Structural characterisation, gastrointestinal digestion stability and transepithelial transport study of casein peptide–zinc chelate

Summary In this study, a promising nanoparticle of casein peptide–zinc chelate (CNP‐Zn) for zinc supplementation was obtained. The structure properties and transepithelial transport mechanism were investigated. The amino acid composition, particle size, zeta potential and microstructure were significantly changed after chelation with zinc ions. The results of fourier‐transform infrared spectroscopy suggested that the oxygen atoms from both the carboxyl and carbonyl groups, amides, were responsible for zinc chelation. After gastrointestinal digestion, over 40% of zinc remained bound in CNP–Zn. The transepithelial transport results showed that paracellular route and PepT1 transporter were involved in the absorption of CNP–Zn, and almost 50% of the bound zinc was co‐transported with peptides. These findings would provide a relatively comprehensive cognition for developing efficient dietary zinc carriers.