Chromatography in Milk Composition and Feeding Regimens

A study conducted by researchers at the Catholic University of the Sacred Heart (Piacenza, Italy) implemented an integrated approach based on ultrahigh-pressure liquid chromatography-high resolution mass spectrometry (UHPLC-HRMS) metabolomics and ion mobility (IM)-HRMS lipidomics to resolve the interaction between feeding and milking time in the overall chemical profile of Parmigiano Reggiano (PR) milk. Analysis of variance multiblock orthogonal partial least squares (AMOPLS) modelling exposed the complementarity of the assays in combining the effect of these two crucial parameters, with metabolomics highlighting the presence of plant-derived compounds (specifically terpenoids and phenolic compounds) in grass-enriched milk as opposed to those produced with a more intensive alfalfa-based diet. Conversely, lipidomics emphasized noteworthy changes in morning milk that involved di- and triacylglycerols, ceramides, and sphingomyelins enrichment. A paper based on this study was published in Food Chemistry.¹

The composition of milk is affected by a variety of factors, such genetic background of the source, the stage of lactation stage, environmental conditions, and the cow’s diet;of these factors, cow feeding systems play critical roles in theshaping of the resulting milk's biochemical and nutritional profile.^2,3 To produce PR protected designation of origin (PDO) cheese, there are strict feeding protocols and milking practices put in place for maintaining the quality and authenticity of this unique product.^4,5 Variations in the feeding of the cows (for example, grass- and alfalfa-based diets) and the differences between morning and evening milkings may introduce distinct metabolic and lipidomic signatures into the milk, with major distinctions in the product’s compositional, functional, and organoleptic properties being derived from these varying regimens possibly impacting its processability, traceability, and sensory attributes.⁶

The food cows eat directly changes the nutritional makeup and flavor profile of their milk and the resulting cheese. For instance, cows grazing in mountain meadows produce milk enriched with unique plant compounds like terpenoids and flavonoids, while those on an alfalfa-based diet produce milk higher in energy-rich components like amino acids and healthy fats. Even the specific time of day a cow is milked can shift these levels, meaning that every choice in a cow's daily routine ultimately shapes the quality, texture, and health benefits of the dairy products we enjoy.¹

“The existence of alpha-linolenic acid in milk,” write the authors of the paper,¹ “produced with a pasture-based diet has previously been detected and is gaining interest due to consumer demand for a healthy diet. This approach is essential as it enables a thorough analysis of small molecules with different polarities, providing a more complete understanding of the biochemical processes and interactions in milk.”

The researchers believe that future study should concentrate on larger datasets by including samples from a variety of dairy farms across the PR production district, with the goal of covering different seasons to account for the high biological variability in pasture-based systems. In addition, further variables such as lactation stage, rumen fluid metabolome, and environmental stressors could be considered as additional topics where this data-fusion approach can be applied on different omics platforms.¹

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References

1. Becchi, P. P.; Rocchetti, G.; Froldi, F. et al. Unravelling the Interaction Between Feeding Regimens and Milking Time in Parmigiano Reggiano PDO Milk: An Integrated Metabolomics and Ion Mobility Lipidomics Approach. Food Chem. 2026, 501, 147637. DOI: 10.1016/j.foodchem.2025.147637
2. Schwendel, B. H.; Wester, T. J.; Morel, P. C. H. et al. Invited Review: Organic and Conventionally Produced Milk—An Evaluation of Factors Influencing Milk Composition. J. Dairy Sci. 2015, 98 (2), 721-746. DOI: 10.3168/JDS.2014-8389
3. Niu, M.; Ying, Y.; Bartell, P. A. et al. The Effects of Feeding Time on Milk Production, Total-Tract Digestibility, and Daily Rhythms of Feeding Behavior and Plasma Metabolites and Hormones in Dairy Cows. J. Dairy Sci. 2014, 97 (12), 7764-7776. DOI: 10.3168/jds.2014-8261
4. Mordenti, A. L.; Brogna, N.; Formigoni, A. Review: The Link Between Feeding Dairy Cows and Parmigiano-Reggiano Cheese Production Area. Prof. Anim. Sci. 2017, 33 (5), 520-529. DOI: 10.15232/PAS.2016-01602
5. Summer, A.; Sandri, S.; Franceschi, P. Effects of Collection Conditions on Maturation of Milk in the Production of Parmigiano-Reggiano Cheese. Vet. Res. Commun. 2007, 31 (s1), 405-408. DOI: 10.1007/S11259-0067-7
6. Magan, J. B.; O’Callaghan, T. F.; Kelly, A. L. et al. Compositional and Functional Properties of Milk and Dairy Products Derived from Cows Fed Pasture or Concentrate-Based Diets. Compr Rev Food Sci Food Saf. 2021, 20 (3), 2769-2800. DOI: 10.1111/1541-4337.12751