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 ’ 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)

The Process Aerobic respiration release of energy from glucose or another organic substrate in the presence of Oxygen CO 2, H 2 O, an energy produced Anaerobic respiration release of energy from glucose or another organic substrate in the absence of Oxygen Products: CO 2, 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 + CO 2 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 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