Name the test employed to check the purity of butter through the estimation of volatile fatty acid is

RRB Nsg Superintendent -29 April 2025 (Shift-1st)

Applied Nutrition & Dietetics

Easy

Appeared in: RRB Nsg Superintendent -29 April 2025 (Shift-1st)

Explanation

The Reichert-Meissl (RM) number is the standard measure for volatile, water-soluble fatty acids.
Butterfat is uniquely rich in these volatile fatty acids, such as butyric and caproic acid.
A high RM value (20-30) is characteristic of pure butter, while adulterants like vegetable oils have an RM value near zero.
Therefore, this test is highly specific for detecting the adulteration of butter with other fats.

Option A: The Iodine number measures the degree of unsaturation (number of double bonds) in a fat, not the quantity of volatile fatty acids.
Option B: The Saponification number indicates the average molecular weight of the fatty acids in a fat. While related to chain length, it is not a direct measure of volatile acids.
Option C: The Acid number measures the amount of free fatty acids present due to hydrolysis. It is a measure of rancidity or spoilage, not adulteration.

Visual 1: Infographic: A chart comparing the fatty acid profiles of butter, coconut oil, and sunflower oil, highlighting the high percentage of short-chain volatile acids (butyric, caproic) in butter.
Visual 2: Flowchart: A simple diagram illustrating the steps of the Reichert-Meissl distillation and titration process to determine the RM value.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Biochemical tests for the analysis and purity of fats and oils as background academic context rather than a clinical decision trigger.
Food Safety and Adulteration: Understanding these tests is crucial in public health and nutrition for ensuring food quality and safety. Detecting adulterated butter protects consumers from fraud and potential health risks associated with consuming unknown fats.
Nutritional Assessment: The type of fatty acid in a diet has significant health implications. These tests form the basis of food science that informs nutritional guidelines.
What if?: If the question asked for a test to determine if an oil has gone bad or is rancid, the correct answer would be the Acid number, as it specifically measures the free fatty acids produced during spoilage.

How to Approach the Question

First, identify the key terms in the question: "purity of butter" and "volatile fatty acid".
Recognize this as a factual recall question from biochemistry or food chemistry.
Mentally review the purpose of each analytical 'number' listed in the options.
Connect the unique composition of butter (high in short-chain, volatile acids like butyric acid) to the specific test designed to measure this property.
Eliminate the other options by recalling what they measure: Iodine (unsaturation), Saponification (chain length/MW), and Acid (rancidity).
Select the Reichert-Meissl number as it is the only test directly related to quantifying volatile fatty acids for purity assessment.

Concept Tested & Keywords

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