Abstract: In this study, microcapsules were prepared using conjugated linoleic acid (CLA) from Tan sheep tail fat as the core material and whey protein isolate (WPI) and maltodextrin (MD) as the wall material, and their physicochemical properties were characterized using scanning electron microscopy (SEM), laser scanning confocal microscopy (LSCM), thermogravimetric analysis (TGA), and X-ray diffraction (XRD) analysis. Besides, the oxidative stability and release behavior of the microcapsules were analyzed through accelerated storage experiments and in vitro simulated digestion experiments, and their antioxidant and cholesterol lowering activities were evaluated as well. The results showed that the particles of the CLA microcapsules were intact, with a relatively smooth surface, and had good thermal stability, oxidative stability, and sustained-release performance. After gastrointestinal digestion, the antioxidant stability and cholesterol lowering activity of the microcapsules were significantly higher than those of free CLA. At the end of in vitro simulated digestion, the scavenging rates of the microcapsules against 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) cation radical, and superoxide anion radical were (70.84 ± 3.97)%, (78.53 ± 4.28)%, and (59.88 ± 2.58)%, respectively. The inhibition rate against cholesterol micelles was (73.48 ± 2.53)%, and the binding rates to sodium taurocholate, sodium glycine cholate, and sodium cholate were (40.62 ± 3.14)%, (66.79 ± 3.01)%, and (55.43 ± 2.39)%, respectively. This study indicates that microencapsulation not only significantly enhances the oxidative stability of Tan sheep tail fat CLA, but also improves its antioxidant and cholesterol lowering activity. This study provides a theoretical basis for the deep processing and comprehensive utilization of Tan sheep tail fat CLA.

Key words: conjugated linoleic acid microcapsules; physicochemical properties; antioxidant activity; cholesterol lowering activity