Describe how pectinase is used in the production of fruit juice, and explain why this enzyme increases the yield of juice obtained.

Cambridge International IGCSE Biology (0610) — 21.1 Biotechnology and genetic modification · Describe · 4 marks · View as Markdown

Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).

Model answer (4 marks)

Pectinase is added to fruit pulp during juice production. The enzyme hydrolyses pectin, a polysaccharide that links plant cell walls together. By breaking down the pectin, the cell walls become loose and the juice inside the cells is released. This releases more juice from the fruit, increasing the overall yield.

Examiner tips

Use the word ‘hydrolyses’ or ‘breaks down’ for the action of pectinase. Mention pectin’s role in holding cell walls together. Show the link between cell wall loosening and juice release. Keep the answer short and to the point.
Remember the command word ‘Describe’ – give a clear, factual explanation rather than a narrative.
Use UK spelling (e.g., ‘hydrolyses’).

Common mistakes

Confusing pectinase with other enzymes such as cellulase.
Failing to state that pectin holds cell walls together.
Omitting the step that cell contents are released, or the yield increase.

Mark scheme (4 marks)

Pectinase breaks down pectin in plant cell walls
Pectin holds adjacent plant cell walls together
Breaking down pectin releases the contents of the cells
This increases the yield of fruit juice obtained

Key terms in this question

pectinase · pectin · yield