A novel polysaccharide/zein conjugate as an alternative green plastic

The flax seed cake is a waste product from flax oil extraction. Adding value to this wasted material aligns with the concept of circularity. In this study, we explored zein protein conjugation with flax mucilage for packaging material development. Although both flax mucilage and zein have excellent film-forming properties, they lack the required mechanical properties for industrial processing and are sensitive to high humidity. We present a simple and non-toxic one-pot method for developing the novel flax mucilage/zein conjugate. Where the flax mucilage undergoes oxidation to form aldehyde groups, which then react with zein's amino groups in a glycation process. The conjugates were analyzed using different techniques. The flax mucilage conjugate had a water-holding capacity of 87–62%. Increasing the zein content improved the surface smoothness of the films. On the other hand, higher levels of zein led to a significant decrease in film solubility (p < 0.05). The flax mucilage conjugate exhibited thermoplastic and elastic properties; revealing Young's modulus of 1–3 GPa, glass transition temperature between 49 °C and 103 °C and excellent processability with various industrial techniques. Showing its potential as a sustainable alternative to traditional plastics.