Michal Kumšta

Comparison of anthocyanins present in grapes of Vitis vinifera L. varieties and interspecific hybrids grown in the Czech Republic

Anthocyanins present in the grapes of nine grapevine (Vitis vinifera L.) varieties and ten interspecific hybrids were compared. Total anthocyanin levels were determined in fresh grapes and the values ranged from 0.50 g kg−1 to 4.99 g kg−1. A total of twenty-two different anthocyanins were identified. Malvidin 3-glucoside was the most abundant anthocyanin, with concentrations ranging from 30 % to 64 % of the totals observed. The ratio of acetylated to coumaroylated malvidin and peonidin derivatives ranged from 0.09 (variety: Regent) to 1.34 (variety: Cerason), depending on the variety. Diglucosylated anthocyanins were not found in particular interspecific hybrids such as the teinturier XIV 26–56, Laurot, Merlan, and Nativa.

Phenolic profile in Czech white wines from different terroirs

Grapevine cv. Riesling is a traditional variety of cool climate viticulture regions to which the Czech Republic belongs too. In total 35 wine samples from 9 different terroirs of wine-growing regions in the Czech Republic were evaluated for the content of 20 phenolic compounds comprising hydroxybenzoic acids, hydroxycinnamates, stilbenes, and flavan-3-ols. Phenolic compounds were evaluated by an HPLC method. Methods of multivariate statistical analysis were used to discriminate wine samples on the basis of their geographical origin. Canonical variate analysis proved that it is possible to differentiate wines according to their geographical origin by following authenticity markers: gallic acid, caffeic acid, caftartic acid, p-coutaric acid, ferulic acid ethylester, p-coumaric acid ethylester, (+)-catechin, and (−)-epicatechin. On the basis of statistical analyses, 100% wine samples were correctly classified. The results indicate that, for the case of white wines, mainly hydroxycinnamates and flavan-3-ols can be used for differentiation of their geographical origin.

Terpene content of wine from the aromatic grape variety ‘Irsai Oliver’ (Vitis vinifera L.) depends on maceration time

Abstract This study deals with the determination of the content of both free and bound terpenes in berries and wine of the aromatic grapevine variety ‘Irsai Oliver’. Grapes were macerated in juice for different time intervals (viz. 0; 5; 12; 24 hours) and thereafter processed to wine. The objective was to map the dependence of some selected terpenes on the period of maceration. Using gas chromatography, some nine organic compounds were detected. Attention was paid to contents of linalool (3,7-dimethylokta-1,6-dien-3-ol), 2,6-dimetyl-3,7-octadiene-2,6-diol, hotrienol ([(5E)-3,7-dimethylocta-1,5,7-trien-3-yl] acetate), αterpineol (2-(4-Methyl-1-cyclohex-3-enyl)propan-2-ol), β-citronellol (3,7-Dimethyloct-6-en-1-ol), nerol ((Z)-3,7-dimethyl-2,6-octadien-1-ol), geraniol ((trans)-3,7-dimethyl-2,6-oktadien-1-ol) and epoxylinalool (2-(5-ethenyl-5-methyloxolan-2-yl)propan-2- ol): epoxylinalool 1 (trans-linalool oxide (furanoid) cis-linalool oxide (furanoid)) and epoxylinalool 2 (trans-linalool oxide (pyranoid) cis-linalool oxide (pyranoid)). Some basic wine parameters (alcohol, pH, sugars and total acids) were estimated as well. The terpene content in wine increased gradually with the period of maceration. The highest and the lowest amounts of terpenes were recorded after 24 hours of maceration and no maceration, respectively. The terpene glycosides content was higher than that of the aglycones. Linalool and 2,6-dimetyl-3,7-octadiene-2,6-diol were the most abundant terpenes. Based on the results of this study it is possible to conclude that the ‘Irsai Oliver’ variety of grape has a very high terpene content. To improve the aromatic profile of the wine, the grape must should be macerated for 24 hours.

