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