Development and characterization of a novel biodegradable and antioxidant film based on marine seaweed sulfated polysaccharide

This research aims to produce an antioxidant and biodegradable polysaccharide film by using macroalgae agar and sulfated polysaccharide. Agar and sulfated polysaccharide (fucoidan) were extracted from Gracilaria corticata and Sargassum angustifolium macroalgae. Five treatments were conducted: (A) agar film (1%, W:V), (C) chitosan film (1%, W:V + 1% acetic acid), (AC) agar:chitosan composite (50:50, V:V), (ACF) AC film with fucoidan (0.5%, W:V), and (ACFA) ACF film with citric acid (30% of the dry weight of film) as a cross‐linking agent. Then, 0.75% (V:V) of glycerol was added to all films. The physical, mechanical, antioxidant, color variations, microstructure (SEM), and Fourier transform infrared (FT‐IR) spectroscopy were investigated. Based on the results, modifying the agar film with chitosan improved the mechanical strength, humidity, and solubility in the AC composite film (p < .05). Further, adding sulfated polysaccharide and citric acid cross‐linking agent to the agar–chitosan composite led to a significant decrease in solubility, humidity, and permeability to water vapor in ACFA films (p < .05), indicating strong cross‐linking and reduction in film pores based on the SEM pictures and FTIR results. However, the physical and mechanical properties of the agar‐based film obtained from Gracilaria algae can be improved by adding chitosan and citric acid cross‐linking agent, and the addition of fucoidan obtained from Sargassum algae has improved its antioxidant properties. This biodegradable film can be a good candidate for preserving perishable products.