yeast in food production Flashcards
5.5
what is yeast?
a single celled fungus that can carry out both aerobic and anaerobic respiration
what does yeast produce when it carries out anaerobic respiration?
alcohol (ethanol) and carbon dioxide
when will yeast respire anaerobically?
if it has access to plenty of sugar, even if oxygen is available
what is yeast mixed with in bread production?
flour and water
what does the yeast produce?
enzymes that break down the starch in the flour, releasing sugars that can then be used by the yeast in anaerobic respiration
what happens to the carbon dioxide produced by the yeast during anaerobic respiration?
it is trapped in small air-pockets in the dough, causing the dough to rise (expand in volume)
what is the dough baked in?
a hot oven to form bread
formula for anaerobic respiration in yeast?
glucose -> ethanol + carbon dioxide
C6H1206 -> 2C2H5OH + 2CO2
what does the high temperatures used in bread making mean?
means that the ethanol does not remain in the bread after cooking has finished- it has evaporated
what type of product is the ethanol formed in anaerobic respiration?
a waste product
what happens to the yeast during baking?
it is killed by the high temperatures- ensures there is no further respiration by the yeast
