This set of Food Processing Unit Operations Multiple Choice Questions & Answers (MCQs) focuses on “Size Reduction – Emulsification”.
1. What is emulsification?
a) Process of separating two or more miscible liquids
b) Process of dispersing two or more immiscible liquids
c) Process of dispersing two or more miscible liquids
d) Process of separating two or more immiscible liquids
View Answer
Explanation: Emulsification is the process of dispersing two or more immiscible liquids together to form a semi-stable mixture. It helps in stabilization of the product.
2. What type of emulsion is milk?
a) Oil in water
b) Water in oil
c) Water in water
d) Oil in oil
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Explanation: In every emulsion there is a continuous phase that suspends the droplets of the other element which is known as dispersed phase. In oil-in-water emulsion, the continuous phase is the water and the dispersed phase is the oil.
3. What type of emulsion is butter?
a) Oil in water
b) Water in oil
c) Water in water
d) Oil in oil
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Explanation: In every emulsion there is a continuous phase that suspends the droplets of the other element which is known as dispersed phase. In water-in-oil emulsion, the continuous phase is the oil and the dispersed phase is the water.
4. What is the purpose of homogenization?
a) Emulsification
b) Evaporating
c) Heating
d) Freezing
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Explanation: The purpose of homogenization is emulsification where it breaks down fat molecules in milk and resists separation. Without homogenization process, fat molecules in milk will rise to the top and form a layer of cream.
5. What type of emulsion is mayonnaise?
a) Temporary
b) Semi-permanent
c) Permanent
d) Semi- temporary
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Explanation: There are three types of emulsions they are temporary, semi-permanent, and permanent. An example of a temporary emulsion is simple vinaigrette while mayonnaise is a permanent emulsion.
6. What are factors that can destabilize an emulsion?
a) Temperature
b) Droplet size
c) Droplet-size distribution
d) Temperature, droplet size and droplet-size distribution
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Explanation: Factors that can affect stabilization of an emulsion are heavy polar fractions, solids, including organic and inorganic materials, temperature, droplet size and droplet-size distribution.
7. What increases the viscosity of emulsion?
a) Stabilizers
b) Catalysts
c) Temperature
d) Pressure
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Explanation: The viscosity is improved by stabilizers in the continuous phase of emulsions. Mobility of the droplets and their collision rate decreases. Therefore, stabilizers improve the stability of emulsions by hydrodynamic effects.
8. What is creaming in emulsions?
a) Migration of the dispersed phase of an emulsion
b) Emulsion separation into its separate ingredients
c) Migration of the continuous phase of an emulsion
d) Emulsion reaction
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Explanation: Creaming is defined as the migration of the dispersed phase of an emulsion, under the influence of buoyancy. It occurs when isolated oil droplets combine where it sinks to the bottom in w/o emulsions or rises to the top of an o/w emulsion.
9. What is cracking in emulsions?
a) Migration of the dispersed phase of an emulsion
b) Emulsion separation into its separate ingredients
c) Migration of the continuous phase of an emulsion
d) Emulsion reaction
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Explanation: Cracking in emulsion is defined as the separation of emulsified product into its separate ingredients where the oil and water are clearly separated and will not recombine.
10. How to determine type of emulsion?
a) Conductivity test and boiling test
b) Conductivity test and distillation
c) Dilution test and boiling test
d) Dilution test and conductivity test
View Answer
Explanation: Emulsion Type is determined by two tests, they are dilution Test where o/w emulsion is diluted with water and w/o emulsion is diluted with oil. Conductivity test is done where electrodes are used.
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