Optimization of the sample preparation for analysis of polyphenolic compounds in the grape skins by high performance liquid chromatography

Cilj ovoga rada bio je optimirati uvjete priprave uzoraka kao i metode za ekstrakciju polifenola kožica grožđa. Ispitan je utjecaj različitog načina sušenja kožica bobica grožđa, sušenje u pećnici, na zraku pri sobnoj temperaturi te liofilizacija, na maseni udio pojedinih fenola te je utvrđeno da je liofilizacija najučinkovitija metoda. Optimiran je postupak zamrzavanja i odmrzavanja uzoraka bobica grožđa pri čemu su zamrzavane bobice sa i bez jastučića. Kožica je odvojena od ostatka bobice sa još zamrznutih bobica te nakon odmrzavanja u mikrovalnoj pećnici, hladnjaku i na sobnoj temperaturi. Najveći maseni udjeli pojedinih fenola očuvani su kod uzoraka zamrznutih sa jastučićem, a sa kojih je kožica odvojena s još zamrznutih bobica. Provedeno je optimiranje pet metoda (ekstrakcija čvrsto-tekuće, ultrazvukom potpomognuta ekstrakcija, mikrovalovima potpomognuta ekstrakcija, enzimima potpomognuta ekstrakcija te raspršenje matrice uzorka kroz čvrstu fazu) za ekstrakciju flavonoida iz kožica bobica grožđa te je usporedbom masenih udjela flavonoida u ekstraktima dobivenim tim metodama utvrđeno da je ultrazvukom potpomognuta ekstrakcija najučinkovitija metoda.The aim of the present study was the optimization of the sample preparations of grape skins and the extraction methods for polyphenols, as well. The investigation was done into the effect of the different drying methods of grape skins (oven drying, room temperature drying and freeze-drying) on the content of phenolic compounds. The most effective drying method was found to be freeze-drying. The process of freezing and thawing grape samples was undertaken. The grape berry samples were frozen with and without a receptacle. The skin of the frozen berries was separated from the rest of the berries after thawing in a microwave oven, a refrigerator and on room temperature. The largest content of individual phenols was preserved in samples frozen with a receptacle, where the skin was separated from the still frozen berries. The optimization was done for the five methods (solid-liquid extraction, ultrasound assisted extraction, microwave assisted extraction, enzyme assisted extraction and matrix solid phase dispersion) of flavonoid extraction from the grape berry skins. The comparison of flavonoid content in the extracts obtained by the five methods showed that the ultrasound assisted extraction was the most effective method

Chemical composition of aronia berry wine

U novije vrijeme zabilježen je rastući interes za konzumacijom funkcionalne hrane koja svojim sastavom pozitivno utječe na razvoj i funkcioniranje ljudskog organizma. Plodovi aronije (Aronia melanocarpa) i proizvodi dobiveni njihovom preradom predstavljaju vrijedan izvor polifenola, posebno proantocijanidina i antocijana. Zbog visoke zastupljenosti u plodovima voća i visoke antioksidativne aktivnosti, polifenoli se smatraju najznačajnijim dijetarnim antioksidansima. Antioksidansi su tvari koje usporavaju procese oksidacije u organizmu, te na taj način usporavaju procese starenja. Cilj ovog istraživanja je bio utvrditi kemijski sastav, koncentraciju ukupnih i pojedinačnih antocijana te antioksidacijski kapacitet voćnih vina od aronije proizvedene u kontinentalnoj Hrvatskoj.Recently there is a growing interest in consumption of functional food whose composition has a positive effect on the development and functioning of human organism. Chokeberry (Aronia melanocarpa) and derived products represent a valuable source of polyphenols, specifically proanthocyanidins and anthocyanins. Due to high representation in fruits and high antioxidant activity, polyphenols are considered to be the most important dietary antioxidants. Antioxidants are substances that delay the oxidation processes in the body, thereby slowing down the aging process. The aim of this study was to determine the chemical composition, total anthocyanin content, amount of single anthocyanins and antioxidant capacity of chokeberry fruit wines produced in continental part of Croatia

