Brewing and baking and mycoprotein

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Brewing and baking and mycoprotein

• Ancient biotechnologies
• (mycoprotein is not ancient!)

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Bread making

• Basic ingredients are wheat, water, yeast, fat,
  sugar and salt.
• Dough is made by mixing ingredients together.
• Dough then ferments at 27oC in a humid
  atmosphere.

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Bread making

• The yeast, Saccharomyces cerevisiae, feeds on the
  sugar breaking it down anaerobically to ethanol
  and carbon dioxide.

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Bread making

• The bubbles of CO2 remain trapped in the sticky
  dough causing it to rise.
• Dough is then cut and placed in loaf tins.
• Dough then goes through a final fermentation at
  45oC.

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Bread making

• The baking kills the yeast, evaporates off the
  alcohol and cooks the flour.
• A modern bakery can make 10 000 loaves of bread
  per hour.

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Beer Making

• Most beers are made from barley and hops.
• The process consists of seven stages!

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Beer Making

• Malting
• Barley steeped in water
• Then allowed to germinate.
• Gibberellic acid is added to speed up germination
• During process amylases are mobilised (to
  hydrolyse seeds starch into maltose)

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Beer Making

• Kilning
• Malt is gradually heated to between 65 and 80oC
• This kills the embryos without destroying the
  amylase.
• Higher the temp. the darker the beer.

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Beer Making

• Milling
• Barley grains then crushed into a powder called
  grist.

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Beer Making

• Mashing
• The grist is mixed with water at 65o C.
• The amylase breaks down the starch into sugars.
• The nutrient rich liquor (sweet wort) is
  separated from the spent grains.
• The spent grains can be used as cattle feed.

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Beer Making

• Boiling
• Hops added for bitter flavour
• Further enzyme action is stopped
• Full flavour is extracted.

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Beer Making

• Fermentation
• Boiled wort is cooled to 30oC and innoculated
  with yeast
• Left to ferment for 7 to 10 days.
• Sugars turned into alcohol and CO2

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Beer Making

• Finishing
• Beer is filtered (spent yeast sold to make yeast
  extract Marmite)
• Modern beers are pasteurised, standardised and
  finally bottled or canned.

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Mycoprotein

• A food protein made from microorganisms

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Mycoprotein

• Made from the hyphae of the fungus Fusarium
  graminearum
• Cultured on a solution of
• glucose from cereal starch (carbon source)
• ammonia (nitrogen source)
• mineral salts
• choline (promotes longer hyphal growth)

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Mycoprotein

• Cultured in air lift fermenter (see special hand
  out from Edexcel)
• Culture maintained at 30oC to promote optimum
  growth rate.
• Grown by continuous culture.
• High in protein but low in fat a healthy food?

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Mycoprotein

• Problem is that it contains too much RNA
• This has to be removed by enzymes.
• Tastes of nothing!
• Fungal hyphae do resemble myofibrils in meat.
• Marketed under the name of Quorn.