Fermentation
The good, the bad, and the smelly
History of Fermentation
Age old applications:
1. Wine/ Beer/ Spirits
2. Cheese and Yoghurt
Louis Pasteur: Hypothesised that bacteria spoils wine Suggested that wine be heated to kill bacteria Hence: pasteurization of milk
Fermentation’sPros and Cons
Extended shelf life of food (ex. Cheese)
Eases Digestion (ex. Wild rice)
New [better] flavours (ex. Chocolate)
Can be unpredictable (i.e. bad bacteria win the battle)
New [worse] flavours (ex. Mouldy bread tastes terrible)
The Process
Aerobic respiration release of energy from
glucose or another organic substrate in the presence of Oxygen
CO2, H2O, an energy
produced
Anaerobic respiration release of energy from
glucose or another organic substrate in the absence of Oxygen
Products: CO2, energy, and alcohol or various organic acids
Fermentation Definition: Anaerobic respiration of food by micro organisms
Types of fermentation:
1. Bacterial fermentation
2. Yeast fermentation
3. Mold and Enzyme fermentation
1. Bacterial Fermentation (4 types)
a) Lactic Acid Bacteria (pickles, sauerkraut)
b) Acetic Acid Bacteria (vinegar)
c) Carbon Dioxide Bacteria (Edam, Gouda, Swiss)
d) Proteolytic Bacteria (cocoa, chocolate)
bacteria
2. Yeast Fermentation
Glu Ethyl alcohol + CO2
Best temperature: 27 degree C (warm)
Other sugars will ferment (mal, suc, fru)
Too much salt ruins the process
When baking: follow the recipe
3. Mold and Enzyme Fermentation
Enzymes in Mold can be useful:
-Break down cellulose thus grains easier to chew
-Add flavour and texture to cheeses (ex- blue)
Wine
Dates back to Middle east 3000 bc
Fermentation of grapes Scientific process yet so
many variables Growing years affect
vintages
Coffee
Coffee beans fermented by bacteria and enzymes (2 methods):
1. Wet Method: soaked for 12-24 hours and dried
2. Dry Method: washed then dried for 2-3 weeks
Tea
3000 AD (at the latest)- Cultivated in China
Rolled leaves begin to ferment
Lets stand at 27 degree C for 2-3 hrs
Types: Green, Oolong, Black
Chocolate
1.5 million tons cocoa produced each year
Supply: W. Africa Produced: S. America
Enzyme fermentation in the sun via proteolytic bacteria
Bitter beans become sweeter and brown
Fermentation around the world
Food, drink, sauces,
et cetera