Enhancing lutein and anthocyanins stability and bioaccessibility through simultaneous encapsulation into starch/zein gels using coaxial 3D food printing

This study investigated the use of 3D printing to co-encapsulate, protect, and enhance the bioaccessibility of lutein and anthocyanins. Coaxial extrusion 3D printing in a spiral-cube geometry was utilized with lutein-loaded zein as the core material and anthocyanins-loaded corn starch paste as the shell material. The research examined various printing conditions, including starch concentrations of 10% and 11%, and printing temperatures ranging from 45°C to 85°C. A comprehensive analysis of the inks' properties, such as printability, viscosity, microstructural characteristics, storage stability, and bioaccessibility of the encapsulated compounds, was conducted. The results indicated that the sample printed with 11% starch at 75°C exhibited superior shape integrity, while the sample with 10% starch at 55°C showed good shape and significantly enhanced the stability of lutein and anthocyanins compared to their crude forms. Encapsulated lutein showed only a 29–55% degradation rate after 21 days at 25°C, while 97% of crude lutein was degraded under the same conditions. Similarly, encapsulated anthocyanins had 42–55% degradation rates depending on the 3D printing conditions compared to 70% for crude anthocyanins. Furthermore, the bioaccessibilities of encapsulated lutein (9.8%) and anthocyanins (37.5%) were significantly higher compared to their crude counterparts (1.5% and 20.3%, respectively). This innovative 3D printing encapsulation system effectively enhances the chemical stability and bioaccessibility of these model bioactive compounds, presenting a promising method for their integration into food products.