•Bentonite fining during fermentation reduced the required dose up to 21%.•The most effective was fining in the middle and at the end of fermentation.•Wines fermented with bentonite had more ...hydroxycinnamoyltartaric acids than control.•The effect on varietal aromas was weak to moderate.•Bentonite in fermentation preserved key esters and enhanced wine sensory quality.
To test the effects of bentonite addition at various stages of fermentation, five Malvazija istarska white grape must vinification treatments were performed with 100 g/hL of bentonite added in clear juice, at the beginning, in the middle, and at the end of fermentation, while control was fermented without bentonite. Phenols and free and bound volatile aromas were determined by HPLC-DAD and SPE-GC-MS. Wines were evaluated sensorially. Fining during fermentation reduced the total bentonite dose required, and was most effective near the end of fermentation with the reduction of 16% and 21%, depending on the protein stability test. All treated wines preserved more hydroxycinnamoyltartaric acids with respect to control. The side-effect of these treatments on varietal aromas was moderate, but enhanced the preservation of key fermentation volatiles in relation to control, and exhibited positive sensory effects. It was concluded that bentonite added during fermentation may positively affect wine quantity and quality.
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•Maceration and non-maceration treatments increased phenolic content in wines.•Wine bitterness and astringency were least affected by cold maceration treatment.•Prolonged maceration ...treatment obtained the highest colour intensity.•Late harvest vinification wine was the most favourable according to taste scores.
To investigate the effect of several vinification techniques aimed to enhance wine phenolic profile and sensory quality, maceration treatments of different duration and temperature (pre-fermentative cold one day maceration at 10 °C, seven days maceration at 16 °C, and prolonged post-fermentative 21 day maceration at 16 °C) and non-maceration treatments including tannin addition and late harvest grapes vinification were performed and compared to a standard white grape processing treatment. Produced wines were subjected to the analysis of phenols by high-performance liquid chromatography, colour intensity, and quantitative descriptive and hedonic sensory analysis. The increase in individual phenolic compound concentrations was mostly pronounced in maceration treatment wines, for both phenolic acids and flavan-3-ols, as well as for the sum of phenolic compound concentrations determined by high-performance liquid chromatography that tripled in relation to that determined in control treatment wine. Pre-fermentative cold maceration led to a moderate increase in phenolic compounds content without accentuating bitterness and astringency sensations. Wine phenolic composition and colour intensity were mostly affected by the prolonged post-fermentative 21 day maceration. Vinification of late harvest grapes produced a wine graded with the highest positive score for taste. The obtained distinct wine styles resulting from the application of the investigated practices may lead to a further diversification of white wine market.
The effect of four different winemaking processes on phenolic compounds, macro- and microelements, and taste sensory attributes of Teran red wines was studied. The study covered seven days of ...maceration as a control (TM7), prolonged 10-day maceration (TM10), prolonged post-fermentative 21-day maceration (TM21), and 48-h pre-fermentative maceration heating at 45 °C followed by eight-day standard maceration (TPHT). Phenolic compounds were analyzed using high-performance liquid chromatography with UV–Vis diode array and fluorescence detection. Analysis of macro- and microelements was conducted by inductively coupled plasma - optical emission spectrometry. Sensory profiles of wine samples were obtained using quantitative descriptive analysis and the 100-point O.I.V./U.I.O.E. method. The results showed a significant increase of 25% in total flavan-3-ols content in TM21 wine. The concentrations of hydroxybenzoic acids increased significantly upon TM21 and TPHT treatment, while particular hydroxycinnamic acids showed a significant increase after TPHT treatment. The obtained results showed differences in the content of macro- and microelements, with significantly higher values of particular elements in TM21 and TPHT wines. Sensory analysis results corresponded to the chemical content of the wines to a great extent. The findings showed that TM21 and TPHT treatments have a positive influence on the taste attributes of the investigated wines.
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•Maceration applied for 7, 10, and 21 days (TM7, TM10, and TM21).•Pre-fermentative maceration heating treatment (TPHT) at 45 °C for initial 48 h.•Phenols, macro- and microelements, and sensory attributes were examined.•TPHT produced more phenols, microelements and positively affected taste attributes.•TM21 produced more phenols, macroelements and positively affected taste attributes.
