Structural Characterization of Lactoferrin–Sodium Caseinate Complexes and their Stability

Abstract

Sodium caseinate (NaCas) forms complexes with lactoferrin (LF), yet their structural characteristics and stability before and after heating are not well understood. This study demonstrated that LF and NaCas exhibit weak electrostatic interactions prior to heating. Upon heating at 90 °C for 10 minutes, these interactions were significantly enhanced, resulting in the formation of stable LF/NaCas complexes at ratios of 2:1 and 1:1. Complexes formed at a 1:2 ratio initially displayed smaller particle sizes and lower turbidity but experienced precipitation during storage. Conversely, complexes at 2:1 and 1:1 ratios maintained consistent turbidity and particle size over 20 days, indicating excellent long-term stability. These findings reveal the important role of NaCas in stabilizing LF during heat treatment and storage, providing valuable insights for the development of stable protein-based functional food ingredients.