Refrigeration and Freezing

Question 1

Refrigeration of foods falls between -2°C to 16°C.
A drop of ___°C slows down rate of senescence by 2 to 3 times and microbial growth by 3 to 6 times.

Answer 1

10

Question 2

Molecular mobility is depressed and consequently chemical reactions and biological processes are slowed down at low temperature.

Answer 2

Refrigeration

Question 3

Refrigeration storage of foods CANNOT improve the quality of a food item that is low of quality when placed into cold storage.

Answer 3

TRUE

Question 4

_______________ and ________________ must be maintained to prevent dehydration of the food while avoiding creation of conditions that are so humid that mold growth and food spoilage are favored.

Answer 4

Humidity and gas atmosphere composition

Question 5

A _______________________ refers to a CONDITION in which the atmosphere surrounding a food product is different from that of the normal atmosphere.

Answer 5

controlled atmosphere

Question 6

_______________________ refers to the CREATION of atmospheric conditions around the product that are different from the normal atmosphere.

Answer 6

Modified atmosphere

Question 7

Changes the physical state of a substance by changing WATER INTO ICE.

Answer 7

Freezing

Question 8

Commercial freezing requires a minimum of ___°C.

Answer 8

-18

Question 9

Household freezers only reach temperatures of ____ to ___°C

Answer 9

-12 to - 14

Question 10

a moderately FAST FREEZE because of vigorous circulation of cold air.

Answer 10

Air blast freezing

Question 11

Also known as, Individually Quick Frozen. Solid particles ranging in size from peas to strawberries are being exposed through a MOVEMENT of the COLD AIR (-18°C to -34°C) at high velocity as they pass along a conveyor belt.

Answer 11

Fluidized-bed freezer

Question 12

Type or freezer where cold air is being forced upward through the bed lifts and suspends the food particles allowing fluidization.

Answer 12

Fluidized-bed freezer

Question 13

Food is placed on belts or trays and a refrigerant circulates through a wall beside the food. As the food comes into “contact” with the COLD WALL, it quickly cools down and freezes.

Answer 13

Indirect Contact Freezers

Question 14

involves the immersion of packaged or unpackaged food products directly in a non-toxic refrigerant fluid.

Answer 14

Immersion freezing

Question 15

A very rapid freezing method in which unpackaged or thinly packaged foods are exposed to extremely cold freezant.

Answer 15

Cryogenic Freezing

Question 16

A freezing method in which the product is first placed on a conveyor belt and is moved into the pre-cooling part of the freezing unit. The food is allowed to equilibrate to the desired final temperature (between -18°C to -30°C).

Answer 16

Liquid nitrogen cryogenic freezing

Question 17

A type of freezer that simply uses moving, frigid air to cool the food.

Answer 17

Air-blast freezer

Question 18

A type of freezer in which CONDUCTION is the main method of heat transfer.

Answer 18

Contact Freezer

Question 19

This technology uses liquefied gases.

Answer 19

Cryogenic freezer

Question 20

Also known as blast rooms, these are cold storage rooms. There usually isn’t any forced airflow, resulting in a slow freezing rate.

Answer 20

Sharp Freezers

Question 21

Refrigerated air is circulated over the product that’s placed on trays or special spacers.

Answer 21

Tunnel Freezers

Question 22

Single-, multi-, or spiral-belt freezer systems typically use a vertical airflow, forcing cold air through a product layer that’s evenly distributed over the entire belt area.

Answer 22

Belt Freezers

Question 23

Fluidization occurs when individual food particles of relatively uniform shapes and size (i.e., peas) are subject to an upward airstream.

Answer 23

Fluidized-bed freezers

Question 24

These consist of a tank of a cooling solution, such as salt, sugar, or alcohol and water.

Answer 24

Immersion Freezers

Question 25

Either vertical or horizontal, manual or automatic, plate freezers sandwich the product between two metal plates for rapid heat transfer.

Answer 25

Plate Freezers

Question 26

These are used to freeze thin product layers.

Answer 26

Band Freezers

Question 27

These appliances have the same general shape and appearance as home refrigerators. They have one or two outside doors and from three to seven shelves for storing food.

Answer 27

Upright Freezers

Question 28

Freezers of this type require more floor area than the uprights but are more economical to buy and operate. These freezers lose less cold air each time they’re opened.

Answer 28

Chest Freezers

Question 29

This is a single appliance with one or two doors. It has one compartment for frozen foods and another for refrigerated foods.

Answer 29

Refrigerator-Freezer Combination

Question 30

effective in preventing discoloration in most fruits. It adds nutritive value as well. Leaving fruit in this solution for two minutes will prevent discoloration.

Answer 30

Ascorbic Acid (Vit C)

Question 31

sometimes used in place of ascorbic acid; however, it has little anti-darkening effect unless used undiluted and can mask natural fruit flavors.

Answer 31

Lemon juice

Question 32

During ________________, food products are placed in contact w metal surface w/ch is cooled by a cold brine, or a vaporizer refrigerant such as AMMONIA

Answer 32

plate freezing

Question 33

Scraped surface heat exchangers. Can be used only for fluid food products.

Answer 33

Slush freezers

Question 34

____________ in the freezer can cause the migration of water vapor from the product to the surface of the container.

Answer 34

Fluctuating temperatures

Question 35

a grainy, brownish spot where the tissues become dry and tough

Answer 35

Freezer burn