Microorganisms for food

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  • Created by: Laura
  • Created on: 17-05-13 10:50


made of fungus called Fusarium

sold as Quorn TM

Fusarium is made up on tiny fibres called hyphae therefore there is no stirrer in the fermenter to avoid fibres tangling and breaking.

They are collected and heat-treated to remove a bitter-tasting substance that they contrain.

They are dried, pressed to form a fibrous substance which has a similar texture to meat

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Advantages of food from microorganisms

  • populations can double in 20 minutes - much faster than crops can grow
  • Easy to handle and manipulate
  • Take up less room
  • Can be grown in any part of the world
  • Can be grown using waste material from other processes as their food source
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Mycoprotein as a food source

Doesn't contain any saturated fat like meat does - therefore it's healthier 

High fibre content slows the rate at which glucose is absorbed from food. This stops blood glucose concentration rising rapidly after a meal.

Stops insukin and glucose surges which are thought to contribute to developing type 2 diabetes

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Making yogurt

  • Made from milk by bacteria such as Lactobacillus bulgaricus
  • They convert lactose into lactic acid as they respire anerobically 
  • This causes pH to go down as it gets more acidic

Factors affecting it:

  • bacteria used
  • milk used
  • legvels of nutrients in the milk
  • temperature of the mixture of milk
  • bacteria
  • pH

Can affect tghe speed at which the yoghurt is made and the type

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Enzyme Technology

Enzymes are proteins produced by living organisms

Invertase - (sucrase)

  • peoduced by cultivating a yeart called Saccharomyces cerevisae in fermenters
  • Converts sucrose to glucose and fructose
  • This mixture is sweeter than original sucrose and less is needed to make sweet foods
  • Good for soft centred sweets

Washing Powders

  • detergents cannot remove some kinds of stains therefore they need enzymes
  • Lipases and proteases 
  • Proteases breaks down proteins such as haemoglobin in blood stains
  • Lipases break down fats such as grease
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  • made from milk
  • traditionally, an enzyme from calves stomach called chymosin was added to the milk 
  • makes the milk separate into curds (semi-solid mix of protein and fat and liquid)
  • curds are pressed to produce cheese


  • In 1980's scientists found a way of making shymosin using bacteria
  • Took a calf gene for chymosin and put it into the bacteria which then produced chymosin.
  • Genetic modification
  • Today, most chymosin is made from genetically modified yeast. 
  • Easier and cheaper to produce large quantities and very pute chymosin is made
  • Makes cheese suitable for vegetarians
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Genetic Modification


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Genetic Modification

  • DNA from a human cell is cut into pieces using enzymes called restriction enzymes. Leaves a few unpaired bases at each end called sticky ends.
  • Bacteria cells contain small circles of DNA called plasmids. The same restriction enzymes are used to cut the plasmids open, leaving sticky ends with matching sets of unpaired bases.
  • The pieces of DNA containing the human gene are mixed  with the plasmids.  The bases in the sticky ends paiur up. An enzymes called DNA ligase is added linking the DNA back into the continuous circle.
  • The recombinant plasmids are inserted back into the bacteria. It is then grown in fermenters and produce the human gene is large quantities such as insulin.
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Immobilised enzymes

immobilised enzymes - trapped on or in an inert material

They can be used time after time

  • Lactase can be immobilised and used to break down lactose in milk, which is useful for people who are lactose intolerant

Immobilise enzymes but mixing an enzyme with sodium alginate solution. Add drops of this solution to calcium chloride solution you will get insoluble beats of calcium alginate containing the enzyme immobilised in the bead.

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