Incorporation of curcumin microcapsules in bread: stability, antioxidant activity and bioaccessibility

Curcumin is a polyphenol, used for centuries in traditional Indian and Chinese medicine. The fortification of food products such as turmeric ensures health benefits such as in the treatment of neurodegenerative, liver, lung and gastrointestinal diseases. To improve its application and bioaccessibility, the aim of the present study was to microencapsulate curcumin by complex coacervation and incorporate them into bread. Curcumin was encapsulated by complex coacervation using different core/wall ratios and total biopolymer concentration analyzed in a phase diagram. The encapsulation efficiency was evaluated and the microcapsule with the best efficiency was applied to the bread, to be analyzed for its stability after baking, antioxidant activity and bioaccessibility. Antioxidant capacity was evaluated by FRAP and DPPH methods. The bioaccessibility of bread containing encapsulated curcumin and bread containing free curcumin were determined according to the INFOGEST® method. The results showed that the coacervate complexes achieved a curcumin encapsulation efficiency of 74.86%. In the bread in which the curcumin was microencapsulated there was a 6.11% loss of curcumin content, while in the bread containing free curcumin there was a much greater loss of 35.10% in the curcumin content. Therefore, it was possible to observe that the microcapsule protected curcumin by 93.89% and the cooking process (200°C) did not compromise the curcumin content present in the bread. After gastrointestinal digestion, the bioaccessibility of encapsulated curcumin was approximately 31% while the bioaccessibility of free curcumin was 24.3%. Bread containing encapsulated curcumin showed DPPH free radical scavenging activity of 2.58 ± 0.2 TEA µmol/g and antioxidant reducing capacity (FRAP) of 3.41 ± 0.25 TEA µmol/g. The antioxidant activity of bread containing curcumin microcapsule indicated that the bread manufacturing process did not impair the antioxidant activity of curcumin. Therefore, curcumin containing microcapsules formed by complex coacervation can be employed to fortify and enrich bakery products such as bread.