Preparação e caracterização de filmes de proteínas de sementes de girassol contendo eugenol e nanopartículas de hidroxiapatita

Abstract

Sunflower seed proteins with low chlorogenic acid content (PISGa) and high chlorogenic acid content (PISGb) were used as base material in biopolymeric films, combined with sunflower oil, eugenol and hydroxyapatite nanoparticles (HAp) produced from chicken eggshells. The antioxidant and water vapor barrier properties of the films were analyzed. The physical and optical properties of the films were also evaluated, as well as the crystallinity and particle sizes of HAp. Good mechanical characteristics were demonstrated by the control films containing only proteins and glycerol, but they revealed high water vapor permeability and low antioxidant properties. Phenolic compounds, naturally present in the sunflower protein, together with eugenol added in the filmogenic solution, conferred antioxidant properties to the film, with activity strength depending on the state of the compound (whether it was free or bound to the protein) and its amount in the filmogenic solution. The addition of eugenol improved the antioxidant capacity of the films. No change in antioxidant capacity was observed by the addition of HAp nanoparticles. However, it was observed that the absence of chlorogenic acid (5-CQA) in PISGa increased the protein solubility in the filmogenic solution, and the addition of fillers in the biopolymer matrix showed a decrease in the ductility of the films. On the other hand, the addition of HAp nanoparticles increased the tensile strength of the films and caused a lowering in water solubility. PISGa films were found to be more susceptible to having a lighter and yellowish color than the films with PISGb, that presented a darker and greenish color because of the presence of 5-CQA in its composition. These results revealed that sunflower isolate protein films, added with sunflower oil, eugenol and HAp nanoparticles, can be an alternative to edible films in food industries.