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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.
•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.
Suočavajući se sa sve drastičnijim utjecajem klimatskih čimbenika na kemijski sastav grožđa, enologija traži i proučava nove metode u tehnologiji proizvodnje vina, posebice bijelih, kako bi se ...očuvale primarne arome te postigla ravnoteža između alkoholne jakosti i ukupne kiselosti. Kao jedno od rješenja nudi se primjena ne- Saccharomyces kvasaca. U ovom istraživanju analiziran je utjecaj sekvencijalne inokulacije komercijalnih sojeva Torulospora delbrueckii i Lachancea thermotolerans sa sojem kvasca Saccharomycem cerevisiae na vino ´Malvazija istarska´. Istraživanje je obuhvatilo inokulacije mošta s ne-Saccharomyces kvascima, a 48 h kasnije i sa sojem S. cerevisae te kontrolnu varijantu isključivo sa S. cerevisae. Ne-Saccharomyces kvasci utjecali su značajno na koncentraciju alkohola, mliječne kiseline te pH vrijednost. Fermentacija sa S. cerevisiae utjecala je na višu koncentraciju ukupnih aromatskih spojeva u vinu. Intenziteti boje i mirisa najbolje su ocijenjeni u kontrolnom uzorku, a metodom redoslijeda najbolje je rangirana ´Malvazija´ iz tretmana T. delbrueckii/ S. cerevisiae.
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.
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.
During a two-year study, the effect of different grape mash maceration treatments (skin contact at 20 degree C for 10, 20 and 30 h) and cryomaceration (skin contact at 7 degree C for 10, 20 and 30 h) ...on the concentration of free and bound monoterpenes and total phenols in Malvazija istarska wine (the most spread white wine variety in Istria) was monitored. Monoterpenic alcohols linalool, alpha -terpineol, citronellol, nerol and geraniol were determined by gas chromatography after isolation on octadecylsilica (C sub(18)) sorbent and elution with pentane/dichlorometane ratio of 2:1, while total phenols were determined spectrophotometrically with Folin-Ciocalteau reagent. Sensory evaluation of wines was performed using the Buxbaum method. The obtained results show that linalool and geraniol are the most abundant monoterpenes in Malvazija istarska, and that grape mash maceration treatments cause significant increase of free and bound monoterpene concentrations compared to those in control treatment wine obtained without maceration. The content of phenols, which are subject to oxidation, was found to be significantly lower in wines produced by cryomaceration treatments, while in those produced by maceration at 20 degree C the concentration of total phenols increased proportionally with the duration of maceration, negatively influencing wine quality by causing higher colour intensity and bitter taste.
To investigate the varietal aroma compound composition of monovarietal grape marc distillates made from six different varieties (Vitis vinifera L.) in the region of Istria (Croatia), 30 samples were ...subjected to GC/MS and GC/FID analysis. A total of 73 compounds were identified: 45 monoterpenes, 20 sesquiterpenes, 3 diterpenes, and 5 C13-norisoprenoids. The largest number and the highest concentration of monoterpenes were found in Muscat Blanc, followed by Rose Muscat of Poreč (Muškat ruža porečki) distillates, which were both characterized as highly aromatic. Lower, but still significant monoterpenol content was determined in distillates made from Istrian Malvasia (Malvazija istarska) grape marc. Chardonnay, Cabernet Sauvignon, and Teran distillates exhibited poorer monoterpene profiles, while Teran distillates contained elevated sesquiterpene concentrations. It was concluded that investigated monovarietal grape marc distillates significantly differ in varietal aroma compound composition. Stepwise linear discriminant analysis provided efficient discrimination models, and extracted various monoterpenes, sesquiterpenes and C13-norisoprenoids as important differentiators of distillates according to varietal origin.
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.
Tijekom ovog istraživanja, u berbi 2011. godine, praćen je utjecaj pedoklimatskih karakteristika različitih lokaliteta u komercijalnim vinogradima općine Brtonigla, vinogorja Zapadna Istra, odnosno ...različitih tipova tala (crveno, crno, sivo i bijelo) na senzorne karakteristike vina Malvazije istarske (Vitis vinifera L.). Radi praćenja razvoja senzornih karakteristika vina provedena je odvojena vinifikacija u bačvama volumena 130 L, u studentskom podrumu Poljoprivrednog odjela u Poreču, koristeći isti protokol vinifikacije. Za određivanje parametara uzeti su uzorci mošta u fazi taloženja i uzorci vina po završetku alkoholne fermentacije. Kemijske analize rađene su prema analitičkim metodama OIV-a. Senzorno ocjenjivanje, vina Malvazije istarske provedeno je u dva navrata, u prosincu 2011. i u svibnju 2012. godine, kroz opisno ocjenjivanje aromatskih karakteristika vina, ocjenjivanje metodom redoslijeda, te bodovno ocjenjivanje vina metodom OIV 100 bodova. Prema dobivenim rezultatima u I. senzornom ocjenjivanju aromatskog profila vina u svim varijantama najviše su bile zastupljene cvjetnovoćne note aroma vina dok u II. dolaze do izražaja biljne note i note aromatičnog bilja. Iz rezultata senzornog ocjenjivanja intenziteta i tipičnosti arome, u I. ocjenjivanju najintenzivniju aromu iskazala je varijanta crno tlo, a u II. crveno tlo. Što se tiče tipičnosti arome u I. senzornom ocjenjivanju kao najtipičniji uzorci ocijenjeni su uzorci s crvenog i bijelog tla dok je u II. kao najtipičnija Malvazija istarska izdvojena varijanta s crvenog tla. Iz
navedenih rezultata možemo zaključiti da se, u agroekološkim uvjetima berbe 2011. godine, izdvojila varijanta s crvenog tla, u kojoj su dominirale aromatske karakteristike koje su degustatori prepoznali i ocijenili kao „tipična Malvazija istarska“.
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