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Prirodno pjenušavo ružičasto vino od autohtonog kultivara vinove loze Teran (Vitis vinifera L.) proizvedeno je metodom vrenja u boci uz primjenu inkapsuliranog kvasca ProElif® (Saccharomyces cerevisiae) i komercijalnog suhog kvasca Fermol Blanc (Saccharomyces bayanus). Tijekom istraživanja uspoređivana je aktivnost korištenih kvasaca s obzirom na brzinu razgradnje šećera tijekom fermentacije u boci te njihov utjecaj na osnovna fizikalno kemijska svojstva i fenolni profil gotovog pjenušavog vina te parametre pjene i iskrenja. Brža razgradnja šećera, kao i veći udio pojedinačnih i ukupnih fenolnih spojeva utvrđen je u pjenušavim vinima proizvedenim primjenom inkapsuliranog kvasca ProElif®. S druge strane, vina proizvedena kvascem Fermol Blanc odlikovala su se višim suhim ekstraktom te većom kvalitetom pjene i iskrenja. Uočene senzorske razlike u vinima nisu imale negativnih implikacija pri definiranju njihove sveobuhvatne kakvoće, The influence of encapsulated yeast ProElif® (Saccharomyces cerevisiae) in comparison with the yeast Fermol Blanc (Saccharomyces bayanus) in the production of naturally sparkling rosé wine by bottle fermentation produced from the indigenous grape cultivar Teran (Vitis vinifera L.) was investigated. During the research, the following were monitored: the length of sugar decomposition during fermentation in the bottle, and in the finalized sparkling wines, physicochemical parameters, foam and sparkling parameters and phenolic profile. Faster breakdown of sugars, as well as a higher proportion of individual and total phenolic compounds have been recorded in wines with ProElif® yeast. On the other hand, wines produced with Fermol Blanc yeast were characterized by a higher dry extract and higher quality of foam and sparkling. Sensory differences were observed in wines without negative implications for their final quality.

Six vinification treatments, including control treatment (K7) were carried out to investigate: the impact of 48-h pre-fermentative mash cooling (8 °C) followed by 13-days maceration (C15), 28- days maceration (C30) and saignée technique (CS15) ; and the impact of 48-h heating (50 °C) followed by 13-days maceration (H15) and 28 days (H30) on total phenolic content (TPC) and antioxidant capacity (AC) in Teran wines. TPC was analysed by a method based on Folin–Ciocalteu reagent and AC was determined by FRAP and ORAC assay. The results showed higher TPC and AC in all treatments compared to the control wine (K7). The highest TPC was found after saignée technique applied (CS15). Pre-fermentative heating and 30-day maceration treatment (H30) showed the strongest antioxidant capacity, with both FRAP and ORAC assay.

This study aimed to determine antioxidant capacity and total phenolic content in red wine obtained from cv. Teran (Vitis vinifera L.), autochtonous Croatian grape variety. Five different vinification treatments were submitted to: 48-hour pre-fermentative mash cooling (8 °C) followed by prolonged post-fermentative maceration of 13 days (C15), 28 days (C30), and saignée technique (juice runoff) proceeded with maceration of 13 days (CS15) ; and to 48-hour heating (50 °C) followed by maceration of 13 days (H15) and 28 days (H30). Also, this experiment included a control treatment (K7), with a standard 7-day maceration. The antioxidant capacity of the wines was determined by the ferric reducing/antioxidant power (FRAP) assay and the oxygen radical absorbance capacity (ORAC) assay. Fluorescence was measured by spectrofluorometer. The FRAP assay results are expressed in mmol/L FeSO4 × 7H2O, and the ORAC assay results are expressed as mmol/L of Trolox equivalents (TE). Total phenolic content (TPC) was determined by the Folin–Ciocalteu colorimetric method using a UV/Vis spectrophotometer. The results are expressed as gallic acid equivalents in mg/L of wine (mg GAE/L). Obtained results showed that both FRAP and ORAC assay values in all treatments were significantly higher compared to the control treatment (K7). Also, the two assays showed a strong correlation (r= 0.998). FRAP assay values ranged from 10.77 to 23.67 mM Fe2+, and ORAC assay values ranged from 17.77 to 31.67 mM Trolox. The highest values of both assays were obtained in treatment submitted to pre-fermentative heating and 30-day maceration (H30). Total phenolic content varied from 821.52 mg GAE/L in control wine (K7) to significantly the highest value, 2710.61 mg GAE/L in treatment where saignée technique and 15-day maceration were performed (CS15). In comparison to control wine (K7) TPC in all treatments was statistically higher. Obtained results suggested a noticeable impact of saignée technique and 15-day maceration on TPC, and the impact of pre-fermentative mash heating and 30-day maceration on antioxidant capacity. According to our results, Teran red wine, affected by particular vinification processes considered a strong source of bioactive compounds, as well their beneficial properties can contribute to human health.

The purpose of this study was to investigate the effect of different non-Saccharomyces yeasts on volatile aroma profile in early fermentation of a white cultivar Malvazija istarska(Vitis vinifera L.). The grape must was inoculated in monoculture with Torulaspora delbrueckii, Metschnikowia pulcherrima, Pichia kluyveri, Lachancea thermotolerans and Schizosaccharomyces pombe. Saccharomyces cerevisiae was inoculated as a control. The identifi cation and quantifi cation of volatile compounds was done with gas chromatographymass spectrometry, after headspace solid-phase microextraction. The chromatographic data were elaborated by statistical analysis. Each of the studied non-Saccharomyces yeasts influenced volatile aroma composition in a unique way in early fermentation. The analysis showed that many of the investigated yeasts caused an increase in linalool and β-damascenone concentrations and improved synthesis of many major and minor esters, while simultaneously caused lower production of higher alcohols and fatty acids. T. delbrueckii and M. pulcherrima induced the synthesis of compounds not commonly found in S. cerevisiae fermented wines. Multivariate statistical analysis confirmed that each of the investigated yeasts generated a particular volatile profile in early fermentation. The obtained results showed that non-Saccharomyces yeasts have a potential that could be used to produce wines with complex and distinct volatile aroma compound profiles.

