Malolactic fermentation in wine

Jabučno-mliječna fermentacija (JMF) je proces biološkog otkiseljavanja vina u kojem se dikarboksilna L-jabučna kiselina pretvara u monokarboksilnu L-mliječnu kiselinu i ugljik(IV)-oksid. JMF provode bakterije mliječne kiseline (BMK) iz rodova Oenocossus, Pediococcus i Lactobacillus. Na rast BMK u vinu i njihov metabolizam utječu razni fizikalno-kemijski čimbenici, poput pH, temperature, koncentracije sumpor(IV)- oksid i etanola. Kompleksne i raznovrsne metaboličke aktivnosti BMK tijekom JMF mogu na kakvoću vina utjecati pozitivno (smanjenje kiselosti, modifikacija mirisa i okusa, mikrobiološka stabilnost) ili negativno (promjene mirisa, boje i tvorba amina).Malolactic fermentation (MLF) is the biological process of wine deacidification where dicarboxylic L-malic acid is converted to monocarboxylic L-lactic acid and carbon (IV)-oxide. MLF is carried out by lactic acid bacteria (LAB) belonging to three genera: Oenocossus, Pediococcus and Lactobacillus. The growth of LAB and their metabolism in wine is affected by various physico-chemical factors such as pH, temperature, concentration of sulfur (IV)-oxide and ethanol. Complex and diverse metabolic activity of LAB during the MLF can affect the wine quality positively (reduced acidity, aroma and taste modification, microbiological stability) or negatively (changes in odor, color and formation of amines)

BENTONITE - WATER SUSPENSIONS: THE IMPACT ON THE PROTEIN STABILITY OF ISTRIAN MALVASIA WINES

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.Bentonite is an important enological agent in the white wines production. The effect of three bentonite types (sodium, calcium and sodium / calcium) and two types of water (tap / hard; distilled / soft) was investigated on the doses of bentonite required to stabilize the protein, and consequently on the sensory properties of Istrian malvasia wine. A significant difference in doses of bentonite in terms of water hardness was determined. Minimum dose for the stabilization of proteins (100 g / hl) were recorded for the use of sodium and calcium bentonite in distilled water. Also the least impact on the sensory properties of Istrian malvasia wine has been observed in these treatments

Effect of commercial yeasts (Saccharomyces cerevisiae) to anthocyanin profile of wines Teran and Cabernet sauvignon

Antocijani su pigmenti crvene boje smješteni uglavnom u kožici bobice crvenog grožđa te pridonose boji crvenih vina. Njihova koncentracija u vinima ovisi o: sorti, području uzgoja, tehnikama vinifikacije. Najzastupljeniji antocijan u vinima proizvedenim od grožđa Vitis vinifera L. je u pravilu malvidin-3- monoglukozid. Utjecaj na ekstrakciju i degradaciju antocijana mogu imati i Saccharomyces cerevisiae kvasci. Identifikacija antocijana u vinima Teran i Cabernet sauvignon berbe 2009. provedena je tehnikom tekućinske kromatografije visoke djelotvornosti. Istraživan je utjecaj tri komercijalna Saccharomyces cerevisiae kvasca (Uvaferm BDX, D254 i Fermol Premier Cru) na koncentraciju antocijana. Rezultati istraživanja pokazali su da kvasci Uvaferm BDX i D254 ekstrahiraju više aciliranih i neaciliranih antocijana.Anthocyanins are red, blue and purple pigments located mainly in the skin of red grape berries and contribute to the color of red wines. Their concentration in wine depends on variety, ecological conditions, growing and vinification techniques. The most common anthocyanin in red wines made from Vitis vinifera L. grapes is generally malvidin-3-monoglucoside. Saccharomyces cerevisiae yeast may have the impact on the extraction and degradation of anthocyanins. Identification of anthocyanins in wines Cabernet Sauvignon and Teran in harvest 2009 was analyzed by the technique of high performance liquid chromatography. The effects of three commercial Saccharomyces cerevisiae yeasts (BDX Uvaferm, D254 and Fermol Premier Cru) on the concentration of anthocyanins were investigated. The results showed that yeasts Uvaferm BDX and D254 extracted more non- acylated and acylated anthocyanins

Utjecaj različitih načina provedbe jabučno-mliječne fermentacije na promjene kemijskih svojstava i hlapivih komponenti crnog vina Teran (Vitis vinifera L.)

