EmulsificationEmulsification is the name given to the process of making an emulsion. An emulsion is a mixture of two or more liquids that are normally immiscible, and are held together by an emulsifier. Emulsifying agents have a hydrophylic head and a hydrophobic tail, meaning that they are able to join the two immiscible substances together and hence, stabilise the emulsion.
The pictures to the right are examples of foods that are or contain emulsions, with different emulsifying agents that hold them together. |
In this recipe... |
Emulsification occurs in the garlic aioli recipe, but not the recipe for the beef burger which contains the emulsion. The chemical reactions denaturation and coagulation are involved in the recipe for the beef burger.
The ingredients in the garlic aioli recipe that are involved in the chemical reaction fermentation are water, olive oil and egg. Water and oil are the two substances that are normally immiscible and require the presence of an emulsifier to stay permanently mixed. In this recipe, the emulsifier is lecithin which can be found in the egg. Emulsions are classified as systems of matter called colloids. The type of colloid this recipe creates is a liquid within a liquid. Analysis of chemical reaction in method: The emulsifier (the egg) is processed with other ingredients in step one. In step 2, the oil is added and mixed with the emulsifying agent. They are able to be mixed together because the emulsifier has a hydrophobic tail, which can attract the oil. In step 4, the water is added to the mixture and is not repelled by the oil because the emulsifier holds the water with its hydrophilic head. This means that the water and oil have successfully been mixed together and are stabilised by the emulsifier. |
Physical changes |
There is a colour change after the water and oil are mixed together with egg. Originally, water and oil would remain separate, and the colours would stay separate too. After emulsification has occurred, the mixture will have acquired a pale orange colour from the egg yolk.
After water and oil have undergone emulsification, the taste would have changed as well. Aside from the flavourings that are added to the aioli, which include salt and garlic, water and oil blended together would have a taste improvement from the original mixture of oil on top of water. There would have been a great change in appearance after a mixture has gone through emulsification. Instead of oil sitting on top of water, the two substances would be mixed together along with the egg yolk. The viscosity of the mixture would be changed with emulsification as well. Originally, water and oil would be liquids of high viscosity, but when they are turned into an emulsion, the viscosity is lowered considerably as they are turned into a sauce. Oily water and garlic aioli have very different textures. While the original mixture would have been watery, the aioli after emulsification would have a smooth texture such as that of mayonnaise. |
Evaluation of recipe
Emulsification is a very significant chemical reaction in the recipe for garlic aioli. If it didn't occur, the aioli would not even look like a sauce and definitely would not taste like one. This chemical reaction greatly improves the eating quality of aioli.
The chemical reaction greatly impacts the physical properties of the final product, as explained in the above section. The physical changes significantly improve the eating quality of the aioli. Compared to garlic flavoured oily water, garlic aioli is much better in taste and texture.
Two factors that can determine the success or failure of the chemical reaction and recipe are the ratio of olive oil to water and the amount of egg yolk that is added. Too much oil or too little oil can lead to some parts of the mixture still being immiscible and emulsification would not be able to occur in the entire aioli. As previously mentioned in other recipes, the solution to this is to read the ingredients section and ensure that the correct measurements are used. It is also important to ensure that enough egg yolk (the emulsifier) is added to the mixture so that it can be successfully turned into an emulsion. To ensure enough is added, the egg yolk and the egg whites have to be carefully separated so that some of the egg yolk does not get mixed up with the egg white, otherwise there will not be enough left to act as an emulsifier.
The chemical reaction greatly impacts the physical properties of the final product, as explained in the above section. The physical changes significantly improve the eating quality of the aioli. Compared to garlic flavoured oily water, garlic aioli is much better in taste and texture.
Two factors that can determine the success or failure of the chemical reaction and recipe are the ratio of olive oil to water and the amount of egg yolk that is added. Too much oil or too little oil can lead to some parts of the mixture still being immiscible and emulsification would not be able to occur in the entire aioli. As previously mentioned in other recipes, the solution to this is to read the ingredients section and ensure that the correct measurements are used. It is also important to ensure that enough egg yolk (the emulsifier) is added to the mixture so that it can be successfully turned into an emulsion. To ensure enough is added, the egg yolk and the egg whites have to be carefully separated so that some of the egg yolk does not get mixed up with the egg white, otherwise there will not be enough left to act as an emulsifier.