Advanced

The effect of Lactobacillus plantarum 299v on the flocculating behaviour of beer starter culture yeast strains

Keronika, Charles LU (2017) KLGM01 20161
Food Technology and Nutrition (M.Sc.)
Abstract
The aim of this project was to investigate the effect of Lactobacillus plantarum 299v on the flocculating behaviour of beer starter culture yeast strains isolated from both top and bottom fermenting yeasts from a previous study (Li.Yu.,2014 unpublished). In the present study,microbial enumeration was done through basic culturing and plating techniques. Yeast strains and isolates of Lactobacillus plantarum 299v were cultured in selective medium such as malt and MRS (de Man,Rogosa and Sharpe Agar).
The colony counts obtained were all above the detection limit (> 1.00 log CFU/g) for pure strains of Lactobacilli and Saccharomyces. A flocculation assay test was then performed on yeast and yeast, and bacteria induced yeast assay both in... (More)
The aim of this project was to investigate the effect of Lactobacillus plantarum 299v on the flocculating behaviour of beer starter culture yeast strains isolated from both top and bottom fermenting yeasts from a previous study (Li.Yu.,2014 unpublished). In the present study,microbial enumeration was done through basic culturing and plating techniques. Yeast strains and isolates of Lactobacillus plantarum 299v were cultured in selective medium such as malt and MRS (de Man,Rogosa and Sharpe Agar).
The colony counts obtained were all above the detection limit (> 1.00 log CFU/g) for pure strains of Lactobacilli and Saccharomyces. A flocculation assay test was then performed on yeast and yeast, and bacteria induced yeast assay both in phosphate Buffered Saline media and a percent attenuation was determined after brewing, cell counts or optical density (OD) measurements determined spectrophotometrically at 600 nm and a final estimation of percent flocculation activity determined. The result observed from the analysis showed that Lactobacillus plantarum 299v had no significant effect on the flocculating behaviour of beer starter culture yeast strains (Saccharomyces). (Less)
Popular Abstract
Beer is a popular and a hot commodity in the food market world over. Today this drink has become
increasingly important and is deeply rooted in many social events.
However, not so many of us understand the major driving force behind it's production. For thousands of years, beer was consumed with little or no knowledge of the organisms driving the process.
Much of it's production was thought to either occur by luck or as in ancient times mostly attributed to the "works of gods". Lately, with advanced research both producers and consumers alike have become seemingly keen to know more about this unique organisms and their magical art of work in beer fermentation.
Yeast in particular has proved priceless and successfully served as an... (More)
Beer is a popular and a hot commodity in the food market world over. Today this drink has become
increasingly important and is deeply rooted in many social events.
However, not so many of us understand the major driving force behind it's production. For thousands of years, beer was consumed with little or no knowledge of the organisms driving the process.
Much of it's production was thought to either occur by luck or as in ancient times mostly attributed to the "works of gods". Lately, with advanced research both producers and consumers alike have become seemingly keen to know more about this unique organisms and their magical art of work in beer fermentation.
Yeast in particular has proved priceless and successfully served as an important organism in brewing.
Generally speaking, it is through yeast fermentation that much of the beer is produced, where by yeasts consume most of the sugars in wort solution, producing alcohol, carbon dioxide and other compounds. Flocculation occurs normally towards the end of fermentation by a natural process when yeast cells stick together to form large floccs. These formed floccs then either drop or rise above the fermenters.
Despite the heavy modernisations in breweries, traditional flocculation remains unchanged and continues to serve as an effective means of beer clarification and yeast recovery, usually the recovered yeast cakes are further processed and used in the next brewing operations.
This current study reports on the interesting interactions between these organisms and their ultimate role in flocculation. In this work a bacterium, Lactobacillus plantarum 299v was used and it's effects on the flocculating properties of the different yeast strains assessed. However, it was observed that the interactions between this bacteria Lp 299v and yeasts was not significant in the bacteria-yeast induced flocculation assay. (Less)
Please use this url to cite or link to this publication:
author
Keronika, Charles LU
supervisor
organization
course
KLGM01 20161
year
type
H2 - Master's Degree (Two Years)
subject
keywords
Beer starter culture, Saccharomyces, Lactobacillus plantarum, wort, food technology, livsmedelsteknologi
language
English
id
8906271
date added to LUP
2017-05-31 15:50:57
date last changed
2017-05-31 15:50:57
@misc{8906271,
  abstract     = {The aim of this project was to investigate the effect of Lactobacillus plantarum 299v on the flocculating behaviour of beer starter culture yeast strains isolated from both top and bottom fermenting yeasts from a previous study (Li.Yu.,2014 unpublished). In the present study,microbial enumeration was done through basic culturing and plating techniques. Yeast strains and isolates of Lactobacillus plantarum 299v were cultured in selective medium such as malt and MRS (de Man,Rogosa and Sharpe Agar).
The colony counts obtained were all above the detection limit (> 1.00 log CFU/g) for pure strains of Lactobacilli and Saccharomyces. A flocculation assay test was then performed on yeast and yeast, and bacteria induced yeast assay both in phosphate Buffered Saline media and a percent attenuation was determined after brewing, cell counts or optical density (OD) measurements determined spectrophotometrically at 600 nm and a final estimation of percent flocculation activity determined. The result observed from the analysis showed that Lactobacillus plantarum 299v had no significant effect on the flocculating behaviour of beer starter culture yeast strains (Saccharomyces).},
  author       = {Keronika, Charles},
  keyword      = {Beer starter culture,Saccharomyces,Lactobacillus plantarum,wort,food technology,livsmedelsteknologi},
  language     = {eng},
  note         = {Student Paper},
  title        = {The effect of Lactobacillus plantarum 299v on the flocculating behaviour of beer starter culture yeast strains},
  year         = {2017},
}