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 (coinoculation) 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. Coinoculation 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.Jabučno-mliječna fermentacija (JMF) složen je biokemijski proces koji ima važnu ulogu u proizvodnji većine crnih vina. Glavni učinci primjene JMF su snižavanje ukupne kiselosti uz rast pH vrijednosti, mikrobiološka stabilnost vina te promjena aromatskih senzornih svojstava vina. Cilj ovog istraživanja bio je utvrditi utjecaj različitih načina jabučnomliječne fermentacije na kompatibilnost kvasca i bakterija, duljinu trajanja fermentacije, koncentraciju pojedinačnih organskih kiselina i spojeva arome te senzorna svojstva vina sorte ´Teran´ (Vitis vinifera L.). Pokus je obuhvaćao kontrolni tretman (bez JMF), spontanu JMF, induciranu JMF u početku alkoholne fermentacije (koinokulacija) te induciranu JMF po završenoj alkoholnoj fermentaciji. U svim tretmanima alkoholna fermentacija je u potpunosti završila, bez zastoja ili usporavanja. Koinokulacija je utjecala na značajno kraće trajanje JMF. Svi tretmani s JMF značajno su utjecali na sniženje koncentracije titracijske kiselosti i povećanje pH vrijednosti. Najviše koncentracije hlapive kiselosti i etil acetata utvrđene su u vinima spontane JMF. U svim tretmanima s JMF zabilježena je potpuna razgradnja jabučne kiseline te sniženje koncentracije limunske kiseline, ukupnih viših alkohola i acetaldehida. Nadalje, značajno više koncentracije etilnih estera, diacetila, acetoina i 2,3-butandiola zabilježene su u svim tretmanima s JMF

Influence of encapsulated yeast on the quality of ´Teran´ rosé sparkling wine

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 kakvoćeThe influence of encapsulated yeast ProElif® (Saccharomyces cerevisiae) in comparison with the yeast Fermol Blanc (Saccharomyces bayanus) in the production of naturally sparkling rosé wine by bottle fermentation produced from the indigenous grape cultivar Teran (Vitis vinifera L.) was investigated. During the research, the following were monitored: the length of sugar decomposition during fermentation in the bottle, and in the finalized sparkling wines, physicochemical parameters, foam and sparkling parameters and phenolic profile. Faster breakdown of sugars, as well as a higher proportion of individual and total phenolic compounds have been recorded in wines with ProElif® yeast. On the other hand, wines produced with Fermol Blanc yeast were characterized by a higher dry extract and higher quality of foam and sparkling. Sensory differences were observed in wines without negative implications for their final quality

Influence of lactic acid bacteria on aroma compounds and sensory properties of red wine Teran

