Mushroom-Derived Chitosan: A Promising Alternative for Sustainable Packaging Films

Chitosan, a biopolymer known for its film-forming, antimicrobial, and biodegradable properties, has long been sourced from shellfish waste. But new research led by scientists at the University of Sheffield explores a fungi-based alternative using Agaricus bisporus, the common white button mushroom, to develop active packaging films.

The study evaluates the performance of mushroom-derived chitosan as a replacement for crustacean-derived chitosan in food packaging, using glycerol and grape seed extract to improve flexibility and antioxidant activity.

Image credits: Pexel

A Cleaner, Fungal-Based Source of Chitosan

Shellfish-sourced chitosan poses several challenges: limited supply chains, seasonal dependence, and allergen risks. Fungal chitosan, especially from mushrooms like A. bisporus, avoids these issues and can be grown on agricultural waste.

In this study, researchers extracted chitosan from mushroom stems using mild acid and alkali treatments, achieving a deacetylation degree of 83% and a yield of 10.2%. The resulting polymer was blended with glycerol (a plasticiser) and grape seed extract (rich in polyphenols) to produce active films.

Comparable Barrier and Mechanical Properties

Film thickness ranged from 50 to 70 µm, with tensile strength values between 24.3 and 36.8 MPa—within range of commercial low-density polyethylene (LDPE). The water vapour permeability and oxygen transmission rates were also comparable to shellfish-based chitosan films.

Notably, the films with 2% grape seed extract showed the highest antioxidant activity, as measured by DPPH radical scavenging, while maintaining good mechanical flexibility. FTIR and SEM analysis confirmed uniform blending and surface homogeneity.

Antimicrobial Potential and Shelf-Life Benefits

The films inhibited the growth of E. coli and S. aureus in vitro, with enhanced performance in those incorporating grape seed extract. In preliminary shelf-life trials with strawberries, the films delayed microbial spoilage and surface degradation for up to four days compared to control packaging.

Applications and Outlook

These findings support mushroom chitosan as a viable, sustainable alternative to traditional packaging films. Beyond reducing reliance on animal-sourced materials, it offers potential for local production, circular material flows, and allergen-free applications.

Further work is needed to optimise large-scale production and investigate long-term food compatibility, but the case for fungi in packaging continues to grow.