[B] Food Tests Flashcards
What is the purpose of food tests in the AQA GCSE required practical?
To identify the presence of different nutrients in food samples.
What reagent is used to test for reducing sugars?
Benedict’s solution.
True or False: A positive test for reducing sugars will change the color of Benedict’s solution to brick red.
True.
Fill in the blank: The test for starch is conducted using __________.
iodine solution.
What color indicates a positive test for starch?
Blue-black.
Which reagent is used to test for proteins?
Biuret reagent.
What color change indicates a positive protein test?
Purple.
What is the test for lipids?
Emulsion test.
What indicates a positive lipid test?
A white emulsion forms.
Which food test involves heating the sample?
Reducing sugars test with Benedict’s solution.
True or False: Proteins can be tested with Benedict’s solution.
False.
What is the first step in testing for starch?
Add a few drops of iodine solution to the food sample.
What is the purpose of the emulsion test?
To detect the presence of lipids in a food sample.
Fill in the blank: A positive test for reducing sugars is usually assessed after __________ minutes of heating.
2 to 5.
What color will Benedict’s solution turn if no reducing sugars are present?
Blue.
How can you confirm the presence of a fat in a food sample?
By observing a milky white emulsion after adding ethanol and water.
What is the role of heat in the reducing sugars test?
It facilitates the reaction between the reducing sugars and Benedict’s solution.
True or False: Lipids are soluble in water.
False.
What safety precaution should be taken when performing food tests?
Wear safety goggles and gloves.
What is the main component of Biuret reagent?
Copper sulfate.
What is the procedure for testing for starch?
Add iodine solution to the food sample and observe the color change.
True or False: The emulsion test can be used to test for carbohydrates.
False.
What color indicates the presence of proteins when using Biuret reagent?
Purple.
What type of carbohydrate can be tested using Benedict’s solution?
Reducing sugars.
Fill in the blank: The presence of starch is indicated by a __________ color change.
blue-black.
What happens to the iodine solution when starch is present?
It changes from brown to blue-black.
What is the main purpose of the food tests in the AQA GCSE curriculum?
To enable students to identify nutrients in various food samples.
What type of test detects the presence of glucose specifically?
Benedict’s test.
Fill in the blank: The test for proteins is known as the __________ test.
Biuret.
What is the significance of the color change in food tests?
It indicates the presence or absence of specific nutrients.
True or False: All food tests require heating the sample.
False.
What is the final step in the lipid emulsion test?
Add water to the test tube after ethanol.
What is the expected result when testing for proteins with Biuret reagent?
A color change to purple.
