Question 1

Dehydration is a new technology for the preservation of food.

Accepted Answer

Dehydration is an ancient method of preserving food that involves removing moisture to inhibit the growth of microorganisms, and it has been used for thousands of years.

Question 2

If done correctly,all of the components of a food freeze at the same time during the process of freeze concentration.

Accepted Answer

During freeze concentration, different components of a food freeze at different temperatures due to their varying freezing points, leading to the separation of water as ice from the concentrated solution.

Question 3

The high sugar and acid content of fruits make them safe to dry outdoors when conditions are favorable for drying.

Accepted Answer

The high sugar and acid content in fruits lowers their water activity, which, combined with favorable drying conditions (like low humidity and high temperature), inhibits the growth of spoilage microorganisms, making fruits safe to dry outdoors.

Question 4

Which of the following food items is safest to dry outdoors?​
A)Vegetables
B)Fruits
C)Fish
D)Meat jerkies

Accepted Answer

Fruits are the safest option to dry outdoors as they have a low risk of bacterial growth compared to other food items. Vegetables and meat jerkies have a higher risk of bacterial growth, while fish may attract flies and other insects during the drying process, increasing the risk of contamination.

Question 5

_____ is caused by enzymes and can be prevented by inactivating the enzymes before drying.
A)Caramelization
B)Maillard browning
C)Enzymatic browning
D)Crusting

Accepted Answer

Enzymatic browning is caused by enzymes, such as polyphenol oxidase, and can be prevented by inactivating the enzymes before drying. Caramelization involves the breakdown of sugars at high temperatures, Maillard browning involves a reaction between amino acids and reducing sugars, and crusting refers to the formation of a dry, outer layer on a food surface.

Question 6

The purpose of drying is to remove enough moisture to _____.
A)eliminate microbes
B)prevent microbial growth
C)sterilize the food
D)slow down microbial growth

Accepted Answer

Drying helps to reduce the moisture content of the food, which inhibits microbial growth by creating an environment where microorganisms cannot easily survive and proliferate. However, complete elimination of microbes or sterilization may not always be achievable through drying alone.

Question 7

Microwave ovens should not be used for drying herbs.

Accepted Answer

The answer of Microwave ovens should not be used for...

Question 8

Dehydration removes all water from food.

Accepted Answer

Dehydration removes most of the water from food but not all, so it is not accurate to say that it removes all water from food.

Question 9

The lower limit of moisture content by the sun-drying method is _____.
A)approximately 15 percent
B)nearly 25 percent
C)50 percent
D)roughly 40 percent

Accepted Answer

The lower limit of moisture content by the sun-drying method is approximately 15 percent. This is because the sun-drying method is not as effective as other methods of drying, such as oven drying or freeze-drying, which can remove more moisture. Therefore, the minimum moisture content that can be achieved through sun-drying is around 15 percent.

Question 10

Dried foods are sterile.

Accepted Answer

Drying can reduce the moisture content in foods, making it less conducive for bacterial growth, but it does not necessarily make the food completely sterile. Some bacterial spores can still survive in dried foods, and there is the possibility that bacteria can contaminate the food during the drying process or afterwards.

Question 11

Ultrafiltration is a membrane-filtration process operating from _____ bars.
A)1 to 3
B)4 to 12
C)12 to 20
D)2 to 10

Accepted Answer

Ultrafiltration typically operates from 2 to 10 bars (or 30 to 150 psi) to push water through a semi-permeable membrane and remove particles and molecules larger than the membrane's pore size. Therefore, choice D is the correct answer.

Question 12

_____ is the oldest method of food concentration.
A)Solar evaporation
B)Open-kettle evaporation
C)Freeze concentration
D)Thin-film evaporation

Accepted Answer

Solar evaporation is the oldest method of food concentration, which involves letting the sun's energy evaporate water from the food. This method has been used for centuries, particularly in areas with high sun exposure and low humidity, to preserve fruits, vegetables, and fish.

Question 13

A typical _____ has an insulated enclosure,a way of circulating air through the enclosure,and a way to heat this air.
A)drum drier
B)air convection drier
C)vacuum drier
D)household oven

Accepted Answer

An air convection drier is typically used for drying food, wood, or other materials. It has an insulated enclosure to prevent heat loss, a way of circulating air through the enclosure to promote drying, and a heating source to heat the circulating air. The other options do not necessarily have all of these features or are not commonly used for drying materials.

Question 14

Solar evaporation is the oldest method of food concentration.

Accepted Answer

Solar evaporation has been used for centuries to concentrate foods such as salt and fish.

Question 15

Freeze concentration is used commercially in _____ production.
A)buttermilk
B)cheese
C)orange juice
D)jam and jelly

Accepted Answer

Freeze concentration is commonly used in the production of orange juice to remove water and concentrate the juice, resulting in a richer flavor and increased shelf life.

Question 16

Reverse osmosis can be used to recover rinsing water by concentrating it from tanks,pipes,and so onto help recover milk solids.

Accepted Answer

Reverse osmosis can remove impurities from water and concentrate it, making it suitable for reuse in various applications, such as recovering milk solids.

Question 17

A minimum temperature of _____ is needed for drying food outdoors.
A)85 degrees F
B)90 degrees F
C)95 degrees F
D)100 degrees F

Accepted Answer

A minimum temperature of 85 degrees F is generally needed for drying food outdoors to ensure that the food dries efficiently and safely, preventing spoilage and bacterial growth.

Question 18

Drying and dehydration both remove water from foods.

Accepted Answer

Both drying and dehydration involve the removal of water from foods. However, dehydration is a specific form of drying that is achieved through applying heat, while drying can also be done through other methods such as evaporation or freeze-drying.

Question 19

As a product dries,its _____ water evaporates first.
A)salt hydrate
B)glucose monohydrate
C)colloidal gel
D)free

Accepted Answer

Free water is the first to evaporate during the drying process, leaving behind the solutes or solids in the product. This is because free water has the lowest binding energy with the product molecules, making it easier to evaporate compared to other types of water such as bound water or chemically bound water. Choices A, B, and C refer to specific types of products or compounds and are not related to the evaporation process.

Question 20

Dehydrated and dried foods are heavier.

Accepted Answer

Dehydrated and dried foods are actually lighter than their fresh counterparts as they have had their water content removed. This makes them a popular option among backpackers and hikers as they are easier to carry due to their lighter weight.

Quiz 11: Drying and Dehydration

Dehydration is a new technology for the preservation of food.

If done correctly,all of the components of a food freeze at the same time during the process of freeze concentration.

The high sugar and acid content of fruits make them safe to dry outdoors when conditions are favorable for drying.

Which of the following food items is safest to dry outdoors?​

_____ is caused by enzymes and can be prevented by inactivating the enzymes before drying.

The purpose of drying is to remove enough moisture to _____.

Microwave ovens should not be used for drying herbs.

Dehydration removes all water from food.

The lower limit of moisture content by the sun-drying method is _____.

Dried foods are sterile.

Ultrafiltration is a membrane-filtration process operating from _____ bars.

_____ is the oldest method of food concentration.

A typical _____ has an insulated enclosure,a way of circulating air through the enclosure,and a way to heat this air.

Solar evaporation is the oldest method of food concentration.

Freeze concentration is used commercially in _____ production.

Reverse osmosis can be used to recover rinsing water by concentrating it from tanks,pipes,and so onto help recover milk solids.

A minimum temperature of _____ is needed for drying food outdoors.

Drying and dehydration both remove water from foods.

As a product dries,its _____ water evaporates first.

Dehydrated and dried foods are heavier.

Which of the following food items is safest to dry outdoors?