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.
Utjecaj globalnog zagrijavanja nije zaobišao niti vinarsku industriju. To se najbolje očituje kroz porast alkoholne jakosti vina te smanjenje ukupne kiselosti što u konačnici dovodi do značajne ...promjene u senzornim svojstvima vina. Jedna od mogućnosti smanjenja alkoholne jakosti obuhvaća primjenu različitih selekcioniranih kvasaca (Saccharomyces i ne-Saccharomyces). U provedenom istraživanju ispitane su mogućnosti primjene komercijalnih Saccharomyces kvasaca (IONYSWF™, Enoferm RP15 i Uvaferm BDX) sa ciljem smanjenja alkoholne jakosti te povećanja ukupne kiselosti vina sorte Cabernet franc. Po provedenim fizikalno-kemijskim analizama utvrđeno je da je primjena kvasca IONYSWF™ dala vina manje alkoholne jakosti uz naglašeniju ukupnu kiselost. Nadalje, nisu utvrđene značajne razlike u kinetici alkoholne fermentacije među tretmanima, ali su utvrđene razlike u senzornim svojstvima. Prema rezultatima deskriptivne analize vino sorte Cabernet franc (Vitis vinifera L.) proizvedeno primjenom kvasca IONYSWF™ izdvojilo se nešto jačim tijelom te naglašenijim intenzitetom i trajnošću mirisa u kojem su dominirale začinske note i mirisi crvenog voća. Vino navedenog tretmana bilo je ujedno i najbolje brojčano ocjenjeno.
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.
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
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
The aim of this study was to investigate the impact of early leaf removal (ELR) and cluster thinning (CT) on the phenolic composition of cv. Teran berries and wines, and the sensory profile of wines ...at 6 and 24 months after fermentation. Although only ELR increased the concentration of total anthocyanins in the berries as compared to the untreated control (UC), both ELR and CT had higher concentration of total anthocyanins and greater colour intensity in the resultant wines than the UC. Similar effects were obtained with total phenolics in the berries and the wines; while CT obtained higher concentration of total phenolics in the berries than UC only in one season, same treatment obtained higher concentration of total phenolics in the wine in both seasons as compared to UC. Only minor sensory differences in wines were obtained at the age of 6 months, while treatments were highly discriminated 24 months after fermentation, when both ELR and CT wines had more enhanced fruitiness, aromatic intensity, complexity, body, balance and wine overall quality than UC. The obtained results indicate that adequate wine aging period is needed for a relevant assessment of the impact of vineyard management practices on wine sensory characteristics.
•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.
The effect of four different maceration times (5, 10, 15 and 20 days) on anthocyanins, phenolic acids (hydroxybenzoic, gallic, protocatechuic, vanillic, syringic, caffeic and p-coumaric acids), ...flavan-3-ol composition, vanillin index and antioxidant activity of Teran red wine (Vitis vinifera L.) has been investigated. Phenolics were determined by HPLC with UV-diode array detection. Vanillin index was determined by UV-VIS spectrophotometry. The total antioxidant capacity of wine was measured with three different methods: 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical and 2,2'-azinobis(3-ethylbenzothialozine-6-sulphonic acid) radical cation (ABTS.sup.+) scavenging methods and ferric reducing antioxidant power (FRAP). Sensory evaluation of wine samples was performed. The obtained results show positive correlation between phenolic acids, flavan-3-ols (+)-catechin and (-)-epicatechin and vanillin index and the duration of maceration. Anthocyanin content increased to the maximum within 10 days of skin maceration. The major anthocyanins in Teran wine were malvidin-3-O-glucoside, malvidin-3-glucoside acetate and petunidin-3-O-glucoside. Antioxidant activity of Teran wines significantly increased with prolonged skin contact as well as total phenolic content (p<0.001). Wine produced with maceration time of 10 days had the best sensory properties. Key words: Teran wine, phenolic composition, antioxidant activity, maceration time
PDF
