Structure and digestibility of bovine casein complexes formed by enriching κ- and β-caseins in micellar casein concentrate together with minerals adjustment

Abstract

Colloidal structure and infant in vitro gastrointestinal digestibility of casein complexes simulating caseins and minerals compositions of human casein micelles were studied. κ- and β-Caseins were fractionated from bovine micellar casein concentrate (MCC), and mixed with MCC to increase their ratios to 20% and 68%, followed by adding citrate (Cit), calcium (Ca), and inorganic phosphate (Pi) to obtain the casein complexes. The complexes enriched with κ- and β-caseins showed higher percentages of serum Ca, Pi and caseins, larger particle size, and looser internal structure. During gastric digestion, the complexes enriched with κ- and β-caseins formed smaller and looser coagula, which promoted degradation of intact caseins and formation of free amino groups and small peptides. During initial intestinal digestion, the complexes enriched with κ- and β-caseins formed more free amino groups and smaller peptides. These results offered a potential strategy to form human casein micelles analogues for use in infant formula.