In the context of a project in collaboration with ISIS that focuses on structural studies under mechanical confinement, with a specific focus on biological lubricants, the applicants performed preliminary neutron reflectometry experiments at D17 (ILL) on the hydration of confined layers of mucins, the long glycoproteins that account for most of the material in biological fluids such as mucus and saliva. These experiments indicated that mucins can hold large amounts of water up to pressures as high as 5 bar. However, further controls are needed to support this interpretation. Here, we apply for investigating how the data obtained for mucins differ from that of a compact globular protein i.e., albumin. This will confirm that our previous results do indeed originate from the long unstructured nature of mucins and not by an instrumental artefact.