Effects of agar-carrageenan wall materials and core-to-wall material ratio on physicochemical properties and in vitro bioaccessibility of microencapsulated bioactive peptides

Abstract

The effects of different agar and/or carrageenan proportions as wall material and the core-to-wall material ratio on physicochemical properties, delivery and bioaccessibility of microencapsulated brewer's spent grain (BSG) bioactive peptides were evaluated. Also, peptides from BSG hydrolysate were identified by LC-MS/MS. Microencapsulation was carried out by spray drying. All microcapsules exhibited negative charge both, at pH 2.0 and 7.0. Peptide release was higher at pH 7.0 than pH 2.0, showing a higher release at the site of absorption. Higher proportion of agar in the formulation had a positive impact on both, spray drying yield and encapsulation efficiency. Moreover, higher core-to-wall material ratio (1:4) improved encapsulation efficiency and maintained and even increased ABTS scavenging, ACE-I and DPP-IV inhibition, after a simulated gastrointestinal digestion process. Peptides identified from BSG hydrolysate ranged from 8 to 21 residues, contained mostly glutamic and glutamine residues and were rich in hydrophobic amino acids. Using in silico predictions, 16 peptides identified could act as antihypertensive and antidiabetogenic compounds, showing a multifunctional potential of BSG.