Improved mechanical, functional and antimicrobial properties of corn starch-based biodegradable nanocomposites films reinforced with lemongrass oil nanoemulsion and starch nano-crystal

Abstract

In recent times, negative influence of petroleum-based packaging materials on environment, sustainability and health has become a serious issue. Therefore, development of biodegradable packaging material for food related applications is rapidly gaining attention. The present study evaluates the influence corn starch nanocrystals (SNCs) (0.5%, 1% and 2%) in conjugation with lemongrass oil nanoemulsion (LNE) (2%) on the functionality of corn starch based film. The develop nanocomposite films were evaluated for their functional, tensile, barrier and functional properties and also characterized using X-ray diffraction (XRD), Nuclear Magnetic Resonance (NMR), Fourier transform infrared spectroscopy (FTIR) and Field-Emission Scanning Electron Microscopy (FE-SEM) techniques. Results revealed an increase in SNCs concentration caused a significant (p < 0.05) reduction in water barrier properties whereas incorporation of SNCs (≤1%) exhibited homogenous dispersion of nanocrystals into the matrix, improving tensile properties (15.53%). Opacity, color and crystallinity were influenced by the concentration of SNCs. SNCs/LNE loaded films exhibited increased opacity (↑63.1%) and antioxidant activity (↑348.2%). LNE induced small cavities on the film's surface, reducing the tensile strength and increasing elongation at break compared to SNCs loaded films. Antimicrobial activity of SNCs/LNE loaded films against E. coli. (ZOI-7.33 mm) and Staphylococcus aureus (ZOI-10.59 mm) was higher than SNCs-loaded films. SNCs and LNE, both reduced the degradation rate, yet films were completely degradable in soil, proving their potential utility in the development of functional and biodegradable food packaging.