Desenvolvimento de microcápsulas de compostos bioativos de barbatimão (Stryphnodendron adstringens (Mart.) Coville) para aplicação em filmes biodegradáveis ativos

Abstract

ABSTRACT: Stryphnodendron adstringens (Martius) Coville is a plant species well known for its antibacterial, anti-inflammatory and antioxidant properties. These are related to the high content of tannins present in their shells and leaves. Industrial applicability is a very limited product because it is an unstable compound. The technique of microencapsulation is an alternative safety to compound stability. Microcapsules can be incorporated into food or biodegradable films. The aim this work was development and characterization of microcapsules of bioactive compounds of barbatimao, for an application in biodegradable films. A study of the extraction of the compounds was done through a factorial design 23, with the purpose of evaluating the influence of the independent variables (extraction temperature, solution pH and mesh) as dependent variables (total polyphenols, activity antioxidant by DPPH radical and condensed tannins). Through the planning, an extract with a high value for the three response variables was obtained. Microencapsulation of the bioactive compounds by the lyophilization process was performed as encapsulating agents ƒÀ-cyclodextrin (CD) and ƒÀ-cyclodextrin plus 1% xanthan gum (CD/X). To confirm an encapsulation with Differential Scanning Calorimetry (DSC) and Scanning Electron Microscopy (SEM) techniques. Also was evaluated the encapsulation efficiency of total polyphenols and condensed tannins, such as physical properties and the release profile of microencapsulated in hydroalcoholic solution. The microcapsules presented the significant difference only for the efficiency of condensed tannins with 44.55% for CD formulation and 27.18% for CD/X. The physical properties differed only in apparent density, presenting lower value for CD/X. In the release kinetics, microcapsules showed a high rate of release of phenolic compounds independent of the coatings. Reduction in release rate for observation for condensed tannins, especially for an increased formulation of xanthan (CD/X). The microcapsules was to use for the production of biodegradable films the alginate base (FCD and FCD/X). Control films was elaborated with empty microcapsules (FCD-C and FCD/X-C) and free extract (FEXT). It was evaluated the mechanical and thermal active, permeability to water vapor (PVA) and the release profile of the microencapsulated in hydroalcoholic solution. The films that presented free or microencapsulated extract had lower solubility, lower PVA and greater tension and rupture. The films with barbatimão microcapsules presented a high rate of release of phenolic compounds and condensed tannins, however, not gradually. The film with free extract presents reduction of the rate of release of the bioactive compounds, demonstrating greater control of release.