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Mjölksyrabakterier i suröl

Andersson, Fredrik LU and Koleszar, Sandy LU (2019) YTHL01 20191
Food Technology and Nutrition (M.Sc.)
Food Science
Abstract (Swedish)
Suröl är en dryck som ökat i populäritet, speciellt bland folk med stort intresse för hantverksöl och mikrobryggerier. Allt fler bryggerier vågar nu att gå utanför sin trygghetszon med att använda jäst av typen Saccharomyces cerevisiae och istället börjar experimentera med bakterier och jäst som tidigare ansetts vara produktförstörande, till exempel olika mjölksyrabakterier och vildjäst. Genom forskningsstudier har man sett att mjölksyrabakterier, även kallat probiotika, har agerat hälsofrämjande när det administrerats i samband med sjukdomar och operationer. Stammarna av Lactobacillus som tillsätts i suröl omvandlar glukos till mjölksyra, CO2 och etanol. Det är med hjälp av mjölksyrabakterierna Lactobacillus plantarum 299v samt två olika... (More)
Suröl är en dryck som ökat i populäritet, speciellt bland folk med stort intresse för hantverksöl och mikrobryggerier. Allt fler bryggerier vågar nu att gå utanför sin trygghetszon med att använda jäst av typen Saccharomyces cerevisiae och istället börjar experimentera med bakterier och jäst som tidigare ansetts vara produktförstörande, till exempel olika mjölksyrabakterier och vildjäst. Genom forskningsstudier har man sett att mjölksyrabakterier, även kallat probiotika, har agerat hälsofrämjande när det administrerats i samband med sjukdomar och operationer. Stammarna av Lactobacillus som tillsätts i suröl omvandlar glukos till mjölksyra, CO2 och etanol. Det är med hjälp av mjölksyrabakterierna Lactobacillus plantarum 299v samt två olika stammar av Lactobacillus brevis som ölen från South Plains Brewery får sin syrliga karaktär.
Syftet med detta examensarbete är undersöka om mjölksyrabakterier överlever i surölen från vårt lokala mikrobryggeri, i vilken volym och vilka specifika bakteriestammar det handlar om.
Prover från starterkultur samt färdig öl odlades upp i petriskålar och en mätning av pH-värde utfördes. Bakterier isolerades från kolonier som hade ett antal högre än 30, men mindre än 300, och DNA extraherades. PCR och gelelektrofores genomfördes innan proverna skickades till ett laboratorium i Tyskland för sekvensering. Genom sekvenseringen av proverna fick vi fram att de tillsatta mjölksyrabakterierna L. plantarum 299v och L. brevis med stor sannolikhet inte överlevt i den färdigbryggda ölen, utan i själva verket var det Lactobacillus paracasei som dominerade.
Den totala mängden potentiella levande mjölksyrabakterier hos den utvalda ölen är mycket lägre än den som återfinns i produkter som marknadsförs som probiotiska. Ölen får därmed anses ha svaga eller obefintliga probiotiska egenskaper. (Less)
Abstract
Sour beer is rapidly gaining popularity among people that have an interest in craft beer and the microbrewing scene. This leads to breweries starting to venture outside their comfort zones regarding the more traditional brewing yeast Saccharomyces cerevisiae and instead have started experimenting with different kinds of bacteria and yeast that in a normal process is regarded as spoilage bacteria, such as Lactobacilli and wildyeast. Lactobacillus, which also could be regarded as probiotic, has shown promising benefits when administered in relation to health related problems and surgery. The Lactobacillus used in sour beer converts glucose to lactic acid, carbon dioxide and ethanol. It is with the help of Lactobacillus plantarum 299v and two... (More)
Sour beer is rapidly gaining popularity among people that have an interest in craft beer and the microbrewing scene. This leads to breweries starting to venture outside their comfort zones regarding the more traditional brewing yeast Saccharomyces cerevisiae and instead have started experimenting with different kinds of bacteria and yeast that in a normal process is regarded as spoilage bacteria, such as Lactobacilli and wildyeast. Lactobacillus, which also could be regarded as probiotic, has shown promising benefits when administered in relation to health related problems and surgery. The Lactobacillus used in sour beer converts glucose to lactic acid, carbon dioxide and ethanol. It is with the help of Lactobacillus plantarum 299v and two different strains of Lactobacillus brevis that the beer from South Plains Brewery gets parts of its acidic character. The purpose of this thesis is to evaluate if lactic acid bacteria survives in the final product, and if so, in what capacity and what specific strains.
Samples from the starter culture and bottled beer where cultivated in vitro and a measurement of the pH-levels where conducted. The cultivated bacteria were isolated from agar containing a range of 30 to 300 colonies, and the DNA was extracted from these. PCR and gel electrophoresis where conducted on the samples before sending them to a laboratory in Germany for sequencing. By sequencing the DNA, we could see that the added lactic acid bacteria L. plantarum 299v and L. brevis with high probability did not survive in the finished beer, instead we found a strain of Lactobacillus paracasei.
The total potential amount of living lactic acid bacteria in the selected beer is much lower than the amounts used in other commercial products designed specifically to be advertised as probiotic. The beer can thus be considered as having low or non-existing probiotic properties. (Less)
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author
Andersson, Fredrik LU and Koleszar, Sandy LU
supervisor
organization
alternative title
Lactic acid bacteria in sour beer
course
YTHL01 20191
year
type
M1 - University Diploma
subject
keywords
Suröl, mjölksyrabakterier, probiotika, Sour beer, lactic acid bacteria, probiotics, livsmedelsteknik, food engineering
language
Swedish
id
8982773
date added to LUP
2019-07-04 11:40:58
date last changed
2019-07-04 11:40:58
@misc{8982773,
  abstract     = {Sour beer is rapidly gaining popularity among people that have an interest in craft beer and the microbrewing scene. This leads to breweries starting to venture outside their comfort zones regarding the more traditional brewing yeast Saccharomyces cerevisiae and instead have started experimenting with different kinds of bacteria and yeast that in a normal process is regarded as spoilage bacteria, such as Lactobacilli and wildyeast. Lactobacillus, which also could be regarded as probiotic, has shown promising benefits when administered in relation to health related problems and surgery. The Lactobacillus used in sour beer converts glucose to lactic acid, carbon dioxide and ethanol. It is with the help of Lactobacillus plantarum 299v and two different strains of Lactobacillus brevis that the beer from South Plains Brewery gets parts of its acidic character. The purpose of this thesis is to evaluate if lactic acid bacteria survives in the final product, and if so, in what capacity and what specific strains.
Samples from the starter culture and bottled beer where cultivated in vitro and a measurement of the pH-levels where conducted. The cultivated bacteria were isolated from agar containing a range of 30 to 300 colonies, and the DNA was extracted from these. PCR and gel electrophoresis where conducted on the samples before sending them to a laboratory in Germany for sequencing. By sequencing the DNA, we could see that the added lactic acid bacteria L. plantarum 299v and L. brevis with high probability did not survive in the finished beer, instead we found a strain of Lactobacillus paracasei.
The total potential amount of living lactic acid bacteria in the selected beer is much lower than the amounts used in other commercial products designed specifically to be advertised as probiotic. The beer can thus be considered as having low or non-existing probiotic properties.},
  author       = {Andersson, Fredrik and Koleszar, Sandy},
  keyword      = {Suröl,mjölksyrabakterier,probiotika,Sour beer,lactic acid bacteria,probiotics,livsmedelsteknik,food engineering},
  language     = {swe},
  note         = {Student Paper},
  title        = {Mjölksyrabakterier i suröl},
  year         = {2019},
}