color of red wines. Their concentration in wine depends on variety, ecological conditions, growing and vinification techniques. The most common anthocyanin in red wines made from Vitis vinifera L. grapes is generally malvidin-3-monoglucoside. Saccharomyces cerevisiae yeast may have the impact on the extraction and degradation of anthocyanins. Identification of anthocyanins in wines Cabernet Sauvignon and Teran in harvest 2009 was analyzed by the technique of high performance liquid chromatography. The effects of three commercial Saccharomyces cerevisiae yeasts (BDX Uvaferm, D254 and Fermol Premier Cru) on the concentration of anthocyanins were investigated. The results showed that yeasts Uvaferm BDX and D254 extracted more non- acylated and acylated anthocyanins.

The evolution of free anthocyanins during the five different fermentation temperatures (control treatment at 22 °C, 5 days pre-fermentative cryomaceration at 5 °C followed by maceration at 25 °C, maceration at 25 °C, maceration at 30 °C and maceration at 25 °C + heated post-fermentation maceration to 35-40 °C after finished alcoholic fermentation) of Teran wine was studied. Sampling was made at day 5, 10, 15 and three months after the end of maceration during storage time. Anthocyanins were determined by high performance liquid chromatography method coupled with photodiode array detection (HPLC-PDA). The results showed that the modification of the temperature conditions during maceration increased the anthocyanin concentration for pre-fermentative cryomaceration and maceration at 25 °C, while the maceration at higher temperatures showed a decrease in the anthocyanin concentration in young Teran wine. Quantitatively, malvidin derivatives were the most abundant anthocyanin compounds in all studied wines. Malvidin-3-glucoside was the major anthocyanin in Teran wine, with concentrations up to 138.59±1.22 mg/L and 76.93±0.36 mg/L for C treatment in 2008 and 2009 vintage, respectively. Results of this study indicate that five days pre-fermentative cryomaceration at 5 °C followed by maceration at 25 °C is most appropriate in order to achieve maximum anthocyanin concentration in Teran wines.

The colour of red wine is a sensory attribute, related to the extraction of anthocyanins from grape skin during maceration. The extraction of anthocyanins from the grape into the wine is therefore main diffusion process. Rate and extent of extraction are influenced by concentration of anthocyanins, its localization in the berry, and processing methods where temperature and duration of maceration are deteminating factors. The free anthocyanins in wine are mono- or diglucosides of five anthocyanins, namely delphinidin, cyaninid, petunidin, peonidin and malvidin. The acylated anthocyanins are esters of the glucose part of the free anthocyanins with acetic, p-coumaric or caffeic acid. The aim of the present work was to study the influence of different temperatures (pre-fermentative cryomaceration, maceration at 25 °C and 25 °C + short-term, post-fermentative warming to 35-40 °C) on extraction of anthocyanins, colour density and hue of wine, from Croatian native red grape variety Teran. Anthocyanins were quantified using a high performance liquid (HPLC) with UV-Diode Array detection. Pre-fermentative cryomaceration increased the pigment extraction, and the wine produced by this technique contained a significantly higher content of total monoglucosides and total monoglucosides p-coumarats then the other wines. Quantitatively, malvidin derivates were the most abundant anthocyanin compounds in all studied wines. With the respect to the colour, pre-fermentative cryomaceration has proven to be a useful technique to obtain darker and less brown wines.

The composition and concentration of the anthocyanins in red wine depend on the grape variety, ripening, climatic conditions, wine making practices and ageing. Among these factors, maceration conditions have a largest impact on the anthocyanins and other sensory characteristics of red wines. Anthocyanins are located in grape skins and are transferred to must and wine during maceration. Maceration duration greatly influences extraction and concentration of anthocyanins in must and wine. The objective of this study was to determine the influence of different maceration time (3, 7, 12, 17 and 21 days) on the anthocyanin composition of red wine made from Istrian (Croatian) native grape variety Teran (Vitis vinifera L.). Anthocyanins were determined by HPLC with UV-Diode Array detection. Eleven different anthocyanins were detected and determined quantitatively in Teran’s wines. Malvidin-3-O-glucoside and its acylated esters were the major anthocyanins. The maximum increase in anthocyanin concentration was found between days 3 and 7. On day 7, the total amount of anthocyanins in Teran wine reached a maximum of 771.22 mg/L. Little change was detected from day 7 to day 12. Decrease in anthocyanin concentration was observed from day 12 to day 17 (from 761.74 to 729.76 mg/L). Results of this study indicate that maceration duration of seven days is most appropriate in order to achieve maximum anthocyanin concentration in Teran wines.