Phenolic acids and stilbenes are important groups of non-flavonoid phenolic compounds present in grapes and wine. Their content in wine may be modulated by the vinification technique applied. The present study aimed to determine the impact of the application of different grape mash maceration treatments on the composition of hydroxycinnamic (HCA) and hydroxybenzoic acids (HBA) and stilbenes in Malvazija istarska wines. The research was conducted at the Institute of Agriculture and Tourism (Poreč, Croatia) with Malvazija istarska (Vitis vinifera L.), an autochthonous Croatian white grape variety. A total of six vinification treatments were carried out: two days maceration treatment at 8 °C (CRYO), and seven (M7), 14 (M14), 21 (M21), and 42 days (M42) maceration treatments at 16 °C, compared with the control treatment without maceration (C). Identification and quantification of phenolic acids and stilbenes was performed after direct injection of the filtered wine sample, using a high performance liquid chromatograph (HPLC) equipped with a diode array detector (DAD). The obtained results were statistically processed by one-way analysis of variance (ANOVA) and Fisher's test of least significant differences (LSD). According to the obtained results, the highest concentration of total HBAs was recorded in prolonged post-fermentative maceration treatment M42, and among all HBAs gallic acid had significantly the highest concentrations. Regarding HCAs, the total content was significantly the highest in seven days maceration treatment (M7), while in longer maceration treatments (M14, M21, M42) total HCA content 58 gradually decreased as maceration progressed. When observing individual HCAs, transcaftaric acid had the highest concentrations, especially in M7 treatment wine, while caffeic and ferulic acids reached the highest concentrations in pre-fermentative two days (CRYO) treatment. Regarding total stilbene content, treatments M7, M14, and M21 obtained the highest concentrations, but did not significantly differ between each other, and when observing individual stilbenes, cis-piceid concentrations were the highest in those treatments and among all identified stilbenes. Obtained results show that HBA content benefits from the prolonged maceration, while for the most HCAs and stilbenes concentrations increase up to seven days of maceration and then decrease during prolonged maceration, possibly due to oxidation and other reactions.

To investigate the effect of different maceration techniques on the mineral composition of Malvazija istarska wines, five different maceration treatments were carried out. Maceration techniques of two days at 8 °C (CRYO), and seven (M7), 14 (M14), 21 (M21), and 42 days (M42) at 16 °C, were studied and compared to control treatment without maceration (C). Analysis of macro- and microelements was conducted by inductively coupled plasma- optical emission spectrometry (ICP-OES). According to the obtained results, the longest maceration treatments (M21 and M42) resulted with the highest concentration of almost all macroelements. A proportional increase with maceration time was observed in the concentration of all analyzed microelements, with M42 treatment wine resulting in significantly highest concentrations.

Moderate wine consumption may impact several human health aspects, among other as a result of phenolic compounds present in wine and their bioactive properties. The aim of this study was to determine whether six weeks of daily, moderate Teran red wine consumption affects the levels of total cholesterol, high-density lipoprotein cholesterol – HDL, low-density lipoprotein cholesterol – LDL, and triglycerides. Sixty-eight healthy adults (46 women and 22 men) aged 25-64 years voluntarily agreed to participate in the study. The study was carried out in accordance with the Declaration of Helsinki developed by the World Medical Association and was approved by the Ethics Committee of the Clinical Hospital Center Rijeka (Croatia). Informed consent was obtained from all subjects involved in the study. Participants were divided into two groups, consumers (49 participants) and non-consumers (19 participants). Non-consumers were asked to avoid any alcohol intake during the six study weeks, while consumers were asked to consume one glass of red wine (200 mL) per day and not to drink any extra alcohol. Blood samples for laboratory tests were drawn just before the start and at the end of the study period. Total cholesterol, HDL, LDL, and triglycerides were analyzed on biochemistry analyzer at Clinical Hospital Centre Rijeka, using standard laboratory methods. Total phenols in wine expressed as gallic acid equivalents in mg/L of wine (mg GAE/L) were determined by the Folin- Ciocalteu colorimetric method using a UV/Vis spectrophotometer. One-way analysis of variance and Fischer’s least significant difference test at the level of significance p ≤ 0.05 were used to compare the groups of participants. The differences between the values obtained in the second (the end of the study period) and the first measurement (before the start of the study period) of their blood parameters were used in statistical analysis. The consumed red wine was produced at the Institute of Agriculture and Tourism (Poreč, Croatia) from an old autochthonous grapevine variety Teran (Vitis vinifera L.). The total phenolic content in the produced wines ranged from 2369 mg to 2917 mg GAE/L. No significant differences were observed between the consumers and non-consumers regarding blood lipid profile. However, considering that alcohol consumption generally can negatively affect cholesterol levels, our findings suggest that the beneficial effects of phenolics and/or other wine constituents possibly overcame the negative alcohol effects on health. Although it does not provide any evidence of significant positive or negative effect of moderate Teran red wine consumption on blood lipid profile, this study could suggest that daily moderate wine consumption can be considered as a component of the healthy lifestyle regarding the investigated parameters.

The objective of this study was to determine the effects of four winemaking techniques on water- soluble vitamin content and estimate the changes in their range during the barrel aging of Teran red wines. The study covered seven days of maceration as a control treatment (TM7), prolonged 10-day maceration (TM10), prolonged post- fermentative 21-day maceration (TM21), and 48-h pre-fermentative maceration heat treatment at 45 °C followed by eight-day standard maceration (TPHT). The fermentation of all treatments was conducted at 24 °C. Accordingly, all the wine samples were aged in oak barrels for six months. Vitamins were analyzed using high-performance liquid chromatography with UV-Vis diode array and single quadrupole mass detector equipped with electrospray ionization interface. The thiamine (vitamin B1), riboflavin (vitamin B2), niacin (vitamin B3), pyridoxine (vitamin B6), and ascorbic acid (vitamin C) were determined. Total B complex vitamin content of young Teran wines significantly increased with prolonged skin contact. Furthermore, the results showed that significantly the highest content of total B- complex vitamins was detected in TM21 wine, followed by TM10 treatment. Regarding the vitamin C concentration in young Teran wines, there were no statistical differences between TM7, TM10, TM21 treatments, while TPHT treatment showed a significantly lower concentration. Wine barrel aging significantly reduced the level of all investigated vitamins except vitamin B6, which remained stable in all treatments. This study showed that winemaking techniques could affect the vitamin concentrations in wine.

Yeasts from the genus Saccharomyces are most commonly used in wine production. On the other hand, in the last years there is a growing interest in use of non-Saccharomyces yeasts for reducing the content of ethanol, modifying acidity, improving protein stability, and enhancing wine aroma. In this experiment, grape must of Malvazija istarska was inoculated with five commercial non-Saccharomyces yeasts and a Saccharomyces cerevisiae/Saccharomyces paradoxus hybrid with the aim to investigate the effect of yeast on the content of volatile esters, key compounds that determine wine aroma and flavour. Saccharomyces cerevisiae was inoculated at 1.5-2.0 % (v/v) of ethanol to finish fermentations and was also inoculated in monoculture as a control treatment. Ester profiles were analysed by comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry (GC×GC-TOF- MS) combined with conventional mono-dimensional GC–MS. More than a hundred esters were identified or tentatively identified, providing one of the most detailed profiles of volatile esters in wine in general. Torulospora delbrueckii showed the highest potential to produce ethyl isobutyrate, isopropyl, isoamyl, 2-phenethyl, and geranyl acetates, ethyl 3-hexenoate, and ethyl 4- hexanoate. Pichia kluyveri produced most trans-3- hexenyl acetate, ethyl 2-methylbutyrate, and ethyl 3-methylbutyrate, Metschnikowia pulcherrima produced the highest amounts of ethyl decanoate and ethyl phenyl lactate, S. cerevisiae/paradoxus hybrid excelled in the production of 2-phenethyl isobutyrate and ethyl benzeneacetate, while Lachancea thermotolerans wine was the most abundant in isobutyl octanoate. Schizosaccharomyces pombe treatment wine was characterized by elevated concentrations of particular esters not commonly reported in wine aroma studies, such as esters of isoamyl alcohol with propanoic, isobutyric, isovaleric, lactic, and succinic acid, esters of 2-phenylethanol with formic, propanoic, isovaleric, hexanoic, and octanoic acid, as well as S-ethyl octanethioate. The control S. cerevisiae treatment wine contained most ethyl 4-hydroxybutyrate and amyl methacrylate. The approach reported may have practical application in better understanding and managing the content and composition of odoriferous volatile esters in Malvazija istarska and wine in general. This study was funded by Croatian Science Foundation under the projects IP- 2020-02-4551 and DOK-2021-02-5500.

