Revealing the structure of cow and goat milk proteins
19 Feb 2026 - Peter Hurrell
For the first time, researchers from Wageningen University and Research and Eindhoven University of Technology, in the Netherlands, and scientists at the ISIS Neutron and Muon Source, have used spin echo small angle neutron scattering (SESANS) to examine the structure of the protein casein in heated and unheated milk from cows and goats.
They found that different treatments resulted in structural differences, which will help food manufacturers design and optimise the properties of new dairy products.
Casein forms most of the protein found in milk, where it clumps together with calcium phosphate to form self-assembled proteins structures called casein micelles. The aggregation of these micelles causes gelation, which is required for cheese and yoghurt production. To induce gelation, manufacturers use acid or enzyme treatments, which alter the structure of the casein micelles in different ways.
Milk undergoes various treatments before it can be used in food. These include heat treatment, which is important for food safety as it destroys harmful bacteria, but this can introduce structural changes. In milk, casein micelles react with heat-denatured whey proteins at high temperatures. This causes structural changes in the casein micelles and changes their gelation behaviour.
Understanding the structure of food materials and the changes they undergo when processed will help manufacturers to develop and refine their products and manufacturing processes. However, it can be difficult as the materials cover a range of different length scales. SESANS is ideal for this, as it can provide information about materials between 30nm and 20μm; much larger than regular SANS, which works between 1nm and 300nm.
Caseins and their aggregation are very complex. Not many techniques allow us to study both the effects of processing on casein micelle structure and their gel structures in such detail. Conducting this research at this cutting-edge facility was an incredible experience, and we were delighted to have such friendly and supportive beamline scientists supporting us throughout the experiment.
Swantje Breunig, Wageningen University & Research
The researchers collected milk from a cow and goat farm in the Netherlands, treated it, then used the Larmor instrument at ISIS, together with confocal microscopy and rheological studies, to investigate the structure of the casein micelles and the gels.
They found that goat milk forms larger, less hydrated, micelles than cow milk. After heat treatment, casein micelles in both cow and goat milk increase in size, due to aggregation with whey proteins in the milk.
The results also showed that the effects of heat treatment were greater in cow milk gels than in goat milk gels, suggesting that the micelles in cow milk underwent more substantial structural changes. Heat treatment also had different effects on gel structure depending on whether the milk was acid or enzyme treated.
The findings will help manufacturers better control and optimise food production. The research also demonstrated the utility of the SESANS technique to study multi-length scale, hierarchical materials, such as those in food products.
The full paper can be found at: https://doi.org/10.1016/j.foodhyd.2025.112242
