Utilization of chestnut shell lignin in alginate films

Abstract

Background Lignocellulosic structures obtained from agricultural wastes can re-design sustainable packaging materials. In this study, the utilization of lignocellulose (LS), alkali lignin (L), and hydroxymethylated (modified) lignin (ML) separated from chestnut shells in alginate (AL) films at 100 and 200 mg g^-1 (10 and 20%, w/w based on AL) as reinforcing agents were investigated. Lignin modification and concentration effects on the AL films were characterized by water vapor permeability (WVP), morphological, mechanical, optical, thermal, and active properties. Results Fourier transform infrared spectroscopy (FTIR) results showed that extracted L and LS had different structures, and the modification of L resulted in a peak shift and a decrease in peak intensities between 1250-800 cm^-1. The antioxidant and antimicrobial activity tests showed that films containing L had higher activity values (pL* values (p<0.05). Conclusion These results presented that lignin addition to biopolymers is a promising method to improve the properties of biopolymers and provide functional attributes. LS had no or little effect on the film properties; however, the modification of L had the advantage of enhancing WVP and thermal properties while showing a decrease in functional properties compared to L.