The rising trend of moderate wine consumption as a part of a healthy lifestyle promotes white wines with higher phenolic content because of their bioactive properties. Duration and temperature of the maceration process have a marked impact on the content and composition of wine phenolics. The aim of this study was to explore the effect of applying maceration processes of different durations and temperature on total phenolic content and flavan-3-ol compounds concentration of Malvazija istarska (Vitis vinifera L.) wines, an autochthonous Croatian white grape variety. Vinification took place at the Institute of Agriculture and Tourism (Poreč) where pre-fermentative two days cryomaceration treatment at 8 °C (CRYO), seven days maceration treatment at 16 °C (M7), and prolonged post- fermentative maceration treatments at 16 °C for 14 days (M14), 21 day (M21), and 42 days (M42) were studied and compared to non- maceration control treatment (C). Total phenolic content was determined by the Folin-Ciocalteu colorimetric method using a UV/VIS spectrophotometer and the results were expressed as gallic acid equivalents (mg/L GAE). The analysis of flavan-3-ols was carried out by high performance liquid chromatography (HPLC). Identification was performed by comparing retention times and spectra with those of pure standards. Procyanidins B1, B2, B3, C1, and (+)-catechin and (-)-epicatechin were identified in all wine samples. Statistical data analysis was performed using one-way analysis of variance (ANOVA) and Fischer’s least significant difference (LSD), while Pearson’s correlation was used to observe the relationship between total phenolic content and total flavan-3-ols. According to the obtained results, total phenolic content increased in all maceration treatments when compared to C treatment wine. The increase in total phenolic content was the highest in post- fermentative maceration treatments, M14 and M42. Total flavan-3-ol content showed a similar trend, also reaching the highest values in M14 and M42 treatment wines, while the lowest concentrations were observed in both C and CRYO treatments. A high positive correlation was observed between total phenolic content and total flavan-3-ols. When observing individual flavan-3-ol compounds, (-)-epicatechin reached the highest concentrations, especially in M42 treatment. Procyanidin B3 and C1 significantly increased only when 42 days maceration was applied, while shorter maceration durations or temperature did not affect the increase in these compounds. It can be concluded that the investigated phenolics highly depended on the maceration conditions applied. Additionally, the increase levels of bioactive phenols resulting from the application of the investigated maceration practices might attract those consumers interested in moderate white wine consumption for specific health reasons. The study was funded by the Croatian Scientific Foundation under the projects IP 2018-5049 and DOK-2020-01-1901.

Wine is a rich source of various nutritive bioactive compounds, including macro- and microelements. A moderate wine consumption of 250-300 ml/day contributes to the requirements of the human organism for essential elements. Current studies attribute the consumption of foods rich in nutrients even as potential inhibitors of SARS-CoV-2. Moreover, supplementation of micronutrients may positively impact the recovery from COVID-19 infection. However, some metals can be potentially toxic when consumed in excess, and the maximum acceptable levels in wine have been established. The aim of this study was to determine the effects of vinification techniques on mineral composition and estimate the changes in composition during the barrel aging. The experiment was performed in vintage 2019, with grapes from Teran (Vitis vinifera L.) variety. Vinification took place in the experimental wine cellar of the Institute of Agriculture and Tourism in Poreč (Croatia). The study covered seven days of maceration as a control treatment (TM7), prolonged 10-day maceration (TM10), prolonged post-fermentative 21-day maceration (TM21), and 48-h pre-fermentative maceration heat treatment at 45 °C followed by eight-day standard maceration (TPHT). The fermentation of all treatments was conducted at 24 °C. Accordingly, all the wine samples were aged in oak barrels for six months (TM7-B, TM10-B, TM21-B, TPHT-B). The determination of eight elements was conducted by Optima DV 2000 inductively coupled plasma-optical emission spectrometer. Analysed elements were identified by ICP-OES and were quantified by the direct calibration method. Statistical data analysis was performed using one-way analysis of variance (ANOVA) and Fischer’s least significant difference (LSD) to compare the means (n = 3) at the level of significance of p ≤ 0.05. In the investigated wines, K, Ca, Mg, and Na were identified as macroelements, and Al, Cu, Fe, and Mn as microelements. Results in this study showed the significant impact of different treatments on mineral composition. More precisely, compared to control (TM7), TM10, and TM21 treatments showed significantly higher concentrations of total macroelements, while TPHT treatment showed significantly lower concentrations. The significantly highest concentration of macroelements in aged wines was found in TM21-B wines. It is important to note that wine barrel aging significantly reduced the level of all investigated macroelements except Mg, which remained stable in all treatments. The content of total microelements in young wines was significantly the highest in pre-fermentative heating treatment. The same trend continued in aged wines, with the highest concentration in TPHT-B treatment. It should be pointed that the concentration of all investigated microelements was significantly reduced during barrel aging. This result indicates that some interesting differences can be obtained among wines by applying maceration, heating, and barrel aging in the composition of macro- and microelements. In addition, since metals can form organometallic complexes with anthocyanins and tannins and cause the formation of precipitates, it was very interesting to monitor the evolution of wines during maturation and aging. Obtained results can probably be attributed to the different extraction mechanisms/kinetics from solid parts of grapes, particularly the skin, which was shown to be the most important fraction in terms of metal concentration. Regarding aging, earlier studies indicated, that metal composition is not stable, which was also confirmed in this research. However, the intensity of these changes can vary depending on grape and wine composition. This study was funded by the Croatian Science Foundation under the projects VINUM SANUM (IP 2018-5049) and DOK-2018-09.

Six vinification treatments, including control wine (TK7) were carried out to investigate: the impact of 48-h pre-fermentative mash cooling (8 °C) followed by maceration of 13 days (TC15), 28 days (TC30) and saignée technique (TCS15) ; and the impact of 48-h heating (50 °C) followed by maceration of 13 days (TH15) and 28 days (TH30) on anthocyanin concentration and color in Teran wines. Anthocyanins, intensity, hue and composition of color were analyzed by UV/Vis spectrometry. The results showed that total anthocyanins and color hue values in all treatments were higher compared to control wine. The highest concentrations of free anthocyanins were found in wines with pre-fermentative heating treatment. Color intensity exposed the best results in 15-day macerations regardless of pre- fermentative treatment.

