3.2.3

Raising Agents

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Raising Agents - Carbon Dioxide

Raising agents help cakes to 'rise' by producing gas which expands in doughs and mixtures when they're heated. Some agents add carbon dioxide.

Chemical raising agents

Chemical raising agents

  • Bicarbonate of soda is an alkali raising agent that breaks down when it's heated. Carbon dioxide bubbles form and, when they expand, cause a mixture to rise.
  • Baking powder contains both bicarbonate of soda and an acidic substance called cream of tartar. Heating baking powder sparks a neutralisation reaction.
  • Self-raising flours are made up of baking powder and plain flour.
Biological raising agents

Biological raising agents

  • Yeast is a microorganism that's used to help bread dough rise.
  • Yeast releases carbon dioxide and alcohol through the process of fermentation.
  • We usually have to prove doughs that contain yeast. This involves letting them stand in a warm environment to let fermentation happen.
  • During the proving process, the carbon dioxide that's released gets trapped and the dough rises.
  • When the dough is baked, the high heat kills the yeast and ends the fermentation process. Baking causes the carbon dioxide in the dough to expand (and the bread to rise) and the alcohol to evaporate.

Raising Agents - Steam and Air

Raising agents help cakes to 'rise' by producing gas which expands in doughs and mixtures when they're heated. Some agents produce steam or air.

Steam

Steam

  • When very liquidy mixtures (e.g. Yorkshire puddings) are cooked in hot ovens, water escapes as steam. The rising steam helps to raise the mixture.
  • The mixture bakes and solidifies as water escapes.
  • Any cold air that gets added (e.g. from opening the oven door) will sink the mixture.
Mechanical processes

Mechanical processes

  • We can fold air into doughs and mixtures by:
    • Literally folding pastry doughs into layers. Air gets trapped between folds.
    • Using the folding technique for mixtures. This involves using a spatula or spoon to cut through the mixture and pour it over itself to trap air.
  • Sieving ingredients like flour traps air between individual particles.
  • Creaming adds air.
  • Rubbing fat into flour introduces air between individual flour particles.
Mechanical processes (continued)

Mechanical processes (continued)

  • Beating adds air to mixtures very rapidly. Beating involves mixing ingredients with a spoon or fork.
  • If a whisk is used, we call this process whisking.
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1

Food Preparation Skills

1.1

Food Preparation Skills

1.1.1General Practical Skills1.1.2Knife Skills1.1.3Preparing Fruit, Vegetables & Using Equipment1.1.4Cooking Methods: Prepare, Shape & Combine1.1.5Sauce Making, Tenderising & Marinating1.1.6Dough & Pastry1.1.7Shaping & Finishing Dough1.1.8Raising Agents & Mixtures1.1.9End of Topic Test - Food Preparation Skills 1
2

Food, Nutrition & Health

2.1

Macronutrients

2.1.1Proteins2.1.2Proteins 22.1.3Fats2.1.4Carbohydrates2.1.5Carbohydrates 2
2.2

Micronutrients

2.2.1Fat-Soluble Vitamins2.2.2Water-Soluble Vitamins2.2.3Minerals & Water2.2.4Minerals & Water 22.2.5End of Topic Test - Macro & Micronutrients
2.3

Nutritional Needs & Health

2.3.1Informed Choices for a Balanced Diet2.3.2Informed Choices for a Balanced Diet 22.3.3Energy Needs2.3.4Nutritional Analysis2.3.5Diet Modifications2.3.6Diet-Related Problems2.3.7Diet-Related Problems 22.3.8End of Topic Test - Nutritional Needs & Health
3

Food Science

3.1

Cooking of Food & Heat Transfer

3.1.1Reasons for Cooking & Heat Transfer3.1.2Water-Based Cooking Methods3.1.3Fat-Based Cooking Methods3.1.4Dry Cooking Methods3.1.5Dry Cooking Methods 2
3.2

Functional & Chemical Properties of Food

3.2.1Proteins & Carbohydrates3.2.2Fats & Oils3.2.3Raising Agents3.2.4End of Topic Test - Food Science
4

Food Safety

4.1

Food Spoilage & Contamination

4.1.1Microorganisms & Signs of Food Spoilage4.1.2Enzymes & Signs of Food Spoilage4.1.3Food Poisoning4.1.4Bacterial Contamination4.1.5Microorganisms in Food Production
4.2

Principles of Food Safety

4.2.1Temperature Control4.2.2Ambient Foods & Food Labels4.2.3Preparing, Cooking & Serving Food4.2.4End of Topic Test - Food Safety
5

Food Choice

5.1

Factors Affecting Food Choice

5.1.1Factors Which Influence Food Choice5.1.2Food Choices5.1.3Religious Food Choices5.1.4Food Labels5.1.5Mandatory Food Labels5.1.6Optional Food Labels5.1.7Marketing Influences5.1.8End of Topic Test - Food Choice
5.2

British & International Cuisines

5.2.1British Cuisine5.2.2Japanese Cuisine5.2.3Japanese Ingredients & Dishes5.2.4Spanish Cuisine5.2.5Spanish Ingredients & Dishes
5.3

Sensory Evaluation

5.3.1Taste Receptors & Olfactory Systems5.3.2Sensory Testing Methods5.3.3Sensory Testing Methods 25.3.4End of Topic Test - Cuisines & Senses
6

Food Provenance

6.1

Environmental Impact & Sustainability of Food

6.1.1Food Sources - Intensive & Organic Farming6.1.2Food Sources - Genetically Modified Crops6.1.3Food Sources - Reared Food6.1.4Food Sources - Caught Food6.1.5Food & The Environment6.1.6Food & The Environment 26.1.7Sustainability of Food6.1.8Sustainability of Food 26.1.9End of Topic Test - Environmental Impacts
6.2

Food Processing & Production

6.2.1Primary Food Processing6.2.2Primary Food Processing 26.2.3Secondary Food Processing6.2.4Fortification6.2.5Additives6.2.6End of Topic Test - Food Processing & Production

Practice questions on Raising Agents

Can you answer these? Test yourself with free interactive practice on Seneca — used by over 10 million students.

  1. 1
    What type of raising agent is yeast?Multiple choice
  2. 2
    What are the ingredients of baking powder?Fill in the list
  3. 3
    Making Bread with YeastPut in order
  4. 4
    What do we call it when ingredients are mixed with a spoon or a fork?Multiple choice
  5. 5
    Which of the following processes does NOT add air to mixtures?Multiple choice
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Fats & Oils

End of Topic Test - Food Science