Protection of native lactoferrin under gastric conditions through complexation with pectin and chitosan

The aim of this work was to encapsulate native bioactive lactoferrin (Lf) in pectin-based colloidal delivery systems with and without a chitosan (CS) coating, and to explore their fate under digestive conditions. We compared the abilities of low methoxyl (LM) pectin and high methoxyl (HM) pectin to form complexes with Lf at different mass ratios. LM pectin led to a smaller particle size (256 nm) and a higher Lf encapsulation efficiency (>72%) than HM pectin because of its greater negative charge (−43.6 versus −16.4 mV). After validating the retention of the bioactivity of native Lf (antimicrobial activity) in these complexes, we coated the Lf‒LM pectin complex with a layer of CS, which had no significant effect on the Lf encapsulation but improved the colloidal stability under gastric conditions. Both Lf‒pectin complexes and chitosanCS-coated complexes retained >90% of the Lf from release in simulated gastric fluid. This resulted in gastric protection of Lf against pepsin-mediated hydrolysis for at least 60 min, relative to free Lf solution. CS-coated complexes also delayed the degradation of released Lf, possibly because of the interaction between this cationic biopolymer and pepsin.