Microencapsulation of an Angiotensin I-Converting Enzyme Inhibitory Peptide VLPVP by Membrane Emulsification

The bioavailability of angiotensin I-converting enzyme inhibitory peptides (ACEIPs) plays a major role in their practical applications, and microencapsulation has emerged as an effective way to realize the targeted and controlled release of bioactive peptides. In this work, sodium alginate–O-carboxymethyl chitosan microspheres loaded with an ACEIP Val-Leu-Pro-Val-Pro (VLPVP) were prepared by Shirasu Porous Glass (SPG) membrane emulsification. The effects of VLPVP addition amount and SPG membrane pore size on microencapsulation were studied, and the impacts of the microencapsulation process on the transport and in vitro ACE inhibitory activity of VLPVP were investigated as well. The results indicated that the microspheres could be saturated by VLPVP and their particle size could be predicated by using a linear equation when the SPG membrane pore size was 5.0 μm or higher. The membrane emulsification method was more effective than the encapsulator and needle extrusion methods in terms of microencapsulation efficiency, VLPVP load, protection against gastric fluid, and controlled/sustainable release without changing the transport behavior or in vitro ACE inhibitory activity of VLPVP. Hence, SPG membrane emulsification was a potential method for the intestine-targeted delivery of ACEIPs.