Antioxidants
Stop fatty foods from going rancid and protect fat soluble vitamins from the harmfull effects of oxidation

Colours
Make food more colourfull, compensate for colour lost in processing

Emulsifiers
Enable fats and oils to mix with water in foods, Adds to smoothness and creaminess of texture, retards baked goods going stale

Stabilisers
Stabilises emulsions formed by emulsifiers, which would otherwise seperate out

Preservatives
Protect against microbes which cause spoilage and food poisoning. Also increase storage life of foods (retards chemical changes)

Sweeteners
Two types of sweeteners: Intense sweeteners and bulk sweeteners.
Intense sweeteners have a sweetness many times that of sugar and are therefore used at very low levels.
Bulk sweeteners have about the same sweetness as sugar and are used at the same sort of levels as sugar