Fermentation is a metabolic process that consumes sugar in the absence of oxygen. The products are organic acids, gases, or alcohol. It occurs in yeast and bacteria, and also in oxygen-starved muscle cells, as in the case of lactic acid fermentation.

1. Fermentation
The good, the bad,
and the smelly

2. 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

3. Fermentation’s
Pros 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)

4. 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

5. Fermentation Definition:
Anaerobic respiration of food by
micro organisms
Types of fermentation:
1. Bacterial fermentation
2. Yeast fermentation
3. Mold and Enzyme fermentation

6. 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

7. 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

8. 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)

9. Wine
 Dates back to Middle
east 3000 bc
 Fermentation of grapes
 Scientific process yet so
many variables
 Growing years affect
vintages

10. 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

11. 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

12. 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

13. Fermentation around the world
 Food, drink, sauces,
et cetera