(a) State what is meant by the term 'raising agent'. [2] (b) Name one chemical raising agent, one biological raising agent and one mechanical raising agent....
Question 1 Report
(a) State what is meant by the term 'raising agent'. [2]
(b) Name one chemical raising agent, one biological raising agent and one mechanical raising agent. [3]
(c) Explain how baking powder works as a raising agent. [4]
(d) Describe how air can be used as a mechanical raising agent. Give one example of a food product where this method is used. [3]
Answer Details
(a) State what is meant by 'raising agent'. [2]
- A raising agent is a substance or method (1) that produces gas in a mixture, causing it to rise and become light in texture (1).
(b) Name one of each type of raising agent. [3]
- Chemical: baking powder or bicarbonate of soda (1)
- Biological: yeast (1)
- Mechanical: air (trapped by whisking, sieving, creaming, folding or rubbing in) or steam (1)
(c) Explain how baking powder works. [4]
One mark for each valid point (max 4):
- Baking powder contains bicarbonate of soda (an alkali) and cream of tartar (an acid) (1)
- When liquid is added, the acid and alkali react together (1)
- The reaction produces carbon dioxide gas (1)
- The carbon dioxide gas expands when heated in the oven, causing the mixture to rise (1)
- The heat then sets the protein structure, holding the risen shape (1)
(d) Describe how air is used as a mechanical raising agent. [3]
- Air is trapped in a mixture by actions such as whisking, sieving flour, or creaming fat and sugar together (1)
- When the mixture is heated, the trapped air expands and causes the product to rise (1)
- Example: a whisked sponge cake, where egg whites are whisked to trap air which makes the cake light (1)
OR meringues (1)
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