INTRODUCTION During the ageing of wine the complexity of the phenolic components is increased due to the condensation and polymerization among certain compounds present in wine. Phenolic compounds contribute directly or indirectly to wine organoleptic characteristics such as colour, astringency, bitterness and aroma. The objective of this study was to determine concentrations of phenolic compounds and antioxidant capacity of red wine made from Croatian native grape variety Teran (Vitis vinifera L.) during the six months ageing in oak barrels. MATERIALS AND METHODS This study was performed on samples of wine produced from native grape variety (Vitis vinifera L.) Teran, vintage 2006. The wine was maturated from January 2007 to June 2007 in oak barrels. The content of total phenolic compounds in wine samples was determined by the Folin-Ciocalteu's reagent. Anthocyanins were determined by HPLC with UV-Diode Array detection. The total antioxidant capacity of wine was measured by three different analytical methods: 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging method, 2, 2'-azinobis(3-ethylbenzothialozine-6-sulfonic acid) radical cation (ABTS۰ +) and ferric reducing antioxidant power (FRAP). RESULTS AND DISCUSSION The amount of total polyphenol content in the period of ageing was slightly decreased (1514 mg/L to 1399 mg/L GAE). As a result of anthocyanins analysis of all the wines studied a total of eleven different anthocyanins compounds were detected and determined quantitatively. Significant differences were found in the concentrations of all the anthocyanins compounds identified due to ageing time. The concentrations of identified anthocyanins diminished during the six months ageing in barrel, possibly due to typical oxidation and condensation reactions occurring in barrels. In Teran wine malvidin-3-O-glucoside was the major anthocyanin, with concentrations up to 358.23± 1.53. After six month of ageing the concentration of malvidin -3-O-glucoside was 198.34± 3.42. During the ageing of wines the antioxidant capacity was constantly decreasing and was found to be the highest in the beginning of ageing in oak barrels.

The main purpose of grapevine solarization technique is reflection of sunlight into the grapes, and therefore changes in light spectrum and temperature can be noticed. An artificial solarization experiment was conducted on a parcel of Teran grapevines grown in the subregion Istra (Brtonigla vineyard location) of Croatia in the year 2005 and 2006. Main organic acids (tartaric, malic, lactic, citric and succinic) were analysed by HPLC using DAD set at 210 nm on C-18 analytical column. Samples were prepared by solid phase extraction using SAX cartridges in order to clean up interferences like sugars and alcohols. It is well known that Teran is one of the red grape varieties characterized by high to very high total acidity (8, 0-14, 0 g/L) and high content of malic acid (4, 0-10, 0 g/L). Compared with standard vinestocks grown on bare soil, solarization technique also caused higher anthocyanins content in Teran wines, analysed by HPLC method just after the end of alcoholic fermentation. A simple and fast method was used for separation of nine anthocyanins in Teran wine by direct injection using DAD set at 518 nm. Phosphate buffer at pH 1.6 and acetonitrile were used as mobile phases. The low pH of the mobile phase is required to keep the anthocyanins homogeneous in the flavylium form according to the pH-dependent equilibria. The linearity was investigated for malvidine-3- glucoside in the range of 5-250 mg/L at seven concentration levels. All of the samples exhibited malvidin-3-monoglucoside as the major compound, representing about 55% of the sum of all individual anthocyanins. The strongest solarization effect was seen through the higher content of 3-O-glucosides of delphinidine, petunidin and malvidin and acetylated as well as coumarylated forms of malvidine and peonidin. Total phenolic contents of samples were also determined using the Folin-Ciocalteu method. The wines were sensory tested by the O.I.V./U.I.OE. method by 100 positive points. This study suggested that solarization technique positively influenced the quality of Teran wines.

The colour of red wines is a remarkable sensory attribute, related to the extraction of anthocyanins from grape skins during winemaking. Anthocyanins are accumulated in berry skins during the ripening of grapes and several agroecological factors, such as cultivar, climate, soil conditions, crop level, irrigation, have been related to anthocyanins accumulation in grape red skins (Esteban et al., 2001). The free anthocyanins in wine are mono- or diglucosides of five anthocyanidins, namely delphinidin, cyanidin, petunidin, peonidin and malvidin. The acylated anthocyanins are esters of the glucose part of the free anthocyanins with acetic, p-coumaric or caffeic acid (Berente et al., 2000). The aim of the present work was to study the anthocyanin composition in the wine made of the Croatian autochthonous grape variety Teran (Vitis vinifera L.) The anthocyanin composition of wine was determined by the high performance liquid chromatography (HPLC) with UV-Diode Array detection. In all samples determined total anthocyanin content and antioxidant activity. The total antioxidant capacity of wine was measured with four different methods: 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging method, β-carotene bleaching (BCB) method, 2, 2'-azinobis(3-ethylbenzothialozine-6-sulfonic acid) radical cation (ABTS۰+) and ferric reducing antioxidant power (FRAP). Five different anthocyanins were detected and determined quantitatively in the studied red wines: delphinidin-3-glucoside, cyanidin-3-glucoside, petunidin-3-glucoside, peonidin-3-glucoside and malvidin-3-glucoside. In Teran malvidin-3-glucoside was the major anthocyanin, with concentrations up to 114±3.06 mg/L. The obtained results showed a good correlation between the total monoglucosides content of studied samples and their total antioxidant capacity.