Chapter 20 - Food Preservation Flashcards
Uses for pressure canning
Vegetables, meats, low-acid foods (above 4.5 pH) that have potential to carry Clostridium botulinum & its heat-resistant pores
Uses of water bath canning
▫High-acid foods below 4.5 pH – sufficiently acidic enough to prevent the growth of Clostridium botulinum
▫Fruits, tomatoes, pickles
Pressure canning process
Processed under pressure (pressure cooker) to control the processing temperature; 240° to destroy bacteria
Water bath canning process characteristics
Time required in bath depends on the size of jar, type of food & elevation
▫Hydrogen swells
How does drying kill microorganisms
if the moisture level reaches low enough levels to kill microorganisms
How is dehydration accomplished
▫Mild heating & evaporation
3 methods to avoid color changes during dehydration
oSulfuring
oBlanching
dip in acidic juice to avoid color changes.
Sulfuring
expose cut fruit to smoke from burning sulfur flowers; apricots
Blanching purpose in dehydration
minimizes color changes in dried vegetables.
What fruits benefit from being dipped in acidic juice to avoid color changes during dehydration
oApples & bananas
When does Maillard reaction occur during dehydration
when moisture level drops from 20 to 15%
Four classes of freezing
oPerishable raw foods
oPerishable heated or cooked foods
oSemi-perishable foods
oNon-perishable foods
3 benefits of freezing
- Convenience
- Quality
- Can be stored up to 6 months, some 12
Possible negative of freezing
Altered textures
4 types of commercial freezing
- Sharp freezing
- Air-blast freezing
- Indirect contact freezing
- Immersion freezing
What happens to starch during freezing
Starch thickened mixtures curdle during storage
Prep needed for meats, fish, and poultry before freezing
None
Perishable food items freezing prep time
Limited prep time needed
Preservation with sugar mechanism
High concentration of sugar creates an unfavorable osmotic pressure
How can preservation with sugar kill microorganisms
combined with boiling kills microorganisms
What is kimchi?
Fermenting and salting seasonal vegetables, typically cabbage
What culture is kimchi a traditional dish for?
•Korean traditional dish
2 types of canning
Pressure canning
Water bath canning
