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

Rocio Aguilar-Sánchez,Carlos Enrique Ochoa-Velasco,Teresa Soledad Cid-Pérez,Addí Rhode Navarro-Cruz,Raúl Avila-Sosa,Silvia Del Carmen Beristain-Bauza,Paola Hernández-Carranza,Fatima Reyes-Jurado,Ricardo Munguía-Pérez

doi:10.3390/molecules24122340

Rocio Aguilar-Sánchez, Carlos Enrique Ochoa-Velasco + Show 7 more

Open Access

https://doi.org/10.3390/molecules24122340

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Abstract

The aim of this study was to evaluate the structural, physical, and antifungal characteristics of starch edible films added with nanocomposites and Mexican oregano (Lippia berlandieri Schauer) essential oil (EO). Starch edible films were formulated with Mexican oregano EO (0%, 1%, or 2% v/v) and bentonite or halloysite (2%). Physical properties such as L* (luminosity), hue, film thickness, and O2 and CO2 permeability were determined. Structural analysis was carried out via atomic force microscopy (AFM). Antifungal activity against Aspergillus niger, Fusarium spp., and Rhizopus 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 A. niger. 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.

Highlights

Starch is one of the most abundant natural biopolymers and is attractive due to its low-cost biodegradability, edibility, ease of chemical modification and sustainability, which is why many studies have focused on its application to designing edible films and coatings [1,2]
The aim of this study was to evaluate the structural, physical, and antifungal characteristics of starch edible films added with nanocomposites and Mexican oregano essential oil (EO)
The main component of Mexican oregano EO is thymol, and its concentrations are greater when the extracts are obtained from younger plants [21]

Summary

Introduction

Starch is one of the most abundant natural biopolymers and is attractive due to its low-cost biodegradability, edibility, ease of chemical modification and sustainability, which is why many studies have focused on its application to designing edible films and coatings [1,2]. EOs’ incorporation into edible films to obtain active food packaging is of key interest for food preservation [5] These compounds seem to be promising additives which could interact with film-forming polymers and improve edible films’ physical and functional properties via the production of cross-links between polysaccharides [6], which can extend product shelf life and reduce the risk of pathogen growth on food surfaces [7]. In this aspect, some extracts have evaluated, for example, extracts of rosemary, peppermint oil, thyme, olive, and ginger and found that they showed excellent antimicrobial potential, and their incorporation in films considerably delayed the microbial growth [8]

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