Protein levels, including collagen (hydroxyproline, proline, glycine)

collagen marker analysis allows for the precise quantification of a product's overall protein content, as well as the presence of collagen-specific amino acids: hydroxyproline, proline, and glycine . This type of analysis is essential for manufacturers of dietary supplements, functional ingredients, nutritional products, or formulations designed for joint health, skin well-being, or muscle performance. It also enables the validation of claims, the evaluation of raw material purity, and the verification of finished product conformity.

Industrial challenges of protein and collagen assays

In the human nutrition, nutraceutical, animal nutrition, and plant-based ingredient sectors, protein content is a key parameter. Protein analysis ensures the consistency of formulations, verifies stability over time, monitors functional performance, and assesses the quality of raw materials. For collagen in particular, hydroxyproline quantification is a reliable indicator for identifying the origin and actual proportion of collagen in a sample.

This analysis helps to:
• confirm compliance with the stated nutritional values
​​• differentiate between native, hydrolyzed, and fortified plant-based collagen
• monitor structural amino acid intake
• verify the quality of joint or aesthetic formulations
• prevent collagen fraud or overpricing

Analytical methods: Kjeldahl, HPLC and spectrophotometry

Protein quantification can be performed using different approaches depending on the objectives and the nature of the sample.

The Kjeldahl method allows for the determination of the total nitrogen content of samples, which is then converted into protein content using a factor. It is particularly useful in food matrices, both plant and animal-based.

Liquid chromatography (HPLC or UHPLC) allows for the specific quantification of hydroxyproline, proline, glycine, and other amino acids after derivatization. This method is recommended for supplements containing hydrolyzed collagen or formulations combining multiple protein sources.

Spectrophotometry can complement the analysis to assess the presence of total proteins or absorbing amino acids, according to established protocols.

By combining these techniques, it is possible to obtain a complete profile: total protein content, specific collagen markers, verification of authenticity and quality assessment.

Matrices analyzed and areas of application

The analyses apply to a wide range of products: food supplements based on collagen or marine peptides, protein powders, liquid or gel formulations, functional ingredients, plant extracts enriched with amino acids, nutritional meals, animal feed or veterinary formulations.

They are used to:
• standardize batches of hydrolyzed collagen
• characterize the amino acid composition of protein ingredients
• compare different protein sources
• validate claims related to joint, skin, or metabolic health
• secure the supply chain and raw materials

YesWeLab Support

YesWeLab relies on a network of expert laboratories specializing in nutritional, physicochemical, and chromatographic analyses. These laboratories are rigorously selected and the majority are certified or accredited according to ISO 17025 and COFRAC standards. Our team will assist you in defining the most suitable method (Kjeldahl, HPLC, spectrophotometry), choosing relevant markers, interpreting the results, and addressing your formulation, compliance, and quality control challenges.

Thanks to our digital platform, you can easily manage your analysis requests, track your samples, and view your results with ease. Since 2020, numerous nutraceutical brands, food companies, and specialized formulators have entrusted us with their protein and collagen analyses.

Other analyses from the YesWeLab catalogue

• Amino acid analysis
• Hydrolyzed collagen assay
• Bioactive peptide assay