Preparing food samples for all food tests:

1. Grind piece of food with a pestle and mortar
2. Add some distilled water and filter the solution

Benedict’s solution for sugar

• Add the food to a boiling tube
• add benedicts solution using a pipette
• Put it into a water bath set at 75 degrees

(RISK) Boiling water / flame can burn skin: use a water bath and wait for equipment to cool before touching (RISK) Benedict’s reagent spitting into eyes when heating: wear eye protection and point test tube away from face when heating (RISK) Benedict’s reagent as an irritant: clean up spills immediately and wear eye protection

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Colour change —> Turns from blue to brick red = sugar is present

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Iodine solution for starch

• Add the food and iodine solution to a test tube using pipettes
• Gently shake

(RISK) Iodine solution as an irritant: clean up spills immediately and wear eye protection

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Colour change —> Turns from orange to blue-black = starch is present

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Biuret for proteins

• Add the food and biuret solution to a test tube using pipettes
• Gently shake