Chemical and sensory characterization of Chardonnay wines

Tijekom berbe 2017. proizvedena su četiri vina ´Chardonnay´ uz upotrebu različitih komercijalno dostupnihsojeva Saccharomyces cerevisiae i bayanus kvasaca te je uspoređen njihov aromatski profil. Primjenom ekstrakcije na čvrstoj fazi te vezanim sustavom plinska kromatografija- spektrometar masa, u vinima je identificirano oko 70 hlapljivih spojeva. Analizirani spojevi, podijeljeni u 7 kemijskih grupa, značajno su utjecali na senzorni profil vina i njihovu različitost. Rezultati su pokazali značajan i pozitivan utjecaj korištenih sojeva kvasaca na neke grupe spojeva koji doprinose kakvoći vina, poput etil-estera, izoamil i izobutil-acetata, nekih viših alkohola te monoterpena (linalol, citronelol i geraniol). Određena je i aktivna mirisna vrijednost (OAV) pojedinih aromatskih spojeva koji su prema sličnosti deskriptora grupirani u aromatske serije poput voćne, cvjetne, začinske i maslačne, što je omogućilo i opisno definiranje aromatskog profila svakog vina.During the vintage 2017 four wines obtained by fermenting Chardonnay musts with commercial starter cultures of Saccharomyces cerevisiae and bayanus yeast strains were compared in terms of their volatile aroma compounds composition. An easy handle methodology Solid Phase Extraction Gas Chromatography Mass Spectrometry-based enabled the identification of almost 70 volatile compounds. These aroma compounds, arranged in seven chemical groups strongly influenced the sensory profile of each wine allowing their differentiation. The results revealed marked influence and positive contribution of yeast strains that were used on several wine quality contributors such as ethyl esters, isoamyl and isobutyl acetate, some higher alcohols and monoterpenes like linalool, citronellol and geraniol. Odor activity value of aroma compounds (OAV) was determined and by grouping the once with similar descriptors into aromatic series such as fruity, floral, spicy and buttery a descriptive organoleptic profile of each wine was established

The effect of grape harvest date on polyphenols and anthocyanins content of different red grapes varieties

S ciljem istraživanja utjecaja roka berbe, postavljen je pokus na četiri crne sorte vinove loze u čijem je grožđu popraćen sadržaj tradicionalnih pokazatelja kakvoće grožđa, kao što su šećer i ukupna kiselost, ali i sadržaj ukupnih polifenola i antocijana. Istraživane su sorte iz različitih vinogorja primorske Hrvatske, u tri različita roka berbe, uzimajući u obzir dvije proizvodne godine u nizu. Rezultati su ukazali na nepouzdanost tradicionalnih načina određivanja zrelosti grožđa, kao isključivih pokazatelja za određivanje roka berbe. Obzirom da dodatnim tjednom dozrijevanja u većini slučajeva nije došlo do daljnjeg porasta ukupnih polifenola i antocijana u grožđu, početak berbe ne bi trebalo bezrazložno odgađati.Four red grape cultivars were investigated in order to study the effect of grape harvesting date (ripening stage of the grape) on traditional indicators of maturity such as soluble solids and titratable acidity content, as well as on their total polyphenols and total anthocyanins content. Grape varieties grown in different coastal vinegrowing regions, at three different harvesting dates, and from two consecutive vintages, were examined. The results showed uncertainty of traditional indicators of maturity as the only parameter for harvest date determination, since the maximum concentration of soluble solids didn’t correlated with maximum concentration of total polyphenols and anthocyanins in the most of harvest dates. Furthermore, grapes from the third harvest date mostly didn’t have consistently higher polyphenols and anthocyanins levels, so the harvest should not be postponed unduly

Izvor osvjetljenja i tip citokinina utječu na stopu multiplikacije, sadržaj klorofila i formiranje puči kod izdanaka Amelanchier alnifolia u in vitro uvjetima

