Vinogradarstvo Šibensko-kninske županije s posebnim osvrtom na vinogorje Primošten

Vinogardarska područja Europe proizvodi su baštine određenoga kraja. Realnost je vinogradarstva u primoštenskom kraju da se zadrži na sadašnjoj razini. Razlozi su višestruki: nedovoljna populacija; imovinsko-pravni odnosi; turistička djelatnost; nerazvijenost znanja i tehnika održavanja i podizanja nasada; nedovoljno razumijevanje lokalne sredine prema vinskomu turizmu i općenito prodaji vina; loša zakonska regulativa o trgovanju vinom (možda se to riješi nedavnim ulaskom u EU). Budućnost vinogradarstva ovoga kraja može se odvijati u različitim pravcima. Uslijed intenzivnoga trenda razvoja vinskoga turizma u svijetu, sudionici se uključuju u taj trend i ponuda se razvija. Mogući je razvoj i da se kupuje i prerađuje grožđe s drugih područja (zbog niže cijene grožđa). U svijetu postoji praksa zadržavanja specifičnih i teže obradivih područja gdje se, radi očuvanja baštine, odnosno krajolika, potiče i podržava vinogradarstvo s različitih državnih ili lokalnih razina. Ekološka se proizvodnja može uvrstiti zbog proširenja ponude i kao jedan od razloga da proizvod uspije na tržištu, ali su troškovi takve proizvodnje veći, a cijena gotovoga proizvoda uvećava se za rast troškova. Razvoj ovoga kraja moguć je kroz razvoj brenda vina, za što postoje svi potrebni preduvjeti (sorta, karakteristični terroir). Sličan scenarij trebao bi vrijediti i za ostala specifična i turistički razvijena područja u poriječju Krke. Najveća je prednost vinogradarskih područja Šibensko-kninske županije specifični terroir koji se posebno ocrtava kroz autohtone sorte grožđa koje su temelj razvoja hrvatskoga vinogradarstv

Usporedba kemijskog sastava, reoloških i senzorskih svojstava kefira proizvedenog primjenom kefirnih zrnaca i starter kulture

The main objective of this study was to compare chemical, rheological and sensory characteristics of kefir produced by using kefir grains and kefir starter. The intent was also to investigate whether it is plausible to use a combined inoculum (kefir grains and starter) in order to obtain a kefir with improved characteristics in terms of sensory and rheological characteristics. Kefir samples were produced at 25 °C and 35 °C by using starter culture XPL-1, kefir grains and their combinations. All of the produced kefir samples were analysed for acidity, total dry matter, ethanol content, syneresis, viscosity and were sensory evaluated by a specially trained panel. There were no significant differences considering the total dry matter, syneresis, ethanol content and acidity. Excess viscosity was observed in samples produced by starter culture at 35 °C, which was described as untypical, yoghurt like and unsatisfactory by a sensory panel. The sample produced at 25 °C by equal amounts of kefir grains and starter culture received the highest scores at sensory evaluation and showed the best potential for optimizing the further use. Further investigations need to focus on examining kefir properties during the storage period, especially regarding microbiological and sensory properties, ethanol content and texture profile.Cilj ovog rada bio je usporediti kemijski sastav, reološka i senzorska svojstva kefira proizvedenog pomoću kefirnih zrnaca i starter kulture. Osim toga, namjera je bila ispitati i opravdanost uporabe inokuluma dobivenog kombinacijom kefirnih zrnaca i starter kulture u svrhu postizanja kefira poboljšanih senzorskih i reoloških svojstava. Uzorci kefira proizvedeni su pri 25 °C i 35 °C primjenom starter kulture XPL-1, kefirnih zrnaca i njihove međusobne kombinacije. Svim proizvedenim uzorcima određivana je kiselost, ukupna suha tvar, udio etanola, sinereza, viskoznost i senzorska svojstva. Pri tom nisu zamijećene značajnije razlike u ukupnoj suhoj tvari, sinerezi, udjelu etanola i kiselosti. Međutim, u uzorcima proizvedenim pri temperaturi fermentacije 35 °C utvrđena je prekomjerna viskoznost koju je senzorski panel okarakterizirao kao netipičnu, svojstvenu jogurtu i nezadovoljavajuću. Uzorak proizveden fermentacijom pri temperaturi od 25 °C primjenom inokuluma sastavljenog od podjednakih dijelova starter kulture i kefirnih zrnaca najbolje je ocijenjen od strane senzorskog panela te je pokazao najveći potencijal za optimiranje i daljnju uporabu. Buduća istraživanja trebala bi se usredotočiti na ispitivanje svojstava kefira tijekom skladištenja, prije svega u pogledu mikrobioloških i senzorskih svojstava, udjela etanola i teksture

