Microencapsulation of turmeric extract by complex coacervation: in vitro, gastrointestinal digestion and stability study during kefir storage

The present work investigated the possibility of encapsulating turmeric extract (TE) by complex coacervation using gelatin and carrageenan as the encapsulating wall to act as a delivery system in the production of TE-enriched kefir. Curcuminoids were the major compounds in TE, as shown by TLC and HPLC analysis. The free extract exhibited interesting biological effects, including antioxidant, anti-inflammatory, and antidiabetic effects, making it an interesting bioactive ingredient for functional foods. The extract was successfully incorporated into gelatin/carrageenan coacervates as indicated by a high encapsulation yield of 82.11 and an encapsulation efficiency of 92.2% for the ratio wall/core2:1.FTIR analysis showed that electrostatic interactions are the principal driving forces involved in the encapsulation process. The micro-particles presented a round shape with different sizes by Scanning Electron Microscopy (SEM) observation. The antibacterial effect of the encapsulated TE was lower compared to the free extract due to its entrapment by the biopolymers. Simulated digestion of TE-loaded microcapsules showed a burst release during the gastrointestinal phase (32.97% after the first 30 min and reach 39.56% after 2 h) and a gradual release during the intestinal digestion (48.01% at the end of the phase). The encapsulation of TE improved its stability during kefir storage compared to free extract. Thus, the encapsulation of TE gelatin/carrageenan microcapsules improved the stability of curcuminoids and can be serve as a carrier in food systems.