To Study the Role of Emulsifying Agents in Stabilising the Emulsions of Different Oils

This article comprises the procedure to perform an experiment to study the role of emulsifying agents to stabilize the emulsions of different oils. It aims to give a simple process to understand an emulsifying agent, the role of emulsifier.

Before actually undertaking the experiment is to know a bit, or we can say essential about the emulsifier. So, here arises the first question i.e., How do emulsifying agents stabilize the emulsion and how to emulsify oil?

Emulsifier Definition

An emulsifier can be defined as a substance that acts as a stabilizer for emulsions. And it also prevents liquids that ordinarily don’t mix from separating.

Emulsifiers can also be known as an apparatus that stirs or shakes ingredients to form an emulsion.

How does an Emulsifier work?

By increasing the kinetic stability of the mixture, an emulsifier keeps immiscible compounds from separating. Surfactants are also a type of emulsifier, which lower surface tension between a liquid and solid or between liquids. Surfactants prevent droplets from getting large enough for components to be able to separate based on their density.

Examples of Emulsifier

Some examples of emulsifiers are- Homogenized milk, metalworking cutting fluids and vinaigrettes are some common emulsifiers.

Other examples include egg yolks, it is used in mayonnaise to keep the oil from separating out. The emulsifier agent present in eggs is lecithin. Soy lecithin, sodium phosphates, mustard, stearoyl lactylate.

After having the basic knowledge comes the experiment:

Aim: To study the role of emulsifying agents to stabilize the emulsions of different oils.


An emulsion is a colloid where both the dispersion medium and the dispersed phase are in liquid form. 

Here it has been differentiated based on their relative proportions.

The dispersed phase is in a smaller quantity and the dispersion medium is present in a larger proportion.

If you mix oil and water, after shaking the mixture you will notice a slightly milky solution that is soluble, is unstable and is known as an emulsion of oil in water. It will form two layers, separating water and oil.

If you want to increase the stability of the emulsion of oil and water soap solution can be added. Since it acts as an emulsifying agent. The interfacial surface tension between the two layers is decreased by the carboxyl polar group.

Soap concentration is the optimum concentration required to complete the emulsification process. To get an effective stabilization the amount should not be more or less than optimum concentration.

Materials required: The materials required for the experiment are given below:

1) Test tube - 1

2) Glass rod -1

3) Stopwatch

4) Soap or detergent -5g

5) Droppers - 5

6) Mustard oil, linseed oil, machine oil, and castor oil - 10mL each.

7) Test tubes – 6


  1. Take a test tube. Put 10mL of distilled water and dissolve 1g of detergent in it. Vigorously shake the test tube and label the test tube as “A”.

  2. Take 4 more test tubes and label them as B, C, D, E. Add 5mL distilled water in each test tube. Put 10 drops of mustard oil in the test tube B, 10 drops of linseed oil in C, 10 drops of castor oil in D, and 10 drops of machine oil in test tube E.

  3. Take the test tube B in your hand and shake it vigorously for 5 minutes and keep it aside in a test tube Stand. Start your stopwatch to record the time required to separate the two layers.

  4. Follow the same process with other test tubes – C, D and E.

  5. Add two drops of soap solution or detergent which were prepared in the test tube A into each test tube. Shake each test tube for 5 minutes. And record the time taken to separate two layers.

  6. Make a table as given below and record the results :

Specification of test tube

Oil used for emulsion

With soap or detergent

Without soap or detergent





Precautions to Be Taken During the Experiment:

Given below are some precautions you need to take while performing the experiment.

  • First thing is to add to all the five test tubes an equal amount of detergent solution.

  • To minimize the error in recording the time, shake all the test tubes for an identical time span.

  • Start your stopwatch as soon as you stop shaking the test tubes and stop it immediately when you notice the layers are separated.

FAQ (Frequently Asked Questions)

1. What makes an emulsion stable?

Emulsion stability can be referred to as the system’s ability to resist changes in its physicochemical properties over time.  It is important in many industrial appliances such as 

Food products, coatings, agriculture formulations, personal care and petroleum. There are several mechanisms such as creaming, flocculation and coalescence which cause emulsion breakdown.

Although emulsion stability is required in many industrial processes and products, there are also some processes where emulsion stability is not required.

For example, wastewater treatment where the emulsion is unwanted or oil recovery where crude oil needs to be separated from the water before transportation.

2. What are the best natural emulsifiers?

  • CANDELILLA WAX – It’s a plant-based and allergy-free wax emulsifier. It is derived from the wild Mexican candelilla plant, which forms the wax on the outside of its leaves to protect it from water loss. Lotions made with candelilla wax sit on the skin for a longer time without breaking down, making them great for drier or sensitive skin that needs more protection.

  • BEESWAX- Beeswax has a softening and healing properties on its own and also works well as a thickener and emulsifier. It's best used in oil-in-water emulsions. It also makes a base for creams when used along with other emulsifiers. 

  • LECITHIN- This fatty phospholipid mixture is a perennial widely used by the Dyers because it is versatile and easy to use. Lecithin is found in a wide variety of plant and animal products. It is ideal for anti-aging products for drier, more mature skin.