Which of the following is used to detect the presence of starch in food?

Question

Question

This question was previously asked in

RRB Group D 17 Sept 2022 Shift 3 Official Paper

Answer 1

The correct answer is "Iodine solution".

Key Points

Iodine solution can be added as a chemical test for starch to examine if it changes color from brown to blue or black. This iodine solution test allows the separation of starch from other carbohydrates.
- Example: Iodine, for instance, will cause a peeled potato to turn black.
One of the main sources of dietary energy for people is starch, a type of carbohydrate that is frequently discovered in nature.
Starch can be detected using a triiodide solution, which is created by combining iodine and an iodide solution (most commonly potassium iodide).
This solution generates a strong blue-black starch-iodine combination. The triiodide solution's brown hue persists in the absence of starch.
When triiodide anion solution is added to starch, a charge transfer complex between the molecules forms, which is the cause of the complex that results.
It is crucial to understand that this complex formation does not take place in solutions containing only iodine or iodide.
Therefore, an Iodine solution is used to detect the presence of starch in food.

Additional Information

Solution	Use
Litmus solution	Blue litmus paper turns red under acidic conditions, while red litmus paper turns blue under basic or alkaline settings. This property of litmus allows it to be used as a primary indicator of the acidity or basicity of a solution.
Phenolphthalein	As an indicator in titration tests to show the titration's endpoint, phenolphthalein is a colorless, weak acid that is frequently utilized.
Benedict's solution	This chemical solution, which is employed in clinical urine testing for diabetes, changes color with the presence of glucose and other reducing sugars. It consists of a combination of copper sulfate, sodium or potassium citrate, and sodium carbonate.