Analysis of aroma of white wine (Vitis vinifera L. Pošip) by gas chromatography-mass spectrometry

The aroma is one of the main characteristics that define the differences among the wines and it is affected by the numerous possible variations in wine’s production, both in viticulture and in winemaking (Swiegers et al, 2005). Compounds derived from grapes are responsible for so-called varietal aroma, whereas monoterpenes, norisoprenoids, C6 compounds and varietal thiols are main representatives. Varietal thiols, namely 4-mercapto-4-methyl-pentan-2-one (4MMP), 3-mercaptohexanol (3MH) and 3-mercaptohexylacetate (3MHA) are highly aroma active compounds, responsible for the tropical flavor of wines, and their positive contribution to the aroma of wines made from several grape varieties has already been proven (Tominaga et al, 1998, Murat et al, 2001; Álvarez-Pérez et al, 2012). These compounds belong to the class of varietal aromas because, despite they result from the cleavage of odorless precursors present in grapes or musts by yeast enzymes during alcoholic fermentation they are not product of yeast metabolism (Roland et al, 2011). In wine, aroma compounds are usually dominated by fermentation products, given that these compounds are present in the highest concentrations (Romano et al, 2003). Alcoholic fermentation increases the chemical and aroma complexity of wine by assisting in the extraction of compounds from solid parts present in grape musts, modifying some grape derived compounds and producing a large amount of yeast metabolites, some of which are aroma compounds (Lambrecht and Pretorius, 2000). Consequently, different yeast populations or strains used for alcoholic fermentation may result with different aroma characteristics of produced wines. Grape juice fermentation can either be natural, conducted by the microflora present in the grapes and in the winery, or inoculated with commercial Saccharomyces cerevisiae strain (Lambrecht and Pretorius, 2000). Inoculation minimizes the influence of wild yeast on wine quality and produces wines with consisted quality with predictable and desired characteristics. On the other hand, spontaneous fermentation may result in a significant and favorable effect on aroma development and in a new wine styles production. Final aroma of wine is influenced by the chemical reactions that occur during wine aging and storage. During that period, oxidative processes lead to the loss of some characteristic aroma compounds and the appearance of new and distinctive aromas of older wines and/or atypical ones associated with wine deterioration (Escudero et al, 2002; Lambropoulos and Roussis, 2007). In order to preserve wine against oxidative degradation, the addition of antioxidants prior to bottling is widespread practice; whereas addition of glutathione (GSH) has been suggested since GSH exhibited increased protection toward important aroma compounds (Ugliano et al, 2011)

