DRYING

Question 1

Dehydration

Moisture removal by:

Answer 1

Evaporation
Osmosis
Sublimation

Question 2

Dehydration

Reduction of moisture content (Inhibition of):

Answer 2

Microbial Activity

Enzyme Activity

Question 3

a general term applied to all methods of removing moisture from the food which inhibits the growth of microorganisms.

Answer 3

Drying

Question 4

achievement of a low moisture level in food (below 13%) to prevent spoilage by molds.

Answer 4

Dehydration

Question 5

• Most widely used drying method in agricultural processing operation
• Food is laid and turned in drying beds or mats

Answer 5

Solar Drying (Sun Drying)

Question 6

Commercial Drying (4) 
CVOF

Answer 6

Conventional drying
Vacuum drying
Osmotic drying
Freeze-drying

Question 7

uses heat to evaporate the water in food

Answer 7

Conventional drying

Question 8

dehydrates foods to very low moisture levels of 1-3% through the use of a vacuum.

Answer 8

Vacuum Drying

Question 9

Examples of vacuum-dried foods

Answer 9

Milk, tomato paste, orange juice, coffee

Question 10

The method preserves flavor and color and increases shelf life.

Answer 10

Vacuum Drying

Question 11

2 disadvantages of vacuum drying

Answer 11

1) Expensive

2) Requires dehydrated food to be stored in airtight containers to prevent rehydration by drawing moisture from air

Question 12

it reuses a strong syrup with a high sugar concentration that osmotically draws water from the food being dried.

Answer 12

Osmotic drying

Question 13

caused by osmotic pressure from concentrated solutions of sugar and salt

Answer 13

Osmotic dehydration

Question 14

The removal of water from food when it is in a frozen state usually under a vacuum

Answer 14

Freeze-drying

Question 15

Food is frozen then placed in a vacuum where the ice sublimates.

Answer 15

Freeze Drying

Question 16

To minimize color changes during dehydration

Answer 16

1) Blanching

2) Sulfuring

Question 17

exposure of cut fruits to the smoke fumes created by burning sulfur flowers to retain a bright color during drying

Answer 17

Sulfuring

Question 18

Reqs for dehydration (3)

1) Low relative humidity
2) Warm air temperature
3) Air is circulating above the food

Answer 18

Aside from preserving qualities:

• Decrease in height and weight
• Change in texture and flavor/color/odor

Question 19

Factors affecting the drying process (TRTV)

Answer 19

Temperature
Relative humidity of air
Time of Drying
Velocity of Air

Question 20

The best temperature of drying is 110-115 deg F but exact temperatures will vary with the type, size, and thickness of food and the method of drying

Answer 20

Temperature

Question 21

varies with the type of food and the method and stage of drying.

Answer 21

Relative humidity of the air

Question 22

It is usually high at the start of drying and becomes less as drying progresses

Answer 22

Relative humidity of the air

Question 23

this is a directly proportional to the desired dryness of the product and the initial moisture content of the product

Answer 23

Time of drying

Question 24

this is proportional to the transfer of heat from the food to the environment.

Answer 24

Velocity of Air

Question 25

Primary purpose is to alter the properties of food

Answer 25

Frying

Question 26

Preservative effect is due to:

1) Thermal destruction of enzymes and microbes
2) Reduction of water activity of food

Answer 26

Frying