CHARACTERIZATION OF MICROENCAPSULATED EUGENOL FOR BIOACTIVE FILMS

Autores UPV
Año
CONGRESO CHARACTERIZATION OF MICROENCAPSULATED EUGENOL FOR BIOACTIVE FILMS

Abstract

Eugenol is a phenolic compound abundant in clove (90%) and cinnamon (60%) essential oils with interesting antimicrobial and antioxidant properties. This natural compound can be incorporated into the formulation of bioactive films to be used for food preservation. However, they are difficult to handle due to the limited water solubility and they are susceptible of losing functionality during the film formation (by drying or extrusion). The aim of this work was to encapsulate eugenol by using WPI and a double layer system composed of WPI and chitosan (CH). Moreover, the effect of the addition of oleic acid (OA) on the emulsion properties was studied. All emulsions were processed with Rotor Stator, and three times microfluidized with the high pressure homogenizer, dissolving previously 43%(w/w) of WPI:MD solids (ratio 1:42). 3%(w/w) of eugenol was added to emulsions, with and without 7%(w/w) of OA. The coating of primary capsules with a second layer of CH (1% solution w/v) was assessed by measuring the change in the electrical surface charge of emulsions as a function of chitosan concentrations. Characterization of the emulsions were carried out in terms of particle size, zeta-potential, optical microscopy, rheological properties and TGA. Eugenol encapsulated with WPI showed a bimodal distribution, between 0,1-10µm. The addition of oleic acid provided a more homogenous dispersion (monomodal) of around 0,5m, with similar rheological properties than the previous eugenol-WPI dispersion. The CH second layer was added to the OA emulsion in a CH:emulsion ratio of 1.5:10, where a charge saturation occurred. The incorporation of CH shifted the particle size distributions towards greater and more heterogeneous sizes due to the presence of large aggregates, in coherence with the microscopy observations and rheological behaviour. From the TGA results, a similar thermal stability was observed in all samples.