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A student makes pineapple jelly using two different methods - OCR Gateway - GCSE Biology - Question 20 - 2023 - Paper 3
Question 20
A student makes pineapple jelly using two different methods. Both methods use a protein called gelatin which causes the jelly to set. Tinned pineapple is fresh pine... show full transcript
Worked Solution & Example Answer:A student makes pineapple jelly using two different methods - OCR Gateway - GCSE Biology - Question 20 - 2023 - Paper 3
Step 1
Explain why the jelly made with fresh pineapple does not set but the jelly made with tinned pineapple does set.
Answer
The jelly made with fresh pineapple does not set because fresh pineapple contains the enzyme bromelain, which breaks down proteins, including the proteins in gelatin. When fresh pineapple is added to the gelatin, bromelain digests these proteins, preventing the gelatin from forming a stable gel structure.
On the other hand, tinned pineapple is heated during the canning process. This heat treatment deactivates the bromelain enzyme, meaning it is no longer able to digest the gelatin’s proteins. As a result, when tinned pineapple is added to the gelatin, the proteins can properly coagulate, allowing the jelly to set as intended.