fnes final ch 28

what is Fermentation?

The conversion of carbohydrates to carbon dioxide and alcohol by yeast or bacteria.

what is freeze-dry?

To remove water from food when it is in a frozen state, usually in a vacuum.

what is sublimation?

The process in which a solid changes directly into a vapor without passing through the liquid phase

what is cure?

To preserve food through the use of salt and drying. Sugar, spices, or nitrates may also be added.

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 using 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?

A food preservation process in which 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?

a food preservation process utilizing ultrahigh pressures to inhibit the chemical processes of food deterioration.

what is the moisture level to survive for bacteria, molds, and yeast?

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)

what are requisites (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)

what are four problems with frozen food?

1. Freezer burn

2. Cell rupturing

3. Fluid loss

4. Recrystallization :occurs with longer storage times and temperature fluctuations

what is sous-vide technique and its drawback?

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

what is the benefit of ohmic heating ?

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

what are effects of irradiation on food?

Reduces Spoilage, Lengthens Shelf Life, Sterilizes or Kills Insect

pros & cons of irradiation on food?

Reduce Need for Chemical Fumigants. Consumer Fear: possible nutrient loss, free radicals

what are High-Pressure Processing (HPP)?

process using high pressure and water to make food safe and give it a somewhat extended shelf life during refrigerator storage

what is ozonation?

effective disinfectant and sanitizer b/c it kills viruses, molds, and bacteria

what is Modified atmosphere packaging (MAP)?

Changes the air’s composition; by reducing oxygen and increasing CO2

what is Controlled-atmosphere packaging (CAP)?

The concentrations of oxygen, carbon dioxide, and nitrogen in shipping containers of fruits or vegetables. An oxygen-absorbing sachet inside a container. Sulfur dioxide-producing pads in shipping containers of grapes

what is vacuum packaging?

In pouch packaging: oxygen is “vacuumed” out