(342a) An Innovative 3D Printing Approach for Encapsulating Lutein into Dual-Layered Starch-Ethylcellulose/Zein Gels

In recent years, the development of personalized foods has received significant attention as a result of growing concerns about foods for people with special needs, such as the elderly, children, astronauts, and athletes. Three-dimensional (3D) printing is a novel additive manufacturing technology that allows the fabrication of customized foods that can be tailored to nutritional demands, calorie consumption, color, texture, and flavor preferences. Despite their health-promoting activities, lipophilic bioactive compounds are difficult to incorporate into foods due to their low stability and water solubility. To address the stability and/or bioavailability issues, different delivery systems have been developed for encapsulating bioactive compounds. In this study, the potential of starch, ethyl cellulose, and zein gels to encapsulate lipophilic bioactive compounds and increase their stability was investigated. To explore the capability of this formulation in improving compounds’ stability, release, and bioaccessibility, lutein was used as a model lipophilic bioactive compound. A 3D food printer was used to fabricate dual-layered gels consisting of starch, ethyl cellulose, and zein for lutein encapsulation. A spiral-cube-shaped geometry was used to investigate the effects of printing parameters, namely, starch (9, 10, 11, and 12%, w/w), ethyl cellulose (6, 8, and 10%, w/v), and zein (10, 15, 20%, w/v) concentrations, layer height (0.4, 0.7, and 1 mm), and printing temperature (55, 65, and 75 °C). A coaxial nozzle setup was used to encapsulate lutein into starch-ethyl cellulose, and starch-zein gels, where starch was used as the outer flow (shell) and lutein-loaded ethyl cellulose, and lutein-loaded zein as the inner flow (core). The ink viscosities, microstructural characteristics, storage stability, in-vitro lutein release, and bioaccessibility of encapsulated lutein were investigated. The results indicated that the rheological properties of inks are critical for ensuring good extrudability and printability throughout the printing process. Printability of the gels and lutein stability were affected by starch concentration and printing temperature; the maximum shape fidelity and storage stability were attained with 10 and 11% (w/w) starch concentrations at printing temperatures of 55 and 65 °C, respectively. The layer height of 0.7 mm resulted in the best printing accuracy, highest resolution, and fewest internal cavities. The 3D-printed sample exhibited considerably higher lutein retention indexes after 21 days of storage at 25 °C and 50 °C than crude lutein at the same storage conditions. The 3D-printed dual-layered encapsulation technique can be utilized to load bioactive compounds into food products with greater stability and bioaccessibility while eliminating the use of toxic organic solvents. The proposed approach allows the food industry to design functional foods with higher flexibility and precision.