The majority of chemical compounds that contribute to varietal aroma originate from grape skin. To investigate the differences between volatile aroma compounds when different maceration conditions ...are applied, a total of six vinification treatments were carried out on Malvazija istarska (Vitis vinifera L.) variety, non-maceration control treatment (C), pre-fermentative two days cryomaceration treatment at 8 °C (CRYO), seven days maceration treatment at 16 °C (M7), 14 days maceration treatment at 16 °C (M14), and prolonged post-fermentative maceration treatments at 16 °C for 21 day (M21) and 42 days (M42). Wines were subjected to GC/MS and sensory analysis. Obtained results showed that prolonged post-fermentative maceration treatments contained the highest concentration of total volatile aroma compounds, precisely monoterpenes, alcohols, and other esters. Contrary, C and CRYO wines resulted in highest concentration of ethyl and acetate esters, and fatty acids. In addition, sensory analysis showed that longer maceration treatment wines (M14, M21, M42) were characterized by more aroma complexity, varietal flowery typicity, pronounced fruitiness, with accentuated dried fruit, moderate honey, and herbal notes. Obtained results can provide valuable information to producers when choosing an appropriate vinification technique based on the desired wine style which may lead to a further diversification of white wine market.
Viticulture production is challenged by climate change and the consequent higher accumulation of carbohydrates in grapevine berries, resulting in high-alcoholic wines. This study investigates the ...application of severe shoot trimming performed at three different stages and crop size management as tools for the modulation of cv. Merlot berry composition, aimed at reducing the sugar content in the berry. In the first study, the effects of severe shoot trimming carried out at three different phenological stages were studied. In the second study, late severe shoot trimming was combined with two crop sizes and regulated by shoot thinning. The obtained results demonstrated that severe shoot trimming in earlier stages of berry development limited the accumulation of both sugars and anthocyanins as compared to the control treatment. However, when severe shoot trimming was performed at late veraison (at approximately 14 Brix), it decreased only the accumulation of sugars, without affecting the accumulation of anthocyanins. The results of the second study showed that the modification of crop size by shoot thinning significantly affected the measured yield parameters, whereas the effect on Brix and anthocyanins was seasonally dependent. It was concluded that among the studied techniques, severe shoot trimming at late veraison is the most effective way to reduce sugar content in the berry without affecting the accumulation of anthocyanins.
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.
There is a lack of studies evaluating the metabolic contribution of non-Saccharomyces yeasts in early fermentation phases. This study aimed to investigate the volatile aroma profiles produced by ...various non-Saccharomyces yeasts just before sequential inoculation with Saccharomyces cerevisiae to provide an insight into the particular effects they induce at this stage. The grape must of Malvazija istarska was inoculated with monocultures of Torulaspora delbrueckii, Metschnikowia pulcherrima, Pichia kluyveri, Lachancea thermotolerans, and Schizosaccharomyces pombe, alongside a S. cerevisiae control. Eighty volatile compounds were quantified via headspace solid-phase microextraction and gas chromatography–mass spectrometry, and the data were statistically elaborated. Volatile profiles of non-Saccharomyces yeasts differed significantly from the S. cerevisiae control. Most treatments caused increases in linalool and β-damascenone, decreases in higher alcohols and fatty acids, and improved synthesis of odoriferous esters. Torulaspora delbrueckii and M. pulcherrima produced compounds not commonly found in S. cerevisiae fermented wines. Multivariate statistical analysis linked the investigated yeasts to specific, particularly abundant compounds. Future studies should explore to what degree these contributions persist after sequential inoculation with S. cerevisiae in diverse grape must matrices.
Plusieurs chercheurs ont démontré que des connaissances insuffisantes dans le domaine du marketing et des nouvelles technologies peuvent être à la base de l'échec d'un produit. Le but de cette étude ...est de découvrir les préférences des consommateurs à l'égard des vins issus d'un cépage local de l'Istrie, Croatie, à savoir le Muscat rosé de Porec. En même temps, on passera en revue les travaux de la littérature portant sur la qualité du vin et sur la segmentation du marché des vins et on présentera les résultats des recherches réalisées en Croatie. L'étude permettra de démontrer que le vin doux est le plus apprécié et que les consommateurs achèteraient ce produit pour une occasion spéciale et/ou pour l'offrir comme cadeau. Par conséquent, celle-ci pourrait être la manière la plus appropriée d'offrir ce type de vin aux consommateurs. Cependant, si les producteurs entendent produire différents types de vin en utilisant ce cépage, ils devraient envisager des stratégies de marketing différentes. Mots-clés: vin, préférences des consommateurs, segmentation, Croatie, Muscat rosé de Porec. 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 rosé 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; thus, this can be the best way to offer this wine to consumers. If winemakers would like to produce different types of wine from this variety, they should create different marketing strategies. Key words: wine, consumers' preferences, segmentation, Croatia, Muscat rosé of Porec.
