This experiment looks at how egg white ( albumen ) is transformed as it is whisked. Egg white is about 2/3 of the total weight of an egg, and is 10% protein, the rest being mostly water. To demonstrate the change in the egg white we are going to make Meringue.
What you need:
- A bowl
- A whisk
- Baking sheet
- 4 egg whites
- 225g caster sugar
You can use less eggs as long as you use about 55g of caster sugar per egg white.
- Pre-heat the oven to 140 degrees, gas mark 1.
- Line 2 baking sheets with parchment
- Put the egg whites in a bowl and whisk slowly at first then faster as they expand. Once you get stiff peaks the egg whites are ready.
- Add the sugar slowly a few tablespoons at a time and whisk after each sugar addition.
- Place 2 heaped tablespoons of mixture onto the baking parchment, leave a gap and then repeat until all your mixture is used up.
- Place in the oven on a low shelf for about 45 minutes. Then turn the oven off, but leave the meringues inside for a further 15 minutes.
- Serve with whipped cream and fruit.
The Science Bit
When we whisk the egg white, two things happen:
- The whisk creates a force through the egg white which unfolds the protein molecules.
- The whisking also causes air bubbles to be trapped in the unfolded proteins which makes a foam.
When baked the foam hardens into meringue.