Hydrogels obtained by acidification with glucono-δ-lactone (GDL), starting from nanoemulsions formulated with different concentrations of sodium caseinate (1–4 wt%) or 4 wt% sodium caseinate and sucrose (2–8 wt%), were prepared with the aim of quantifying structural parameters of both, initial nanoemulsions and hydrogels after 2.5 h of GDL addition, using the Guinier-Porod (GP) or the generalized GP models. Gelation process was followed by performing in situ temperature-controlled X-ray small angle scattering experiments (SAXS) using synchrotron radiation. In nanoemulsions, the calculated radius of gyration for oil nanodroplets (Rgoil) decreased with increasing protein concentration and for the 4 wt% protein nanoemulsion, with increasing sucrose content. Calculated values of Rgoil were validated correlating them with experimental Z-average values as measured by dynamic light scattering (DLS). For hydrogels, radii of gyration for the sphere equivalent to the hydrogel scattering object (Rgsph) were close to 3 nm while correlation distances among building blocks (Rg2) were dependent on formulation. They increased with increasing contents of sodium caseinate and sucrose. Rg2 parameter linearly correlated with hydrogel strength (G’∞): a more connected nanostructure led to a stronger hydrogel. Display omitted •Nanodroplets gyration ratio decreased with increasing protein and sucrose contents•Nanodroplets coverage increased with increasing protein and sucrose contents•Building blocks gyration ratio of gels were independent on composition•Building blocks correlation distances were significantly affected by composition•Rg2 distances correlated with asymptotic values of G’ (G’∞)