Development of compartmentalized encapsulation system for carrying yerba mate antioxidants and zinc mineral

ALEX LÓPEZ CÓRDOBA; LORENA DELADINO; MIRIAM MARTINO

San pablo

Simposio; São Paulo School of Advanced Science on Advances in Molecular Structuring of Food Materials, São Paulo University; 2012

Compartmentalized encapsulation systems are promissory strategies for simultaneous carrying of different active compounds with complementary function. In our research group, such type of matrix was developed employing alginate beads added with native starch as vehicle of zinc. Initially, different concentration of native corn starch were added to alginate matrix (0.1, 0.5, 1, 2, 5, 10 % w/w) to optimize the entrapment of principal active compound (yerba mate antioxidant extract). Capsules were obtained by ionic gelation of alginate with calcium ions. The higher encapsulation efficiency (65 %) was achieved with alginate beads loaded with starch at 2%. This formulation was selected as optima. Starch-zinc samples were prepared suspending corn starch 10 % w/v in deionized water and different concentrations of zinc sulphate (0.32, 0.65 and 0.96 g zinc/ g of native starch) with continuous stirring (180 rpm, 37°C, 12 h.). The zinc loading in native starch was determined by atomic absorption spectroscopy, previous acidic digestion with chloride acid. The amount of zinc absorbed in native starch increased proportionally to zinc dosage employed in the preparation of vehicle, the lowest concentration was since higher doses provoked the crosslinking of zinc ions and sodium alginate generating gels of irregular forms. A homogenous distribution of zinc metal in the starch granules was showed by SEM-EDX analysis. The incorporation of zinc loaded starch into yerba mate alginate matrix, did not modified the yerba mate antioxidant capacity towards DPPH radical. The obtained capsules showed a loading of yerba mate polyphenols above to 16.2 mg equivalents of chlorogenic acid/ g dried beads and a zinc content of 3.89 mg Zn/g dried beads. This concentration of metal corresponded to 30% of recommended diary ingest according to FAO and WHO. Application of compartmentalized systems in food formulations could be advantageous for preserving substances prone to oxidation and provide compounds with biological activity to prevent illness appearance.