Besides its hedonic nature, wine is a natural beverage with certain health-related properties, which is why the consumer’s interest towards wines with a higher concentration of bioactive compounds has increased over recent years. Extracted from grapes, antioxidants and vitamins are naturally present in wines but their concentrations differ according to the applied winemaking technique. The maceration process is less frequently carried out for the production of white wines in relation to red wines for several reasons, but its application may be suggested to increase wine antioxidant capacity and nutritional value. The aim of this study was to investigate the effect of applying different maceration processes on antioxidant capacity and vitamin content of wines produced from an autochthonous Croatian white grape variety, Malvazija istarska (Vitis vinifera L.). Vinification took place in vintage 2019 at the Institute of Agriculture and Tourism (Poreč, Croatia) where six vinification treatments were carried out: non-maceration control treatment (C), pre-fermentative two days cryomaceration treatment at 8 °C (CRYO), seven days maceration treatment at 16 °C (M7), and prolonged post-fermentative maceration treatments at 16 °C for 14 days (M14), 21 day (M21), and 42 days (M42). The antioxidant capacity of the wines was determined by the ferric reducing/antioxidant power, FRAP (mM Fe2+) assay and the oxygen radical absorbance capacity, ORAC (mM Trolox) assay. Chromatographic analyses were performed on a liquid chromatography system with a DAD and single quadrupole mass detector equipped with electrospray ionization interface. Identification of five vitamins (B1, B2, B3, B6 and C) was carried out by comparison to the retention times of authentic standards and their spectral properties. Statistical data analysis was performed using one-way analysis of variance (ANOVA) and Fischer’s least significant difference (LSD). According to both FRAP and ORAC assay, antioxidant capacity increased proportionally with the maceration duration, with control treatment wine having the lowest, opposed to M42 treatment wine having the highest values. Such results indicate that the antioxidant properties are mostly related to phenolic compounds which are mainly present in prolonged maceration treatments such as M42. Contrary results were noted for vitamin C content that showed a decreasing trend as maceration progressed. Vitamin C was not detected in M42 treatment wine while the highest concentration was reported in control treatment wine. When observing total B-group vitamins, a significant difference was noted between treatments. Prolonged post-fermentative maceration treatment M42 resulted with the highest concentration of total B-group vitamins in relation to other treatments. The increase in total B-group vitamin was proportional with maceration time, while CRYO and M7 treatments did not significantly differ from control treatment wine. Regarding the concentrations of each individual vitamin, vitamin B3 reached the highest values, and its concentration was significantly the highest in M42 treatment wine. A similar trend was noted in the concentration of vitamin B6. Obtained results showed that prolonged maceration significantly affects both the antioxidant capacity of the wines and their vitamin content, particularly B-group vitamins. Such information may serve producers for choosing the adequate technological practice for improving wine quality and its nutritional value. The study was funded by the Croatian Scientific Foundation under the projects VINUM SANUM (IP 2018-5049) and DOK-2020-01-1901.

The aim of this work was to determine the relationship between some aroma sensory descriptors and wine quality scores of white wines made from cv. Malvazija istarska (Vitis Vinfera L.). Six different vinification techniques were carried out: control treatment – fast grape processing without maceration (BP), fast grape processing with the addition of oenological tannin (BPT), pre-fermentative cold 1-day maceration (MM1), 7 days maceration (MM7), 21 days maceration (MM21) and vinification of dried grapes (MP) of cv. Malvazija istarska. Sensory profile of wine samples was obtained using both quantitive descriptive analysis (QDA) and 100 points O.I.V/U.I.O.E. evaluation method. The results showed a positive correlation between the presence of fruit and floral aroma attributes and overall wine impression. All observed treatments contributed to the positive effect on fruit and floral aromatic profile and overall wine impression in respect to control treatment.

The aim of this study was to establish the relationship between some sensory attributes and the overall impression of native Croatian red wine variety Teran (Vitis vinifera L.). Wines were produced with four different vinification techniques: control (7-days maceration, TM7), prolonged maceration 10 and 21 days (TM10, TM21 respectively), and pre- fermentation heating treatment (TPHT). The sensory profile of wine samples was obtained using quantitative descriptive analysis (QDA) and 100 points O.I.V/U.I.O.E. evaluation method. Five panelists rated the intensity of body/fullness, astringency, viscosity, aftertaste quality, and varietal typicity of taste. The results showed a positive correlation between the intensity of most taste attributes and the overall wine impression. A strong negative correlation was observed for astringency. All observed treatments, highlighting post-fermentative prolonged 21-day maceration and pre-fermentation heating treatment, contributed to the positive effect on taste profile and overall wine impression regarding control treatment.

Malolactic fermentation (MLF) is a complex biochemical process playing an important role in the production of red wines. The main reasons for its implementation are the reduction of titratable acidity and the consequent increase of pH, microbiological stability of wine, and changes in aromatic and sensory properties of wine. The aim of this study was to determine the compatibility of yeast and bacteria used by different malolactic fermentation techniques and their influence on the fermentation duration, concentration of individual organic acids, aroma compounds, and on chemical and sensory properties of Teran wines. The experiment included control treatment (without MLF), spontaneous MLF, induced MLF at the beginning of alcoholic fermentation with simultaneous inoculation of yeast and bacteria (coinoculation) and induced MLF after alcoholic fermentation (sequential MLF). In the co-inoculation treatment MLF had no negative effect on the alcoholic fermentation kinetic. Alcoholic fermentation was complete in all treatments. Coinoculation resulted in a significantly shorter duration of the MLF process. In all MLF treatments, significant reduction of titratable acidity and the increase of pH values was noted. Wines of the spontaneous MLF treatment obtained the highest concentration of volatile acidity and ethyl acetate. In all MLF treatments a complete consumption of malic acid and a decrease in concentration of citric acid, total amount of higher alcohols, and acetaldehyde were observed. Furthermore, significantly higher concentrations of ethyl esters, diacetyl, acetoin, and 2,3 butanediol were present in wines from all MLF treatments., Jabučno-mliječna fermentacija (JMF) složen je biokemijski proces koji ima važnu ulogu u proizvodnji većine crnih vina. Glavni učinci primjene JMF su snižavanje ukupne kiselosti uz rast pH vrijednosti, mikrobiološka stabilnost vina te promjena aromatskih senzornih svojstava vina. Cilj ovog istraživanja bio je utvrditi utjecaj različitih načina jabučnomliječne fermentacije na kompatibilnost kvasca i bakterija, duljinu trajanja fermentacije, koncentraciju pojedinačnih organskih kiselina i spojeva arome te senzorna svojstva vina sorte ´Teran´ (Vitis vinifera L.). Pokus je obuhvaćao kontrolni tretman (bez JMF), spontanu JMF, induciranu JMF u početku alkoholne fermentacije (koinokulacija) te induciranu JMF po završenoj alkoholnoj fermentaciji. U svim tretmanima alkoholna fermentacija je u potpunosti završila, bez zastoja ili usporavanja. Koinokulacija je utjecala na značajno kraće trajanje JMF. Svi tretmani s JMF značajno su utjecali na sniženje koncentracije titracijske kiselosti i povećanje pH vrijednosti. Najviše koncentracije hlapive kiselosti i etil acetata utvrđene su u vinima spontane JMF. U svim tretmanima s JMF zabilježena je potpuna razgradnja jabučne kiseline te sniženje koncentracije limunske kiseline, ukupnih viših alkohola i acetaldehida. Nadalje, značajno više koncentracije etilnih estera, diacetila, acetoina i 2,3-butandiola zabilježene su u svim tretmanima s JMF.

