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Biodiversitet i naturleg gjær i siderproduksjonen i Hardanger
Lorena Butinar, Eivind Vangdal, Melita Sternad Lemut, Branka Mozetič Vodopivec, 2017, professional article

Keywords: biodiverziteta, kvasovke, jabolčno vino, fermentacija
Published in RUNG: 01.02.2018; Views: 4409; Downloads: 0
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Eivind Vangdal, Melita Sternad Lemut, Branka Mozetič Vodopivec, Lorena Butinar, 2017, published scientific conference contribution abstract

Abstract: Na območju fjorda Hardanger, del zahodne Norveške, ima proizvodnja jabolčnega vina dolgo tradicijo in sicer sega v 12. stoletje, ko so menihi na tem območju začeli uvajati sadjarstvo. Danes je to glavno območje pridelovanja sadja na Norveškem. Kljub strogi regulativi proizvodnje alkoholnih pijač, pa se je na tem območju na nekaterih kmetijah ohranila tradicionalna proizvodnja jabolčnega vina. Namen naše študije je bil predvsem preučiti ekologijo in biotsko raznovrstnost kvasovk, ki so povezane s proizvodnjo tradicionalnega jabolčnega vina na območju Hardanger. Na tem območju smo tekom dveh zaporednih let vzorčili na 11-ih različnih lokacijah, kjer smo pri proizvajalcih vzorčili jabolčno vino, tla in različne dele jablan v sadovnjakih. Tako smo s pomočjo bogatitve v gojišču s povišanim sladkorjem in etanolom osamili približno 1300 izolatov kvasovk. Kvasovke smo s pomočjo multipleks PCR testa ločili na skupino kompleksa Saccharomyces sensu stricto in ne-Saccharomyces kvasovke. Nadalje smo izolate določili do nivoja vrste z izvedbo restrikcijske analize ITS PCR produktov, v nekaterih primerih smo za potrditev identifikacij opravili še določitev nukleotidnih zaporedij D1/D2 domene 26S rDNA. Kot pričakovano smo ugotovili, da sadovnjake naseljujejo predvsem ne-Saccharomyces kvasovke iz rodov Metschnikowia in Hanseniaspora, v tem okolju so bile Saccharomyces izolirane iz tal in jabolk. V jabolčnem vinu pa je bila pretežno izolirana vrsta S. uvarum, občasno pa tudi S. cerevisiae, Torulaspora delbrueckii in P. membranifacies.
Keywords: kvasovke, biotska raznovrstnost, jabolčno vino
Published in RUNG: 09.11.2017; Views: 4962; Downloads: 0
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Biodiversity of cider yeasts and their cider-making potential
Eivind Vangdal, Melita Sternad Lemut, Branka Mozetič Vodopivec, Lorena Butinar, 2017, published scientific conference contribution abstract

Abstract: 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.
Keywords: indigenous yeasts, biodiversity, spontaneous fermentation, cider-making
Published in RUNG: 08.11.2017; Views: 5897; Downloads: 0
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Phenolic Contents and Postharvest Quality Changes of Norwegian ‘Mallard’ plums (Prunus domestica L.) as a Consequence of Delayed Time to Low Temperature Storage : /
Branka Mozetič Vodopivec, Alena Gibalova, Eivind Vangdal, 2012, published scientific conference contribution

Abstract: During the picking season in the Norwegian plum production areas, the harvested plums are brought to cold storage in packing houses once or twice a day. Plums picked late in the afternoon may even not be cooled properly until the next day. The average time from picking until the plums are placed in a cold storage is approximately 8 hours. Previous reports have shown that delayed cooling of sweet cherries and apples reduced the fruits’ susceptibility to physiological or fungal decay. An experiment was performed in order to evaluate the impact of different delay-to-cold storage times (0, 5, 10, 15 and 25 hours) on quality and phenolic contents changes of Norwegian ‘Mallard’ plums during cold storage, transport, and retail in normal atmosphere (NA). The fruits (10 fruits in PE tray, n=3) were stored for 14 days at 1°C, followed by 3 days at 7°C and then for 4 days at 20°C. Fruit quality parameters (firmness, colour in CIE L, a*, b* colour space, weight, rot occurrence (%)) and total phenol and anthocyanin content were determined. Samples were analyzed just before cold storage and then after 14 days at 1°C, 3 days at 7°C, or 4 days at 20°C. Evaluation of results has shown that delay of cooling has a retarding effect on rot development during 20°C storage (post cold transport), weight loss and stimulates anthocyanin accumulation and colour changes to some extent. At the end of storage no effect on fruit firmness could be observed.
Keywords: anthocyanins, total phenols, colour, rot, firmness, postharvest, plums, cold storage
Published in RUNG: 11.11.2016; Views: 4428; Downloads: 0
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