The encapsulation of curcumin by whey protein: Assessment of the stability and bioactivity

Abstract Aims The aims of the present work were to encapsulate curcumin in denaturated whey protein isolate and investigate the physicochemical and morphological properties of whey protein isolate‐based nanoparticles (WPI‐NPs). Methods Scanning electron microscopy (SEM) was used to investigate the morphological properties of WPI‐NPs. The crystalline structure of the developed NPs was evaluated by using an X‐ray diffraction technique. Antiradical activity of pure and loaded curcumin was also tested. in vitro release of curcumin into the simulated stomach and small intestine was evaluated. The stability of pure and encapsulated curcumin against pH and oxidation was compared. Results WPI‐NPs had a spherical shape‐like structure with smooth surface. The encapsulation efficiency of curcumin in WPI‐NPs was found to be 93.1%, demonstrating that the encapsulation system used in the present work was effective to entrap curcumin molecules. WPI‐NPs showed more stability at pH 7, indicating that the developed system is suitable for application of beverages with neutral pH. Furthermore, the encapsulation of curcumin into nanoparticles led to improvement of the oxidation stability of curcumin from 10% to 70%. The developed nanoparticles improved the release of curcumin in the simulated gastrointestinal tract. The release of curcumin in simulated gastric medium was low, but in the intestine, most of the curcumins were released in the early hours. The release of curcumin followed non‐Fickian mechanism in the intestine and stomach environment. Conclusion The developed encapsulation system can be introduced as a viable strategy to improve the bioavailability of curcumin. Practical Applications Considering the diverse biological activity of curcumin and high oxidation stability of WPI‐NPs, the developed nanoparticles can be used as a valuable additive compound in food and pharmaceutical systems, especially in beverages with neutral pH.