Utjecaj vinskih sorta na aromu destilata

Aroma is a phenomenon that occurrs when food and live organism mutually react during the process of consumption. Many factors influence the making of aroma of wine distillates (e.g. cognac) during the technological process of distillation. It is extremely difficult to bring an objective judgement on the influence of individual factors since aroma is very subjective in its nature. The possibility of objective assessment of the influence of grape varieties on wine distillate was performed in this work using a computer in processing the results of cromatographic analyses of aroma substances. The given results were verified by sensor analyses. The achieved results have shown that mathematical model for calculating aroma chromatogram similarity can be successfully used for objective assessment of the influence of individual factors on aroma of wine distillates and that grape varieties have significant impact on aroma and the quality of wine distillates.Aroma je fenomen koji se pojavljuje tijekom konzumiranja hrane u organizmu. Pri stvaranju ukupne kakvoće (tip cognac) vinskih destilata upravo taj fenomen ima dominirajuću, a vrlo često i odlučujuću ulogu. Na aromu vinskih destilata utječe mnogo činitelja tijekom njezina stvaranja u tehnološkom procesu proizvodnje. Međutim, objektivnu je prosudbu o utjecaju pojedinog činitelja iznimno teško donijeti jer aroma ima i subjektivni karakter. U ovom je radu ispitana mogućnost objektivne procjene utjecaja sorte na aromu vinskih destilata primjenom računala u obradbi kromatografskih rezultata analize tvari arome, a navedeni su rezultati provjereni senzorskim analizama. Dobiveni su rezultati pokazali da se matematički model za kompjutorsko izračunavanje sličnosti kromatograma arome može uspješno koristiti pri objektivnoj procjeni utjecaja pojedinih činitelja na aromu vinskih destilata, te da sorta grožđa bitno utječe na aromu i kakvoću vinskih destilata

Influence of Blending on the Aroma of Malvasia istriana Wine

Malvasia istriana (Vitis vinifera) is a domestic and widespread grape cultivar in the Istrian wine region that gives the characteristic white wine. Istrian region is situated in the western part of Croatia (Adriatic coast). In the ageing process, Malvasia istriana loses its aroma (freshness and fruitiness) and hence it is usually consumed as a young wine. Therefore, blending is used to improve the quality of Malvasia istriana wine, to enrich its aroma and to maintain its varietal recognizability during the consumption period. Malvasia istriana base wine (85 %) was blended with Chardonnay, Sauvignon blanc, Pinot blanc, Prosecco and Muscat, from grape varieties grown in the Istrian region. The change in volatile compounds of the blends was observed throughout the year by using headspace solid phase microextraction (HS-SPME). Based on the analysis of the volatile compounds and sensory evaluation of the wine quality, the best result was obtained by blending Malvasia istriana with Sauvignon blanc and Pinot blanc. Chardonnay, Pinot blanc, Sauvignon blanc and Prosecco proved to be suitable for blending with Malvasia istriana, giving blends of high quality of the desired aroma profile. Muscat wine blended independently with Malvasia istriana or in combination with other wines proved to be unsuitable for blending due to its specific muscat aroma which dominates over the base wine aroma in the blend. Blending Malvasia istriana with other selected wines produced wines of better sensory quality, richer in volatile compounds, which can justify the blending

Study of Trehalose Addition on Aroma Retention in Dehydrated Strawberry Puree

In order to improve the quality of dehydrated fruit products, the influence of the addition of two sugars (sucrose and trehalose) on the retention of aroma components during dehydration of strawberry puree was investigated. Manual headspace solid-phase microextraction (SPME), containing polydimethylsiloxane coated fibre (100 μm) coupled with gas chromatography (GC-FID and GC-MS) was used for the analysis of the aroma of strawberry puree dehydrated by using freeze drying and foam-mat drying. The analytes identified included esters, carbonyl compounds, terpenoids, several alcohols and acids. The results obtained in this study give further insight into the mechanisms concerning the application of trehalose as flavouring additive, due to its ability to retain and preserve the fruit volatiles responsible for the characteristic flavour of fresh fruits during dehydration processes. The best retention of aroma components in dehydrated strawberry puree was obtained by trehalose addition when combined with freeze drying

Monitoring the influence of high power ultrasound treatment and thermosonication on inactivation of Brettanomyces bruxellensis in red wine

Brettanomyces bruxellensis is one of the most important spoilage microorganisms in winemaking. It is harmful for wine industry because it produces volatile phenols, compounds primarily responsible for off-odours in wine. One of the possible solutions for preventing its growth is using new non-thermal processing technologies. The aim of this study was to investigate the application of one non-thermal processing technology, high power ultrasound and its combination with heating (thermosonication) on the inactivation of B. bruxellensis in red wine in batch systems. Various parameters, such as treatment duration (1, 2, 3, 6, 10 and 15 minutes), temperature (25, 35, 40 and 43 ºC) and probe diameter (12.7 mm and 19.1 mm), were examined. The combination of high power ultrasound and heating (thermosonication) proved to be a better method compared to solely using high power ultrasound. However, the production of volatile phenols by B. bruxellensis was also reduced after high power ultrasound treatment. The optimal treatment of 3 min at 43 ºC with high power sonicator at ultrasound frequency of 20 kHz with 12.7 mm diameter ultrasonic probe for complete inactivation of B. bruxellensis was determined