Jabučno-mliječna fermentacija (JMF) složen je biokemijski proces koji se obično nastavlja na završenu alkoholnu fermentaciju te ima važnu ulogu u proizvodnji većine crnih vina. Istraživanja na ovu temu navode da su glavni razlozi za njeno provođenje sniženje ukupne kiselosti koju prati porast pH vrijednosti, mikrobiološka stabilnost vina uslijed razgradnje jabučne kiseline te promjena fizikalno-kemijskih i senzorskih svojstava vina. Cilj ovog istraživanja bio je utvrditi utjecaj različitih tipova jabučno-mliječne fermentacije na kompatibilnost kvasca i bakterija, dužinu njenog trajanja, promjene koncentracija pojedinačnih organskih kiselina, spojeva arome te promjene u fizikalno-kemijskim i senzorskim svojstvima vina Teran (Vitis vinifera L.). Pokus je obuhvaćao sljedeće tretmane: kontrola (bez JMF), spontana jabučno-mliječna fermentacija, jabučno-mliječna fermentacija po završenoj alkoholnoj fermentaciji te koinokulacija kvasca i bakterija mliječne kiseline na početku alkoholne fermentracije. Korišten je komercijalni soj kvasca Uvaferm 299 (Saccharomyces cerevisiae) i dva komercijalna soja bakterija mliječne kiseline Uvaferm AlphaTM i LALVIN 31TM (Oenococcus oeni). Osnovna analiza vina provedena je prema metodama O.I.V.-a. Koncentracije pojedinačnih organskih kiselina određene su spektrofotometrijski i primjenom tehnike tekućinske kromatografije visoke djelotvornosti (HPLC). Za određivanje tvari arome korištena je instrumentalna metoda plinske kromatografije (GC). Sva vina senzorski su ocijenjena metodom 100 pozitivnih bodova, rangiranjem i opisno. Jabučno-mliječna fermentacija značajno je utjecala na smanjenje ukupne kiselosti i povećanje pH vrijednosti. Najviše koncentracije hlapive kiselosti utvrđene su u vinima spontane jabučno-mliječne fermentacije. U svim tretmanima kod kojih je primijenjena jabučno-mliječna fermentacija zabilježena je potpuna razgradnje jabučne kiseline, smanjenje koncentracije limunske kiseline, ukupnih viših alkohola te acetaldehida. Značajno više koncentracije etilnih estera, diacetila, acetoina i 2,3-butandiola zabilježene su u svim tretmanima s provedenom jabučno-mliječnom fermentacijom. Pravilnost u porastu koncentracije ukupnih acetatnih estera utvrđena je kod tretmana spontane jabučno-mliječne fermentacije. U istom tretmanu zabilježena je i značajno viša koncentracija etil acetata. U svim tretmanima s jabučno-mliječnom fermentacijom,alkoholna fermentacija je u potpunosti završila, bez zastoja ili usporavanja. Koinokulacija je utjecala na značajno kraće trajanje jabučno-mliječne fermentacije. Senzorskom analizom bolje su ocijenjena vina koinokulacije i naknadne inokulacije, bez značajnih razlika u kakvoći pojedinih svojstava. Karakterizirale su ih izraženije voćne arome, puniji okus, kremoznija struktura te blaža kiselost i manja astringentnost. Unatoč značajnim promjenama senzorskih svojstava, primjenomjabučno-mliječne fermentacije vina Teran nisu izgubila sortna obilježja, a koinokulacija kao tretman nije imala negativan utjecaj na protjecanjei ishod alkoholne fermentacije.Malolactic fermentation (MLF) is a complex biochemical process that usually continues, to complete alcoholic fermentation and plays an important role in the production of most red wines. Research on this topic states that the main reasons for its implementation are the reduction of total acidity accompanied by an increase in pH, microbiological stability of wine due to the decomposition of malic acid and changes in physicochemical and sensory properties of wine. Teran (Vitis vinifera L.) is an autochthonous grape variety, and the wine produced from it is characterized by high total acidity and as such, this research is extremely suitable. The aim of this study was to determine the influence of different types of MLFon the compatibility of yeast and bacteria, its duration, changes in concentrations of individual organic acids, aroma compounds and changes in physicochemical and sensory properties of Teran (Vitis vinifera L.). The chapter Review of previous research provides data on the influence of environmental factors on malolactic fermentation as well as those on strains of lactic acid bacteria (LAB) and provides an overview and comparison of different types of MLF (co-inoculation, inoculation during alcoholic fermentation, subsequent inoculation and spontaneous MLF). The subchapter on the time of LAB inoculation on physicochemical changes in wines deals with the influence on the decomposition dynamics of malic and citric acid. Numerous studies indicate the influence of LAB inoculation time on changes in aromatic components of wine such as esters, higher alcohols, volatile fatty acids, acetaldehyde and compounds formed by LAB metabolic activity (diacetyl, acetoin, 2,3-butanediol) as well as on the sensory profile of wine. The chapter Materials and Methods presents the course of research and data processing. A two-year study was conducted that included the influence of different malolactic fermentation techniques on changes in physicochemical, aromatic and sensory properties in wines of the red cultivar Teran (Vitis vinifera L.). The vineyard in which the manual harvest was carried out was 10 years old, planted on a lesivan red (terra rossa) cultivation form of two-limbed Guyot. It was planted on a Kober 5BB substrate, and the planting intervals were 2.20 x 0.80 m, which gives approximately 5600 vines per hectare. After mulching and crushing, the mash is uniform and then evenly distributed in stainless steel tanks. The experiment was set up in three replications (50 L x 3) for each treatment in the experiment: Treatment K (control - suppressed MLF), S (spontaneous MLF-MLF takes place by the action of epiphytic LAB's), KIA (co-inoculation of LAB Oenococcus oeni Uvaferm AlphaTM), KI31 (co-inoculation of LAB Oenococcus oeni LALVIN 31TM), NIA (subsequent inoculation of LAB Oenococcus oeni Uvaferm AlphaTM), NI31 (subsequent inoculation of LAB Oenococcus oeni LALVIN 31TM). Alcoholic fermentation was carried out with classical maceration for seven days with manual, immersion of the cap three times a day using a commercial strain of yeast Uvaferm 299 (Saccharomyces cerevisiae). Alcoholic and malolactic fermentation were conducted at a temperature of 24⁰C until their completion. In all treatments, samples for chemical analysis were taken at the following times: (I) in the must, after filling the vessels, and before sulfitation and the addition of oenological agents, (II) every 2 days during alcoholic fermentation until its completion, (III) every 2 days during malolactic fermentation until its completion, (IV) in young wine after completed alcoholic and malolactic fermentation, and before overflow and sulfitation. Chemical analysis of must include determination of sugar concentration, total acidity, pH value and the determination of individual organic acids. Basic chemical analysis (% vol. Alcohol, reducing sugar, total extract, total acidity, pH, volatile acid, ash) was performed in wine samples. Concentrations of individual organic acids were determined spectrophotometrically and using high performance liquid chromatography (HPLC) techniques. The instrumental gas chromatography (GC) method was used to determine the flavor substance. All wines were sensory evaluated by the method of 100 points, ranking and descriptive.The Results section presents the main results obtained by the research. Malolactic fermentation significantly affected the reduction of total acidity with increasing pH. The highest concentrations of volatile acidity were found in wines of spontaneous malolactic fermentation. The time of LAB inoculation did not affect the concentration of volatile acidity, while lower concentrations were produced by wines obtained using the Uvaferm AlphaTM strain. The inoculation time and the LAB strain used had no effect on succinic acid concentrations, the reduction of which was observed only in spontaneous MLF treatments. Degradation of malic acid was in all MLF treatments regardless of inoculation time and strain LAB was complete while significantly the lowest lactic acid concentration was found in the control treatment. Citric acid concentrations recorded a statistically significant decrease in wines with MLF, with significantly higher degradation in the treatment of co-inoculation and the use of LALVIN 31TM strain. MLF significantly reduced the total concentration of higher alcohols and increased concentrations of ethyl esters in all treatments, while a significant increase in the concentration of acetate esters in both years was recorded only in the treatment of spontaneous MLF with a significant increase in ethyl acetate and hexyl acetate. Co-inoculation significantly reduced the concentrations of isoamyl alcohol, 2-phenylethanol, ethyl acetate and isoamyl acetate, and increased the concentrations of ethyl lactate and diethyl succinate. The UvafermAlphaTM strain had a significant effect on increasing the concentrations of isoamyl alcohol, 2-phenylethanol, ethyl lactate and diethyl succinate, and a decrease on ethyl acetate and isoamyl acetate. The most common volatile fatty acids were caproic and caprylic acid with concentrations above the sensory detection threshold regardless of treatment. Significantly the highest concentration of caproic acid was recorded in the treatment of subsequent inoculation with LALVIN 31TM strain, and caprylic in the treatment of co-inoculation with Uvaferm AlphaTM strain during 2005. MLF resulted in significantly lower concentrations of acetaldehyde and significantly higher concentrations of diacetyl, acetoin and 2,3-butanediol compared to control treatment. Significantly lower acetaldehyde concentrations were affected by inoculation time while LAB strains used for inoculation had no effect. An increase in 2,3-butanediol concentrations and a decrease in acetoin concentrations were found in the co-inoculation treatment using the LAB strain Uvaferm AlphaTM. The lengths of the LAG phase and the total duration of MLF showed regularity in both years of the study and lasted the shortest in treatments with co-inoculation, then with subsequent inoculation and the longest in spontaneous MLF. The duration of MLF was also affected by the LAB strain, whereas MLF was significantly shorter than the LALVIN 31TM strain using the Uvaferm AlphaTM strain. Furthermore, the presence of LAB did not negatively affect the viability of the yeast and in all treatments, alcoholic fermentation had the correct dynamics with a complete breakdown of sugar. The results of the sensory analysis of wine confirmed the positive impact of the application of selected LAB's on the quality of Teran wine. Co-inoculation and subsequent inoculation treatments were rated the best, and spontaneous MLF wines the worst in both years of the study. In relation to the control treatment, comparing the sensory properties of the aroma and taste of the wine, co-inoculations and subsequent inoculations had a more pronounced fruity character with an emphasis on plums with a lower intensity of cherry aroma and lower sensations of spicy notes, while the taste of wines was fuller, creamier with less pronounced acidity and astringency. Despite the significant changes of sensory properties, wines produced by co-inoculation and subsequent inoculation did not lose the varietal characteristics of Teran wine, which proved that co-inoculation as a treatment did not have a negative impact

