Abstract

MENDOZA-MENESES, C.J.; GAYTAN-MARTINEZ, M.; MORALES-SANCHEZ, E.  and  CONTRERAS-PADILLA, M.. Physicochemical and thermal characteristics of microencapsulated Fe by electrostatic coacervation. Revista bio ciencias [online]. 2020, vol.7, e680.  Epub Nov 18, 2020. ISSN 2007-3380.  https://doi.org/10.15741/revbio.07.e680.

Fe (iron) is one of the micronutrients required by the human body. When Fe is directly added to the food, it can cause sensory changes in flavor and color, causing rejection by consumers. The use of techniques such as coacervation and electrostatics (electrostatic coacervation) to micro encapsulate Fe can be a solution for Fe inclusion in food. The aim of the present work was to microencapsulate Fe in sodium alginate by electrostatic coacervation using calcium chloride as crosslinker material. In a suspension of 1.5 % sodium alginate, FeSO4 was added at 16 %, 33 % and 50 %. The viscosity of alginate and FeSO4 suspensions was determined. Results showed a linear increase in viscosity in relation with the FeSO4 content. The microcapsules were obtained by dripping on a 5.5 % CaCl2 crosslinker solution using a syringe pump, at an electric potential of 6, 7 and 8 KV and distance of 10 cm from the syringe with the crosslinker solution. The greater the electric potential, the smaller the diameter of the capsules, due to the electrostatic attraction forces. Once the sodium alginate/Fe microcapsules were obtained, the capsules size, encapsulation efficiency and Fe release kinetics were determined. The results showed that the highest encapsulation efficiency was 66.94 ± 1.11 % using 16 % FeSO4 at 8 KV. According to SEM micrographies , microcapsules size was 500 ± 100 μm with a spherical and smooth shape. At pH 7, 82.39 ± 0.72 % of Fe were released at 240 min, these values of time and pH could indicate that Fe release would be in the small intestine. The results showed that the technique of electrostatic coacervation has potential to obtain sodium/Fe alginate microcapsules, having application as an additive in food (fortification).

Keywords : Electrostatics; microcapsules; iron; coacervation.