Food groups and Food tests LO: to sort food into food groups and carry out food tests TASK: 1.Why do we need to eat food and plants don’t? 2.Which food groups are in these pictures? 3.What is an balanced diet? (not kfc everyday!) 4.What happens to a human body if we don’t have balanced diet?

What happens if you lack vitamins and minerals? Vitamins =A, B, C, D etc Fruit, Vegetables and cereal Minerals = Iron, Sodium, Calcium etc Meat, Milk, cereal If we don’t have enough of something we call it a deficiency Scurvy- lack of vitamin C found in oranges, lemons, fruit and vegetables. Rickets- lack of calcium and vitamin B

A Balanced diet Balanced diet contains suitable proportions of each group of nutrients – carbohydrates, fats, proteins, minerals, vitamins, water and fibre – and the correct amount of energy. A balanced diet may differ depending on a persons age sex and level of physical activity Video: fast food vomit starvation, coronary heart disease, constipation and obesity

1. Benedicts test for reducing sugars 1. Add 2ml of unknown/control solution 2. Add 2ml of Benedict’s solution (WEAR GOGGLES!!) 3. Mix gently. Make sure tube is labeled on the top – as the label will soak in water! 4. Place test tube in a beaker and heat with Bunsen burner for 10 minutes 5.Record the color development after 10 minutes 3. Potassium Iodide test for Starch 1.Add 1 ml of unknown/control in a spotting tile 2. Add 1 drop (2mL) of Iodine solution If solution turns blue black, starch is present Increasing concentration of reducing sugar 2. Emulsion test for lipids/fats 1. Place the food sample into 2cm 3 of ethanol. 2. Pour the sample and ethanol into another test tube containing 10 cm 3 of water White emulsion/cloudy= presence of fats 4. Biuret test for Protein 1. Add 2 mL of unknown/control solution to a test tube 2. Add 4 drops of Biuret ’ s Reagent 1(NaOH) then 2 drops Biuret reagent 2(CuSO 4 ) (WEAR GLOVES AND GOGGLES!!) 3. Mix gently 4. Record color development against a white background Blue (-) Purple (+ test for protein) FOOD TESTS Draw a neat results table in your book and remember All food samples must be grind up first

Food sample Colour after adding Reagent Iodine test for Starch Benedict test for Sugar Biuret Test for Protein Emulsion test for Fats Apple Bread Potato chips Milk Steamed rice

Questions- answer in full sentences 1.Describe how you tested for starch 2.Describe how you tested for sugar 3.Describe how you tested for protein 4.Explain how you tested for fats 5.Which food contained sugar and which food had the highest concentration of sugar? 6.Which food contained protein and fat

Which chemical tested for which? Iodine Biuret solution Benidict’s solution Ethanol Iodine Biuret solution Benidict’s solution Ethanol Protein Starch Fat Sugar Protein Starch Fat Sugar

Copy and complete Starch will turn __________ from an _______________ colour to a _______________ colour _______________ will tune Biuret’s solution from a ___________________colour to a _________________ colour When heated with_____________ _______________ solution will turn ________________ Fat will turn a water and ______________ mixture____________milky