ADDITIVES

Additives are used in the manufacture of margarine and spreads to improve their keeping properties, appearance and stability.

Antioxidants

Antioxidants prevent fats and oils from going rancid due to oxidation of the unsaturated fatty acid radicals in the triglycerides of which fat is composed. Antioxidants which occur naturally in fats tend to prevent the oxidative changes which produce rancidity. The most effective being vitamin E.

Rancidity

Oils and fats are liable to spoilage which results in the production of unpleasant odours and flavours; such spoilage is usually described by the general term rancidity. Different types of oil and fat show varying degrees of resistance to spoilage; thus most vegetable oils deteriorate only slowly, whereas animal fats deteriorate more rapidly and marine oils, which contain a relatively high proportion of combined highly unsaturated fatty acids deteriorate so rapidly that they need to undergo refining and hydrogenation if they are to be used for edible purposes.

Emulsifiers

When oil is added to water it forms a separate layer above the water; the oil and water do not dissolve in each other and are said to be immiscible. If oil and water are shaken together the two liquids become dispersed in each other and an emulsion is formed. If the liquid is allowed to stand then it reverts back to the two layers, therefore this form of emulsion is termed an unstable emulsion.

Emulsions are described as being either oil in water (O/W) or water in oil (W/O) emulsions. Margarine is termed a water in oil emulsion as small droplets of water are dispersed through the oil. In order for the oil and water to form a stable emulsion a third substance called an emulsifying agent or emulsifier is used. In the case of margarine, the emulsifying agents most commonly used are proteins e.g. casein, lecithin or glycerol monostearate (GMS).

Stabilisers

Stabilisers are sometimes used to maintain the emulsion once it has been formed.

Colours

Colours are added to replace colour lost during processing, the colour most commonly used is Beta Carotene.

Preservatives

Preservatives are used to extend the products shelf life and to prevent microbial growth which can cause food spoilage, products most commonly used in the manufacture of margarine and spreads include sorbic acid and lactic acid.

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