In vitro evaluation of gastro-intestinal digestion and colonic biotransformation of curcuminoids considering different formulations and food matrices

Pharmaceutical formulations for improving stability and bioavailability of curcuminoids are often produced using excipients unsuitable for food applications. In this work, turmeric oleoresin was microencapsulated by spray drying using gum arabic and maltodextrins to prepare a new ingredient (GA/MD) for food industry. In vitro bioaccessibility and degradation of curcuminoids along the gastro-intestinal tract was investigated, and compared with two commercial ingredients, turmeric powder and Meriva®. Curcuminoids were significantly degraded under the gastro-intestinal conditions in all the formulations; however, their bioaccessibility in GA/MD ingredient was 25-fold higher than that of turmeric powder, but slightly lower (1.2-fold) to that of Meriva®. After addition to rice and yoghurt, the curcuminoid bioaccessibility of GA/MD was about 2- fold higher than for the ingredient alone and 1.5- fold higher than for Meriva®; furthermore, addition to rice improved bioaccessibility more than in yogurt. Studies using different coating agents and other food matrices are needed.