Gastrointestinal digestive fate of whey protein isolate coated liposomes loading astaxanthin: Lipolysis, release, and bioaccessibility

Whey protein isolate coated astaxanthin-loaded liposomes were prepared in this work. The gastrointestinal digestive fate of whey protein isolate coated astaxanthin-loaded liposomes was evaluated in terms of particle size, size distribution, zeta potential, and morphology during in vitro digestion as a function of time. Analysis on the particle size and morphology of whey protein isolate coated astaxanthin-loaded liposomes showed that the majority of particles maintained spherical shape with a progressive increase of particle size after passage through the digestion. The zeta potential on whey protein isolate coated astaxanthin-loaded liposomes became highly negative after digestion. As compared in uncoated liposomes, the astaxanthin release in whey protein isolate coated liposomes was slower in simulated gastric fluid digestion, while was faster in simulated intestinal fluid digestion. Through in vitro digestion, the bioaccessibility of astaxanthin was improved significantly after whey protein isolate coating. It was also found that the whey protein isolate coating could protect liposomes against destruction and suppress the lateral mobility of pyrene, resulting in lower micropolarity and fluidity of liposomal membrane during the digestion. These findings may guide the potential application of whey protein isolate coated liposomes for improving the bioaccessibility and stability of astaxanthin in nutraceuticals and pharmaceutics.