Food test practical

• Which test is used for sugars?

  Benedict's test
• What is the iodine test used for?

  Testing for starch
• What does the Biuret test detect?

  Proteins
• What does the Sudan 3 test check for?

  Lipids
• What additional test is covered for Edexcel students?

  Emulsion test for lipids
• What is the first step in preparing a food sample?

  Break it up using a mortar and pestle
• What should you do after crushing the food sample?

  Add it to distilled water and stir
• Why do you filter the solution after preparing the food sample?

  To remove solid bits of food
• What are the two types of sugars mentioned?

  Reducing sugars and non-reducing sugars
• What does a blue solution indicate in the Benedict's test?

  No reducing sugars are present
• What color change indicates the presence of reducing sugars in the Benedict's test?

  Green, yellow, or brick red
• How do you perform the iodine test for starch?

  Add a few drops of iodine solution
• What color change indicates the presence of starch in the iodine test?

  From browny orange to blue-black
• What is the procedure for the Biuret test?

  Add 2 cm³ of sample and Biuret solution
• What color change indicates the presence of protein in the Biuret test?

  From blue to pink or purple
• What additional reagents are needed for the Edexcel Biuret test?

  Potassium hydroxide and copper sulfate
• What is the purpose of the Sudan 3 test?

  To stain lipids in the sample
• What indicates the presence of lipids in the Sudan 3 test?

  A bright red layer at the top
• What is the procedure for the Emulsion test for lipids?

  Add ethanol and shake vigorously
• What indicates the presence of lipids in the Emulsion test?

  A cloudy white color
• What is the temperature setting for the water bath in the Benedict's test?

  75° C
• Why should you point the test tube away from yourself?

  For safety reasons during heating
• What is the volume of food sample used in the Biuret test?

  2 cm³
• What is the volume of food sample used in the Sudan 3 test?

  5 cm³
• What is the role of the glass rod in preparing the food sample?

  To stir the mixture
• What happens if no lipid is present in the Emulsion test?

  No cloudy white color appears
• What is the significance of the color change in the tests?

  Indicates the presence of specific nutrients
• What is the main difference between reducing and non-reducing sugars?

  Reducing sugars can donate electrons
• What is the purpose of using distilled water in the food tests?

  To avoid contamination from minerals
• What is the role of the filter paper in the preparation of the food sample?

  To remove solid food particles
• What is the significance of the color blue in the Biuret test?

  Indicates no protein is present
• What does a blue-black color indicate in the iodine test?

  Presence of starch in the sample
• What is the importance of gently shaking the test tubes during the tests?

  To mix the solutions thoroughly
• What is the expected result if a food sample contains no lipids in the Sudan 3 test?

  No bright red layer will form
• What is the expected result if a food sample contains starch in the iodine test?

  The solution will turn blue-black
• What is the expected result if a food sample contains protein in the Biuret test?

  The solution will turn pink or purple
• What is the expected result if a food sample contains reducing sugars in the Benedict's test?

  The solution will change color
• What is the expected result if a food sample contains no reducing sugars in the Benedict's test?

  The solution will remain blue
• What is the expected result if a food sample contains lipids in the Emulsion test?

  The solution will turn cloudy white
• What is the expected result if a food sample contains no starch in the iodine test?

  The solution will remain browny orange