Raising Agents

• Definition of raising agents.

  An ingredient or process that introduces a gas into a mixture so that it rises when it is cooked.
• Why are raising agents used?

  Consumers expect baked products to have a light, airy, soft and spongy texture. e.g. bread, cakes

  Gas, air or steam produce air bubbles when heating and will expand the mixture to create the desired texture as it sets.
• Types of raising agents

  • Mechanical raising agents
  • Physical
  • Chemical raising agents
  • Biological raising agents
• Mechanical raising agents

  Air - sieving, whisking, rubbing in, creaming, lamination (layers) e.g. flour, meringues, biscuits, sponge cake, pastry
• Physical

  Steam - water changes to steam when it reaches boiling point, 100C. The steam escapes from the mixture pushing it up and the mixture sets on cooling. e.g. Yorkshire pudding, choux pastry, bread, cakes
• Chemical raising agents

  Produce CO2 which is released into the product on heating. The gas expands and pushes up the surrounding mixture. The product cooks and sets.

  Bicarbonate of soda e.g. fruit cakes, sticky toffee pudding

  Baking powder incl, self-raising flour e.g. scones, cakes and puddings
• Biological raising agents

  Yeast - produces CO2 during fermentation e.g. bread
• Why are raising agents added into food?

  A cake which is cooked without using a raising agent will be moist, stodgy and heavy inside as the mixture has not produced air bubbles to help lift it properly.
• A successful raising agent

  A successful product should have a light texture and the product should have volume.

  It should be light and well risen.

  It should have clear air bubbles.
• Raising agents are used in food production because they add:

  • Consistency
  • Volume
  • Texture
  • Air bubbles
  • Correct finished product
• What are the 3 common raising agents?

  Air, steam and carbon dioxide.
• Air

  Mixture of gases.

  Incorporated in mechanical ways (e.g. using something else to help the process).

  There are 6 mechanical methods.

  Can you list them?

  Describe the process.

  Think of examples of products.
• Mechanical Methods

  Mechanical - manually adding air into food products using different techniques.

  1. Sieving flour.
  2. Creaming fat and sugar.
  3. Rubbing fat into flour.
  4. Whisking.
  5. Beating.
  6. Folding/rolling.

  The processes of sieving, whisking, folding, rolling, creaming all mechanically add in air during food production.
• Steam

  Water turns to steam when heated at 100C. Steam can expand up to 1600 its original volume.

  Only works if mixtures have:

  • High amounts of liquid
  • High baking temperature
• Steam

  • As liquid reaches boiling point steam is released.
  • Steam forces its way up through the mixture, stretching and rising the structure.
  • The mixture bakes and sets in shape.
  • Open and uneven texture where steam has escaped.
• Chemical (carbon dioxide)

  Adding a chemical which causes a chemical reaction producing CO2 gas expands and pushes up the mixture. Some of the gas escapes but some is trapped in the mixture as it cooks and sets.

  Examples in food production include baking powder and bicarbonate of soda.

  Bicarbonate of soda is used to make soda bread, the bread which does not use yeast as the raising agent.

  Bicarbonate of soda + cream of tartar = baking powder
• Biological (carbon dioxide)

  A biological raising agent is added which produces CO2 gas.

  The fermentation process is activated during bread production when yeast is combined with sugar in a warm moist condition. When the fermented yeast is added to the flour and warm liquid it increases in size during the "proving" stage.

  Example: bread