Test vinných želé

Sotolář, R., Sotolářová, O., Kumšta, M., 2018: Test of wine jelly. Kvasny Prum. 64(2): 71–75 The purpose of this study was to test different ways of producing jelly from wine, sugar and gelling material in varying proportions, using several wine varieties. Two different wine varieties were used to produce the tested jelly. White wine of the traminer aromatic variety Pálava and red wine of fruity aromatic variety Regent. Gelling agents chosen were: a commonly available agar (for harder consistency), a confectionery jelly (carrageenan + carobin – vegetable gelatin) and pork gelatin. Full doses of the gelling agent (as specifi ed by the manufacturer) and half-doses were tested. Basic analytical determinations were carried out for the selected wine and the subsequently produced jelly. The aim was to fi nd which formula is best suited for the production of the studied product and, according to sensory evaluation, which product is considered the tastiest and the most interesting by consumers. The consistency, appearance (clarity), aroma and the taste of the resulting jelly were evaluated. The best results were achieved using confectionery jelly (carobin + carrageenan) in the prescribed full dose of 10 g / 0.25 l of wine (sample 3). The sample had the best consistency, appearance and taste. Sample No. 4 was also very good, once again using the confectionery jelly, but in a half dose of gelling material (carobin + carrageenan in a dose of 5 g / 0.25 l of wine).Ukolem teto studie bylo vyzkouset různe způsoby výroby žele z vina, cukru a želirovaci latky v různem poměru, a to z několika odrůd. K výrobě žele bylo použito vino dvou odrůd. Bile vino traminově aromaticke odrůdy Palava a cervene vino ovocně aromaticke odrůdy Regent. Jako želirovaci latky byly zvoleny běžně dostupný agar (pro tužsi konzistenci), cukrarenske žele (karagenan + karubin - rostlinna želatina) a vepřova želatina. Testovala se plna davka želirovaci latky (uvaděna výrobcem) i jeji polovicni davkovani. Provedla se zakladni analyticka stanoveni u vina i nasledně vyrobeneho žele. Cilem bylo tedy zjistit, ktera receptura je pro daný výrobek nejvhodnějsi a dle senzorickeho hodnoceni posoudit, který výrobek je pro spotřebitele nejchutnějsi a nejzajimavějsi. Hodnotila se konzistence, vzhled (cirost), vůně a chuť výsledneho žele. Nejlepe vychazelo cukrarenske žele (karubin + karagenan) v předepsane plne davce 10 g / 0,25 l vina (vzorek c. 3). Vzorek měl nejidealnějsi konzistenci, dobrý vzhled i chuť. Velmi dobře vychazel i vzorek c. 4, tedy opět cukrarenske žele v polovicni davce želirovaci latky (karubin+karagenan v davce 5 g / 0,25 l vina).

Effect of the Period of Maceration on the Content of Antioxidant Substances in Grape Juice

The study deals with the monitoring of the content of antioxidant components in grape juice in the course of cold maceration of grapevine varieties ‘Italian Riesling’ and ‘Cabernet Sauvignon’, vintages 2011 and 2012. For analyses, grape juice was sampled after the maceration intervals of 0; 2; 4; 6; 8; 12 and 24 h. Spectrophotometry was used to estimate antioxidant activity (by the DPPH test), total flavanols, contents of anthocyans and contents of hydroxycinnamic acids. The content of total acidity and pH were estimated as well. Obtained results indicated that contents of aforementioned compounds increased with the increasing time of mush maceration.

Srovnání rosé vín dle obsahu vybraných fenolických látek a antiradikálové aktivity.

Rosé vína si v posledních letech vydobyla pozornost a těší se velké oblibě nejen v ČR, ale i jinde ve světě. V ČR se vyrábějí nejčastěji z tradičních odrůd jako je ‘Rulandské modré’, ‘Frankovka’, ‘Zweigeltrebe’, ‘André’ a ‘Cabernet Sauvignon’. Nyní se však objevují rosé vína vyrobená z nověji registrovaných odrůd jako ‘Cabernet Moravia’ či ‘Merlot’. Zcela novým počinem jsou rosé vína vyrobená z českých interspecifických modrých moštových odrůd, jako ‘Cerason’ nebo ‘Laurot’. Tyto odrůdy mají zvýšenou odolnost proti houbovým chorobám, často obsahují v bobulích více barviv, ale i dalších látek fenolické povahy, tedy flavanolů, katechinů a stilbenů. Řada obsažených látek vykazuje antiradikálovou aktivitu a tím i zdravotní prospěšnost. Vína z těchto odrůd mají obvykle vyšší barvu, bývají svěží a intenzivně ovocná. Srovnání rosé vín dle obsahu vybraných fenolických látek a antiradikálové aktivity