Influence of lactic acid bacteria on aroma compounds and sensory properties of red wine Teran

Jabučno-mliječna fermentacija (JMF) složen je biokemijski proces koji se obično nastavlja na završenu alkoholnu fermentaciju te ima važnu ulogu u proizvodnji većine crnih vina. Istraživanja na ovu temu navode da su glavni razlozi za njeno provođenje sniženje ukupne kiselosti koju prati porast pH vrijednosti, mikrobiološka stabilnost vina uslijed razgradnje jabučne kiseline te promjena fizikalno-kemijskih i senzorskih svojstava vina. Cilj ovog istraživanja bio je utvrditi utjecaj različitih tipova jabučno-mliječne fermentacije na kompatibilnost kvasca i bakterija, dužinu njenog trajanja, promjene koncentracija pojedinačnih organskih kiselina, spojeva arome te promjene u fizikalno-kemijskim i senzorskim svojstvima vina Teran (Vitis vinifera L.). Pokus je obuhvaćao sljedeće tretmane: kontrola (bez JMF), spontana jabučno-mliječna fermentacija, jabučno-mliječna fermentacija po završenoj alkoholnoj fermentaciji te koinokulacija kvasca i bakterija mliječne kiseline na početku alkoholne fermentracije. Korišten je komercijalni soj kvasca Uvaferm 299 (Saccharomyces cerevisiae) i dva komercijalna soja bakterija mliječne kiseline Uvaferm AlphaTM i LALVIN 31TM (Oenococcus oeni). Osnovna analiza vina provedena je prema metodama O.I.V.-a. Koncentracije pojedinačnih organskih kiselina određene su spektrofotometrijski i primjenom tehnike tekućinske kromatografije visoke djelotvornosti (HPLC). Za određivanje tvari arome korištena je instrumentalna metoda plinske kromatografije (GC). Sva vina senzorski su ocijenjena metodom 100 pozitivnih bodova, rangiranjem i opisno. Jabučno-mliječna fermentacija značajno je utjecala na smanjenje ukupne kiselosti i povećanje pH vrijednosti. Najviše koncentracije hlapive kiselosti utvrđene su u vinima spontane jabučno-mliječne fermentacije. U svim tretmanima kod kojih je primijenjena jabučno-mliječna fermentacija zabilježena je potpuna razgradnje jabučne kiseline, smanjenje koncentracije limunske kiseline, ukupnih viših alkohola te acetaldehida. Značajno više koncentracije etilnih estera, diacetila, acetoina i 2,3-butandiola zabilježene su u svim tretmanima s provedenom jabučno-mliječnom fermentacijom. Pravilnost u porastu koncentracije ukupnih acetatnih estera utvrđena je kod tretmana spontane jabučno-mliječne fermentacije. U istom tretmanu zabilježena je i značajno viša koncentracija etil acetata. U svim tretmanima s jabučno-mliječnom fermentacijom,alkoholna fermentacija je u potpunosti završila, bez zastoja ili usporavanja. Koinokulacija je utjecala na značajno kraće trajanje jabučno-mliječne fermentacije. Senzorskom analizom bolje su ocijenjena vina koinokulacije i naknadne inokulacije, bez značajnih razlika u kakvoći pojedinih svojstava. Karakterizirale su ih izraženije voćne arome, puniji okus, kremoznija struktura te blaža kiselost i manja astringentnost. Unatoč značajnim promjenama senzorskih svojstava, primjenomjabučno-mliječne fermentacije vina Teran nisu izgubila sortna obilježja, a koinokulacija kao tretman nije imala negativan utjecaj na protjecanjei ishod alkoholne fermentacije.Malolactic fermentation (MLF) is a complex biochemical process that usually continues, to complete alcoholic fermentation and plays an important role in the production of most red wines. Research on this topic states that the main reasons for its implementation are the reduction of total acidity accompanied by an increase in pH, microbiological stability of wine due to the decomposition of malic acid and changes in physicochemical and sensory properties of wine. Teran (Vitis vinifera L.) is an autochthonous grape variety, and the wine produced from it is characterized by high total acidity and as such, this research is extremely suitable. The aim of this study was to determine the influence of different types of MLFon the compatibility of yeast and bacteria, its duration, changes in concentrations of individual organic acids, aroma compounds and changes in physicochemical and sensory properties of Teran (Vitis vinifera L.). The chapter Review of previous research provides data on the influence of environmental factors on malolactic fermentation as well as those on strains of lactic acid bacteria (LAB) and provides an overview and comparison of different types of MLF (co-inoculation, inoculation during alcoholic fermentation, subsequent inoculation and spontaneous MLF). The subchapter on the time of LAB inoculation on physicochemical changes in wines deals with the influence on the decomposition dynamics of malic and citric acid. Numerous studies indicate the influence of LAB inoculation time on changes in aromatic components of wine such as esters, higher alcohols, volatile fatty acids, acetaldehyde and compounds formed by LAB metabolic activity (diacetyl, acetoin, 2,3-butanediol) as well as on the sensory profile of wine. The chapter Materials and Methods presents the course of research and data processing. A two-year study was conducted that included the influence of different malolactic fermentation techniques on changes in physicochemical, aromatic and sensory properties in wines of the red cultivar Teran (Vitis vinifera L.). The vineyard in which the manual harvest was carried out was 10 years old, planted on a lesivan red (terra rossa) cultivation form of two-limbed Guyot. It was planted on a Kober 5BB substrate, and the planting intervals were 2.20 x 0.80 m, which gives approximately 5600 vines per hectare. After mulching and crushing, the mash is uniform and then evenly distributed in stainless steel tanks. The experiment was set up in three replications (50 L x 3) for each treatment in the experiment: Treatment K (control - suppressed MLF), S (spontaneous MLF-MLF takes