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1.
Chemical composition of apple cider : a comparative study of Norwegian and French ciders
Ingunn Ovsthus, Mitja Martelanc, Tatjana Radovanović, Marko Lesica, Lorena Butinar, Branka Mozetič Vodopivec, Guillaume Antalick, 2024, objavljeni znanstveni prispevek na konferenci

Opis: Norwegian apple ciders have recently gained attention at the levels of international competitiveness. Accordingly, a comparative study on the chemical composition of selected Norwegian and French apple ciders was conducted to gain knowledge on what ubiquitous chemical parameters make the Norwegian ciders different from ciders from well-established producing regions. A total of 43 ciders, 24 Norwegian and 19 French, in the category of acidic dominant ciders, were included in the study. Ethanol, individual sugars and organic acids, pH, total phenols, aroma compounds including esters, C6-alcohols, volatile phenols and terpenoids, were analysed. Norwegian ciders showed higher contents in ethanol, malic and citric acids, whereas total phenols, pH, glucose, and fructose were higher in French counterparts. Regarding the aromatic profile, no significant differences were observed for C6-alcohols. In contrast, differences were more expressed in the case of esters and volatile phenols. Norwegian ciders were characterised by higher average concentration for all the groups of esters, with the most important differences measured for higher alcohol acetates. Norwegian ciders also displayed higher contents of 4-vinylphenol and 4-vinylguaiacol while French ciders contained substantially higher levels of 4-ethylphenol and 4-ethylguaiacol. These results are in mutual correlation with the empirical observation reporting Norwegian apple ciders as more acidic, alcoholic and with lighter body but fruitier profile. Whereas French ciders are often perceived with more structure and animalistic profile.
Ključne besede: alcohol, acidity, total phenols, aroma-compounds, apple cider
Objavljeno v RUNG: 25.03.2024; Ogledov: 384; Prenosov: 3
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Biogenic amines in Hardanger ciders : the effect of native cider yeasts on biogenic amine production
Urban Česnik, Mitja Martelanc, Branka Mozetič Vodopivec, Ingunn Ovsthus, Lorena Butinar, 2023, objavljeni povzetek znanstvenega prispevka na konferenci

Opis: The presence of bioactive compounds in food and beverages of plant origin is mainly connected with higher nutritional value and better sensory properties. However, some of them can pose a threat to food product quality and human health. For example, excess biogenic amines (BAs) intake can cause different allergenic responses in individuals who have such intolerances. BAs have been intensively studied in recent years, especially in fermented foods like wine, meat, fish, and cheese. Among fermented beverages is apple cider still rather unexplored from this perspective. Especially since no such data exist for the Norwegian cider. Norwegian cider is becoming more and more popular in Norway in recent years among producers and consumers. Hardanger cider from Western Norway is very different from French, English, or Spanish ciders in terms of sensory characteristics, apple cultivars, and in the fermentation process. In Hardanger, the traditional cider is still produced by spontaneous fermentation of apple juice with naturally occurring yeasts that originate from the fruit or processing equipment surfaces. Lactic acid bacteria are known to be associated with BA formation. However, several studies reported about the BA-producing yeasts in winemaking. Due to the important role of natural yeasts in the production of Hardanger cider, we focused on the ability of BA formation by native yeasts. Thus, in our study, we followed the amounts of BAs in the Hardanger ciders during the fermentation process and characterize isolated yeasts if they have the ability to produce BAs under cidermaking conditions by performing a micro-fermentation experiment. From must/cider samples, taken during the fermentation process at 13 producers in the Hardanger region, we isolated 530 yeast isolates. Based on the sequencing of the D1/D2 domain of the 26S rDNA we identified 25 different yeast species. As expected, yeast diversity was higher at the beginning compared to the middle fermentation stage, when mostly different non-Saccharomyces yeast species prevailed, while at the end of fermentation mainly Saccharomyces species with high ethanol tolerance were present. BAs were analyzed with the HPLC-UV method. In all apple juice/cider samples 4 different BAs (putrescine, cadaverine, histamine, and tyramine) were detected and quantified with external calibration. On average in all cider samples from the producers total BA (summation of all BAs) concentration reached 9,45 mg/L, however in one case even 25 mg/L. Tyramine was the most abundant BA in all fermentation stages. 40 isolated yeast strains were further tested for BA formation in a small-scale experiment by fermenting apple juice. Results show that non-Saccharomyces yeasts mainly form histamine (1,68 mg/L) and tyramine (1,30 mg/L), while Saccharomyces yeasts putrescine (0,48 mg/L) and tyramine (3,53 mg/L). As a general conclusion, the occurrence and distribution of BA concentrations in the small-scale fermentation were lower (2,96 mg/L and 4,01 mg/L) and less variable than in the real ciders (average in final ciders 9,45 mg/L) and with tyramine being the most abundant BA in all samples analyzed.
Ključne besede: cider, yeast, biogenic amines, Hardanger, biodiversity
Objavljeno v RUNG: 23.06.2023; Ogledov: 1029; Prenosov: 5
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Simultaneous determination of chemical parameters for wine and cider quality control using HPLC-UV/RI system based on reverse-phase separation capabilities
Mitja Martelanc, 2022, objavljeni povzetek znanstvenega prispevka na konferenci (vabljeno predavanje)

