Lignin Incorporated Antimicrobial Chitosan Film for Food Packaging Application

By : Sudheer Rai , P. K. Dutta , G. K. Mehrotra

Page No: 171-183

Abstract
To develop a biodegradable antimicrobial composite film lignin was incorporated into chitosan in different compositions. The films were characterized by UV-visible, FT-IR and XRD techniques and evaluated for their potential antimicrobial activities against two food pathogens, namely, Gram (+) ve (Bacillus subtilis) and Gram (–) ve (Pseudomonas aeruginosa) bacteria. FT-IR results showed that an interaction among chitosan polymer matrix and lignin had occurred, absorbance band of chitosan at 3280 cm-1 for hydroxyl is shifted to ~ 3000 cm-1 with the weak intensity (in lignin, 200 μg), 1666 cm-1 for amide bond and it is shifted to 1644 cm-1; 1023 cm-1 for assigned to C–O stretching and shifted to 1066 cm-1. XRD peaks of lignin containing films were more intense, indicating that the interaction of lignin into the film matrix which induces an increase in crystallinity nature. It has been observed that there are no major changes in the thickness of chitosan films after mixing of lignin. Addition of lignin in chitosan films resulted in the decrease in water content and solubility of the composite films. Lignin (200 μg) could be well dispersed and showed strong tensile strength (TS) and ductility in the films. The composite films have shown significant antimicrobial activity against Gram (+) ve and Gram (–) ve bacteria. This study revealed that an antimicrobial chitosan film could be obtained by addition of lignin, which may give a new idea for the development of an active food packaging material.

Authors :
Sudheer Rai, P. K. Dutta and G. K. Mehrotra : Department of Chemistry, Motilal Nehru National Institute of Technology Allahabad-211004, India