Grind, filter, test. Name the reagent and the colour.
Food tests come up in almost every 0610 Paper 6. Here a piece of avocado is ground with distilled water and filtered, and the extract is tested for reducing sugar (Benedict’s solution in a hot water-bath), starch (iodine solution), protein (biuret solution), fat (the ethanol emulsion test) and vitamin C (DCPIP, counting the drops). Watch the set-up built step by step, then build it yourself and check it against the points the examiners look for.
Past-paper referenceOriginal experiment, wording and figures, written in the style of Cambridge IGCSE Biology 0610 Paper 6 (Alternative to Practical). It is not copied from a past paper. The “what the examiners said” notes are our paraphrase of the Principal Examiner Reports for Teachers.
Practise next: 0610/63 May/June 2023, (food tests on three drinks: results table, hazard, DCPIP and the emulsion test) · official past papers
Practise next: 0610/61 October/November 2024, (predicting food test colours, and the test for reducing sugar) · official past papers
Practise next: 0610/62 October/November 2024, (a negative iodine result and describing the Benedict's test) · official past papers
Examiner reports used: 0610 June 2023 (Papers 62 and 63), November 2023, March 2023, March 2024, June 2024, November 2024 (Papers 61 and 62), March 2025 and June 2025.
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What a full-mark diagram shows
Reagent and method
Benedict’s solution heated in a hot water-bath; iodine solution; biuret solution; ethanol then water, shaken; DCPIP added to drop by drop.
Colours
Blue to green, yellow, orange or brick-red; yellow-brown to blue-black; blue to purple; cloudy white; blue to colourless.
Fair comparison
The same volume of extract and of reagent in every tube, measured with a syringe or measuring cylinder; the same volume and concentration of DCPIP.
Table and safety
One table with headings for test and food, recording the colours seen; a real hazard (hot water can scald) with a precaution.
Habits the examiner reports keep asking for
Say hot water-bath. “Put it in a water-bath” alone did not earn the heating mark.
Blue-black, not blue. And iodine solution itself is yellow-brown, which is also the result when there is no starch.
Ethanol first, then water, then shake. The order and the shaking are the marks students lose.
Count drops, not time. Fewer drops of juice to decolourise the same DCPIP means more vitamin C.
One table for everything, with the colours you saw, not “positive” and “negative”.