Testing Foods for Reducing Sugars

Benedict’s solution is used to test foods for the presence of reducing sugars such as glucose. When heated with a reducing sugar, the blue solution changes to green, yellow, orange, or brick red depending on the sugar concentration.

1. Place the food sample in a test tube.
2. Add a few drops of Benedict’s solution.
3. Heat the mixture in a boiling water bath for 2–3 minutes.
4. Observe the color change: green/yellow/orange indicates some sugar, while brick red shows a strong positive result.

Biology - Reducing Sugars using Benedict's Reagent Demonstration - Bury College Official:

Benedict's Test for Reducing Sugars - JamJarMMX:

📄 Food test 2 - Benedict's test for Reducing Sugars - Biology Notes for IGCSE: https://biology-igcse.weebly.com/food-test-2---benedicts-test-for-reducing-sugars.html

• Compare fresh fruit juice to processed drinks.
• Test starchy foods before and after hydrolysis with amylase or acid.
• Quantify results by comparing shades of color to a standard chart.

• Use heat-resistant gloves or tongs when handling hot test tubes.
• Avoid direct flame on Benedict’s solution—use a water bath for heating.
• Dispose of test mixtures properly; do not ingest chemicals or tested food.

• Why does Benedict’s solution change color when reducing sugars are present? (Copper(II) ions are reduced to copper(I) oxide, which forms a red precipitate.)
• What foods are likely to contain reducing sugars? (Fruits, honey, soft drinks, some vegetables.)
• Why must the mixture be heated for the reaction to work? (Heat provides the energy needed to drive the redox reaction.)