The aim of this work was to study the influence of different vinification techniques on stilbenes and total polyphenolic content in red wines made from cv. Teran (Vitis vinifera L.). Four different vinification techniques were carried out: control (7 days maceration), prolonged maceration (10 and 21 days), and thermovinification. Four stilbenes were determined by high-performance liquid chromatography (HPLC), and total polyphenols were determined by spectrophotometric methods. The results showed the treatment of extended maceration (21 days) had a significant effect on the increase of total (35.74 mg/L) and individual stilbenes (trans-piceid, cis-piceid, trans-piceatannol, trans-resveratrol), as well as total polyphenols (2702.88 mg GAE/L). Treatment of thermovinification resulted in significant increase of the total polyphenolic content by nearly 20% in relation to control.

Cilj ovog istraživanja bio je utvrditi utjecaj duljine trajanja i temperature maceracije na koncentraciju slobodnih i ukupnih antocijana te parametre boje u vinima sorte ‘Teran’. Provedena su četiri različita vinifikacijska tretmana: 7 dana maceracije (TM7, kontrolni tretman), 10 dana (TM10) i 21 dan maceracije (TM21) pri temperaturi od 24°C, te 10 dana maceracije uz zagrijavanje masulja na 45°C prvih 48 sati (pred-fermentacijsko zagrijavanje masulja, TPHT). Koncentracija ukupnih i slobodnih antocijana, te intenzitet, nijansa i kompozicija boje određeni su spektrofotometrijski. Koncentracija ukupnih antocijana kretala se od 334, 3 mg/L do 444, 73 mg/L (TPHT, TM21), a slobodnih antocijana od 76, 73 mg/L do 113, 57 mg/L (TM10, TM21), tretman produljene maceracije (TM21) imao je značajan utjecaj na povećanje koncentracije ukupnih i slobodnih antocijana. Intenzitet boje kretao se u rasponu od 1, 59 do 1, 69 (TM10, TPHT), a nijansa boje od 0, 52 do 0, 54, pri čemu je kontrolni tretman imao signifikantno najnižu izmjerenu vrijednost nijanse boje. Unatoč nižoj koncentraciji slobodnih i ukupnih antocijana, kod pred-fermentacijskog tretmana zagrijavanja zabilježen je signifikantno najveći intenzitet boje, što je vjerojatno posljedica procesa kopigmentacije, odnosno tvorbe polimernih pigmenata. Iz dobivenih rezultata može se zaključiti da duljina trajanja i temperatura maceracije značajno utječu na sastav vina. Poduljena maceracija vodi ka povećanju koncentracije slobodnih i ukupnih antocijana, dok pred-fermentacijsko zagrijavanje utječe na povećanje intenziteta i stabilnosti boje, stoga oba tretmana mogu imati praktičnu primjenu u proizvodnji crnih vina.

In the past few decades a significant increase in the alcohol content of red wines in many regions of the world was observed: wines with high alcohol content became a frequent problem of oenology which is the indirect effect of global climate change. The increase in the daily average temperature and in the number of sunshine hours results in the advance in vine phenology and faster sugar production in berries, which culminates in higher sugar concentration in grapes. However, the formation of phenolic and aromatic components and changes in acidity profile is differently influenced by the temperature. In order to develop a viticulture technology which is adapted to the current challenges concerning the climate change, the aim of this study was to investigate the possibilities of adjusting vineyard canopy management practices to reduce the accumulation of sugar during the maturation phase without reducing the accumulation of secondary metabolites in grapes. Four factors which affect grape maturation and its final composition were investigated: the height of shoot trimming, crop level obtained by different number of shoots per vine, cluster thinning, and the date of harvest. The research was conducted on Merlot variety in two climatically different regions ; in Istria (Croatia), under the Mediterranean climate and in Eger (Hungary) under continental climate conditions. The investigated factors differently affected the accumulation of sugar and the secondary metabolites in grapes and wines, and the best growing practices to mitigate the effects on climate change were proposed.

Standard white wine fining with bentonite, still the most efficient fining agent in achieving protein stability, often reduces wine quantity and quality. To evaluate the effectiveness of alternative approaches and possible positive effect of tannins that can react with proteins, bentonite was added to Malvazija istarska must during fermentation and tannins were also applied. After fermentation with bentonite, with tannins, or both, heating tests were performed for evaluation of protein stability. Wine quality was also evaluted by GC-MS measurements of volatile aroma compounds extracted by SPE, by HPLC-DAD measurements of phenolic compounds and by 100-point OIV method and quantitative descriptive sensory analysis. Bentonite treatments in fermentation showed better efficacy in relation to control treatment (standard wine fining after fermentation). Required dose of bentonite was reduced up to 21%, the wines preserved higher concentrations of major fermentation acids and esters, and higher concentrations of hidroxycinnamoyltartaric acids. Sensory attributes were also positively affected. Use of tannins showed positive impact on bentonite efficacy related to protein stabilization. In combination with bentonite, tannins had positive impact on preservation of aromas and hidroxycinnamoyltartaric acids, as well as good sensory quality. Despite higher intensity of sensory descriptors like astringency and bitterness, overall effect was considered positive. This work has been supported in part by Croatian Science Foundation under the project UIP-2014-09-1194.

In order to investigate the effect of the addition of tannins to Malvazija istarska (Vitis vinifera L.) must during fermentation on the protein stability and selected aspects of wine quality, several vinification treatments were performed: addition of tannins during fermentation (TA), addition of bentonite at the end of fermentation (BE), combination of the addition of tannins and bentonite (TA+BE), and a control treatment (CO) without tannin and bentonite added during fermentation. Protein stability of wines was evaluated, additional doses required were determined and applied. Volatile aroma compounds were extracted from wine samples by SPE for the measurements by GC-MS. Hydroxycinnamoyltartaric acids and the corresponding free derivatives were determined by HPLC-DAD. Wines were evaluated by 100-point OIV method and quantitative descriptive sensory analysis. The most effective treatment in terms of achieving total protein stability was TA. The reduction of the total bentonite dose required in relation to CO was 19%. Treatment TA resulted in higher concentrations of the majority of important acetate and ethyl esters. Concentration of most acids detected were higher in wines obtained without tannin addition. TA+BE treatment preserved the highest concentration of hydroxycinnamoyltartaric acids, followed by BE, TA, and CO. Free hydroxycinnamic acid concentrations responded diametrically opposite. Significant differences in the intensity of wine sensory attributes were mainly detected among wines that were not stabilized after fermentation. Wines fermented with tannin addition gained higher scores, but the additional bentonite fining step after fermentation mostly decreased their sensory quality. This work has been supported in part by Croatian Science Foundation under the project UIP2014-09-1194.

