1. Level 3 Food Science and Nutrition
Introductory lesson
Level 3 Food Science and Nutrition

2. When can you cook ice cream with out it melting?!
When Making Baked Alaska!
How and Why does this work?
How can Meringue protect ice cream from the intense heat of an oven!?

3. Practical investigation
Preheat the oven to 200 degrees C.
Cut the cake to form a base for your ice cream mold. (Use a biscuit cutter for individual servings.) The base should be slightly bigger than the molded ice cream.
Separate the egg yolk and White CAREFULLY- no yolk must get into the white.
Make the meringue: Use a mixer to beat the egg white on high until soft peaks form.
Continue beating and add the 50g sugar one tablespoon at a time until you have stiff glossy peaks. (Lift the beater out of the bowl - if the peaks stay standing up, your meringue is ready.)
Place the cake on a Baking tray, then remove the ice cream from the mold and place it on top the cake base.
Use a spatula to quickly spread the meringue over the cake and ice cream, covering it completely. Make sure the meringue goes all the way down to meet the Baking tray. (If you think your ice cream is getting soft quickly, you can put the dessert back in the freezer for minutes before putting it in the oven.)
Place on the middle rack in the hot oven and watch closely. Remove when meringue is golden brown, about 3-5 minutes.

4. why didn't the ice cream melt completely when you put it into that very hot oven?
The answer is that the meringue acted as an insulator, slowing down the transfer of heat.
It works kind of like styrofoam (but tastier); It’s made of thousands upon thousands of tiny bubbles, and each one of them works like a little air gap, slowing down the transfer of heat from the oven to the ice cream.
Still air, you see, doesn’t move heat very well- Convective heat transfer, i.e. movement of heat via air flows (or liquid flows) is prevented.
It’s not so good at preventing the other two major modes of heat transfer: conductive (objects of different temperatures in physical contact with one another) or radiant (electromagnetic radiation).
The good news there is that most of the heat transfer that occurs inside a home oven is of the convective kind.

5. What IS a meringue?
A meringue is an egg white FOAM that has been stabilised using sugar.
A Foam is a ‘colloid’. This means it is a mixture of 2 different substances i.e. A gas that is dispersed through a liquid.
Egg white foams easily- a very fine ‘honeycomb’ mesh is formed.
How does this actually work though?

6. How does egg foaming work?
As liquid egg-white is whisked, the mechanical action causes its proteins to unfold and form a network, trapping air in tiny pockets.
Egg proteins have ‘hydrophobic’ water ‘fearing’ sections so they curl up in tight balls to avoid getting in contact with water.
Once they are whisked the hydrophobic ends attach to the air bubbles whilst the water loving ends attach themselves to the liquid egg.
As the whisking continues, the air pockets become smaller.
The change in colour (from translucent to brilliant white) is due to a trick of the light with the bubbles, rather than the egg's pigment.
Essentially, the foam is composed of small gas bubbles dispersed through the egg-white.
If the foam is baked, protein coagulates and moisture is driven off, forming a solid foam commonly known as meringue
The protein is denaturing

7. Plenary Questions
How can you bake ice cream in the oven without it melting?
What is meringue?
How does Egg Foaming Work?