Trapping of betanin in alginate microcapsules: Stability studies under
accelerated conditions
Abstract
Microcapsules including red beet extract rich in betanin was produced by
ionic gelation. Sodium alginate was used as wall material. Impacts of
coating amount and active material were assessed with respect to
encapsulation efficiency (EE) of the capsules in terms of total phenolic
content (TPC). Encapsulation of the red beet extract in alginate
microbeads was satisfying with >80% under the best
conditions of ionic gelation (15% calcium chloride concentration and
2% sodium alginate for 15 min of hardening time). The interaction
between the active material and the alginate beads were also
investigated by diffuse reflectance fourier transform (DRIFT)
spectroscopy. Accelerated oxidation test was employed to measure the
stability of the microcapsules against oxidation by means of Rancimat
method. Stability of the produced microbeads were evaluated in terms of
kinetic and thermodynamic analyzes. After the induction times were
determined under different temperature conditions (110, 120, 130 and 140
ºC) by Rancimat test, kinetic and thermodynamic parameters of the
product were analyzed. The findings (∆H
++>0, ∆S
++<0, and ∆G ++
>0) indicates that low entropy value is attributed to more
stable microbeads with less energy (<40 kJ mol
-1).