Peña Farfal, Carlos

The study and determination of the antioxidant capacity of the Greigia Sphacelata fruit were carried out. G. sphacelata is an endemic fruit of central-southern Chile, better known as Chupón or Quiscal. Spectrophotometric and modified ORAC test were developed for antioxidant capacity d eterminations, and later an electrochemical method was developed by differential impulse voltammetry (DPV) with a vitreous carbon electrode for the quantification of the antioxidant capacity expressed in equivalent of the Trolox standard in µmolL-1. Once the voltammetric test was developed, the correlation study between both methods used to determine the antioxidant capacity of Greigia sphacelata was carried out. The results of the determination of the antioxidant capacity of Greigia sphacelata by ORAC test report an antioxidant capacity of 3525 µmol/100g equivalents of Trolox. Concerning the concentration obtained by the electrochemical methodology, 724 µmol/100g Trolox equivalents is obtained for a linear correlation r = 0.969 with the spectrophotometric method.

Food packaging for traditional foods mainly serves to isolate foods from external environmental. For this reason, it is a growing interest in developing active packaging materials that can extend foodstuff shelf-life. Also, it could counteract the level of contamination by plastic in the environment using biodegradable polymers. For this purpose, poly(3-hydroxybutyrate) (PHB)-thermoplastic starch (TPS)/ organically modified montmorillonite (OMMT)/eugenol bionanocomposites were prepared by melt blending. Morphology, thermal, and mechanical properties were determined by comparing the concentration influence of eugenol and clay on the PHB-TPS blend and PHB. X-ray diffraction measurements revealed the existence of exfoliated morphology in the bionanocomposites. Atomic force microscopy imaging (AFM) showed the difference in morphological characteristics of the pure PHB and the prepared bionanocomposites. Roughness analysis from the AFM data indicates that the presence of clay and TPS increases the roughness with respect to PHB. Dynamic mechanical thermal analysis (DMTA) showed that bionanocomposites have an improved storage module. Finally, properties such as hardness and elastic modulus studied by nanoindentation showed a decrease with respect to PHB. The presence of eugenol in the bionanocomposites does not show a significant effect on the different properties.