Investigating casein gel structure during gastric digestion using ultra-small and small-angle neutron scattering

• DOI: 10.1016/j.jcis.2021.03.087
• Publication Date: 2021-03-19T22:02:51Z
• Authors: Meltem Bayrak; Jitendra Mata; Jared K. Raynes; Mark Greaves; Jacinta White; Charlotte E. Conn; Juliane Floury; Amy Logan
• Keywords: Neutrons; 0404 agricultural biotechnology; dairy protein gel Casein Structure Digestion Neutron scattering Electron microscopy Solubilised protein; Scattering, Small Angle; Stomach; Caseins; Digestion; 04 agricultural and veterinary sciences; 530; [SDV.AEN]Life Sciences [q-bio]/Food and Nutrition; Gels

This study aimed to understand the structural devolution of 10% w/w rennet-induced (RG) and transglutaminase-induced acid (TG) gels in H2O D2O under vitro gastric conditions with without pepsin. The real-time structure at a nano- (e.g. colloidal calcium phosphate (CCP) micelle) micro- (gel network) level was determined using ultra-small (USANS) small-angle neutron scattering (SANS) electron microscopy. Results demonstrate that gel firmness or elasticity determines disintegration behaviour during simulated mastication consequently particle size entering stomach. Shear mixing stomach, pH, enzyme activity will also affect digestion process. Our results suggest shear primarily erosion surface governs early stages digestion. Pepsin diffusivity, hence action, occur more readily latter via access interior. occurs progressively larger pores looser network channels created within larger, less dense casein micelles RG gels. Gel brittleness were greater samples compared H2O, facilitating disintegration. Despite higher strength TG, protein strands become compact when exposed acidic environment comparatively observed through SEM imaging. led degree digestibility TG is first examine highlights benefits monitor changes multiple length scales.