place by the action of epiphytic LAB's), KIA (co-inoculation of LAB Oenococcus oeni Uvaferm AlphaTM), KI31 (co-inoculation of LAB Oenococcus oeni LALVIN 31TM), NIA (subsequent inoculation of LAB Oenococcus oeni Uvaferm AlphaTM), NI31 (subsequent inoculation of LAB Oenococcus oeni LALVIN 31TM). Alcoholic fermentation was carried out with classical maceration for seven days with manual, immersion of the cap three times a day using a commercial strain of yeast Uvaferm 299 (Saccharomyces cerevisiae). Alcoholic and malolactic fermentation were conducted at a temperature of 24⁰C until their completion. In all treatments, samples for chemical analysis were taken at the following times: (I) in the must, after filling the vessels, and before sulfitation and the addition of oenological agents, (II) every 2 days during alcoholic fermentation until its completion, (III) every 2 days during malolactic fermentation until its completion, (IV) in young wine after completed alcoholic and malolactic fermentation, and before overflow and sulfitation. Chemical analysis of must include determination of sugar concentration, total acidity, pH value and the determination of individual organic acids. Basic chemical analysis (% vol. Alcohol, reducing sugar, total extract, total acidity, pH, volatile acid, ash) was performed in wine samples. Concentrations of individual organic acids were determined spectrophotometrically and using high performance liquid chromatography (HPLC) techniques. The instrumental gas chromatography (GC) method was used to determine the flavor substance. All wines were sensory evaluated by the method of 100 points, ranking and descriptive.The Results section presents the main results obtained by the research. Malolactic fermentation significantly affected the reduction of total acidity with increasing pH. The highest concentrations of volatile acidity were found in wines of spontaneous malolactic fermentation. The time of LAB inoculation did not affect the concentration of volatile acidity, while lower concentrations were produced by wines obtained using the Uvaferm AlphaTM strain. The inoculation time and the LAB strain used had no effect on succinic acid concentrations, the reduction of which was observed only in spontaneous MLF treatments. Degradation of malic acid was in all MLF treatments regardless of inoculation time and strain LAB was complete while significantly the lowest lactic acid concentration was found in the control treatment. Citric acid concentrations recorded a statistically significant decrease in wines with MLF, with significantly higher degradation in the treatment of co-inoculation and the use of LALVIN 31TM strain. MLF significantly reduced the total concentration of higher alcohols and increased concentrations of ethyl esters in all treatments, while a significant increase in the concentration of acetate esters in both years was recorded only in the treatment of spontaneous MLF with a significant increase in ethyl acetate and hexyl acetate. Co-inoculation significantly reduced the concentrations of isoamyl alcohol, 2-phenylethanol, ethyl acetate and isoamyl acetate, and increased the concentrations of ethyl lactate and diethyl succinate. The UvafermAlphaTM strain had a significant effect on increasing the concentrations of isoamyl alcohol, 2-phenylethanol, ethyl lactate and diethyl succinate, and a decrease on ethyl acetate and isoamyl acetate. The most common volatile fatty acids were caproic and caprylic acid with concentrations above the sensory detection threshold regardless of treatment. Significantly the highest concentration of caproic acid was recorded in the treatment of subsequent inoculation with LALVIN 31TM strain, and caprylic in the treatment of co-inoculation with Uvaferm AlphaTM strain during 2005. MLF resulted in significantly lower concentrations of acetaldehyde and significantly higher concentrations of diacetyl, acetoin and 2,3-butanediol compared to control treatment. Significantly lower acetaldehyde concentrations were affected by inoculation time while LAB strains used for inoculation had no effect. An increase in 2,3-butanediol concentrations and a decrease in acetoin concentrations were found in the co-inoculation treatment using the LAB strain Uvaferm AlphaTM. The lengths of the LAG phase and the total duration of MLF showed regularity in both years of the study and lasted the shortest in treatments with co-inoculation, then with subsequent inoculation and the longest in spontaneous MLF. The duration of MLF was also affected by the LAB strain, whereas MLF was significantly shorter than the LALVIN 31TM strain using the Uvaferm AlphaTM strain. Furthermore, the presence of LAB did not negatively affect the viability of the yeast and in all treatments, alcoholic fermentation had the correct dynamics with a complete breakdown of sugar. The results of the sensory analysis of wine confirmed the positive impact of the application of selected LAB's on the quality of Teran wine. Co-inoculation and subsequent inoculation treatments were rated the best, and spontaneous MLF wines the worst in both years of the study. In relation to the control treatment, comparing the sensory properties of the aroma and taste of the wine, co-inoculations and subsequent inoculations had a more pronounced fruity character with an emphasis on plums with a lower intensity of cherry aroma and lower sensations of spicy notes, while the taste of wines was fuller, creamier with less pronounced acidity and astringency. Despite the significant changes of sensory properties, wines produced by co-inoculation and subsequent inoculation did not lose the varietal characteristics of Teran wine, which proved that co-inoculation as a treatment did not have a negative impact

