Antioxidant capacity of bilberry extract microencapsulated in whey protein hydrogels

The application of antioxidative phenolic plantcompounds, such as bilberry anthocyanins, as bioactive food additive maybe facilitated by the protection throughmicroencapsulation. The antioxidant capacity of the encapsulated compounds could thus be preserved until the point of action is reached. Inthis study,whey protein-basedmicrocapsules loaded with an anthocyanin-rich bilberry extract were generated thermally after forming droplets by the emulsion method. The TEAC (Trolox equivalent antioxidant capacity)-assay was used to assess the antioxidant capacity of the anthocyanin-rich bilberry extract during all steps of themicroencapsulation process. It could be shown that the loss of antioxidant capacity during microencapsulation canmainly be attributed to interactions between thewhey proteinsand bilberry extract compoundsother than anthocyanins.Ananthocyanin-attributed loss of antioxidant capacity occurredwhen an emulsifier was used in themicroencapsulation process. In this case, a transition of hydrophilic anthocyanins to the oil phase was observed. Eventually, the generated bilberry-extract loaded microcapsules were investigated in termsof their release behaviour indigestivemedia.Due to the time-dependent diffusive release from the microcapsules, the degradation of anthocyanins at pH 6.8 was retarded in comparison to non-encapsulated bilberry-anthocyanins.However, anthocyanin degradation at pH6.8 was minimal when the non-gelled bilberry extract--whey protein solution was incubated which indicates a protective effect of native whey proteins. The results of this study provide new insights regarding protein-based microencapsulation of phenolic compounds and are thus of relevance for the development of innovative encapsulation systems.     «

The application of antioxidative phenolic plantcompounds, such as bilberry anthocyanins, as bioactive food additive maybe facilitated by the protection throughmicroencapsulation. The antioxidant capacity of the encapsulated compounds could thus be preserved until the point of action is reached. Inthis study,whey protein-basedmicrocapsules loaded with an anthocyanin-rich bilberry extract were generated thermally after forming droplets by the emulsion method. The TEAC (Trolox equivalent antioxidan...     »