Structuring native red seaweed extracts for 3D printing: Rheological synergies with xanthan and locust bean gums

This study explored the gelation and 3D printing properties of native, eco-friendly extracts from three red seaweed species ( Chondrus crispus , Gelidium corneum , and Gracilaria gracilis ) reinforced with xanthan gum (XG) or locust bean gum (LBG). Given the limited information on non-purified seaweed polysaccharide-hydrocolloid interactions, rheological, textural, and compositional analyses were performed to understand how these factors influence gel properties. C. crispus , which is rich in carrageenan, formed the strongest native gel (G 25°C ′ ≈ 30 kPa), with LBG reinforcement boosting its G 80°C ′ tenfold (from 3.65 to 36.54 Pa). For G. gracilis , XG addition significantly enhanced gel strength (G 25°C ′ from 447 to 3897 Pa) and improved gel-like behavior at high temperatures. Textural analysis confirmed that reinforced gels exhibited greater firmness (1.5–4.2 N) than native extracts (0.8–1.2 N). 3D printing was used to evaluate extrusion behavior, shape fidelity, and gel recovery. Hydrocolloid reinforcement improved shape retention by 45–60 %, with optimal printing temperatures between 30 and 40 °C. Differences were primarily attributed to the seaweed's polysaccharide profiles. A life cycle assessment identified G. corneum agar as the most environmentally sustainable option. These results demonstrate the potential of combining native red seaweed extracts with simple hydrocolloids to create customizable, sustainable gels. • CMCH enhances viscoelasticity/thermal resistance of zein bioplastics. • CMCH increases hydrophilicity of zein via carboxylic groups. • A CMCH/GNP synergy exists at 0.01 mM GNP in zein bioplastics. • Properties of zein bioplastics can be tuned through adequate formulation.