Kjeldahl Method: Estimate the protein content in food
About the Kjeldahl Method Virtual Lab Simulation
In the Kjeldahl Method simulation, you will learn how to use the Kjeldahl method to determine the protein content of a food sample, and how to use LC-MS/MS to investigate if the sample has been adulterated to make the protein content seem higher than it is.
Analyze a milk powder sample
Your lab has received batch samples of milk powder from 3 different producers. Your mission is to analyze a sample from one of the batches using the Kjeldahl method, in order to determine the exact protein content, and to make sure this is consistent with the reported value.
Tracing the steps of the Kjeldahl method
An animation will introduce you to each step of the analysis, and show what goes on at the molecular level.You will then perform the acid digestion, steam distillation and finally a colorimetric titration, before being challenged with the calculations needed to transfer the lab result to a protein content in the sample.
Is everything what it appears to be?
How can you be certain that your findings are correct? There might be ways to fool the Kjeldahl method! In the second half of the simulation, you will look into how this can happen, and explore the powerful technique LC-MS/MS, which can be used to detect if a known adulterant has been added to any of the received milk powder batches.
Will you be able to safely release the milk powder batches for consumers around the world?
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Techniques In Lab
- Kjeldahl method
- LC-MS/MS chromatogram interpretation
At the end of this simulation, you will be able to…
- Describe the steps involved in the Kjeldahl method
- Analyze the nitrogen content of a food sample
- Calculate the protein content of a sample from the determined nitrogen content
- Explain why the Kjeldahl method cannot be used to identify milk powder that was cut with melamine
- Apply the principles of spiking and recovery in analytical chemistry
- Interpret basic LC-MS/MS data
- Describe the fundamentals of an LC-MS/MS analysis
- Argue whether food fraud has been conducted based on available data
Screenshots of Kjeldahl Method Virtual Lab Simulation
Dr. Melanie M. ErzingerLaboratory of Food Biochemistry ETH Zürich
Dr. Samy BoulosLaboratory of Food Biochemistry ETH Zürich
Sarah FrédérickxDep. of Health Sciences and Technology ETH Zürich
Dr. Laura NyströmDep. of Health Sciences and Technology ETH Zürich
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