Fabrication and characterizations of biodegradable films based on polysaccharide from Pyropia yezoensis waste with antioxidant and antibacterial activities

Abundant low-grade Pyropia yezoensis and P. yezoensis waste are usually wasted due to poor taste. Pyropia polysaccharides are found in high amounts in low-grade P yezoensis and P. yezoensis waste and are a potential source of biodegradable film. This study evaluated the feasibility of using P. yezoensis polysaccharides to elaborate biobased composite edible biodegradable films blended with sodium alginate and optimized the preparation process of edible film. Film of 1:2 proportion of P. yezoensis polysaccharides and sodium alginate had better morphological and mechanical properties (elongation at break 22.89%, tensile strength 5.65 MPa, water vapor permeability 11.47 × 10⁻¹¹ g m⁻² s⁻¹ Pa⁻¹ and oxygen permeability 3.25 × 10⁻⁵ g m⁻² h⁻¹ atm⁻¹). The films exhibited good antioxidant and antibacterial activity. The degradation experiments indicated that the films could be efficiently degraded. Moreover, the film showed effective preservations on strawberry fruits within 7 days. Therefore, this paper brings a new perspective for the development of low-grade P. yezoensis and P. yezoensis waste to produce sustainable edible biodegradable films, which showed potential applications in active food packaging.