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Mindful Eating: A Pathway to Health - Test for Proteins

Grade 6CBSE

Review the key concepts, formulae, and examples before starting your quiz.

🔑Concepts

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Proteins are often referred to as 'body-building foods' because they are essential for the growth and repair of body tissues.

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The chemical test used to detect the presence of proteins in food items requires two specific reagents: Copper Sulphate (CuSO4CuSO_{4}) and Caustic Soda (NaOHNaOH).

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Preparation of the food sample: If the food item is solid, it must first be ground into a powder or made into a paste by adding a small amount of water.

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The test procedure involves adding 22 drops of Copper Sulphate solution and 1010 drops of Caustic Soda solution to the food sample in a test tube.

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Observation: If the mixture in the test tube turns violet or purple, it indicates that the food sample contains proteins.

📐Formulae

Protein Test→Food Sample+2 drops of CuSO4+10 drops of NaOH\text{Protein Test} \rightarrow \text{Food Sample} + 2 \text{ drops of } CuSO_{4} + 10 \text{ drops of } NaOH

Positive Result=Violet/Purple Color\text{Positive Result} = \text{Violet/Purple Color}

Negative Result=No color change or blue color remains\text{Negative Result} = \text{No color change or blue color remains}

💡Examples

Problem 1:

A student is testing a sample of egg white and a sample of potato for proteins. Describe the expected results for both using the CuSO4CuSO_{4} and NaOHNaOH test.

Solution:

The egg white will turn violet, while the potato sample will not change to violet (it might remain blue or clear).

Explanation:

Egg white is a rich source of protein, so it reacts with the reagents to produce a violet color. Potato primarily contains starch (carbohydrates) and very little protein, so the specific protein test will yield a negative result.

Problem 2:

In an experiment, a student adds 22 drops of Copper Sulphate and 1010 drops of Caustic Soda to a solution. Calculate the total number of drops of reagents added using vertical addition.

Solution:

2+1012\begin{array}{r} 2 \\ + 10 \\ \hline 12 \end{array}

Explanation:

The student added 22 drops of CuSO4CuSO_{4} and 1010 drops of NaOHNaOH, resulting in a total of 1212 drops of chemical reagents added to the food sample.