Influence of lactic acid bacteria on aroma compounds and sensory properties of red wine Teran

Jabučno-mliječna fermentacija (JMF) složen je biokemijski proces koji se obično nastavlja na završenu alkoholnu fermentaciju te ima važnu ulogu u proizvodnji većine crnih vina. Istraživanja na ovu temu navode da su glavni razlozi za njeno provođenje sniženje ukupne kiselosti koju prati porast pH vrijednosti, mikrobiološka stabilnost vina uslijed razgradnje jabučne kiseline te promjena fizikalno-kemijskih i senzorskih svojstava vina. Cilj ovog istraživanja bio je utvrditi utjecaj različitih tipova jabučno-mliječne fermentacije na kompatibilnost kvasca i bakterija, dužinu njenog trajanja, promjene koncentracija pojedinačnih organskih kiselina, spojeva arome te promjene u fizikalno-kemijskim i senzorskim svojstvima vina Teran (Vitis vinifera L.). Pokus je obuhvaćao sljedeće tretmane: kontrola (bez JMF), spontana jabučno-mliječna fermentacija, jabučno-mliječna fermentacija po završenoj alkoholnoj fermentaciji te koinokulacija kvasca i bakterija mliječne kiseline na početku alkoholne fermentracije. Korišten je komercijalni soj kvasca Uvaferm 299 (Saccharomyces cerevisiae) i dva komercijalna soja bakterija mliječne kiseline Uvaferm AlphaTM i LALVIN 31TM (Oenococcus oeni). Osnovna analiza vina provedena je prema metodama O.I.V.-a. Koncentracije pojedinačnih organskih kiselina određene su spektrofotometrijski i primjenom tehnike tekućinske kromatografije visoke djelotvornosti (HPLC). Za određivanje tvari arome korištena je instrumentalna metoda plinske kromatografije (GC). Sva vina senzorski su ocijenjena metodom 100 pozitivnih bodova, rangiranjem i opisno. Jabučno-mliječna fermentacija značajno je utjecala na smanjenje ukupne kiselosti i povećanje pH vrijednosti. Najviše koncentracije hlapive kiselosti utvrđene su u vinima spontane jabučno-mliječne fermentacije. U svim tretmanima kod kojih je primijenjena jabučno-mliječna fermentacija zabilježena je potpuna razgradnje jabučne kiseline, smanjenje koncentracije limunske kiseline, ukupnih viših alkohola te acetaldehida. Značajno više koncentracije etilnih estera, diacetila, acetoina i 2,3-butandiola zabilježene su u svim tretmanima s provedenom jabučno-mliječnom fermentacijom. Pravilnost u porastu koncentracije ukupnih acetatnih estera utvrđena je kod tretmana spontane jabučno-mliječne fermentacije. U istom tretmanu zabilježena je i značajno viša koncentracija etil acetata. U svim tretmanima s jabučno-mliječnom fermentacijom,alkoholna fermentacija je u potpunosti završila, bez zastoja ili usporavanja. Koinokulacija je utjecala na značajno kraće trajanje jabučno-mliječne fermentacije. Senzorskom analizom bolje su ocijenjena vina koinokulacije i naknadne inokulacije, bez značajnih razlika u kakvoći pojedinih svojstava. Karakterizirale su ih izraženije voćne arome, puniji okus, kremoznija struktura te blaža kiselost i manja astringentnost. Unatoč značajnim promjenama senzorskih svojstava, primjenomjabučno-mliječne fermentacije vina Teran nisu izgubila sortna obilježja, a koinokulacija kao tretman nije imala negativan utjecaj na protjecanjei ishod alkoholne fermentacije.Malolactic fermentation (MLF) is a complex biochemical process that usually continues, to complete alcoholic fermentation and plays an important role in the production of most red wines. Research on this topic states that the main reasons for its implementation are the reduction of total acidity accompanied by an increase in pH, microbiological stability of wine due to the decomposition of malic acid and changes in physicochemical and sensory properties of wine. Teran (Vitis vinifera L.) is an autochthonous grape variety, and the wine produced from it is characterized by high total acidity and as such, this research is extremely suitable. The aim of this study was to determine the influence of different types of MLFon the compatibility of yeast and bacteria, its duration, changes in concentrations of individual organic acids, aroma compounds and changes in physicochemical and sensory properties of Teran (Vitis vinifera L.). The chapter Review of previous research provides data on the influence of environmental factors on malolactic fermentation as well as those on strains of lactic acid bacteria (LAB) and provides an overview and comparison of different types of MLF (co-inoculation, inoculation during alcoholic fermentation, subsequent inoculation and spontaneous MLF). The subchapter on the time of LAB inoculation on physicochemical changes in wines deals with the influence on the decomposition dynamics of malic and citric acid. Numerous studies indicate the influence of LAB inoculation time on changes in aromatic components of wine such as esters, higher alcohols, volatile fatty acids, acetaldehyde and compounds formed by LAB metabolic activity (diacetyl, acetoin, 2,3-butanediol) as well as on the sensory profile of wine. The chapter Materials and Methods presents the course of research and data processing. A two-year study was conducted that included the influence of different malolactic fermentation techniques on changes in physicochemical, aromatic and sensory properties in wines of the red cultivar Teran (Vitis vinifera L.). The vineyard in which the manual harvest was carried out was 10 years old, planted on a lesivan red (terra rossa) cultivation form of two-limbed Guyot. It was planted on a Kober 5BB substrate, and the planting intervals were 2.20 x 0.80 m, which gives approximately 5600 vines per hectare. After mulching and crushing, the mash is uniform and then evenly distributed in stainless steel tanks. The experiment was set up in three replications (50 L x 3) for each treatment in the experiment: Treatment K (control - suppressed MLF), S (spontaneous MLF-MLF takes place by the action of epiphytic LAB's), KIA (co-inoculation of LAB Oenococcus oeni Uvaferm AlphaTM), KI31 (co-inoculation of LAB Oenococcus oeni LALVIN 31TM), NIA (subsequent inoculation of LAB Oenococcus oeni Uvaferm AlphaTM), NI31 (subsequent inoculation of LAB Oenococcus oeni LALVIN 31TM). Alcoholic fermentation was carried out with classical maceration for seven days with manual, immersion of the cap three times a day using a commercial strain of yeast Uvaferm 299 (Saccharomyces cerevisiae). Alcoholic and malolactic fermentation were conducted at a temperature of 24⁰C until their completion. In all treatments, samples for chemical analysis were taken at the following times: (I) in the must, after filling the vessels, and before sulfitation and the addition