Aluminium and Aroma Compound Concentration in Beer During Storage at Different Temperatures

Problem prisutnosti aluminija u pivu opisan je u nekoliko radova objavljenih u posljednjih deset godina. Međutim, utjecaj aluminija na organoleptična svojstva piva istražen je u samo nekoliko radova u kojima je navedeno da aluminij daje pivu metalan i gorak okus, bez zapažanja promjene udjela pojedinih sastojaka arome. Također je iznenađujuće oskudan broj izvještaja o točnoj promjeni sastojaka arome pri različitim uvjetima skladištenja. Da bi se istražila promjena koncentracije aluminija i sastojaka arome u ovom radu je primijenjena atomska apsorpcijska spektrometrija s grafitnom peći (GF-AAS) i Zeemanovom pozadinskom korekcijom te plinska kromatografija sa statičkim uređajem za uzimanje uzoraka iz plinskog prostora iznad tekućine (GC-HSS). Analize su provedene periodički tijekom sedam mjeseci skladištenja triju različitih vrsta piva iz poznatih pivovara. Uzorci su uzeti prije i nakon punjenja u aluminijske konzerve. Dio je uzoraka skladišten u hladnjaku (na 4 °C), a ostatak u termostatskoj komori (na 22 °C). Mjeren je utjecaj vrste piva i uvjeta skladištenja na koncentraciju aluminija i količinu sastojaka arome. Za dokazivanje utjecaja koncentracije aluminija na promjenu sastojaka arome dodana je adekvatna količina aluminijeva sulfata u boce piva koje je skladišteno na 28 °C. Iako su različite vrste piva pokazale značajne razlike u koncentraciji aluminija, to može biti posljedica ostalih faktora (različite šarže iste vrste piva također su imale različitu koncentraciju aluminija). Uzorci skladišteni u hladnjaku bili su zaštićeni od migracije aluminija iz konzerve u pivo i pokazali su povećanu stabilnost arome. Koncentracija sastojaka arome značajno se razlikovala u ispitanim vrstama piva. Povećana koncentracija aluminija nije značajno utjecala na koncentraciju sastojaka arome u uzorcima piva skladištenim pri 28 °C.Problem of aluminium in beer has been elaborated in several papers over the last decade. However, the effect of aluminium on organoleptic properties of beer has been observed in few papers where it has been stated that aluminium gives beer a »metallic« and bitter flavour without any observations on particular aroma compound changes. Also, the number of reports on precise changes of aroma components throughout different storage conditions is surprisingly scarce. In order to investigate the changes of aluminium concentration along with aroma compound changes, graphite furnace-atomic absorption spectrophotometry (GF-AAS) with Zeeman background correction and gas chromatography with static headspace sampler (GC-HSS) were used in this work. Analyses were conducted periodically throughout seven months of storage on three different brands of beer from name breweries. Samples were taken before and after filling in aluminium cans. One part of samples was stored in a refrigerator (4 °C) and the other in a thermostatic chamber (22 °C). The effects of beer brand and storage conditions on aluminium concentration and level of aroma compounds were measured. To prove the effect of aluminium concentration on the changes of aroma compounds, the adequate level of aluminium sulphate was added to bottled beer samples stored at 28 °C. Although different beer types showed significantly different aluminium concentration, it could be the result of other factors (different batches of identical beer type showed significantly different aluminium concentration as well). Samples that were stored in the refrigerator were protected from aluminium migration from the can to the beer and showed increased aroma stability. Level of aroma constituents of analyzed beer brands was significantly different. Elevated aluminium concentration did not have any noticeable effect on the level of aroma compounds in beer samples stored at 28 °C