Maillard conjugation of jackfruit seed protein by dextran: structural modulation toward enhanced gelation and 3D...

Jackfruit seeds are an underutilized tropical by-product containing nutritionally valuable proteins, but jackfruit seed protein (JSP) generally exhibits limited heat-induced gelation, which restricts its application in gel-based and 3D-printed food systems. JSP was glycated with dextran via a Maillard-type reaction under neutral (pH 7.0) and mildly alkaline (pH 9.0) conditions at different JSP-to-dextran ratios. Structural analyses revealed that alkaline glycation (pH 9.0) at a JSP-to-dextran ratio of 2:1 (9G-2) achieved a favorable balance between covalent grafting and dispersion-related interfacial properties, accompanied by modulated conformational organization and thermal response. Heat-induced gels of 9G-2 exhibited enhanced gelation performance, including increased water-holding capacity, a compact and homogeneous microstructure, and viscoelastic properties favorable for extrusion-based printing, which were associated with a more favorable distribution of intermolecular interaction contributions within the gel network. Extrusion-based 3D printing further demonstrated that 9G-2 gels at protein concentrations of 6% and 7% (w/w) enabled smooth filament formation, high shape fidelity, and good self-supporting ability. Overall, this study clarified how reaction pH and JSP-to-dextran ratio regulate Maillard glycation and subsequently govern gel network organization and printing-related performance of JSP, providing a sustainable strategy to valorize tropical seed proteins for extrusion-based plant-based food manufacturing.