of oenological agents, (II) every 2 days during alcoholic fermentation until its completion, (III) every 2 days during malolactic fermentation until its completion, (IV) in young wine after completed alcoholic and malolactic fermentation, and before overflow and sulfitation. Chemical analysis of must include determination of sugar concentration, total acidity, pH value and the determination of individual organic acids. Basic chemical analysis (% vol. Alcohol, reducing sugar, total extract, total acidity, pH, volatile acid, ash) was performed in wine samples. Concentrations of individual organic acids were determined spectrophotometrically and using high performance liquid chromatography (HPLC) techniques. The instrumental gas chromatography (GC) method was used to determine the flavor substance. All wines were sensory evaluated by the method of 100 points, ranking and descriptive.The Results section presents the main results obtained by the research. Malolactic fermentation significantly affected the reduction of total acidity with increasing pH. The highest concentrations of volatile acidity were found in wines of spontaneous malolactic fermentation. The time of LAB inoculation did not affect the concentration of volatile acidity, while lower concentrations were produced by wines obtained using the Uvaferm AlphaTM strain. The inoculation time and the LAB strain used had no effect on succinic acid concentrations, the reduction of which was observed only in spontaneous MLF treatments. Degradation of malic acid was in all MLF treatments regardless of inoculation time and strain LAB was complete while significantly the lowest lactic acid concentration was found in the control treatment. Citric acid concentrations recorded a statistically significant decrease in wines with MLF, with significantly higher degradation in the treatment of co-inoculation and the use of LALVIN 31TM strain. MLF significantly reduced the total concentration of higher alcohols and increased concentrations of ethyl esters in all treatments, while a significant increase in the concentration of acetate esters in both years was recorded only in the treatment of spontaneous MLF with a significant increase in ethyl acetate and hexyl acetate. Co-inoculation significantly reduced the concentrations of isoamyl alcohol, 2-phenylethanol, ethyl acetate and isoamyl acetate, and increased the concentrations of ethyl lactate and diethyl succinate. The UvafermAlphaTM strain had a significant effect on increasing the concentrations of isoamyl alcohol, 2-phenylethanol, ethyl lactate and diethyl succinate, and a decrease on ethyl acetate and isoamyl acetate. The most common volatile fatty acids were caproic and caprylic acid with concentrations above the sensory detection threshold regardless of treatment. Significantly the highest concentration of caproic acid was recorded in the treatment of subsequent inoculation with LALVIN 31TM strain, and caprylic in the treatment of co-inoculation with Uvaferm AlphaTM strain during 2005. MLF resulted in significantly lower concentrations of acetaldehyde and significantly higher concentrations of diacetyl, acetoin and 2,3-butanediol compared to control treatment. Significantly lower acetaldehyde concentrations were affected by inoculation time while LAB strains used for inoculation had no effect. An increase in 2,3-butanediol concentrations and a decrease in acetoin concentrations were found in the co-inoculation treatment using the LAB strain Uvaferm AlphaTM. The lengths of the LAG phase and the total duration of MLF showed regularity in both years of the study and lasted the shortest in treatments with co-inoculation, then with subsequent inoculation and the longest in spontaneous MLF. The duration of MLF was also affected by the LAB strain, whereas MLF was significantly shorter than the LALVIN 31TM strain using the Uvaferm AlphaTM strain. Furthermore, the presence of LAB did not negatively affect the viability of the yeast and in all treatments, alcoholic fermentation had the correct dynamics with a complete breakdown of sugar. The results of the sensory analysis of wine confirmed the positive impact of the application of selected LAB's on the quality of Teran wine. Co-inoculation and subsequent inoculation treatments were rated the best, and spontaneous MLF wines the worst in both years of the study. In relation to the control treatment, comparing the sensory properties of the aroma and taste of the wine, co-inoculations and subsequent inoculations had a more pronounced fruity character with an emphasis on plums with a lower intensity of cherry aroma and lower sensations of spicy notes, while the taste of wines was fuller, creamier with less pronounced acidity and astringency. Despite the significant changes of sensory properties, wines produced by co-inoculation and subsequent inoculation did not lose the varietal characteristics of Teran wine, which proved that co-inoculation as a treatment did not have a negative impact

Bentonite fining during fermentation reduces the dosage required and exhibits significant side-effects on phenols, free and bound aromas, and sensory quality of white wine

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

Management of ethanol content and total acidity inwines by use of Saccharomyces cerevisiae yeasts

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.The impact of global warming has not bypassed the wine industry either. This is best manifested through an increase in alcoholic strength, which is accompanied by a decrease in total acidity and significantly affects the sensory properties of wine. One possibility of lowering alcohol strength involves use non Saccharomyces and/or Saccharomyces yeast. The aim of this study was to examine the effect of commercial Saccharomyces yeasts (IONYSWF ™, Enoferm RP15 and Uvaferm BDX) on the reduction of alcoholic strength and increase of the total acidity of Cabernet franc (Vitis vinifera L.) wine. According to the chemical analyzes, it was determined that the wine produced using IONYSWF™ yeast had a lower alcoholic strength with a higher total acidity. Furthermore, no significant differences in alcoholic fermentation kinetics were found between treatments. The wines were sensory different. Descriptive analysis showed that the wine fermented with IONYSWF™ yeast had stronger body without loss of freshness and a more pronounced intensity and lenght of the aroma, which was dominated by spicy notes and aromas of red fruit. This wine was also the best rated