Food Tests - PRACTICAL Flashcards
Organisation (16 cards)
What is the first step in preparing a food sample for testing?
Get a piece of food and break it up using a pestle and mortar.
This step ensures the food is adequately prepared for testing.
What type of water should be added to the ground food in the preparation process?
Distilled water.
Distilled water is used to avoid impurities that could affect the test results.
What is the purpose of stirring the mixture with a glass rod?
To dissolve some of the food.
This helps in extracting the molecules to be tested.
What is the function of the funnel lined with filter paper in the food sample preparation?
To get rid of the solid bits of food.
Filtering is essential for obtaining a clear solution for testing.
What is the Benedict’s Test used for?
To test for reducing sugars.
Reducing sugars react with Benedict’s solution to produce color changes.
What types of sugars can be tested using Benedict’s Test?
Non-reducing and reducing sugars.
This distinction is important for understanding sugar types in food.
At what temperature should the water bath be set for the Benedict’s Test?
75°C.
The temperature is crucial for the reaction to occur properly.
What color change indicates the presence of reducing sugars in the Benedict’s Test?
From blue to green, yellow, or brick-red.
The color change depends on the amount of sugar present.
What is the Iodine Solution used to test for?
Starch.
Starch is commonly found in foods like pasta, rice, and potatoes.
What color change occurs if starch is present when using Iodine Solution?
From browny-orange to black or blue-black.
This reaction is a key indicator of starch presence.
What is the Biuret Test used for?
To test for proteins.
Protein-rich foods like meat and cheese are typically tested.
What color change indicates the presence of protein in the Biuret Test?
From blue to purple.
If no protein is present, the solution remains blue.
What is the Sudan III Test used to detect?
Lipids.
Lipids are found in foods like olive oil, margarine, and milk.
What happens to the mixture in the Sudan III Test if lipids are present?
It separates into two layers with a bright red top layer.
No separate red layer indicates the absence of lipids.
How much food sample should be used for the Sudan III Test?
About 5 cm³.
This volume is sufficient for accurate testing.
What is the role of the Sudan III stain solution in the test for lipids?
It stains lipids.
The staining is essential for visualizing the presence of lipids.