Ampelotehnički zahvati reza u zeleno se redovito primjenjuju u vinogradarskoj proizvodnji budući da mogu u znatnoj mjeri utjecati na tijek dozrijevanja i sastav grožđa. Defolijacija kao mjera reza u zeleno ima poseban značaj u uvjetima visoke bujnosti, gdje zona grozda može biti u velikoj mjeri zasjenjena, dok se prorjeđivanje grozdova uobičajeno provodi kod sorata koje karakterizira visoka rodnost. Cilj ovog rada bio je istražiti utjecaj rane defolijacije i prorjeđivanja grozdova na komponente prinosa i sastav grožđa sorte Teran (Vitis vinifera L.) tijekom dvije godine u uvjetima Vinogorja Zapadna Istra. Oba istraživana tretmana utjecala su na smanjenje prinosa u odnosu na kontrolu, a to je smanjenje bilo izraženije kod prorjeđivanja grozdova. Kod oba istraživana tretmana dobiveno je značajno povećanje udjela šećera i ukupnih fenola u grožđu, dok je povećanje udjela antocijana u grožđu postignuto samo primjenom rane defolijacije. Unatoč većem prinosu i nižem omjeru lisne površine i mase grožđa u odnosu na prorjeđivanje grozdova, rana defolijacija je postigla veći udio antocijana i ukupnih fenola u grožđu, temeljem čega se može zaključiti kako je u svrhu povećanja kvalitete grožđa sorte Teran prikladnije primjenjivati ranu defolijaciju nego prorjeđivanje grozdova.

In Croatia is observed the increasing trend in mean annual air temperature and the large variability in the measured extreme precipitation from prominent drought to severe flooding. Climatological studies based on regional climate models show the intensification of the extreme values of temperature and precipitation over Europe in the future climate. These changes in temperature and precipitation have a great impact on viticulture, considering that of all living organisms, plants react first to the change of surface temperature. Due to climate change, changes in temperature will affect: (i) differently all developmental stages of vines in certain wine-growing areas in Croatia (i.e. their phenological characteristics) and (ii) differently on different varieties. At the same time, the temperature increase changes convective activity (storms) and thus the occurrence of hail that are estimated as the second biggest cause of material damage in Croatia. The trend of increasing average duration of hailfall was also observed on the basis of measurements obtained in the low land of Croatia. Due to mentioned, the VITCLIC project (VITiculture and CLImate Change in Croatia) has several goals. Based on meteorological and climatological datasets and wine and grapevine archive data, the current situation and a monitoring system of key phenological phases of the vine due to climate change will be analyzed and established. Furthermore, the aim is to link the ripening and quality of grapes with agro-climatic indices and determine the relationship between hail parameters and the degree of damages in grapevines. The purpose is also to enable: (i) detailed agronomic and economic evaluation for preserving Croatian autochthonous grapevine varieties, (ii) determination of climate changes through agro-climatic indices in different future periods and (iii) an estimation of the increase or decrease in certain weather types which favor convective developments (and hail).

Excessive use of bentonite for clarification and fining may cause wine quantity losses, and have negative effects on wine quality, so the reduction of its dose is of great interest for producers. This is particularly important for Malvazija istarska (Vitis vinifera L.), the most prevalent native white grape variety in Croatia, whose wines often require very high doses of bentonite (150 - 300 g/hL) for achieving protein stability. To test if the addition of bentonite at various stages of fermentation of Malvazija istarska must may reduce the total dose required, vinification treatments were performed with the addition of 100 g/hL in must after settling, at the beginning, in the middle, and at the end of fermentation, while control was fermented without bentonite. In the produced wines, protein stability was evaluated by heating and heating/tannin tests, additional bentonite doses required were determined and applied, and protein-stable wines were obtained. Phenols and volatiles were determined by HPLC-DAD and GC-MS analyses after extraction. Wines were evaluated by quantitative descriptive sensory analysis and by the 100-point OIV method. The most effective treatments were those applied in the middle and at the end of fermentation, which reduced total bentonite amount for 19 % and 21 %, respectively. All wines fermented with bentonite contained higher amounts of the major hydroxycinnamoyltartaric acids, while control wine had higher amounts of the free forms. Significant changes in volatile aroma profiles were also determined. Sensorially, wines fermented with bentonite, especially those obtained after addition in the middle and at the end of fermentation, were characterised by higher intensities of the majority of positive attributes, as well as higher hedonic scores in relation to control.

In Croatia is observed the increasing trend in mean annual air temperature and the large variability in the measured extreme precipitation from prominent drought to severe flooding. Climatological studies based on regional climate models show the intensification of the extreme values of temperature and precipitation over Europe in the future climate. These changes in temperature and precipitation have a great impact on viticulture, considering that of all living organisms, plants react first to the change of surface temperature. Due to climate change, changes in temperature will affect: (i) differently all developmental stages of vines in certain wine-growing areas in Croatia (i.e. their phenological characteristics) and (ii) differently on different varieties. At the same time, the temperature increase changes convective activity (storms) and thus the occurrence of hail that are estimated as the second biggest cause of material damage in Croatia. The trend of increasing average duration of hailfall was also observed on the basis of measurements obtained in the low land of Croatia. Due to mentioned, this project has several goals. Based on meteorological and climatological datasets and wine and grapevine archive data, the current situation and a monitoring system of key phenological phases of the vine due to climate change will be analyzed and established. Furthermore, the aim is to link the ripening and quality of grapes with agro-climatic indices and determine the relationship between hail parameters and the degree of damages in grapevines. The purpose is also to enable: (i) detailed agronomic and economic evaluation for preserving Croatian autochthonous grapevine varieties, (ii) determination of climate changes through agro-climatic indices in different future periods and (iii) an estimation of the increase or decrease in certain weather types which favor co nvective developments (and hail).

Bentonite is still the most efficient and cost- effective agent in achieving the protein stability of white wines. However, its excessive use may have a negative effect on the properties of final wine, so the reduction of its dose is of great interest for producers. In this work, the effectiveness of bentonite addition at various stages of fermentation of Malvazija istarska (Vitis vinifera L.) must with respect to standard wine fining was evaluated. Doses of 100 g/hL were added in clear must (MU), at the beginning (B), in the middle (MI), and at the end of fermentation (E), while control received no bentonite. In the produced wines, protein stability was evaluated, and additional doses required were determined. The additional doses were applied and protein-stable wines were obtained. Phenolic compounds were determined by HPLC-DAD analysis after fermentation and in protein- stable wines. Bentonite added during fermentation significantly reduced the total amount required in relation to control. The most effective were the treatments MI and E, which reduced its amount for 19 % and 21 %, respectively, as determined by the heating with tannins test. All wines fermented with bentonite contained significantly higher amounts of the major hydroxycinnamoyltartaric acids, such as trans-caftaric, trans-coutaric, and trans-fertaric acid, in relation to control. The control wine had higher amounts of free caffeic, p-coumaric and ferulic acid. It was concluded that bentonite added during fermentation, besides reducing its total amount, probably limits the activity of enzymes responsible for the hydrolysis of hydroxycinnamoyltartaric acids. This work has been supported in part by Croatian Science Foundation under the project UIP-2014-09-1194.

