Food Tests: Standard Tests for Starch, Reducing Sugars, Proteins, and Lipids in Different Foods

The video tutorial covers standard food tests for detecting starch, reducing sugars, proteins, and lipids. It explains the procedures and expected results for each test, using iodine for starch, Benedict's solution for reducing sugars, biuret solution for proteins, and ethanol with water for lipids. The tests are then applied to puffed rice and cottage cheese, demonstrating the presence or absence of these components in each food.

What color change indicates the presence of starch when iodine is added?

• Red

• Blue-black

• Yellow

• Green

Which reagent is used to test for reducing sugars?

• Iodine

• Biuret solution

• Benedict's solution

• Ethanol

What does a brick red color indicate in the Benedict's test?

• Presence of starch

• Presence of proteins

• Presence of reducing sugars

• Presence of lipids

What is the initial color of the biuret solution before testing for proteins?

• Violet

• Green

• Blue

• Red

What color change indicates the presence of proteins when using biuret solution?

• Blue to violet

• Red to green

• Yellow to blue

• Green to red

What forms on top of the mixture if lipids are present in the ethanol test?

• A red precipitate

• A blue layer

• A milky emulsion

• A clear solution

Which test would you use to detect lipids in a food sample?

• Biuret test

• Ethanol test

• Benedict's test

• Iodine test

What was the result of the starch test on puffed rice?

• Negative

• Positive

• Inconclusive

• Not tested

Which component was not found in puffed rice during the tests?

• Starch

• Reducing sugars

• Proteins

• Lipids

What was the result of the protein test on cottage cheese?

• Negative

• Not tested

• Positive

• Inconclusive