food tests

• iodine is used to test for starch.

  iodine is naturally a yellow/brown colour. when starch is present it turns a blue/black colour
• benedicts solution is used to test for glucose. benedicts is naturally a blue colour. there will be no colour change unless the temperature is above 60 degrees celsius. if positive it’ll turn brick red.
• biuret solution is used to test for protein. biuret is naturally a blue colour and will turn violet if protein is present
• you can find out the energy content of food by burning it, placing it under a volume of water and recording the temperature change. to find out the energy per gram you use a calculation
• energy released per gram= mass water (g) x temp. increase (degrees celsius) x 4.2/ mass of sample (g)
• food labels give information of contents per 100g to compare the differ nutrients of other foods