Bioaccessibility of curcuminoids in buttermilk in simulated gastrointestinal digestion models

In vitro gastrointestinal digestion models were used to investigate bioaccessibility of curcuminoids delivered with buttermilk. The percentage of solubilised curcuminoids that partitioned into the micelle in aqueous phase was determined. In fasted states (0-2.5 mg bile extract/mL sample), the bioaccessibility of curcuminoids (2% v/v ethanol) ranged from 16.3% to 26.7% in buttermilk, and from 11.4% to 18.7% with neat curcuminoids. In fed states (10-40 mg bile extract/mL sample), the bioaccessibility of curcuminoids in buttermilk was 21.3% (no ethanol) and ranged from 37.1% to 69.2% (2% v/v ethanol), while for neat curcuminoids bioaccessibility was 14.1% (no ethanol), ranging from 45.6% to 79.6% (2% v/v ethanol). The in vitro bioaccessibility of curcuminoids was influenced by the presence of the carrier (buttermilk) and ethanol, and increased significantly with increasing amount of bile extract. Curcuminoids did not markedly influence the digestibility of protein or lipids. These findings demonstrated that buttermilk could be used as a carrier for curcuminoids especially if delivered with food.