This set of Food Processing Unit Operations Multiple Choice Questions & Answers (MCQs) focuses on “Size Reduction – Oil Extraction”.
1. Why hexane is used for extraction?
a) Easy oil recovery
b) Higher boiling point
c) Easy separation
d) Catalyst
View Answer
Explanation: Hexane is commonly used for oil extraction because of the easy oil recovery, narrow boiling point and also has exceptional solubilizing capability.
2. What is solvent extraction process?
a) Separate components based boiling point
b) Separate compounds based on their relative solubility
c) Separate components at lower temperature
d) Separated through evaporation
View Answer
Explanation: Solvent extraction is oil separation technique which is used to separate compounds based on their relative solubility in two dissimilar immiscible liquids, usually water and an organic solvent.
3. Which of the following method uses odorless fats as solvent?
a) CO2 Extraction
b) Maceration
c) Enfleurage
d) Cold Press Extraction
View Answer
Explanation: In the enfleurage extraction method, petals are placed between layers of purified animal fat, where it gets saturated with flower oil, and alcohol. It is used to recover citrus oils from fruit peels.
4. What is maceration extraction?
a) Immersing a plant in a liquid
b) Separate compounds based on their relative solubility
c) Separate components at lower temperature
d) Separated through evaporation
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Explanation: A maceration extraction consists of preserving contact between the plant and liquid for a period of time. It is an extractive technique that is conducted at room temperature where plant is immersed in a liquid like water, oil, alcohol.
5. Which of the following statements about cold pressingare correct?
Statement 1: Produces higher yield.
Statement 2: Produces lower quality of oil.
a) True, False
b) True, True
c) False, True
d) False, False
View Answer
Explanation: Cold presses are typically mechanically operated. Cold pressing usually produces a lower yield, but higher quality of oil.
6. What is the other name for expression method?
a) CO2 Extraction
b) Maceration
c) Enfleurage
d) Cold Press Extraction
View Answer
Explanation: Expression is method is also called as cold pressed method of extraction where there is no heat needed for extracting essential oil. In this process, the oil is forced from the material under high mechanical pressure.
7. What solvents are used to extract essential oils?
a) Petroleum ether
b) Ammonia
c) Water
d) Distilled water
View Answer
Explanation: Essential oils are extracted by using solvents like ethanol, petroleum ether, hexane, and methanol. They have easy oil recovery, narrow boiling point and also have exceptional solubilizing capability.
8. How to increase the extraction efficiency?
a) Crush the material
b) Dissolve in water
c) Dissolve in distilled water
d) Dry the material
View Answer
Explanation: To increase the extraction efficiency the material should be crushed so that the components are easily dissolved into the solvent. This also results in low time consumption.
9. Is cold extraction the same as cold pressed??
a) True
b) False
View Answer
Explanation: Cold pressed and cold extraction refers to oils that aren’t heated over 27°C during processing, therefore retains nutrients. Cold pressed oil is made by pressing product in the traditional way whereas cold extraction is oil obtained using centrifuge.
10. How do you remove hexane from oil?
a) Vacuum distillation
b) CO2 Extraction
c) Maceration
d) Enfleurage
View Answer
Explanation: To remove the hexane from oil, the miscella is treated in a vacuum distillation process. The hexane is evaporated during the distillation method which is condensed and separated from water in a decanter. The recovered hexane is then reused in the extractor.
Sanfoundry Global Education & Learning Series – Food Processing Unit Operations.
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