Fruits Processing Questions and Answers – Pretreatments Required for Drying/Dehydration

This set of Fruits Processing Multiple Choice Questions & Answers (MCQs) focuses on “Pretreatments Required for Drying/Dehydration”.

1. Which of the following pretreatment are used prior to dehydration process?
a) Blanching
b) Blanching and freezing
c) Dipping
d) Blanching and dipping
View Answer

Answer: d
Explanation: Fruits and vegetables that undergo dehydration process should be ripe and healthy. The fruits and vegetables are rinsed in cold water to remove dust. It is then inspected for cut, bruises and fibrous portions. Then seeds, stems, and pits are removed. Finally, before dehydration process blanching or dipping is done as pretreatment.

2. Which of the following process shortens the drying time?
a) Grinding
b) Blanching
c) Mixing
d) Washing
View Answer

Answer: b
Explanation: Blanching is the process where the food is briefly precooked in steam or boiling water. It is used to stop the enzymatic reactions within the foods. Blanching also shortens the drying time. It also kills many spoilage organisms.

3. Which of the following process prevents browning in fruits?
a) Chopping
b) Dipping
c) Canning
d) Cleaning
View Answer

Answer: b
Explanation: Fruits and vegetables are dipped in ascorbic agents that help in preventing the browning reactions. These coatings maintain the quality of the product by forming a protective film over the product. It acts as a barrier to different gases such as oxygen, carbon dioxide and water vapor.

4. Blanching of fruit removes the trapped air from the product.
a) True
b) False
View Answer

Answer: a
Explanation: True. The blanching process removes the trapped air from the product. It is a unit operation prior canning, drying. The fruits and vegetables are heated for inactivating the enzymes, preserving color, flavor and nutritional value.

5. What is the holding time for blanching process?
a) 1-15 min
b) 1-30 min
c) 30 min
d) 60 min
View Answer

Answer: a
Explanation: The time/temperature combinations vary very broadly according to the fruits and vegetables. It also depends on the pretreatment and processing techniques. Generally, holding times for blanching ranges from 1–15 minutes at 70–100°C. The holding time should not be beyond 20 minutes.

6. Which of the following enzyme is responsible for discoloration?
a) Poly phenol oxidase
b) Amylase
c) Oxidase
d) Lipase
View Answer

Answer: a
Explanation: Poly phenol oxidase is responsible for discoloration in fruits and vegetables in presence of oxygen. It is prevented by blanching, dipping into ascorbic acids. Refrigeration can slow enzymatic browning. Poly phenol oxidase can be mainly seen in apples, potatoes and bananas.

7. How long does it take for enzymatic browning to occur?
a) 20 min
b) 5 min
c) 10 min
d) 15 min
View Answer

Answer: b
Explanation: The enzymatic browning reaction is commenced at the maturity stage itself. It is seen in the flesh and seeds of the fruits. Browning takes place if the fruit is exposed to air when peeled and sliced or diced. Therefore, to prevent this discoloration the products should undergo pretreatments like edible coating and blanching.

8. Which of the following component of fruit acts as antioxidant?
a) Vitamin C
b) Vitamin B
c) Zinc
d) Iron
View Answer

Answer: a
Explanation: Vitamin C in fruits acts as natural antioxidant. It controls the browning reaction in the product. Vitamin C reacts with reactive oxygen-centered radicals resulting in less reactive species. Therefore, it reduces the amount of oxidative damage to the flesh. It helps in maintaining the natural color of the product.

9. What is the major aim in blanching of fruit?
a) Destroy the enzyme
b) Increase the softness
c) Destroy microbes
d) Remove bitter compounds
View Answer

Answer: a
Explanation: Blanching is partial heat treatment followed by cooling. The most important aim is to destroy the enzyme which causes the discoloration in fruits. Apart from it retains the color and flavor of the fruit. It reduces the nutritional losses.

10. Which of the following chemical is added during blanching of vegetables?
a) Sodium chloride
b) Ammonium chloride
c) Sodium bicarbonate
d) Sodium carbonate
View Answer

Answer: c
Explanation: Sodium bicarbonate is added for retaining the green color of the vegetables during blanching. It improves the color and retains the nutritional content. It decreases the Vitamin B content in the product. Water soluble minerals are lost in blanched water.

11. Which of the following statements are correct on post-harvest of fruits?
Statement 1: Fruits are dipped in cold water to remove field heat.
Statement 2: Stems and leaves of fruits are removed.
a) True, False
b) True, True
c) False, True
d) False, False
View Answer

Answer: b
Explanation: The fruits once harvested are cleaned to remove the stems and leaves. Then the fruits are dipped in cold water to remove the field heat. It also removes the microbes present on the surface. It also removes the soil and dust on the surface. They check for physical damage and biological damage of the fruit.

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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Manish Bhojasia - Founder & CTO at Sanfoundry
Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He lives in Bangalore, and focuses on development of Linux Kernel, SAN Technologies, Advanced C, Data Structures & Alogrithms. Stay connected with him at LinkedIn.

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