Amelanchier alnifolia, a deciduous shrub or small tree with edible berry-like fruit, is gaining importance as a commercial fruit crop. The application of micropropagation could complement conventional propagation methods of A. alnifolia. The present study aimed to investigate how two light treatments—a mix of red and blue LED lights with dominant wavelengths of 457 and 658 nm (RB LED) and conventional fluorescent lamps emitting light at broad wavelengths of 400-700 nm (FL)—in combination with three cytokinins (CK) belonging to either substituted adenines (6-benzylaminopurine, BAP; meta-Topolin, mT) or to phenylurea cytokinins (thidiazurone, TDZ) affected the multiplication rate, chlorophyll content, and stomata formation in in vitro culture of A. alnifolia axillary shoots. The two light sources proved equally effective in producing axillary shoots, but FL favorably influenced the elongation and chlorophyll content. On the other hand, RB LED lights triggered a significantly higher stomata number of A. alnifolia plantlets in vitro compared with those developed under FL. Presented results reveal a negative ratio between the stomata number and chlorophyll content in response to different cytokinins: TDZ induced the highest number of stomata while BAP significantly increased the chlorophyll content. As the largest number of axillary shoots per explant was achieved on the medium with addition of TDZ, it could be beneficial to use TDZ for multiplication, whereas the use of BAP could be advantageous in the last passage of multiplication before rooting.Amelanchier alnifolia je listopadni grm ili niže stablo s jestivim bobičastim plodovima radi kojih se sve više komercijalno uzgaja. Primjena mikrorazmnožavanja mogla bi nadopuniti uobičajene metode razmnožavanja A. alnifolia. Ovo istraživanje imalo je za cilj istražiti utjecaj dva tretmana svjetla - mješavine crvenih i plavih LED svjetiljki s dominantnim valnim duljinama od 457 i 658 nm (RB LED) i konvencionalnih fluorescentnih lampi koje emitiraju svjetlost u širokom rasponu valnih duljina od 400 do 700 nm (FL) - u kombinaciji s tri citokinina koji pripadaju bilo supstituiranim adeninima (6 benzilaminopurin, BAP i meta-topolin, mT) ili fenilurea citokininima (tidiazuron, TDZ) na stopu umnažanja, sadržaj klorofila i formiranje puči u in vitro kulturi aksilarnih izdanaka A. alnifolia. Dva izvora svjetlosti pokazala su se jednako učinkovita u stvaranju aksilarnih izdanaka, ali FL su povoljno utjecale na izduživanje izdanaka i sadržaj klorofila. S druge strane, pod RB LED svjetlima formirao se značajno veći broj puči kod A. alnifolia izdanaka in vitro u usporedbi s onima razvijenim pod FL. Ovdje prikazani rezultati otkrivaju negativan omjer između broja puči i sadržaja klorofila pod utjecajem različitih citokinina: TDZ je inducirao stvaranje najvećeg broja puči, dok je BAP značajno povećao sadržaj klorofila. S obzirom da je najveći broj aksilarnih izdanaka po eksplantatu formiran na mediju s dodatkom TDZ-a, TDZ je pogodan u fazi multiplikacije, dok bi se pozitivan utjecaj BAP-a mogao iskoristiti u posljednjoj supkultivaciji prije ukorjenjivanja

Phenolic content of prošek wines of Croatian autochthonous grapevine varieties

Prošek je desertno vino s kontroliranim zemljopisnim podrijetlom iz regije Primorska Hrvatska. Tradicionalna tehnologija proizvodnje podrazumijeva vinifikaciju grožđa sa visokim koncentracijama šećera što se postiže njegovim prosušivanjem na trsu ili u kontroliranim uvjetima. Cilj ovog istraživanja bio je utvrditi sadržaj polifenola u prošecima proizvedenih od 10 autohtonih sorata vinove loze koje se tradicionalno koriste u proizvodnji prošeka na području Dalmacije: Babić, Glavinuša, Grk, Lasina, Maraština, Plavac mali, Plavina, Pošip, Prč, Vugava. Utvrđene su značajne razlike između prošeka dobivenih od različitih sorata, ali generalno je sadržaj ukupnih fenola kod bijelih i kod crnih sorata viši nego u redovnim vinima ovih sorata. Sadržaj pojedinačnih fenolnih spojeva također se značajno razlikuje između sorata, a posebno je zanimljiv relativno visok sadržaj resveratrola utvrđen u prošeku proizvedenom od sorata Plavac mali, Babić i Glavinuša.Prošek is a desert wine with controlled geographical origin from the wine-growing region Primorska Hrvatska. Traditional technology of production implies vinification of grapes with high sugar content, which is accomplished by its drying, either on vines or in controlled conditions. The aim of this research was to determine the content of polyphenols in prošek wines made out of 10 autochthonous grapevine varieties traditionally used in production of prošek in Dalmatia: Babić, Glavinuša, Grk, Lasina, Maraština, Plavac mali, Plavina, Pošip, Prč, Vugava. Significant differences were determined among prošek wines produced of different varieties, but the content of total polyphenols in both white and black varieties is generally higher than in regular wines of these varieties. The content of individual phenols also varies greatly among varieties. The relatively high content of resveratrol observed in prošek made out of Plavac mali, Babić and Glavinuša varieties is especially interesting

