How can we find out if food contains protein, fat, starch or glucose? Food tests How can we find out if food contains protein, fat, starch or glucose? 08/08/2018

Equipment For test 1: Iodine solution in pipette topped bottles (8) Spotting tiles (8) Sample foods For test 2: Benedict’s solution in pipette topped bottles (8) 250 cm³ glass beakers (8) Test tubes & racks (8) Glucose powder Spatulas (8) Eye protection (glasses) (class set) Tripods, Bunsens & matches. For test 3: Biuret solution in pipette topped bottles (HAZARD – CORROSIVE) Hazcard for biuret solution. Protein solution (enough for ½ test tube per class) Eye protection (glasses) (class set) For test 4: Filter paper – (2 or 3 pieces per group) Sample foods 08/08/2018

Test 1: Testing for starch Use a spotting tile with the food samples. Add 2 drops of iodine solution to each food sample. Which of these foods contain starch? Record results. For test 1: Iodine solution in pipette topped bottles (8) Spotting tiles (8) Sample foods 08/08/2018

WASH YOUR HANDS! 08/08/2018

Test 2: Testing for glucose Use 2 spatulas of glucose powder in a third of a test tube of water. Dissolve. Put in 10 drops of Benedict’s solution. Heat carefully in a water bath. Note your result. For test 2: Benedict’s solution in pipette topped bottles (8) 250 cm³ glass beakers (8) Test tubes & racks (8) Glucose powder Spatulas (8) Eye protection (glasses) (class set) Tripods, bunsens & matches. 08/08/2018 HAZARD! Use eye protection

WASH YOUR HANDS! 08/08/2018

Test 3: Testing for protein Use ½ a test tube of protein solution. Put in 10 drops of Biuret solution. Note your result. HAZARD! Biuret solution is corrosive. Wear eye protection throughout the test. Remove only when all packing away is complete. For test 3: Biuret solution in pipette topped bottles (HAZARD – CORROSIVE) Hazcard for biuret solution. Protein solution (enough for ½ test tube per class) Eye protection (glasses) (class set) 08/08/2018

WASH YOUR HANDS! 08/08/2018

Test 4: Testing for fat Rub a small piece of each sample food onto part of a filter paper. Hold the filter paper up to the light. Is fat present? For test 4: Filter paper – (2 or 3 pieces per group) Sample foods 08/08/2018 HAZARD! Use eye protection

Questions What type of food is iodine solution used to test, and how can you tell if the test is positive? In science, what does the word ‘solution’ mean? When rubbing different foods on filter paper, the paper sometimes becomes translucent. What does this tell you about the food? What is the main hazard when using Biuret solution and what precaution should you take? What is the name of the test that will show if prorein is present in a food and how will you be able to tell? Glucose is a type of sugar. Your body uses glucose is a source of what? What test would you use for glucose and how would you know if the test was positive? 08/08/2018

Homework Complete the questions about food testing. Draw 3 diagrams to show the tests for starch, protein and glucose. 08/08/2018