Lecture: ice cream
Ice cream structure
Ice cream is both a emulsion and a foam. The milk fat or yoghurt fat you incorporate in the ice cream
makes globules that form when you blend the mixture. Also, the bobbles of air in the ice cream is
what makes it a foam, the proteins that act as emulsifiers also act as a structure to trap air cells
(bobbles or air). These microstructures together will give the texture and characteristics which is
unique for ice cream.
You can make an ice cream of basically everything, these are the basic ingredients:
- Water: for ice crystals, can be from fruit juices, vegetables or alcoholic drinks
- Anti-freeze agent: sugar and salt can be anti-freezing agents
- Stabilizer/emulsifier: for fat components not able to solubilize in water, increases the
stability of air and fat globules, it can be polysaccharides, thickeners, pectin, gelatine etc.
- Fat (in case of ice cream not for sorbets)
Solubility
Water is considered as a universal solvent because it can basically dissolve almost everything.
However, this not completely accurate since it does only dissolve polar molecules or ions by forming
electrostatic interactions. Attracting ions by the charges what they have, water is a dipolar molecule
with positive ions on the side of the hydrogens and a negative side due to the electrons of the
oxygen. This also explains the liquid behaviour of water, molecules are constantly be rearranged to
form new hydrogen bonds. The property of solubility makes water quite easy to change some of the
other properties, namely the freezing and boiling points. The freezing point is (0 degrees and boiling
points 100 degrees), however, the freezing and boiling point of the solvent in a solution changes as
the concentration of the solute in the solution changes. IT can be calculated based on the molarity of
the components you are adding.
Ice cream structure
Ice cream is both a emulsion and a foam. The milk fat or yoghurt fat you incorporate in the ice cream
makes globules that form when you blend the mixture. Also, the bobbles of air in the ice cream is
what makes it a foam, the proteins that act as emulsifiers also act as a structure to trap air cells
(bobbles or air). These microstructures together will give the texture and characteristics which is
unique for ice cream.
You can make an ice cream of basically everything, these are the basic ingredients:
- Water: for ice crystals, can be from fruit juices, vegetables or alcoholic drinks
- Anti-freeze agent: sugar and salt can be anti-freezing agents
- Stabilizer/emulsifier: for fat components not able to solubilize in water, increases the
stability of air and fat globules, it can be polysaccharides, thickeners, pectin, gelatine etc.
- Fat (in case of ice cream not for sorbets)
Solubility
Water is considered as a universal solvent because it can basically dissolve almost everything.
However, this not completely accurate since it does only dissolve polar molecules or ions by forming
electrostatic interactions. Attracting ions by the charges what they have, water is a dipolar molecule
with positive ions on the side of the hydrogens and a negative side due to the electrons of the
oxygen. This also explains the liquid behaviour of water, molecules are constantly be rearranged to
form new hydrogen bonds. The property of solubility makes water quite easy to change some of the
other properties, namely the freezing and boiling points. The freezing point is (0 degrees and boiling
points 100 degrees), however, the freezing and boiling point of the solvent in a solution changes as
the concentration of the solute in the solution changes. IT can be calculated based on the molarity of
the components you are adding.
