Inhibited digestion of lactoferrin - lactose complexes: Preparation, structural characterization and digestion behaviors

The effects of lactose (La) on the thermal stability and digestion properties of lactoferrin (LF) were investigated. La can interact with LF through mild Maillard reaction and hydrogen bonding. After heating, the particle size of the complex formed by LF and La was 150 nm–200 nm (La concentration 1–2%), and the particle size exceeded 450 nm for La concentration over 3%. La induced the increase of free –OH peak (from 3308 cm−1 to 3378 cm−1) and changed the secondary structure of LF-La complexes. Trpsine residues gradually reduced (from 341.1 nm to 336 nm) with the increase of La concentration (1–5%), and the interaction between La and LF changed the tertiary structure of LF. Subsequently, the properties of LF-La complexes during in vitro simulated digestion were evaluated. When conjugated with La, the degradation of LF was found to be significantly reduced. In addition, the iron retention and binding capacity of LF were improved compared with after heating LF. This study provides a new insight into the targeted release of LF in the intestinal system with La.