Physicochemical properties of WPI coated liposomes serving as stable transporters in a real food matrix

While it is widely accepted that a whey protein isolate (WPI) coating may be applied on a lipid based transporter or carrier system like an emulsion droplet, we still do not know much about coating behavior of WPI on a liposomal surface. In particular, there is lack of information on physiochemical alteration in those modified transporters in real food grade matrices and during in vitro digestion. For this reason, physicochemical and sensory properties of WPI coated and spray-dried liposomes were tested towards those of uncoated liposomes being applied as transporter in a whey drink. Liposomes were formed from highly unsaturated soy phospholipids and incorporated the flavonoid quercetin as model encapsulate. Aroma and flavor profile of the drink were characterized by descriptive analysis and proved for effectively masking of quercetin bitterness. Relative to uncoated liposomes, the WPI coating improved liposome application into a dairy drink as well as physical stability of liposomes towards osmotically active food compounds, towards different storage condition and towards simulated gastric fluid stress. These stabilizing effects arose from the reduction of semi-permeability of the membrane as the WPI coating formed a barrier on the liposomal surface.