Structural, Physical, and Antifungal Characterization of Starch Edible Films Added with Nanocomposites and Mexican Oregano (<i>Lippia berlandieri</i> Schauer) Essential Oil

• Main Authors: Rocio Aguilar-Sánchez, Ricardo Munguía-Pérez, Fatima Reyes-Jurado, Addí Rhode Navarro-Cruz, Teresa Soledad Cid-Pérez, Paola Hernández-Carranza, Silvia del Carmen Beristain-Bauza, Carlos Enrique Ochoa-Velasco, Raúl Avila-Sosa
• Format: Article
• Language: English
• Published: MDPI AG 2019-06-01
• Series: Molecules
• Subjects: gas permeability; thickness; porosity; bentonite; halloysite; <i>Fusarium</i> spp.; <i>Aspergillus niger</i>
• Online Access: https://www.mdpi.com/1420-3049/24/12/2340

The aim of this study was to evaluate the structural, physical, and antifungal characteristics of starch edible films added with nanocomposites and Mexican oregano (<i>Lippia berlandieri</i> Schauer) essential oil (EO). Starch edible films were formulated with Mexican oregano EO (0%, 1%, or 2% <i>v</i>/<i>v</i>) and bentonite or halloysite (2%). Physical properties such as <i>L</i>* (luminosity), hue, film thickness, and O₂ and CO₂ permeability were determined. Structural analysis was carried out via atomic force microscopy (AFM). Antifungal activity against <i>Aspergillus niger, Fusarium</i> spp., and <i>Rhizopus</i> spp. was evaluated. The addition of EO and nanocomposites reduced luminosity, providing color to the edible films. Film thickness increased through the addition of EO concentration. O₂ and CO₂ permeability was increased by bentonite/EO films, and for halloysite films, CO₂ permeability decreased as EO concentration increased. The addition of EO with both nanocomposites shows an evident morphological change in film structure, decreasing pore density and increasing pore size. In general, Mexican oregano EO added to edible starch films has an adequate fungicidal effect. The most sensitive microorganism tested was <i>A. niger.</i> Edible films added with Mexican oregano EO and nanocomposites show better physical and antifungal properties due to an adequate structural change in the biopolymer matrix.