In this research, yak butter (YB) microcapsule with different YB addition was successfully prepared by using maltodextrin/whey protein isolate/sodium caseinate as main wall materials. The microstructures, microencapsulation efficiency and possible sacculation mechanism was then analyzed. The in vitro intestinal digested behavior of the microcapsules affected by bile salts was monitored and investigated in details. The results indicated that microcapsules were hollow spheres with entrapped YB located in the wall materials. Higher YB addition resulted in inhomogeneous larger particles with decreased membrane thickness. H-bonding interactions between protein and carbohydrate ensured the integrity of the capsule wall. The in vitro digestion results suggested that the concentration of bile salts had significant impacts on the digestion behavior of microcapsules. The present of bile salts was necessary for pancreatin hydrolysis of wall material. Hydrolysis of pancreatin, emulsification of bile salt and its positive effect for pancreatin hydrolysis all happened during the digestion and affected the digested behavior in the end. This research would provide valuable information for the bioavailability of microcapsule in human gastrointestinal systems.
Keywords: in vitro digestion; microcapsule; yak butter.