Ključne besede: HPLC-UV-RI, Cider, Wine, Must, Organic aacids, Ethanol, Glucose, Fructose.
Objavljeno v RUNG: 20.02.2023; Ogledov: 993; Prenosov: 0
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6.
Cider yeasts associated with Hardanger cider during fermentation process
Urban Česnik, Mitja Martelanc, Branka Mozetič Vodopivec, Ingunn Ovsthus, Lorena Butinar, 2022, objavljeni povzetek znanstvenega prispevka na konferenci

Opis: In the Hardanger area in Western Norway, the production of cider has a long tradition that goes back to the 12th century, when monks introduced apple growing in this area. Nowadays, this is also the main area of fruit production in Norway. Despite the strict regulation of the alcoholic beverage production in Norway, traditional cider is still produced on some farms in this area. Therefore, our aim was to study the ecology and biodiversity of the yeasts associated with the cider production in the Hardanger area during fermentation process; especially of traditional cider, which is produced by a spontaneous fermentation of apple juice, performed by naturally occurring indigenous yeasts that originate from the fruit or the surfaces of the processing equipment. In our study, samples of fermenting juice/cider were taken during fermentation process from 12 producers, located in 12 different locations in Hardanger region. Classical cultivation methods using WL (Wallerstein Laboratories) agar medium with added chloramphenicol enable us to isolate a total of 530 yeast isolates that were stored in in-house yeast collection at the NIBIO and included also at the Wine Research Centre collection. Based on the sequencing of the D1/D2 domain of the 26S rDNA we managed to identify 357 isolates and distinguished 27 different yeast species as follows: Aureobasidium pullulans, Candida californica, C. oleophila, C, sake, Hanseniaspora meyeri, H. uvarum, H. valbyensis. Kregervanrija fluxuum, Kregervanrija sp., Metschnikowia andauensis, M. chrysoperlae, M. fructicola, M. pulcherrima, Metschnikowia sp, Pichia fermentans, P. kluyveri, P. membranifaciens, P. nakasei, Piskurozyma capsuligena, Rhodotorula nothofagi, Saccharomyces bayanus, S. cerevisiae, S. paradoxus, S. pastorianus, Saccharomyces sp., S. uvarum and Torulaspora delbrueckii. Even though we were not able to obtain samples in three different fermentation stages (beginning, middle and at the end of fermentation) from all producers, we could observe yeast succession during fermentation progress. Yeast diversity was higher at the beginning comparing to the middle of fermentation, when mostly different non-Saccharomyces yeast species prevailed, while in the middle of fermentation 11 species were detected (Candida californica, H. uvarum, H. valbyensis, Kregervanrija sp., K. fluxuum, Pichia membranifaciens, Metschnikowia pulcherrima, Saccharomyces sp, S. bayanus, S. uvarum and S. cerevisie). On the other hand, at the end of fermentation mainly Saccharomyces species with high ethanol tolerance were present (Saccharomyces sp., S. cerevisiae, bayanus, S. uvarum and P. fermentans). In samples that were collected from three producers in all three fermentation stages also quality parameters were determined (ethanol, organic acids, sugars, biogenic amines) with in-house developed methods using HPLC-UV/RID. The most important sugars in ciders were fructose and glucose, as expected. Two producers added sugar to increase the level of ethanol in the middle of fermentation, which is a common procedure in the Hardanger area. Ethanol and organic acid analysis indicated that fermentations went in the right direction, since all parameters were within normal limits. Including the acetic acid level, an indicator of low cider quality, was very low (average around 0,06 g/L). The alcohol incised from the beginning to end fermentation in all samples analysed and minimum concentration was 2,71 g/L. In ciders we detected four biogenic amines (putrescin, cadaverine, histamine and tyramine). The average amount was 32 mg/L and the most abundant was tyramine.
Ključne besede: indigenous yeasts, biodiversity, spontaneous fermentation, cider-making
Objavljeno v RUNG: 18.10.2022; Ogledov: 1291; Prenosov: 0
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7.
Validacija HPLC metode za določanje organskih kislin in sladkorjev v vinu
Kristjan Mesar, 2022, diplomsko delo

