making yoghurt Flashcards
what is fermentation?
Microorganisms break sugars down to release energy
—-> usually by anaerobic respiration
What is the bacteria called that makes yoghurt/ferments milk?
Lactobacillus Bulgaricus
How are the microorganisms grown?
Fermenters
What is lactose sugar fermented to produce?
Lactic acid
What is yoghurt?
Fermented milk
What is pasteurisation and why is it done?
- it’s heated up to kill any other microorganisms
How can a fermenter be used to grow microorganisms?
- They contain a culture medium in which microorganisms can grow
- the conditions are optimum for growth
—-> yield of product will be best
what needs to be kept at optimum conditions?
- pH
- temperature
These will stop enzymes from denaturing
how?
–> thermometer to detect temperature and a cooling jacket to change the temp.
–> pH probe to make sure the pH doesn’t change
what do the other paddles do in the fermenter?
- they agitate the medium meaning that the microorganism can always access nutrients for growth
they pump air to the fermenter because…?
RESPIRATION
- they can always respire as oxygen is being provided because energy is available for growth
Vessels are sterilised between uses because…
The microorganisms aren’t competing with other organisms and the product isn’t contaminated
how are nutrients provided to help the microorganisms grow?
culture medium
