Structure and integrity of liposomes prepared from milk- or soybean-derived phospholipids during in vitro digestion

Abstract

Crude liposomes and nanoliposomes, respectively, formed both from a milk fat globule membrane (MFGM) phospholipid fraction and from soybean phospholipid were prepared by thin layer dispersion and dynamic high pressure microfluidization methods. The structure and the integrity of the liposomes were evaluated in terms of average diameter, zeta potential, microstructure, lipolysis, and membrane permeability during in vitro digestion as a function of time. The physical and chemical properties of the liposomes were little influenced in SGF containing pepsin. However, the liposomes exhibited lower stability in simulated intestinal fluid (SIF) than in simulated gastric fluid (SGF). The liposomes obtained from the MFGM phospholipid fraction were more stable than the soybean-based liposomes, with less change in average diameter, surface charge, morphology, and free fatty acid release, and better membrane integrity during digestion in SIF. However, no differences in the stability between nanoliposomes and crude liposomes were observed during digestion. These results systematically demonstrated the relationship between the stability of liposomes and in vitro digestion, and provided some information for further developing more stable liposomes in the gastrointestinal tract.