Enhancing the properties of gelatin-chitosan bionanocomposite films by incorporation of silica nanoparticles

Functional enhancement of biopolymer was attempted in this work for food packaging application. Incorporation of chitosan (0-9%) and silica (0-10%) nanoparticles (NP's) into gelatin film (Gel) has been tried and their effects on moisture content, tensile strength (TS), elongation at break (%E), wettability, water vapor permeability (WVP), and antimicrobial activities were studied. Morphology of nanoparticles was studied using scanning electron microscopy and transmission electron microscopy. Chitosan NP's showed agglomeration at higher concentration which leads to lower the mechanical as well as barrier properties of the film. However, silica NP's enhanced the properties of bionanocomposite film. TS was increased from 6.05 MPa of pure gelatin film to a maximum value of 38.91 MPa at CS NP's of 5.8% and Si NP's of 7%; however, %E decreased with addition of nanoparticles resulting in brittleness of film. WVP for pure gelatin film was 25.21 g mm/kPa m(2) day, which reduced to 3.30 g mm/kPa m(2) day after incorporation of 10% Si NP's. Antimicrobial activity was observed against E. coli and S. aureus. Incorporation of CS NP's improved the antimicrobial activity of gelatin film. Si NP's showed improvement in mechanical and barrier properties of Gel-CS films, however, had no effect on antimicrobial activities. Practical Application Researchers community are more concerned of natural biopolymers to reduce the use of synthetic polymers, especially in food packaging. Gelatin is one of the natural biopolymer and have potential to be used as food packaging material. Problem with gelatin and many other biopolymer based film is their poor mechanical and barrier properties. Present study was framed to overcome these problems by incorporating silica and chitosan nanoparticles in gelatin film. The results observed would be useful to develop a biopolymer based nanocomposite film with improved mechanical, barrier and antimicrobial properties, which can be used for active food packaging.