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 (co-inoculation) 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. Co-inoculation 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. Keywords: Oenococcus oeni, co-inoculation, aroma compounds, organic acids, duration of malolactic fermentation SAETAK Jabucno-mlijecna fermentacija (JMF) sloen je biokemijski proces koji ima vanu ulogu u proizvodnji vecine crnih vina. Glavni ucinci primjene JMF su sniavanje ukupne kiselosti uz rast pH vrijednosti, mikrobioloka stabilnost vina te promjena aromatskih senzornih svojstava vina. Cilj ovog istraivanja bio je utvrditi utjecaj razlicitih nacina jabucno-mlijecne fermentacije na kompatibilnost kvasca i bakterija, duljinu trajanja fermentacije, koncentraciju pojedinacnih organskih kiselina i spojeva arome te senzorna svojstva vina sorte 'Teran' (Vitis vinifera L.). Pokus je obuhvacao kontrolni tretman (bez JMF), spontanu JMF, induciranu JMF u pocetku alkoholne fermentacije (koinokulacija) te induciranu JMF po zavrenoj alkoholnoj fermentaciji. U svim tretmanima alkoholna fermentacija je u potpunosti zavrila, bez zastoja ili usporavanja. Koinokulacija je utjecala na znacajno krace trajanje JMF. Svi tretmani s JMF znacajno su utjecali na snienje koncentracije titracijske kiselosti i povecanje pH vrijednosti. Najvie koncentracije hlapive kiselosti i etil acetata utvrdene su u vinima spontane JMF. U svim tretmanima s JMF zabiljeena je potpuna razgradnja jabucne kiseline te snienje koncentracije limunske kiseline, ukupnih viih alkohola i acetaldehida. Nadalje, znacajno vie koncentracije etilnih estera, diacetila, acetoina i 2,3-butandiola zabiljeene su u svim tretmanima s JMF. Kljucne rijeci: Oenococcus oeni, koinokulacija, spojevi arome, organske kiseline, trajanje jabucno-mlijecne fermentacije
ABSTRACT
In order to investigate the relationship between sensory and gas chromatographic analysis data, and to establish if particular aroma compounds could be used as Malvazija istarska young wine ...quality markers, 30 samples of Malvazija istarska young wine were subjected to sensory evaluation and gas chromatographic analysis of aroma compounds. Linear regression and principal component analysis were applied in order to establish the relations between sensory evaluation scores and aroma compound concentrations in corresponding wines. The most important contributors to the characterization and differentiation of wines evaluated with higher sensory evaluation scores were isoamyl acetate, ethyl hexanoate, ethyl octanoate, ethyl decanoate, hexanoic acid, octanoic acid and decanoic acid. On the other hand, wines evaluated with lower sensory evaluation scores were characterized and differentiated by higher amounts of isoamyl alcohol and isobutanol. Mentioned esters and acids were also found to be the most important variables for the classification of these wines according to quality using stepwise linear discriminant analysis (SLDA). The evaluation of the SLDA model was performed by cross‐validation, obtaining an average percentage of correct classification of 100.0%, and of correct prediction of 89.3%. The results of this investigation suggest that above‐mentioned esters, acids and alcohols could be used as markers of Malvazija istarska young wine quality.
PRACTICAL APPLICATIONS
Wine aroma is one of the most important parameters responsible for its quality, and hence for consumer acceptance. Sensory evaluation is the most common technique for controlling the organoleptic quality of wine, but it is not always feasible, since it requires specific conditions, and a group of trained expert tasters that can only assess a relatively small number of wine samples for a day. Moreover, the subjectivity of panelists can affect the evaluation in a great measure. The approach proposed in this work suggests the use of a nonsubjective instrumental technique such as gas chromatography for the analysis of volatile aroma compounds as a complementary tool for wine quality control able to predict, confirm or to correct the results of Malvazija istarska young wine sensory evaluation. Although this model is yet far from being practically implemented, information obtained could be used as a starting ground. Moreover, it was assumed that the approach proposed in this work is likely to be applied successfully on the differentiation and classification of other types of wine according to quality.
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