Microencapsulation of anthocyanin pigments obtained from seedless barberry (berberis vulgaris L.) fruit using freeze drying

The acidified ethanol extracts of dried barberry which have a relatively high anthocyanin content (376.28± 1.45 mg c3g/Kg dmp) were freeze dried using maltodextrin (MDX), polyvinyl-pyrrolidone (PVP) and mixture of MDX and calcium alginate (MDX-CaAlg) as a carrier and coating agents. The qualitative attributes of the powders were characterized by their productively encapsulation efficiency, moisture content, bulk density, colour values (L*, a*, b*, C and H° ), particle size, total phenolic compounds (TPC), free radical scavenging activity of DPPH (RSA), ferric reducing-antioxidant power (FRAP) and minimized 50% of radical- scavenging activity (IC50). Scanning electron microscope was used for monitoring the structures of the powders. To determine the stability and half- life period of microencapsulated pigments, samples were stored under different storage temperatures (4◦C and 25◦C) at relative humidity 75%. Results showed that the encapsulated powder containing PVP 8% as wall material represented the best powder quality (p<0.05). The total anthocyanin content of microcapsules decreased during storage at different temperatures, but encapsulated powder containing PVP 8% had the lowest rate of their decrease. Finally, the obtained results showed that microencapsulation by freeze drying could be recommended as a suitable method for stabilizing anthocyanins of barberries’ extract.

Keywords:

Anthocyanins , Antioxidant activity , Barberry , Carrier agents , Encapsulation , Freeze drier , Stability