Opis: V tem diplomskem delu smo obravnavali proces validacije dveh analiznih metod za določanje kakovosti vina. In sicer smo določali organske kisline kot so vinska kislina, jabolčna kislina, mlečna kislina, citronska kislina, ocetna kislina, in monosaharide glukozo in fruktozo. Analiza teh parametrov je pomembna pri nadzoru procesa pridelave vina kot tudi spremljanju kakovosti vina. V diplomski nalogi smo pregledali glavne metode za določanje kislin in sladkorjev v grozdju in vinu, v samem poskusu pa smo uporabili kromatografsko tehniko na osnovi tekočinske kromatografijo visoke ločljivosti v kombinaciji z detekcijo v ultravijoličnem (UV) za organske kisline in z detekcijo lomnega količnika (RID) za monosaharidne sladkorje. HPLC-UV/RID sistem omogoča enostavno pripravo vzorca na analizo (samo filtracija, mogoče redčitev, če je potrebna), hitro analizo in omogoča zadovoljive meje detekcije za potrebe določevanja omenjenih parametrov. Obe metodi smo opisali z različnimi parametri, kot je ponovljivost, linearnost, izkoristek v štirih različnih matriksih (dve beli vini, eno rdeče in eno jabolčno vino – cider), meja detekcije in meja kvantifikacije. Rezultate kvantifikacije skupnih sladkorjev in organskih kislin v vzorcih vin smo primerjali z rezultati akreditiranega laboratorija kjer je bilo to mogoče in ugotovili, da kvantifikacija z metodo standardnega dodatka omogoča primerljive rezultate z akreditiranim laboratorijem, predvsem za parameter skupni fermentirani sladkorji (glukoza in fruktoza). Vsebnost skupnih kislin določenih kromatografsko je bila nekoliko manjša od parametra skupne titrabilne kisline, kar je najverjetneje posledica manjšega števila posameznih kislin, ki smo jih vključili v ta parameter, pa tudi drugačne metode določanja kislin.
Ključne besede: vino, cider, HPLC, UV, RID, organske kisline, sladkorji, validacija
Objavljeno v RUNG: 02.08.2022; Ogledov: 1887; Prenosov: 59
.pdf Celotno besedilo (1,10 MB)

8.
Biodiversity of cider yeasts and their cider-making potential
Eivind Vangdal, Melita Sternad Lemut, Branka Mozetič Vodopivec, Lorena Butinar, 2017, objavljeni povzetek znanstvenega prispevka na konferenci

Opis: In the area of Hardanger, a part of the fjord region in Western Norway, the production of apple wine (cider) has a long tradition that goes back to the 12th century, when monks introduced apple growing in this area. Nowadays, this is also the main area of fruit production in Norway. Despite the strict regulation of the alcoholic beverage production in Norway, traditional cider is still produced on some farms in this area. By tradition cider is produced by a spontaneous fermentation process of apple juice, performed by naturally occurring indigenous yeasts that originate from the fruit or the surfaces of the processing equipment. Therefore, our aim was primarily to study the ecology and biodiversity of the yeasts associated with the production of traditional cider in the Hardanger area. For two consecutive years, we sampled at 11 different locations in the observed region, where we collected cider samples and surface swabs of processing facilities from the cideries, and also soil and various parts of apple trees in orchards owned by the same producers. Thus, by enriching collected samples with the selective medium with high sugar and ethanol concentration, we managed to isolate about 1,300 yeasts. Based on the multiplex PCR results the yeasts were grouped into the Saccharomyces sensu stricto complex and non-Saccharomyces yeasts. The isolates were determined to the species level by performing the restriction analysis of ITS PCR products, and in some cases identifications were confirmed by sequencing of the D1/D2 domain of the 26S rDNA and/ or ITS region. As expected, non-Saccharomyces yeasts from the genus Metschnikowia and Hanseniaspora mainly populated the orchards, while the Saccharomyces yeasts were isolated in the orchards from the soil and fruits. In contrast, in ciders the species S. uvarum was predominantly found, occasionally also S. cerevisiae, Torulaspora delbrueckii and P. membranifacies. Indigenous cider yeasts were further on characterized in micro-plate format for the most important cider-making technological parameters (tolerance to ethanol, SO2, growth at low pH), for the presence of glucoside hydrolase activity, H2S production ability, and assimilation of malic acid. Based on this screenings the micro-scale fermentations of apple juice were performed with 13 different indigenous cider yeasts as monocultures. The most promising indigenous yeasts, T. delbrueckii and S. uvarum, were also tested as mixed cultures in sequential fermentations. Since the tested strain of T. delbrueckii as monoculture was not able to complete the alcoholic fermentation, better results were obtained in sequential fermentation with the mixed culture in combination with S. uvarum.
Ključne besede: indigenous yeasts, biodiversity, spontaneous fermentation, cider-making
Objavljeno v RUNG: 08.11.2017; Ogledov: 6227; Prenosov: 0
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