Chapter 28 Flashcards
What is fermentation?
the conversion of carbs to carbon dioxide and alcohol by yeast and bacteria
What is freeze dry?
preservation of food by first freezing and then placing it in a vacuum, where the ice sublimates to a vapor
What is sublimation
process where solid changes directly to vapor without passing through the liquid phase
What is CURE
to preserve food through the use of salt and drying
What is edible coating
A thin layer of edible material, such as natural wax, oil, or petroleum-based wax, that serves as a barrier to gas and moisture.
What is sterilization
The elimination of all microorganisms through extended boiling, heating to temperatures much higher than boiling, or the use of certain chemicals.
What is freezer burn
White or grayish patches on frozen food caused by water evaporating into the package’s air spaces and possibly recrystallizing as ice on the food’s surface.
What is ohmic heating
an electrical current is passed through food, generating enough heat to destroy microorganisms
What is irradiation
A food preservation process in which foods are treated with low doses of gamma rays, X-rays, or electrons.
What is pascalization
utilizing ultra-high pressures to inhibit the chemical processes of food deterioration
moisture level to survive for bacteria, molds, and yeast
Moisture level to survive
- Bacteria and molds need 15%
- Yeast needs at least 20%
what foods must be processed in a pressure canner
Low acid foods (above pH 4.6) must be processed in a pressure canner.
what are requisites (things that are necessary) for satisfactory preserves
Pectin
0.5 to 1.0 % for Gel
• Sugar
60 to 65 %
• Acid
Flavor Hydrogen Ions (pH 2.8 to 3.4)
what is the ideal temperature interval for refrigeration
Refrigerators should be kept between just above freezing and no more than 40°F (4°C)
Four problems with frozen food
- Freezer burn: white or grayish patches on frozen food; vacuum packaging eliminated the problem of freezer burn
- Cell rupturing
- Fluid loss
- Recrystallization: occurs with longer storage times and temperature fluctuations
what is sous-vide technique and its drawback
Sous-vide
• Cooking it in sealed, airtight plastic bags in a water bath at lower temperatures but for longer times
• Drawback: No browning, crust and flavor development
benefit of ohmic heating
Ohmic heating: eggs, orange juice, and other fruit juices
- Benefit: reduces the need for excess heat→ higher-quality food
what are 3 irradiation sources approved for use in foods
Gamma Rays
X-rays
Electron beams
effects of irradiation on food, and pros & cons
Effects of Irradiation on Food
Reduces Spoilage Lengthens Shelf Life
Sterilizes or Kills Insects
But, too low to eradicate C. botulinum spores
Pros & Cons
Reduce Need for Chemical Fumigants
Consumer Fear-possible nutrient loss, free radicals
what are High-Pressure Processing (HPP)
High-hydrostatic pressure (HHP) or Ultrahigh pressure (UHP)
• Process using high pressure and water to make food safe and give it a somewhat extended shelf life during refrigerator storage
• Refrigerated storage is required.
What is ozonation
- Lightening or high-energy ultraviolet rays trigger ozone formation in the atmosphere. They do so by rupturing oxygen molecules, which produce fragments that then combine with other oxygen molecules to form ozone
- Effective disinfectant and sanitizer b/c it kills viruses, molds, and bacteria
- GRAS granted, approved as a food sanitizing agent in 2001 by the FDA
- Ozone is the principal means of sanitizing the public water supply in Germany and France
what is each of the aseptic packaging methods (MAP, CAP, vacuum packaging?
Modified-atmosphere packaging (MAP)
TURKEY
1% FAT
PREMIUM FRESH
LEAN GROUND
TURKEY
- Changes the air’s composition;
by reducing oxygen and increasing COz
- Fruits and fresh cut vegetables, cured cheese, most meat, poultry, and fresh pasta are packaged using MAP
• Controlled-atmosphere packaging (CAP)
- The concentrations of oxygen, carbon dioxide, and nitrogen in shipping containers of fruits or vegetables
- Oxygen-absorbing sachet inside a container
- Sulfur dioxide-producing pads in shipping containers of grape
• Vacuum packaging
- In pouch packaging: oxygen is “vacuumed” out
Irradiation is effective for eliminating bacteria, yeasts, and molds, but it may not eradicate
which specific organism?
a. E. coli
b. Salmonella
c. botulinum spores
d. Insects
Modified-atmosphere packaging (MAP) operates by reducing ____ and increasing in the air around the food.
a. acid; alkalinity
b. oxygen; carbon dioxide
c. oxygen; ozone
d. humidity; carbon dioxide
