Nitrogen dosage

Nitrogen content analysis is a fundamental method for assessing the nutritional quality of a product, as it indirectly estimates its protein content. This analysis is essential in many industrial sectors, including food processing, nutraceuticals, animal nutrition, and the processing of plant-based ingredients. It is a key criterion for quality control of raw materials, validation of technical specifications, and compliance with applicable regulations.

Two reference methods are used depending on the client's requirements, the type of matrix, and the analytical objectives.

Kjeldahl Method

The Kjeldahl method is recognized as the official method for determining total nitrogen. It is based on three steps:

• Acid digestion of organic matter
• distillation of the mixture,
• titration of the ammonium released.

It offers excellent reproducibility and is particularly well-suited to complex matrices: plant materials, processed food products, flours, protein extracts, nutritional supplements, or premixes intended for animal feed. The results are generally converted to protein content by applying a conversion factor defined by the matrix (6.25 for standard products, or specific factors for milk, soy, fish, etc.).

Dumas Method

The Dumas method offers a modern and rapid alternative. It relies on the high-temperature combustion of the sample, allowing for the direct measurement of the nitrogen gas formed.
Its main advantages are:

• absence of corrosive reagents,
• very short analysis time,
• High level of automation,
• high reproducibility for homogeneous matrices.

It is often preferred for processes requiring fast throughput, routine checks, or matrices with little interference.

The importance of nitrogen dosing for industrial users

Nitrogen dosing is used for:

• to control the quality of protein-rich raw materials,
• verify compliance with specifications or standards,
• to secure nutritional formulations and claims,
• detect any potential adulteration (substitution, artificial enrichment),
• to monitor the stability of protein products over time,
• optimize manufacturing or extraction processes.

This test is also an essential indicator in the marketing of products intended for animal or human nutrition, as regulations often impose a guaranteed minimum protein level.

Matrices analyzed

• vegetable flours and powders,
• protein extracts and concentrates,
• nutritional supplements,
• premix and animal feed,
• functional ingredients,
• processed food products.

Additional analyses available

For a more complete characterization of your ingredients or formulations, YesWeLab recommends combining nitrogen analysis with:

• amino acid dosage
• moisture / dry matter,
• ashes,
• polyphenolic profile (HPLC)
• Heavy metals (ICP-MS)
• pesticides (LC-MS/MS, GC-MS/MS),

Why go through YesWeLab?

YesWeLab relies on a network of more than 200 partner laboratories, selected for their technical expertise, analytical equipment and accreditations (ISO 17025, COFRAC).

Each sample is directed to the most suitable laboratory according to:

• the required technique (Kjeldahl or Dumas),
• the nature of the matrix,
• the expected thresholds,
• the standards or specifications to be met,
• the desired deadlines.

Our scientific team assists manufacturers in selecting the appropriate method, interpreting results, and implementing tailored analysis plans. The YesWeLab digital platform simplifies the management of requests, from sample submission to results retrieval, with real-time tracking.

For a quote request or to discuss a specific need, our team is at your disposal.