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Design & Technology

Functional properties

Foods have different functional properties which can be treated and combined. They can be finished to improve palatability. Additives are used for a number of reasons and can be artificial or natural.

Nutritional properties

Starch

  • thickens a liquid by forming a suspensionsuspension: A mixture of two substances, one of which is finely divided throughout the other. such as a sauce
  • forms a gel when the suspension is heated, like adding cornflour to a custard powder and milk mix

Sugar

  • flavours by sweetening
  • colours by caramelising [caramelise: Turn to caramel - a brown liquid which sugar becomes when heated to the point where all the water has been driven off and the sugar begins to burn. ] when heated
  • aerates [aerate: Aerating mixes air into a material. ] when beaten with a fat such as in a cake mix

Proteins

  • can coagulate which is when a liquid becomes firmer, for example when an egg is heated
  • can aerate a mixture, like whisking egg whites in a meringue mix

Fats

  • shortens pastry (makes it more crumbly) by making it less stretchy
  • can act as an emulsifying agent [emulsifying agent: A substance that helps two liquids (eg oil and water) stay mixed together. ] to stop two liquids from separating
  • moistens a baked mixture such as a cake

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