In vitro digestion of curcumin-nanoemulsion-enriched dairy protein matrices: Impact of the type of gel structure on the bioaccessibility of curcumin

This study examined the impact of the dynamic gastric digestion of two iso-caloric dairy gels containing curcumin nanoemulsion (D3,2 = 0.187 ?m) on the intestinal lipid digestion and the bioaccessibility of curcumin. The residence time in the stomach and the release of oil together with solubilized curcumin were influenced by the type of gel structure. The rennet gel restructured and became denser because of the action of pepsin and the low pH, thus slowing the outflow of both protein and oil from the gel. In contrast, the acid gel experienced rapid protein disintegration under gastric conditions and most of the chyme was emptied out of the stomach within 2 h. Similarly, the content of curcumin-enriched oil in the digesta of the acid gel was higher than that in the digesta of the rennet gel, in which the oil droplets appeared to be embedded in the gelled particles. The size of the oil droplets within the emptied gastric digesta of both gels was not significantly impacted during digestion. The rate of free fatty acid release and the concentration of curcumin during intestinal digestion were linked with the compositional profile of the gastric digesta, whereas the bioaccessibility of curcumin (85?91%) was influenced by the gel type and the gastric disintegration of the gels. This study demonstrates the influence of different gel structures on the bioaccessibility of curcumin, which could be further used to design therapeutic dairy products with health benefits.

Automated summary

The study examined the impact of different gel structures on the bioaccessibility of curcumin, finding that rennet gel had a longer residence time in the stomach while acid gel emptied more quickly. The content of curcumin-enriched oil was higher in the acid gel, while in the rennet gel oil droplets appeared to be embedded in the gelled particles.