Ice cream is a colloid, a type of emulsion. An emulsion is a combination of two
substances that don't normally mix together. Instead, one of the substances is
dispersed throughout the other.
In ice cream, molecules of fat are suspended in a water-sugar-ice structure along with
The presence of air means that ice cream is also technically a foam.
Frozen dessert usually flavoured with fruit, made from water, sugar, flavourings, and
milk or cream.
Egg white or gelatin may be added to ensure a fine texture.
To identify the water content of ice
cream and sherbet mixtures and relate
this to freezing rate
To understand the effect of sugar
concentration on the depression
freezing point of water in ice cream
To understand the effect of a mixture
of salt and ice which surrounds a
container of mixtures of ice cream and
sherbets in the freezing process.
To appreciate the significance of
agitation during freezing, its effect on
the structure of the frozen mixture, and
overrun and its role in breaking up
large ice crystals to form a smooth-
To appreciate the significance of
stabilizers in maintaining the size of
crystals and the firm body of the frozen
Influence the freezing temperature of water.
Addition of a non-volatile solute like salt and sugar the freezing point drops in
proportion to the amount of dissolved substances and for an ionisable one, in
proportion to the dissociated ions.
Created when the water-content in the
base starts to freeze
Gives solidity and body.
The size of the ice crystals largely
determines how fine, or grainy, the ice
cream eventually turns out.
The main objective (apart from the
freezing itself) is therefore to keep the
size of the ice crystals down as much
Often in the form of butter (milk) fat.
Adds richness, stabilises the base mix, improves density and the smoothness of
texture and generally increase flavours
Sugars, honey or syrups
Adds sweetness but also
improves texture and body.
Lowers the freezing point of the
mix, ensuring that the ice cream
does not freeze rock-solid
The invisible (and cheapest) ingredient in ice cream.
The tiny air cells whipped into the base mix are largely responsible for the general
consistency of ice cream, and greatly affect texture and volume.
“Over-run” is the technical term used to indicate how much air an ice cream holds;
since air is free and increase the volume, non-premium commercial ice creams could
well have an overrun sometimes even exceeding 100 %.
Usually so-called non-fat milk solids, such as proteins and mineral
salts, and flavourings such as cookie-crumbles.
Contribute to the body, texture and smoothness.
More solids means less “free-roaming” water in the ice cream – which in turn usually
means less unwanted, large ice crystals in the ice cream.
Too little solids, the ice cream often tends to become unpleasantly icy.
Too much solids, however, may bring about an unpleasantly sandy-like sensation.
added to the ice cream base – one or more ingredients that help the other “unwilling”
ingredients to combine.
Improve the structure and texture by keeping down the growth-rate of the ice crystals
of the ice cream
Reduce the melt-down speed of the ice cream.
Gelatin, egg whites
A well frozen appearance
Absence of large ice particles
A pleasing blend of banana with lemon or lime rind, a subtle
acid taste which complements the bland banana flavor
Introduction to Food Preparation by Guzman, M.P. and Fojas de Luna, M.V.
Chemisrty: The Central Science by Brown and Le May