Accelerated grape ripening with the ensuing high wine alcohol concentration has become widespread problem in various grape growing regions in the recent years. One possibility of adaptation to this emerging problem can be obtained by different canopy management practices in the vineyard. In this study the effects of severe shoot trimming and cluster thinning on grape ripening and grape and wine quality of cv. Teran were investigated, with the aim to find a canopy management practice which will result with lower wine alcohol concentration, without affecting the phenolic composition of grapes and resultant wines. In a Teran vineyard, two different shoot heights (70 and 130 cm), obtained by shoot trimming at the beginning of veraison, were combined with cluster thinning ; with cluster thinning applied at the beginning of veraison (CT) or without cluster thinning (NO CT). At earlier stages of ripening, higher differences in soluble solids among treatments were observed, with severe shoot trimming having larger impact than cluster thinning. With approaching to full maturity, the differences among treatments still remained, but were less pronounced than in earlier stages. The lowest alcohol, total anthocyanins and total phenolics concentrations in wines were achieved with 70 cm/NO CT treatment, while the highest values were achieved with 130/CT treatment. While 70/CT treatment had lower soluble solids in grapes and alcohol concentration in wine than 130/NO CT treatment, the opposite trend was observed with total anthocyanins in grapes and wines, which were higher in 70/CT than in 130/NO CT treatment, and in 70/CT treatment reached almost the same values as in 130/CT treatment. Both severe shoot trimming and cluster thinning can be effectively used in order to manipulate cv. Teran grape and wine quality, taking into account both the desired wine composition and the yield loss as a result of cluster thinning.

Pedološka heterogenost tipična je za vinogradarsku podregiju Istra te je u takvim područjima značaj tla za vinogradarsku proizvodnju posebno naglašen. Rezultati dosadašnjih istraživanja upućuju na povezanost pedoloških uvjeta s kvalitetom grožđa i vina. Cilj ovog istraživanja bio je utvrditi utjecaj tipa tla na profil najvažnijih hlapivih spojeva arome u moštu autohtone sorte Malvazija istarska, koja je ujedno i najzastupljenija sorta u Istri. Istraživanje je provedeno 2011. godine na lokaciji Bajkini, gdje se unutar 1 km udaljenosti nalaze nasadi na 2 tipa tla: rendzini i tipičnoj crvenici. Nasadi su bili u punoj rodnosti, uzgojni oblik bio je dvokraki Guyot te je primjenjivana ista agrotehnika. Uzorci grožđa uzeti su 14 i 7 dana prije redovnog roka berbe te u redovnom roku berbe. Hlapive tvari mošta određene su nakon mikroekstrakcije na čvrstoj fazi tehnikom plinske kromatografije/spektrometrije masa (HS-SPME-GC- MS). Linearna diskriminantna analiza pokazala je da razlikovanju mošteva prema tipu tla najviše doprinose slijedeći terpenski spojevi: cis- linalol-furan-oksid, lilial i linalol. Među alkoholima i aldehidima, u diskriminaciji su najviše sudjelovali: trans-2-heksan-1-ol, trans-2- heksenal, cis-2-heksenal, 1-heksanol, benzaldehid, trans-2-oktenal, 2-feniletanol, nonanal i cis-2- heksan-1-ol. Dobiveni rezultati ukazuju na razlike u aromatskom profilu mošta s obzirom na tip tla te u budućnosti mogu pomoći u formiranju različitih tipova vina Malvazije istarske.

Cilj ovog istraživanja bio je istražiti utjecaj rane defolijacije na sastav i senzorne karakteristike vina sorte Cabernet Sauvignon (Vitis vinifera L.). Ranom defolijacijom uklonjeno je šest bazalnih listova po mladici pred sam početak cvatnje, dok kod kontrolnog tretmana nije provedena defolijacija. Primjena rane defolijacije rezultirala manjim brojem bobica po grozdu uslijed slabije oplodnje i posljedično manjim prinosom po trsu u odnosu na kontrolni tretman. Vino proizvedeno od grožđa iz tretmana rane defolijacije sadržavalo je viši udio alkohola, ukupnih fenola, ukupnih antocijana i imalo je jači intenzitet boje u odnosu na kontrolni tretman. Senzornom analizom utvrđeno je da je vino iz tretmana rane defolijacije imalo naglašenije voćne i začinske mirise te izraženiju kompleksnost u odnosu na kontrolni tretman, dok su vegetativne arome bile naglašenije kod kontrolnog tretmana. Vino iz tretmana rane defolijacije je na okusu imalo izraženiju punoću i trajnost te manje izražen dojam kiselosti u odnosu na kontrolni tretman. Senzornim ocjenjivanjem vina po metodi 100 bodova bolje je ocjenjeno vino iz tretmana rane defolijacije, koje dobilo 85 bodova, dok je kontrolni tretman ocijenjen s 81 bodom. Budući da se ranom defolijacijom postiže manji prinos grožđa po trsu i povećana kvaliteta vina, njena je primjena opravdana kod proizvodnje vina visoke kvalitete, koja će svojom cijenom opravdati smanjeni prinos grožđa i trošak primjene ovog zahvata.

Many researchers pointed out that the lack of marketing knowledge and of the knowledge of new technologies can be the reason for product failure. The aim of the research presented in this paper was to find out the consumers’ preferences about wines made from autochthonous grape variety from Istria, Croatia, namely the Muscat rose of Porec. The paper also gives a review of the background literature about wine quality and segmentation in the wine market and presents the results of a research carried out in Croatia. The study indicated that the sweet wine got the best grade and that consumers would like to buy this wine as a gift and/or for a special occasion, so this can be the best way to offer this wine to consumers. If winemakers would want to produce different types of wine from this variety then they should create different marketing strategies.

The effect of four different maceration times (5, 10, 15 and 20 days) on anthocyanins, phenolic acids, flavan-3-ols composition, vanillin index and antioxidative activity of Teran red wine (Vitis vinifera L.) has been investigated. Phenolics were determined by HPLC with UV-Diode Array detection. Vanillin index were determined by UV-VIS spectrophotometry The total antioxidative capacity of wine was measured with four different 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). Sensory evaluation of wine samples was performed. The obtained results show positive correlation and significant increase between phenolic acids (Gallic acid, Protocatechuic acid, Vanillic acid, Syringic acid, Caffeic acid, p-coumaric acid and Ferulic acid), flavane-3-ols [(+)-catechin and (-)-epicatechin] and vanillin index and length of maceration. Anthocyanins contents increased to the maximum within 10 days of the skin maceration. The mayor anthocyanins in Teran wine were malvidin-3-glucoside, malvidin-3-glucoside-acetate and petunidin-3-glucoside. Antioxidant activity of Teran wines significantly increased with prolonged skin contact as well as total phenolic contents (p < 0.001). Wine produced with maceration time of 10 days was best sensory evaluated.

Antocijani su pigmenti crvene boje smješteni uglavnom u kožici bobice crvenog grožđa te doprinose 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.

