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How is conduction used in the canning process?
Food processed as energy from molecular collisions is passed from the outside food layer in the can to the cold point in the center of the can
How does applying heat act as a preservative?
1. Can destroy microorganisms
2. Can denature Enzymes
3. Can increase shelf life of food with appropriate packaging
How does canning act as a preservation method?
Places sterilized food in a sterilized container. Destroys microorganisms that cause illness, bring about food spoilage, or create toxins
How does dehydrating food act as a preservation method?
•Preserves food by lowering the water content, thus lowering the growth ability of microorganisms
List the 4 natural preservatives we used for the Pumpkin Lab
Lemon juice, salt, vinegar, refrigerator
What is the thermal death curve?
line graph that illustrates how long it will take to kill a microorganism at a certain temperature
What is Blanching? And why is it considered a preservation method?
Submerging food for short time in boiling water or steam
Stops enzyme activity
Name the 2 personal canning processes
Cold Pack and Hot Pack
How does airflow affect the quality of dehydrated food?
–hot air helps remove released moisture away from the food source
Why does vinegar and lemon juice act as a preservative?
The high acidity does not allow microbial growth
At what temperature does water boil?
212 F
What percent of microorganisms must be destroyed to be considered sterile?
100%
All organisms must be completely destroyed
What is Cold Pack Personal canning process?
•Raw food is packed in jars, filled with a boiling liquid, closed with a lid, and then processed
•Used for foods that are easily damaged
How does surface area affect the quality of dehydrated food?
–thinner, uniform slices allow heat to travel more quickly to the center of the food eliminating water
Why is salt a preservative?
Salt draws out moisture
Why can high acidic foods be processed at lower temperature that low acidic foods?
Microorganisms can not survive in high acidic environments.
What is pasteurization? Give one example of a food that is pasteurized.
Heating foods just below the boiling point
Milk, eggs, oysters
What are some negative effects of canning on food?
Can produce flavor and texture changes in the food
What id oxidation
Enzymatic browning
Why does refrigeration act as a preservative?
The cool temperatures slow bacterial growth
Why must foods with ingredients such as fat, oil, protein, starch and sugar be processed at higher temperatures
These ingredients can surround the microbe and protect it from heat
What is the pH of low and high acidity foods?
Low-acid foods = pH of 4.6 or higher
High-acid foods = pH between 2.0 and 4.6
What is the Hot Pack Personal Canning process
•Food is heated in a liquid or syrup to 171°F and packed in jars while still hot; then jars are sealed and processed
Explain how dehydrating/ drying food effect the nutritional value?
Vitamins can be lost, higher amounts of sugar
Which preservation method worked the best on the pumpkins?
Refrigerator