CONICET | Buscador de Institutos y Recursos Humanos

Cassava starch films containing rosemary nanoparticles were successfully produced using a simpleapproach. Different concentrations (5 and 20% w/w) of ethanolic extracts of rosemary were added to thefilm-forming aqueous blends containing cassava starch and glycerol, and in this way, rosemary nanoparticleswere produced by the solvent displacement. The formulations added of the lowest extractamount led to films containing well distributed rosemary nanoparticles within the matrix. In contrast,higher extract concentration provoked the formation of agglomerates of nanoparticles within the films.Fourier transform infrared spectroscopy and thermogravimetric analysis suggested that the availability ofhydroxyl groups within the starch matrix was decreased due to the presence of the rosemary-relatedcompounds. Tensile properties of the cassava starch films were also influenced by the addition ofrosemary extract. It was found that the rosemary nanoparticles were able to act as a reinforcement of thestarch matrix increasing the elastic modulus and the tensile strength of the films up to 4.0-fold and 2.5-fold, respectively; while the strain at break was slightly decreased, compared with the control films.Finally, the release kinetics of rosemary polyphenols from cassava starch active films to aqueous and fattyfood simulants was analyzed. In the aqueous medium, all active films released a polyphenols amountabove 60% within the first hour of assay. In contrast, the release rate of rosemary polyphenols intoethanol (i.e. a fatty food simulant) was slower compared with the aqueous one.