Bentonit je nezaobilazno sredstvo u proizvodnji bijelih vina. Istraživan je utjecaj tri tipa bentonita (natrijev, kalcijev i natrij/kalcijev) i dva tipa vode (vodovodna/tvrda i destilirana /meka) na doze bentonita potrebnih za stabilizaciju bjelančevina, a, posljedično tome, i na senzorska svojstva vina Malvazija istarska. Utvrđena je značajna razlika u dozama bentonita s obzirom na tvrdoću vode. Najmanje doze za stabilizaciju bjelančevina (100 g/hl) zabilježene su kod primjene natrijevoga i kalcijevoga bentonita u destiliranoj vodi. Kod tih je tretmana uočen i najmanji utjecaj na senzorska svojstva vina Malvazija istarska.

Malvazija istarska wines often have a lack of acids (< 4, 50 g /L) reflecting on increased pH and resulting with negative microbiological processes, having thus a negative influence on organoleptical wine image. The aim of this research was to determine the influence of acidification of Malvazija istarska wines from harvest 2009. with hydroxy-carboxilic acids (DL tartaric acid, L(-) malic acid and citric acid) in different quantities on differences of physical-chemical and organoleptical aspects. With all treatments was determined the decrease of initial pH value with range from 0, 03 to 0, 23 depending on type and quantity of added hydroxyl-carboxilic acid. With all treatments with acidification the increase of water intensity (A420+A520+A620) and decrease of colour tonality (A420/A520) in relation to control treatment was recorded. Among treatments with acidification there were no significant differences of colour intensity, while the lowest colour tonality was recorded for samples acidificated with citric acid. Evaluation by a method of 100 poins and a method of ranging gave the best scores to wines acidificated with L(-) malic acid.

The effect of four different maceration times (5, 10, 15 and 20 days) on anthocyanins, phenolic acids, flavan-3-ols composition, vanillin index and antioxidative activity of Teran red wine (Vitis vinifera L.) has been investigated. Phenolics were determined by HPLC with UV-Diode Array detection. Vanillin index were determined by UV-VIS spectrophotometry The total antioxidant capacity of wine was measured with four different 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). Sensory evaluation of wine samples was performed. The obtained results show positive correlation and significant increase between phenolic acids, flavane-3-ols [(+)-catechin and (-)-epicatechin] and vanillin index and length of maceration. Anthocyanins contents increased to the maximum within 10 days of the skin maceration. The mayor anthocyanins in Teran wine were malvidin-3-glucoside, malvidin-3- glucoside-acetate and petunidin-3-glucoside. Antioxidative activity of Teran wines significantly increased with prolonged skin contact as well as total phenolic contents (p < 0.001). Wine produced with maceration time of 10 days was best sensory evaluated.

Malvazija istarska bijela ( Vitis vinifera L.) is the most represented grapevine variety in Istrian winegrowing subregion. Wines of Malvazija istarska contain high quantities of proteins for which removal are required high doses of bentonite, reflecting on physical- chemical and organoleptical aspects of wine. In production of Malvazija wines the most used is Ca-bentonite prepared in aqueduct water of high hardness ((Poreč ; 19, 1 °D / 340 mg CaCO3/L). After performed protein stabilisation, it was determined that treated wines are greatly different from non treated wines in respect of organoleptical characteristics. The aim of this paper was to examine how the bentonite type (Na- ; Ca- and Ca/Na) and water hardness (distilled and aqueduct) for bentonite preparation influence on bentonite doses necessary for protein stabilisation, quantity of originated sediment and physical-chemical and organoleptical parameters of Malvazija istarska wine quality from harvest 2009. It was determined that application of distilled water during bentonite wetting requires generally lower doses of bentonite for protein stabilisation: Ca = Na < Ca/Na ; for aqueduct water, bentonite dose is higher: Na < Ca< Ca/Na. Regardless the water hardness, Ca- bentonite generated most sediments (10 – 12 %). The reduction of total acidity, as well as of hue and colour intensity in relation to control/non treated treatment was determined for all treatments. Wines were organoleptically scored by a method of 100 points. All samples on which were applied distilled water were better scored than ones with aqueduct water.

Three crop levels of cv. Merlot (Vitis vinifera L.) were evaluated in this study in order to assess the impact of crop level on cv. Merlot yield components and wine quality. Different crop levels were obtained with cluster thinning, performed at véraison. Low crop level (LCL) was obtained with 60% of clusters removed, medium crop level (MCL) was obtained with 30% of clusters removed, while on high crop level vines (HCL) cluster thinning was not performed. Planting distances and number of shoots per vine were equal for all treatments. Yield per vine and number of clusters per vine were significantly increased with higher crop level, while cluster weight, berry weight and leaf area/yield ratio were significantly reduced with higher crop level. Lower crop levels hastened fruit maturation. LCL was the first to ripen considering the rate of sugar accumulation and acidity decrease, MCL was intermediate and HCL was the last. The highest levels of total phenolics, total anthocyanins and color intensity of wines were obtained by LCL, while the lowest were obtained by HCL. The intensity, duration and quality of aromas and flavors were more pronounced in the MCL and LCL wines compared to HCL wines. Dominant flavors in the wines were fruity (cherries) and vegetal character in the order MCL > LCL > HCL. It is concluded that crop level considerably affects Merlot wine quality. Increased quality and higher aging potential of Merlot wines were obtained by MCL and LCL treatments.

The phenomenon of untypical aging off-flavor, associated with higher concentrations of 2-aminoacetophenone (2-AAP) in white wines, can stem from some technological treatments applied in grape and wine production. In order to find out if a wine is liable to untypical aging off-flavor, it is necessary to determine the concentrations of indole-3-acetic acid and L-tryptophan, which are the precursors of 2-aminoacetophenone. The purpose of this investigation was to determine the influence of soil type and different yeast strains on the levels of L-tryptophan, indole-3-acetic acid and 2-aminoacetophenone in the Malvasia from Istria must and wine. In the 2007 and 2009. grapes were harvested from two different soil type locations (terra Rosa, terra Bianca), in Istria wine growing region, Croatia, and separately vinified. Vinification was carried up with 4 different wine strains ((Fermol Cryoarome, Fermol Assosiee, Uvaferm CS2, Anchor VIN 13). Young wine samples were taken for analysis after completed alcoholic fermentation. Analyses of L-tryptophan and indole-3-acetic acid were performed using Agilent 1100 equipped with autosampler and fluorescence detector. Separation was achieved on Luna C18 (endcapped) column (5 μm packing, 250 x 4.6 mm i.d.), (Phenomenex, USA), protected with guard column from same material (Phenomenex, USA). 2-aminoacetophenone (2-AAP) analyses were performed using gas chromatography-mass spectrometry (GC-MS). 2-AAP was extracted from wine by direct immersion solid phase microextraction (DISPME). Divinylbenzene / carboxen / polydimethylsiloxane SPME fibres were used. Chemical analyses of compared musts and wines in both investigated years showed differences in L-tryptophan, ranging from 260, 2 up to 1065, 6 μg/L, and indole-3-acetic acid concentrations, ranging from 26, 1 up to 71, 3 μg/L, that depend more upon the soil type than yeast strain used. Different soil type and yeast strains also influenced 2-aminoacetophenone concentrations in Malvasia wines, ranging between 0, 3-1, 2 μg/L. Keywords: indole