Encapsulating anthocyanins from Hibiscus sabdariffa L. calyces by ionic gelation: Pigment stability during storage of microparticles

- Encapsulation of anthocyanins by ionic gelation using a double emulsion showed good results.
- Kinetic parameters of anthocyanin and color degradation were determined and fitted the Arrhenius model.
- Encapsulated anthocyanins showed higher stability when stored at refrigeration temperatures.
- Larger microparticles obtained by ionic gelation have shown better retention of anthocyanins.
- The dripping-extrusion promoted better retention of anthocyanins than the atomization technique.

Hibiscus extract (HE) has a strong antioxidant activity and high anthocyanin content; it can be used as a natural pigment, also adding potential health benefits. The objective of this work was the microencapsulation of HE anthocyanin by ionic gelation (IG) using two techniques: dripping-extrusion and atomization, both by means of a double emulsion (HE/rapseed oil/pectin) and a cross-linked solution (CaCl2). Particles (77-83% moisture content) were conditioned in acidified solution at 5, 15 and 25 °C, absence of light, and evaluated for anthocyanins and color for 50-days. The median diameter (D50) of the particles ranged from 78 to 1100 μm and encapsulation efficiency ranged from 67.9 to 93.9%. The encapsulation caused higher temperature stability compared with the free extract. The half-life (t1/2) values of the particles ranged from 7 (25 °C) to 180 days (5 °C) for anthocyanins and from 25 (25 °C) to 462 days (5 °C) for Chroma value. The IG increased the stability of HE anthocyanin. Both the dripping-extrusion and the atomization have shown to be feasible techniques.