This set of Vegetables Processing Multiple Choice Questions & Answers (MCQs) focuses on “Drying Vegetables: New Technology, Equipment, and Examples”.
1. What is dehydration process?
a) Removal of water by evaporation
b) Removal of field heat
c) Removal of water by crystallization
d) Removal of water by vacuum
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Explanation: Drying or dehydration is the process of removal of water by evaporation, from a solid or liquid food. The main purpose of obtaining a solid product sufficiently low in water content results in higher shelf life of the product. Preservation through dehydration results in depression of water activity.
2. What is a drying oven called?
a) Kiln
b) Oven
c) Drying chamber
d) Product chamber
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Explanation: A kiln is a thermally insulated chamber. It is a type of oven that produces temperatures sufficient to complete the process such as hardening, drying, or chemical changes. It requires high electricity and heating medium for drying.
3. What are the disadvantages of oven drying?
a) Requires minimum heating periods and cooling phases
b) Requires extended cooling phases
c) Requires extended heating periods
d) Requires extended heating periods and cooling phases
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Explanation: Oven drying method requires extended heating periods and cooling phases. Therefore it usually takes time to produce results. The Procedures are laborious and tedious which also involves many manual steps.
4. Higher the humidity, the slower the drying.
a) True
b) False
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Explanation: The greater the surface area, faster the product dries. If the difference between the product and drying medium temperature is greater, then it results in greater rate of drying. The drying depends on humidity. If the humidity is higher, the drying process will be slow.
5. What happens if the product consists of high sugar?
a) Dries slowly
b) Dries quickly
c) Drying does not depend on sugar concentration
d) Drying depends on temperature of the sugar
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Explanation: The drying process depends on the solute concentration. Foods high in sugar and other solutes dry slowly. As drying progresses the concentration of solutes becomes greater in the water causing the slow drying rate.
6. What is the main purpose of osmotic dehydration?
a) Reduce water activity
b) Reduce temperature
c) Increase water activity
d) Increase temperature
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Explanation: Osmotic dehydration is a technique used to reduce water activity (aw) in foods. It improves nutritional, sensorial and functional properties of food. It consists of an immersion of the product into a concentrated solution like sugar, salt, sucralose.
7. Osmosis is an absorption process.
a) True
b) False
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Explanation: Osmosis is not an absorption process. Osmosis is the net movement of solvent molecules from a region of high solvent potential to a region of lower solvent potential through a partially permeable membrane. Whereas absorption is the act or process of absorbing or of being absorbed.
8. Which of the following is also called as dewatering and impregnation soaking (DIS) process?
a) Osmotic dehydration
b) Freeze drying
c) Solar drying
d) Canning
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Explanation: Osmotic dehydration is also called as dewatering and impregnation soaking (DIS) process. It was pioneered by James D. Ponting in 1966. It is a water removal process that involves the soaking of foods in hypertonic salt or sugar or in a combined solution. It reduces the water content while increasing the soluble solid content.
9. Why are vegetables treated with sulphur dioxide before drying process?
a) It acts as anti-browning agent
b) It acts as catalysts
c) It removes surface moisture content
d) It activates the catalysts
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Explanation: Sulphur dioxide and sulphate are well known anti-browning agents. The sulphur dioxide gas competes with peroxidases for the active sites and prevents the oxidation of phenolic substances. In vegetables processing, the vegetables are exposed to fumes of sulphur dioxide. Proper penetration of sulphur dioxide is important to prevent internal darkening during drying.
10. Which of the following drier is use for manufacturing instant mashed potato?
a) Roller drier
b) Solar drier
c) Freeze drier
d) Oven drier
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Explanation: The food product, in a liquid or paste form, is uniformly spread over heated rollers or drums which rotate slowly. The heat causes the moisture to evaporate leaving a dried product behind. A scraper then removes this for use. This method is suitable for instant mashed potato and baby foods.
Sanfoundry Global Education & Learning Series – Vegetables Processing.
To practice all areas of Vegetables Processing, here is complete set of 1000+ Multiple Choice Questions and Answers.
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