How does the temperature of egg white affect the fluffiness of souffle? (Cathy Tsang)

Figure 1: Souffle made by myself

Introduction:

Souffle, a traditional French dessert, palatable for its fluffiness and sweetness. However, its devil high content of butter and sugar discourage dieters like you and me from taking a bite of it. Now, this low sugar souffle, undoubtedly, is the one you should go for!  

The science behind egg white:

To start with, egg white consists of 90% of water and 10% of proteins (Science of Food, n.d.). The egg white proteins are globular protein which maintains its spherical shape by the existence of weak chemical bond like hydrogen bond within it (GIAPO, 2017; Science of Cooking, n.d.).

 Figure 2: Globular protein in egg white

                                                                                                                                           During the whipping of egg white, the incorporation of air bubble into the egg white 
will uncurl the protein, in another word, the egg white protein will denature (Science of Cooking, n.d.). This is because in the process, the hydrophilic part of protein will stick to the water while the hydrophobic part will stick to the air, result in its unfolding (Science of Cooking, n.d.). The uncurling of proteins results in the formation of a network of uncoiled protein that traps air bubbles within it, contribute to the fluffiness of souffle (GIAPO, 2017).

Figure 3: Denatured globular protein

Figure 4: Incorporation of air bubble


Temperature of egg white plays a significant role in the whipping of egg white. It is commonly found that cold egg whites do not whip well when compared with those room-temperature one (GIAPO, 2017; Science of Cooking, n.d.; What’s Cooking America, n.d.). This is because the chemical bonds between egg white protein molecules become stronger when cooled, which makes it more difficult for its denaturation to incorporate the air bubbles into the souffle. While for high temperature, too many bonds will be formed and the egg white end up becoming rubbery (Science of Cooking, n.d.). Therefore, it is an interesting topic to investigate how does the temperature of egg white affect the height (which is related to fluffiness).

It is advisable not to use a plastic bowl for whipping as the grease is easily retained it, which results in failure in whipping (Science of Cooking, n.d.). Copper bowl is advised as the binding between copper molecules and egg white proteins (conalbumin) aid the incorporation of air bubbles and hence contributes to its fluffiness (GIAPO, 2017).

Experimental test: 

Who?

Cathy from group 17.

What?

To investigate whether the temperature od egg white affect the fluffiness of souffle.

Where?

Kitchen at my home.

When?

Measuring the height of the 4 souffles immediately after making them.

Why?

To find the best temperature of the egg white for making the fluffiest (highest) souffle.

How?

Using the same recipe for making the four souffle and the only change in each experiment is the temperature in which the egg white is stored before whisking. Noted that it is crucial to measure the height of souffle immediately after the experiment. This is because when removing the souffle from the hot oven, air inside the souffle will contract, leading to the quick deflation.

Basic Recipe:

Ingredients:

2g butter (for greasing the ramekins)

2g sugar (for coating the ramekins)

10g butter

5g sugar (for the egg yolk mixture)

55ml milk

1 egg yolk

10g cake flour

2 egg whites

10g sugar (for the egg white mixture)

 Preparation:

1. Bring milk, sugar and butter to simmer.

2. Sift in cake flour to the mixture. Blend while sifting in the flour.

3. Turn off the stove when no cake flour granules remain.

4. Add egg yolk to the mixture and mix well.

5. Put the egg whites and sugar into another bowl.

6. Whisk the egg white until it forms a peak.

7. Mix 1/3 of the egg white mixture to the egg yolk mixture.

8. Pour the above egg yolk and egg white mixture into the remaining egg white mixture, mix well.

9. Use the ice-cream scoop to evenly distribute the mixture into the four prepared ramekins

10. Smooth out the surface by spoon.

11. Bake the souffle in the oven at 180°C for 16 minutes.

12. Remove the souffle from the oven and the souffle is ready to be served.

Preparation time: 15mins

Cooking time: 30mins

Total time: 45mins

Independent variable	Dependent variable	Controlled variables
- temperature in which the egg white is stored before whisking. (0 °C, 10 °C, 20 °C, 30 °C, 40 °C, 50 °C, 60 °C, 70 °C and 80 °C)	- the height of the souffle, which implies the fluffiness of the souffle.	- brand of all ingredients (butter, sugar, milk, egg and cake flour). - volume and the amount of all ingredients (butter, sugar, milk, egg and cake flour). - speed of whisking the egg white by electric mixer. - time of whisking the egg white by electric mixer. - time for baking. - the temperature of the oven used. - the fire temperature of the stove used. - time for mixing the cake flour in the stove. - time for mixing the egg yolk mixture. - time for mixing the egg yolk and egg white mixture. - the volume of souffle mixture in each ramekin. - the amount of butter used for greasing each ramekin. - the amount of sugar used for coating each ramekin. - the length of time in which the egg white is stored under different temperature. - the position of ramekins in the oven. - time to measure the height of souffle after baking is completed.

Reference:

German Pool. (2012, December 27). Recipe: 梳乎厘 Souffle[.flv]. Retrieved from https://www.youtube.com/watch?v=K4ykH1SPZQk.

GIAPO. (2017). The chemistry of egg white. Retrieved from https://www.giapo.com/the-chemistry-of-egg-whites/.

Science of Food. (n.d.). Science of egg. Retrieved from https://www.exploratorium.edu/cooking/eggs/eggscience.html.

What's Cooking America. (n.d.). Perfect egg white meringue. Retrieved from https://whatscookingamerica.net/Eggs/perfectmeringue.htm.