Transcript Ancient Biotechnology File

Domestication & Agriculture
• Paleolithic people
(250,000-10,000 yrs.
Ago)
• hunter-gatherers
• move to follow
migrating animals or
find new game
• ate edible plants (i.e.
wheat, barley) as they
traveled
Agrarian Societies Developed
• 10,000 years ago
• Far East, Europe, Egypt
(Fertile Crescent)
• no longer nomadic
• domesticated plants
(wheat, barley, rye) &
animals (goats, sheep,
cattle, dogs for milk,
cheese, butter, meat)
• No longer nomadic
• permanent settlements
now possible
• more “leisure” time meant
opportunities to
develop/invent language, art,
technology
Origins of
Biotechnology
• Plants - saved
seeds from plants
with most desirable
traits & planted
them the following
year
• Animals – only the best were allowed to
breed
• new varieties of plants
and animals arose
through manipulation
of genetic inheritance
– known as artificial
selection or selective
breeding.
• Seeds,
cuttings, &
animals used
for barter
• increased
distribution of
desirable
genes
between
farms,
communities,
& continents
• High tech
seeds & crops
used by
farmers.
• Wild & ancient
varieties being
lost, genetic
diversity
decreasing.
• Gene Banks set
up to save
ancient
“germplasm”
Present Day
• With stationary lifestyle
came need for food storage.
• Fermentation decreases
spoilage, often enhances
flavor, texture.
Fermented
Foods
Fermentation of Glucose
• Above equation shows cellular respiration when
O2 is plentiful. When oxygen is limited, cells
that would have turned sugar into CO2, water,
and ATP instead convert it into CO2 and other
compounds like alcohol or lactic acid.
• Unleavened (flat) bread - made with milled flour,
water, & salt, then baked
Leavened Bread
• Probably discovered
by accident
• Yeast contaminated
stored dough,
fermented, then was
baked.
• CO2 bubbles cause
fluffy texture
• Starter - old, fermented, uncooked dough mixed with
fresh batch of dough - no need for chance
contamination.
• Process brought
from Egypt to
Greece & Rome,
then from Rome to
conquered lands.
• Baker’s yeast - strain
of yeast isolated in
1915.
• Now commercially
grown, dried,
compressed, & packaged.
• Starts with whole,
heated milk
• Acids or enzymes (from
bacteria) cause casein
(milk protein) to
denature & form curds.
• Liquid part - whey.
• Curds skimmed, dried,
pressed, salted, & aged.
• Sometimes innoculated
with mold to enhance
flavor.
Cheesemaking
Some Other Fermented Foods
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Yogurt
Wine vinegar
Soy sauce
Fermented rice
Pickles
• Both Beer making and
bread making began in
Egypt 6,000-5,000 BC
• Beer- & bread makers
often located next door
& shared starters
• No one knew microbes
responsible for
fermentation until
Pasteur (late 1800’s)
• Malt (germinated
barley) & hops made
into dough & fermented
in water.
Fermented
Beverages
Wine
• Probably originated w/
accidental yeast
contamination of
grapes or juice
Vinegar
• Vinegar results from
oxidation of wine or
other fermented fruit
juices, such as cider,
by acetic acid bacteria.