Encapsulation of an argentine propolis: physicochemical properties and polyphenolic content

BUSCH, MARÍA VERÓNICA; PEREYRA GONZALEZ KOCMUR, ADRIANA; SEGATIN, NATASA; SANTAGAPITA, PATRICIO R.; POKLAR ULRICH, NATASA; BUERA, M. PILAR

Concordia, Entre Ríos

Conferencia; III International Conference on Food InnovaTION, FoodInnova 2014; 2014

Universidad Nacional de Entre Ríos // FoodInnova

The antioxidant and antimicrobial capacities of propolis are well known, and they are related to its polyphenol and flavonoid content. Encapsulation of propolis is desired for many reasons: to protect its bioactive compounds, to eliminate the use of ethanol as a solvent, to mask its unpleasant and strong aroma and to widen the dosage options. Among the several materials for preparing encapsulation systems, the use of biopolymers is widely chosen. Vinal gum (VG) is a galactomannan obtained from seeds of vinal, an abundantly growing argentine tree. It has similar properties than those of commercial and widely used gums. The aim of this study was to evaluate different encapsulation matrices for argentine propolis and to characterize their polyphenolic content and release profile. VG extraction was done by a basic treatment of the seeds, endosperm separation and aqueous extraction, and flocculation in ethanol. Three encapsulation systems were prepared from 30 %w/v maltodextrin solutions with 0.3 %w/v of VG (MDV) or arabic gum (MDA), or without gum (MD), stirred for 2 hs. 10 mL of a propolis ethanolic extract (0.35 g/mL) were added, emulsified with an ultraturrax device (15000 rpm, 5 min) and spray-dryed. Water activity (aw), water content (WC), dielectric properties, conductivity, pH, refractive index were measured in water solutions. Propolis release was evaluated by the DPPH-assay; polyphenolic and flavonoids compounds were analyzed by HPLC. Low WC (1.6-2.2 w/w d.b.) and aw (0.216-0.228) powders were obtained for all the formulations. Spray-drying yields were 68% (MD and MDA), and 60% for MDV. SEM showed spherical-shaped particles and partially agglomerated, with a diameter range of 1-15 m for all systems. Polyphenolic and flavonoids profile of the propolis extract remained constant for all systems after spray-drying and the MDA system showed the higher retention ratio. The dielectric properties of the water-solubilized systems were determined by the content of maltodextrin and propolis, without being affected by the addition of gums or by spray-drying. Antiradical activity (AA) by DPPH (stirring capsules in ethanol or water) increased until 15 min. and then decreased in all systems. MDA systems showed the hightest AA in water (0.6 mM of cafeic acid/mg of powder). Several matrices prepared by spray-drying showed to be effective for propolis encapsulation and suspension and represent adequate alternatives for the development of innovative propolis applications in food, cosmetics and pharmaceutical industries.