Quality of red wines from different grape varieties V. vinifere L aged in slavonian oak barrels

Utjecaj srednje i jako paljenih bačava (225 L) od slavonske hrstovine na kakvoću crnih vina praćen je tijekom 9 mjeseci dozrijevanja. Cilj istraživanja bio je utvrditi razlike u kemijskom sastavu i senzornim svojstvima vina ´Cabernet Sauvignon´, ´Merlot´ i ´Petit Verdot´. Promjene u kemijskom sastavu vina praćene su metodom plinska kromatografija-masena spektrometrija (GC-MS) temeljem uzorkovanja vina svakih 3 mjeseca. Utvrđen je različiti intenzitet ekstrakcije polifenolnih spojeva, ovisno o jačini paljenja bačava koji je najviše utjecao na koncentracije eugenola, gvajakola, vanilina te cis i trans-hrastovog laktona. Na koncentracije ostalih laktona (γ-heksalakton, γ-nonalakton, γ-dekalakton) veći utjecaj je imala sorta u odnosu na jačinu paljena i vrijeme dozrijevanja. Ekstrakcija hlapivih spojeva iz drva bila je različita među ispitivanim vinima pri čemu je u vinu ´Cabernet Sauvignon´ bila najintenzivnija. Razlike su utvrđene i u koncentracijama hlapivih fenola. Tako su vina ´Petit Verdot´ imala najnižu koncentraciju etil-fenola i etilgvajakola dok je veća koncentracija zabilježena u vinima ´Cabernet Sauvignon´ neovisno o jačini paljenja. Prema rezultatima senzornog ocjenjivanja bolja su vina dozrijevana u srednje paljenim bačvama u odnosu na ona iz jako paljenih, pri čemu je ukupno najbolje ocijenjeno vino sorte ´Merlot´.The wood-related volatile profile of red wines aged in medium and hard toasted Croatian oak barrels was studied by GC–MS method. The objective of this study was to describe the differences in chemical composition and sensory properties of the \u27Cabernet Sauvignon,\u27 \u27Merlot\u27 and \u27Petit Verdot\u27 wines during the nine months aging period. Different rates of extraction have been observed, depending on the toasting method used. The toasting level influenced more considerably eugenol, guaiacol, vanillin and cis and trans-oak lactone concentrations. Among other lactones analysed (γ-hexalactone, γ-nonalactone, γ-decalactone), grape variety had more pronounced influence than toasting level and aging period. The accumulation of oak compounds was different, depending on the wine aged in the barrels with the extraction rate being more favoured in the Cabernet Sauvignon wines. Marked difference was noted in the ethyl phenols concentrations among tested wines. \u27Petiti Verdot\u27 contained the lowest levels of both phenols (ethyl phenol and guaiacol) while higher concentrations were noted in Cabernet Sauvignon wines regardless of the toasting level. Sensory evaluation pointed out better overall quality of wines aged in medium toasted barrels while among varieties, best results were achieved in Merlot wines

Influence of Different Secondary Fermentation Yeasts on Aromatic Profiles of Sparkling wines

