Fermentation

Question 1

What are industrial fermenters

Answer 1

-industrial scale machines that are used to grow micro-organisms which produce extremely useful chemicals
- eg penicillium produces antibiotic penicillin

Question 2

What does cooling jacket do?

Answer 2

-Flows water around outside of fermenter to regulate temperature to prevent overheating and enzymes denaturing

Question 3

what does air filter do ?

Answer 3

-filters air coming in, maintaining sterile conditions

Question 4

what do stirrers do?

Answer 4

• keep broth well stirred to oxygenate all parts of fermenter- prevents microorganisms settling

Question 5

what does growth medium do?

Answer 5

• contains all necessary glucose and amino acids for micro organism growth

Question 6

what does super-heated steam do?

Answer 6

• applies before fermenter is used, to kill unwanted microorganisms. Leaves only water- no other residue

Question 7

what bacteria is needed to make yoghurt

Answer 7

-lactobacillus bulgaricus

Question 8

Explain steps of making yoghurt

Answer 8

• equipment sterilised
• milk pasteurised by heating to kill bacteria
• lactoballicus is added and mixture maintained at 46 degrees for about 4 hours
• lactobactillus ferments (anaerobic respiration) to form lactic acid
• causes milk to clot and solidify into yoghurt
• samples are taken to see if yoghurt ready
• flavouring and colouring added

Question 9

How is yoghurt preserved?

Answer 9

• lactobacillus respires anaerobically producing lactic acid, lowering pH- acts as preservative
  -acid also coagulates the milk protein, as it changes shape of proteins, giving. yoghurt its texture and flavour