Enhancement effect of gelatin on the rheological properties and 3D printing performance of chestnut flour

3D food printing technology has great potential to achieve textural and nutritional personalization of food products, especially for special dietary needs. In this study, novel composite gels were developed for 3D printing using starch-rich chestnut flour as the main component. Lutein/hydroxypropyl-β-cyclodextrin (HP-β-CD) inclusion complexes were added to enhance color, and the effects of varying gelatin concentrations on the system were systematically evaluated. The results showed that gelatin significantly changed the properties of the composite gels, reduced the dissolution of amylose, and enhanced the gels strength and thermal stability. The addition of gelatin decreased the weakly bound water content, apparent viscosity, and tan δ of the composite gels, while increasing the hardness, viscosity, cohesion, G′ and G′′. The improved rheological and textural properties of the composite gels were attributed to the hydrogen bonding and electrostatic interactions between gelatin and chestnut flour, which enhanced their extrudability, printing accuracy, and structural support. The appropriate amount of gelatin contributed to the formation of a firm, interconnected gel network structure. Among all formulations, 20 % gelatin (CF-20 %G) exhibited the highest printing accuracy, with distinctive shape contours and smooth surfaces. It also showed minimal deformation after 6 h storage, demonstrating optimal overall performance for 3D printing. This study provides a theoretical basis for the development of 3D-printed food products containing bioactive substances (e.g., lutein) and a new strategy for innovative food applications.