Food and Nutrition in Humans

1. Food and Nutrition in Humans Food Test and Storage

2. Food Test theory • Heat is required ONLY for Benedict’s test for reducing and non-reducing sugars • Reducing sugars are so called because they reduce blue copper sulphate (CuSO4) in Benedict’s solution to a reddish precipitate

3. Food Test theory cont’d • Simple sugars are reducing sugars • Some complex sugars are also reducing sugars e.g. maltose • Sucrose, a complex sugar is a non-reducing sugar

4. Food Test theory cont’d • There is no direct test for non-reducing sugars • A non-reducing sugar can be broken down to simple sugars by heating it with a dilute acid like HCl (hydrolysis) • The resulting mixture is acidic and must first be neutralized by adding a small amount of alkali like NaHCO3 • The test for reducing sugar can then be carried out • The red precipitate obtained confirms that a non-reducing sugar was originally present

5. Table summarizing the method and results of food tests

6. Complete the following table to indicate where and in what forms the named organisms store food

7. Complete the blank spaces in the following tale which shows the method and positive results of selected food tests

8. Essay Type • (a) State clearly how you would test a sample of flour for • (b) Include the apparatus and materials you would use • (c) Describe the procedure and the results expected if positive • Starch • Reducing Sugar • Protein • Fat

10. FOOD RESERVES AND SITES OF STORAGE IN SOME COMMON SEEDS