A food is known to contain protein, but no reducing sugar. When this food is tested with biuret solution and Benedict's solution, which colors would a student observe?
| | Biuret test | Benedict's test |
|---|---|---|
| A | blue | blue |
| B | blue | brick red |
| C | lilac/violet | blue |
| D | lilac/violet | brick red |
Answer (2)
In the Biuret test, a food sample containing protein will show a lilac/violet color, while the Benedict's test will remain blue since there are no reducing sugars present. Thus, the correct answer is option C: lilac/violet for the Biuret test and blue for the Benedict's test.
;
Biuret test detects proteins, turning the solution lilac/violet.
Benedict's test detects reducing sugars; without them, the solution remains blue.
The Biuret test will be lilac/violet.
The Benedict's test will be blue, so the answer is C .
Explanation
Understanding the Problem We are given a food sample that contains protein but no reducing sugars. We need to determine the colors observed when this food is tested with Biuret solution and Benedict's solution.
Biuret Test The Biuret test is used to detect the presence of peptide bonds, which are found in proteins. A positive Biuret test results in a color change from blue to lilac/violet. Since our food sample contains protein, we expect a positive Biuret test.
Benedict's Test Benedict's test is used to detect the presence of reducing sugars. A positive Benedict's test results in the formation of a brick red precipitate. Since our food sample does not contain reducing sugars, we expect a negative Benedict's test, meaning the solution will remain blue.
Conclusion Therefore, the Biuret test will show a lilac/violet color, and the Benedict's test will show a blue color. This corresponds to option C in the table.
Examples
Understanding the chemical composition of food is crucial in various real-life scenarios. For instance, athletes need to ensure they consume enough protein for muscle repair and growth, while individuals with diabetes need to monitor their sugar intake. The Biuret test and Benedict's test are simple yet effective methods to quickly assess the presence of proteins and reducing sugars in food samples, helping individuals make informed dietary choices. Imagine a nutritionist using these tests to analyze a new protein bar to ensure it meets the advertised nutritional content and is suitable for clients with specific dietary needs. These tests can also be used in quality control in the food industry to ensure products meet certain standards.
