Different forms of whey protein aggregates as curcumin delivery systems: Evaluation of free radical scavenging activity and drug release kinetics

Abstract

In the present study, different forms of whey protein isolate (WPI) including, native, worm-like aggregates, microgel particles, and nanofibrillar aggregates were employed to encapsulate curcumin as a bioactive ingredient. The results showed that the aggregation improved the capacity of WPI for loading of curcumin and the highest encapsulation efficiency and loading amount were related to the fibrillar aggregates. The curcumin-loaded aggregates also showed a good antioxidant activity as measured by ABTS/DPPH free radical scavenging test. The release of curcumin from aggregates was determined during the simulated gastrointestinal digestion and the results indicated that the capsulation of curcumin in whey protein aggregates can be considered as a hopeful method to control the release of curcumin as well as to site-specific delivery of curcumin. After that, the drug release kinetics and mechanism were evaluated using various kinetic models including zero order, first order, Higuchi, and Korsmeyer-Peppas models. The release modelling results also showed that the release of curcumin from whey protein aggregates was controlled by both diffusing and polymer swelling (i.e. anomalous transport). Generally, this study suggested that the WPI-based aggregates can be used as promising carriers for curcumin delivery.