Structural characterization of nanoemulsions stabilized with sodium caseinate and of the hydrogels prepared from them by acid-induced gelation

JUAN MANUEL MONTES DE OCA-AVALOS; CRISTIAN HUCK-IRIART; VIRGINIA BORRONI; KARINA D. MARTÍNEZ; ROBERTO JORGE CANDAL; MARÍA LIDIA HERRERA

Current Research in Food Science

elsevier

Año: 2020

2665-9271

Hydrogels obtained by acidification with glucono-d-lactone (GDL), starting from nanoemulsions formulatedwith different concentrations of sodium caseinate (1 to 4 wt.%) or 4 wt.%sodium caseinate and sucrose (2 to 8 wt.%), were prepared with the aim of quantifyingstructural parameters of both, initial nanoemulsions and hydrogels after 2.5 hof GDL addition, using the Guinier-Porod (GP) or the generalized GP models.Gelationprocess was followedby performing in situtemperature-controlled X-ray smallangle scattering experiments (SAXS)using synchrotron radiation.Innanoemulsions, the calculated gyration radius for oil nanodroplets (Rgoil) decreased withincreasing protein concentration and for the 4 wt.%proteinnanoemulsion, withincreasing sucrose content.Calculated values of Rgoil were validated correlating them with experimentalZ-average values as measured by DLS. For hydrogels, gyration radii for building blocks(Rg1) were close to 3 nm while correlation distancesamong building blocks (Rg2)were dependent on formulation. They increased with increasingcontents of sodium caseinate and sucrose.Rg2parameterlinearly correlated with hydrogel strength (G?¥): a more connected nanostructure led to a strongerhydrogel.