Proizvodnja pjenušavih vina zauzima sve veći udio u ukupnoj svjetskoj proizvodnji vina. Tijekom posljednjeg desetljeća i Republika Hrvatska bilježi značajan porast proizvodnje i potrošnje pjenušavih vina. Sekundarna fermentacija i dozrijevanje na talogu kvasaca ključne su faze tradicionalne metode proizvodnje koje utječu na aromatski profil pjenušavih vina. U istraživanju na bijelom pjenušavom vinu proizvedenom od sorata \u27Manzoni\u27 i \u27Pinot crni\u27, korištena su tri različita komercijalno dostupna Saccharomyces sp. kvasca u pokretanju sekundarne fermentacije kako bi se analizirale potencijalne razlike u osnovnom sastavu te aromatskom profilu pjenušavih vina. Rezultati analiza dobivenih primjenom plinske kromatografije (GC-MS) jasno izdvajaju aromatske spojeve koji su značajno utjecali na razlike u aromatskim profilima proizvedenih pjenušavih vina.The production of sparkling wines occupies an increasing share of the total world wine production. During the last decade, there has been an increase in the production and consumption of sparkling wines in the Republic of Croatia. Secondary fermentation and maturation on yeast lees are key stages of the traditional production method, which affects the aromatic profile of sparkling wines. In the research on white sparkling wine produced from the varieties \u27Manzoni\u27 and \u27Pinot noir\u27, three different commercially available Saccharomyces sp. yeast in the initiation of secondary fermentation were used to analyze potential differences in the basic composition and aromatic profile of sparkling wines. The results of the gas chromatography (GC-MS) analysis clearly distinguish the aromatic compounds created by the use of different yeasts, which significantly influenced the differences in the aromatic profiles of the produced sparkling wines

Influence of sequential fermentation with Lachancea thermotelerans and Torulaspora delbrueckii yeast on chemical composition of Malvasia Istriana wines

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.As we face drastic climate change, new methods are being sought in the technology of wine production, especially in production of white wines, in order to preserve the primary aromas and achieve the desired balance of alcohols and acids. As a potential solution the use of non-Saccharomyces yeasts whose metabolism differs from Saccharomyces yeasts is suggested. In this study the influence of sequential inoculation of Torulospora delbriueckii and Lahancea thermotolerans with Saccharomyces cerevisiae on Malvasia istriana wine was studied and analyzed. Malvasia Istriana is the second most widespread white grape variety in Croatia and thus one of the most economically important varieties. The study included inoculations of must with non-Saccharomyces yeasts, and 48 h later with S. cerevisae QA23 strain and fermentation exclusively with S. cerevisae QA23. Non-Saccharomyces yeasts contributed to lower ethanol concentration, especially T. delbrueckii which in co-culture with S. cerevisae was not able to ferment a significant amount of fructose and L. theromotolernas by converting sugar to lactic acid. Although differences within the aromatic profile were observed, none of the non-Saccharomyces strains significantly affected the overall wine aroma. Although the aroma, color and color intensity were best evaluated in the sample produced with the S. cerevisiae strain, the best ranked wine was Malvasia T. delbrueckii/S. cerevisiae

Aromatic profile of wines of certified cv. Graševina clones

Klonska selekcija sorte \u27Graševina\u27 rezultirala je registracijom četiri klona, OB-412, OB-414, OB-435 i OB-445. S obzirom na raširenost sorte \u27Graševina\u27 u Hrvatskoj, kvaliteta vina je vrlo važan čimbenik u prihvaćenosti od strane potrošača. Vrlo važnu ulogu u kvaliteti imaju senzorna svojstva vina, koja su određena hlapljivim aromatskim spojevima. Cilj rada bio je analizirati aromatski profil vina \u27Graševina\u27 proizvedenih od četiri klona i provesti senzornu analizu. Rezultati kemijske i senzorne analize pokazali su aromatski sastav vina klonova \u27Graševine\u27, u kojem su se istaknule cvjetne i voćne arome. Najviša koncentracija hlapljivih spojeva zabilježena je u vinima klonova OB-445 i OB-414. Senzornom analizom najbolje je ocijenjeno vino klona OB-414.Clonal selection of the variety \u27Graševina\u27 resulted in the registration of four clones, OB-412, OB-414, OB435 and OB-445. Considering the prevalence of the \u27Graševina\u27 variety in Croatia, the quality of the wine is a very important factor in consumer acceptance. The sensory properties of wine, which are determined by volatile aromatic compounds, play a very important role in quality. The aim of this work was to analyze the aromatic profile of the \u27Graševina\u27 wine produced from four clones and to carry out a sensory analysis. The results of the chemical and sensory analysis showed the aromatic composition of the wine of \u27Graševina\u27 clones, in which floral and fruity aromas stood out. The highest concentration of volatile compounds was recorded in the wines of clones OB-445 and OB-414. According to the sensory analysis, the wine from clone OB-414 was evaluated as the best