In vitro digestion properties of different chitin nanofibrils stabilized lipid emulsions

An in vitro simulated digestion model (saliva, gastric, and intestinal digestion) was applied to explore the effect of chitin nanofibrils on lipase activity, bile acid diffusion, and the formation and following digestion of lipid emulsions in the gastrointestinal tract. Three kinds of chitin nanofibrils were used: deacetylated chitin nanofibril (positive charge, longest), TEMPO oxidized chitin nanofibril (negative charge, the second longest) and combi-nation treated chitin nanofibril (amphoteric, the shortest). All chitin nanofibrils showed no significant effects on inhibiting lipase activity and binding bile acids. While, they exhibited obvious difference during different digestion stages, which were caused by the different surface charge and size. In addition, all three nanofibrils can retard lipid digestion, and reduce the bioavailability of fat-soluble vitamins to some degree. The former is helpful in reducing fat while the latter is not conducive to the absorption of nutrition. This study revealed the gastro-intestinal fate of different chitin nanofibril stabilized Pickering emulsions and the possible mechanism for the chitin nanofibrils as a potential functional food additive, but all their potential effects need to be carefully considered from a nutrition perspective.