This set of Fruits Processing Multiple Choice Questions & Answers (MCQs) focuses on “Freezing Preservation of Fruits”.
1. Which of the following fruit is not be frozen?
a) Orange
b) Apple
c) Grapes
d) Watermelon
View Answer
Explanation: Apple, grapes and watermelon can be stored at refrigeration temperature. But oranges cannot be frozen. The citrus fruits become soft. The structure of the fruit gets disintegrated and becomes mushy. The appearance of the fruit is compromised when these fruits are frozen.
2. What is the selection criterion for freezing the fruits?
a) Fully ripe
b) Unripe
c) Partial ripe
d) Cannot keep fruits in freezer
View Answer
Explanation: The selection criterion for freezing the fruits is it should be fully ripe. But it should also be firm. Freezing under ripe fruits can change the taste of it, it may be bitter in taste. The overripe fruits are always frozen as purees.
3. What is the shelf life of frozen fresh fruit?
a) 1-2 weeks
b) 15 -20 days
c) 1 -6 months
d) 6- 12 months
View Answer
Explanation: The frozen fruit will remain safe to eat for an extended period of time. While using the fruit, it can be thawed or can be thrown into recipes. The refrigeration temperature maintains the nutritional content. The quality is less altered from the fresh fruits.
4. The freezing process destroys vitamins.
a) True
b) False
View Answer
Explanation: The freezing process does not destroy nutrients like vitamins, minerals. The food stored at refrigeration temperature retains the color, flavor and vitamin content. Generally vitamins are lost during high temperature process. Freezing also retards the microbial growth.
5. Which of the following has no effect on freezing?
a) Enzyme
b) Microbes
c) Tissue
d) Flavor
View Answer
Explanation: Enzymes, microbes and tissue are affected during the freezing process. Flavor, color and nutrient content are least changed. The enzymes get inactivated. The tissues are damaged where its structural integrity is affected. Freezing prevents the growth of microbes.
6. Which of the following statements are true with respect to the freezing?
Statement 1: The enzymes are inactivated.
Statement 2: The concentration of cellular constituents increase.
a) True, False
b) True, True
c) False, True
d) False, False
View Answer
Explanation: The enzymes are inactivated or inhibited. During freezing and frozen storage the concentration of cellular constituents like enzymes and their substrate increase. Therefore the rates of activity of the enzymes in frozen tissues are significant, despite the low storage temperatures.
7. What is the advantage of freezing?
a) Retains flavor
b) Cost
c) Energy consumption
d) Time
View Answer
Explanation: Most of the foods can be frozen. Natural color, flavor, and nutritive value are retained. Texture is usually better than other methods of food preservation. Foods can be frozen in less time than other process.
8. What is the disadvantage of freezing?
a) Changes in color
b) Changes in texture
c) Changes in ascorbic acid
d) Changes in color, texture and ascorbic acid
View Answer
Explanation: Disadvantages of Freezing are changes in color especially chlorophyll pigments, and development of off color. Changes in texture like protein denaturation and toughening takes place during freezing. There will changes in flavor such as loss of natural flavor and rancidity.
9. What changes takes place during freezing?
a) Protein denaturation
b) ATP formation
c) Carbohydrate metabolism
d) Amylase metabolism
View Answer
Explanation: There are textural changes during the freezing process. There will be a loss of cloud destruction of gels. The protein denaturation and toughening takes place. Changes in flavor like loss of natural flavor and development of off- flavor takes place.
10. Are these statements about the natural refrigerants true?
Statement 1: Propane is an artificial refrigerant.
Statement 2: It is produced from nature’s bio-chemical processes.
a) True, False
b) True, True
c) False, True
d) False, False
View Answer
Explanation: The natural refrigerants used in freezers are water, air, carbon dioxide, and hydrocarbons such as propane and isobutene. These refrigerants are the chemicals which are manufactured from nature’s bio-chemical methods. They do not deplete the ozone layer.
11. What is the principle of flash cooling?
a) Adsorption refrigeration
b) Steam-jet refrigeration
c) Evaporative cooling
d) Absorption refrigeration
View Answer
Explanation: The principle of flash cooling is achieved in steam-jet refrigeration. Steam-jet refrigeration is based on the chemical agent machines. It achieves the mechanical refrigeration. Generally water is used as a refrigerant.
12. What is freezing point?
a) The temperature at which the first ice crystal appears
b) The temperature at which the second ice crystal appears
c) The temperature at which the third ice crystal appears
d) The temperature at which the final ice crystal appears
View Answer
Explanation: Freezing point is defined as the temperature at which the first ice crystal appears. The liquid at that temperature is in equilibrium with the solid. Freezing point depends on the solute concentration. The freezing point varies from fruit to fruit.
13. What is freezing rate?
a) The ratio of difference between initial and final temperature of product to freezing time
b) The ratio initial temperature of product to freezing time
c) The ratio of final temperature of product to freezing time
d) The ratio of freezing time to the difference between initial and final temperature of product
View Answer
Explanation: Freezing rate is defined as the ratio of difference between initial and final temperature of product to freezing time. The freezing rate depends on the composition of the product. It also depends on the type of freezers used. The freezing rate is higher in air blast freezers compared to conventional freezers.
14. What is freezing time?
a) The time taken to freeze its thermal center
b) The initial time taken by the product
c) The time at which the third ice crystal appears
d) The time at which the final ice crystal appears
View Answer
Explanation: Freezing time is defined as time required to lower product temperature from its initial temperature to a given temperature at its thermal center. It depends on the thickness of the product. The freezing time is faster in quick freezer than slow freezing process.
15. Development of rancid oxidative flavors through contact of the frozen product with air.
a) True
b) False
View Answer
Explanation: Freezing causes negligible changes to pigments, flavors components. When water in the cells freezes, an expansion occurs and ice crystals cause the cell walls to rupture. Chemical changes that can cause spoilage and deterioration of fresh fruits and vegetables will continue after harvesting. In fats, the development of rancid oxidative flavors through contact of the frozen product with air takes place.
Sanfoundry Global Education & Learning Series – Fruits Processing.
To practice all areas of Fruits Processing, here is complete set of 1000+ Multiple Choice Questions and Answers.
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