Question

Emulsion test is conducted to detect
A) Glucose
B) Proteins
C) Starch
D) Fats

Answer 1

Hint: The solubility of a given solution is tested by adding ethanol into it.

Complete answer:
Emulsion test is a food test which determines the presence of lipids. Lipids consist of fats and oils. Commonly used emulsifiers were egg yolk or mustard. Other tests for determining the presence of fat are Sudan stain test and Grease spot test.
Emulsion test for fats and oils
Take the food sample in a test tube.
Add ethanol to the test tube. Shake well and allow them to settle
Add diluted water into it.
Observation: A milky-white emulsion shows the presence of fats. If the solution remains clear, the presence of fat is absent.

Additional information:
Fat means any ester of fatty acids or a mixture of such compounds; most commonly those that occur in living beings or in food.
Along with the carbohydrates and proteins, fats are one of the three main macronutrient groups in the human diet and the main components of common food products like milk, butter, and cooking oils.
In most living beings, fats are the major and dense source of food energy and play an important role in structural and metabolic functions. It helps in energy storage, waterproofing and thermal insulation.
Mainly our body can produce the fat it needs from other food ingredients, except for a few essential fatty acids that must be included in the diet.

So, the correct answer is ‘fats’.

 Note:
-Emulsions are thicker than either the water or fat/oil they contain, which is a useful property for some foods.
-The Grease spot test is conducted on fats which are solid at room temperature. Sudan stain test shows the presence of lipid as red, but is a less common bench reagent than ethanol. Most commonly used method is an emulsion test.