Browsing by Subject "hapate"
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(2021)Mixed culture beer contains additional microbes in addition to brewing yeast, Saccharomyces cerevisiae. Typical microbes found in mixed culture beer are lactic acid bacteria and other yeast species than S. cerevisiae. Mixed culture beers are usually sour so they can be also called sour beers. They also contain a very small number of hops. German Berliner Weisse and Belgian Lambic are traditional mixed culture beers. Craft beer has made mixed culture beers more popular. This has led to development of new kinds of mixed culture beers. The goal of this study is to establish, can alternative souring microbe be used in brewing. This study wanted to establish does the microbe grow in beer, what kind of substances it produces and how does it affect the sensorial qualities of beer. The study was executed by making two identical beers, which the other was inoculated with the souring microbe and yeast and the other with only yeast. CFU/ml of the souring microbe and yeast was determined by plating. In addition, the most vital carbohydrates, organic acids and the ethanol content together with volatile compounds was determined by liquid and gas chromatography respectively. Samples were taken a duration of three months after which there was a sensory evaluation with a trained panel. Based on the results the souring microbe is suitable for brewing. It grew in beer during fermentation and after bottling. Based on the sensory evaluation, beer containing the souring microbe did not differ considerably compared to beer containing only yeast. It was evaluated to be very similar in measured attributes in the sensory evaluation. The biggest difference between specified substances were in organic acids only found in beer containing the souring microbe. Also, beer containing the souring microbe had deviation in maltose and ethanol content possibly because of contamination. Differences between volatile compounds were small in the two beers respectively. More study is needed to optimise the fermentation process and improve the sensorial qualities with more sensorial study.
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(2015)The aim of the study was to optimize growth media and its composition for one Lactobacillus strain. The purposes of the optimized culture media for fermentation were to maximize cell count and amount of viable cells during processing. The raw materials for growth media had to be suitable for industrial use. The study was performed by Bioscreen and fermentation tests in different growth media. At first ability of the strain to grow was tested by Bioscreen C with different raw materials and their compositions. According to literature, six carbon, four nitrogen sources and three other raw material were chosen to Bioscreen tests. Bioscreen C measured turbidity (OD value) of cultivation. According to the results from Bioscreen tests, optimal raw materials were chosen to the fermentation tests. The optimal carbon sources were whey permeate powder and glucose, the optimal nitrogen sources casein peptone and yeast extract and other raw materials manganesulfate, magnesiumsulfate and yeast extract. The cultivations were made in a bioreactor (Biostat Q). The starter strains were concentrated and freeze-dried. Samples from cultivated, concentrated and freeze-dried starter strain were analyzed (cell counts, optical density, growth rate, base consumption and survival-%). Results were compared to those obtained using control medium that is known to support the growth of the Lactobacillus strain. Lactobacillus strain was able to grow in different growth media. In Bioscreen tests compositions of growth media have major effect on lactobacilli growth. Bioscreen experiments revealed that in most cases the Lactobacillus strain grew to higher OD values in the composed media compared to control medium. In Bioscreen tests the sugar based growth media required more added minerals and yeast extract than whey permeate based media. Yeast extract was found to promote Lactobacillus growth in Bioscreen tests. In fermentation tests cells grew on growth media equally as on control media. Suitable alternative options for growth media were found from tests for further studies. Further studies can research functionality of the raw materials in production scale and preservation of the cell concentration during storage.
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(2010)The properties and evaluation methods of viili, the actions and interactions of viili starters in milk and bacteriophages of the viili starters were reviewed. The aim of the experimental study was to explore whether it was possible to make viili with single strain starters and combine them just before adding the starter to the milk. A new, second viili starter was made from the new strains. The success of the new starters was evaluated by sensory evaluation and by analysing the texture and chemical properties of viili. The starter strains were cultivated in a bioreactor, concentrated by a centrifuge and frozen at –75 °C. The starter strains were combined approx. 1 day before the viili production. The sensory evaluation of the viili was performed by groups of 3 to 6 persons. The texture (consistency, firmness and cohesiveness) of the viili and chemical analysis were made. The results of the sensory analysis were analysed statistically and new strain combinations were formulated based results. The viilis made by the traditional viili starter strains were evaluated by the triangle test (n = 10–11) and the second viili starter was evaluated by descriptive analysis (n = 8). The texture measurements and chemical analyses were also performed. The viili produced by the second starter was infected by the factory phage samples and the pH was measured. After infecting the viili with phage samples, the viili produced by second starter was acidified to pH 4.5 from 0 to 10 hours later compared to the viili without the phage sample. The viili produced by traditional starter did not acidify when the phage was added. The aroma producers did not grow properly in viili when the starter was made by single strains. The viilis made by the present viili starter strains were not distinguished by the triangle test which meant that the starters are possible to make from single strains. The viilis produced by the second viili starter differed from the viili made by traditional starter by appearance and texture characteristics. There was no difference in taste characteristics between the traditional and new starter.
Now showing items 1-3 of 3