This set of Food Chemistry Multiple Choice Questions & Answers (MCQs) focuses on “Dispersed Systems – Emulsions”.
1. What is the dispersion of one liquid in another is called?
a) Gel
b) Crystal
c) Foam
d) Emulsion
View Answer
Explanation: An emulsion is said to be the mixture of two or more liquids that usually don’t mix together. For example, oil in water.
2. The word emulsion comes from which Latin word?
a) Nemo
b) Nam
c) Mulgeo
d) Magus
View Answer
Explanation: The word “emulsion” is derived from the Latin mulgeo, mulgere which means “to milk”, as milk is an emulsion of fat and water, and other components.
3. Emulsions contain both a dispersed and a continuous phase.
a) True
b) False
View Answer
Explanation: True, Emulsions contain both a dispersed and a continuous phase.
4. Emulsion appears in which colour when all light scatter equally?
a) Red
b) White
c) Blue
d) Green
View Answer
Explanation: Emulsions tend to appear white in color when all light is scattered equally. It appears blue when low-wavelength light is scattered.
5. If the emulsion is dilute enough which coloured light scatters more?
a) Red
b) White
c) Blue
d) Green
View Answer
Explanation: If the emulsion is dilute enough, higher-frequency (low-wavelength) light will be scattered more, and the emulsion will appear bluer – this is called the “Tyndall effect”.
6. If the emulsion is concentrated enough which coloured light scatters more?
a) Red
b) White
c) Blue
d) Green
View Answer
Explanation: If the emulsion is concentrated enough, the color will be twisted toward comparatively longer wavelengths, and will appear more yellow.
7. Microemulsions are kinetically stable, while translucent nanoemulsions are thermodynamically stable.
a) True
b) False
View Answer
Explanation: Microemulsions are thermodynamically stable, while translucent nanoemulsions are kinetically stable.
8. Flocculation, creaming, coalescence and Ostwald ripening are the instabilities of what?
a) Gelatinisation
b) Emulsions
c) Crystals
d) Foams
View Answer
Explanation: Emulsion stability refers to the ability of an emulsion to resist change in its properties over time. There are four types of instability in emulsions: flocculation, creaming, coalescence, and Ostwald ripening.
9. What occurs when there is an attractive force between the droplets, so they form flocs, like bunches of grapes?
a) Flocculation
b) Creaming
c) Coalescence
d) Ostwald ripening
View Answer
Explanation: Flocculation occurs when there is an attractive force between the droplets, so they form flocs, like bunches of grapes.
10. What occurs when droplets bump into each other and combine to form a larger droplet, so the average droplet size increases over time?
a) Flocculation
b) Creaming
c) Coalescence
d) Ostwald ripening
View Answer
Explanation: Coalescence occurs when droplets bump into each other and combine to form a larger droplet, so the average droplet size increases over time.
11. What happens when the droplets rise to the top of the emulsion under the influence of buoyancy?
a) Flocculation
b) Creaming
c) Coalescence
d) Ostwald ripening
View Answer
Explanation: Creaming occurs when the droplets rise to the top of the emulsion under the influence of buoyancy, or under the influence of the centripetal force induced when a centrifuge is used.
12. What happens when the droplets rise to the top of the emulsion under the influence of buoyancy?
a) Flocculation
b) Creaming
c) Coalescence
d) Ostwald ripening
View Answer
Explanation: Creaming occurs when the droplets rise to the top of the emulsion under the influence of buoyancy.
13. Which is the substance that stabilizes an emulsion by increasing its kinetic stability?
a) Gel
b) Emulsifier
c) Cream
d) Foam
View Answer
Explanation: An emulsifier (also known as an “emulgent”) is a substance that stabilizes an emulsion by increasing its kinetic stability. One class of emulsifiers is known as “surface active agents”, or surfactants. Emulsifiers are compounds that typically have a polar or hydrophilic part and a non-polar part.
14. Emulsifiers those are more soluble in water forms which type of emulsion?
a) Oil in water
b) Water in oil
c) Oil in fat
d) Fat in oil
View Answer
Explanation: Emulsifiers which are more soluble in water and less soluble in oil will generally form oil-in-water emulsions. Water-in-oil emulsions is formed when emulsifiers are more soluble in oil.
Sanfoundry Global Education & Learning Series – Food Chemistry.
To practice all areas of Food Chemistry, here is complete set of Multiple Choice Questions and Answers.
If you find a mistake in question / option / answer, kindly take a screenshot and email to [email protected]
