NATAMYCIN INCORPORATED IN EDIBLE MATRICES BASED ON TAPIOCA STARCH: PHYSICAL AND ANTIMICROBIAL PROPERTIES

OLLE RESA, C; GERSCHENSON, L.N.; JAGUS, R.J.

Congreso; IFT12, Annual Meeting and Food Expo; 2012

Edible films can support antimicrobials in interfaces while producing a localized effect, allowing a slow release and/or minimizing antimicrobial degradation. In this way they can control the microorganisms growth. Natamycin produced by Streptomyces natalensis is an antifungal GRAS agent which is usually applied to the surface of cheeses. The objective of this research was to study the efficiency of natamycin, supported in tapioca starch edible films, on Saccharomyces cerevisiae, Zygosaccharomyces bailii and Rhodotorula mucilaginosa growth as well as the effect of the antimicrobial on film physical properties. Films were casted using a glycerol: starch proportion of 1:2 (w/w) and the formulations included 230 ppm of commercial natamycin. The mechanical properties, solubility and water vapor permeability (WVP) were evaluated. Antimicrobial effectiveness of the films was tested through agar diffusion assay. Results obtained showed that the starch based films without antimicrobials could not inhibit the yeast growth. On the contrary, the starch films containing natamycin yielded a clear inhibition zone around the film disk with a total diameter of inhibition of 2.2cm, 3.2cm and 3.3cm, for R. mucilaginosa, S. cerevisiae and Z. bailii respectively, showing antimicrobial diffusion to the solid medium. All the films showed a plastic behavior and the presence of the antimicrobial produced an increase in the deformation at break and solubility, a decrease in the stress at break and a null effect on WVP. It can be concluded that the films studied are an effective hurdle against microorganisms potentially present in food systems. The antimicrobial agent modifies the physical properties and the goal of film application will determine the importance of these changes.