High internal phase Pickering emulsion stabilized by zein-tannic acid-sodium alginate complexes: ll-Carotene loading and 3D printing

Food-grade compound-stabilized high-internal-phase Pickering emulsions (HIPEs) have received widespread attention in food industry and functional foods. However, challenges are still there regarding the inclusion of active substances and quickly processing molding for food manufacturing. Herein, we used zein, tannic acid (TA) and sodium alginate (SA) to synergistically increase the stability of HIPEs. Owing to electrostatic, hydrophobic and hydrogen-bond interactions among protein, polyphenol and polysaccharide, Zein-TA-SA composite particles-stabilized HIPEs (ZTS-HIPEs) exhibited good pH and ionic strength stability. The HIPEs could further be used to load and solubilize ll-carotene, while significantly improved the retention of ll-carotene in different environ-ments. Simulated in vitro digestion experiments showed that the release rate of free fatty acids and bio-accessibility of ll-carotene in HIPEs were significantly improved, indicating that HIPEs might achieve efficient delivery of ll-carotene in the gastrointestinal environment. In addition, the ZTS-HIPEs could be 3D printed as food-grade inks due to their good rheological properties as the printed models showed good precision and sta-bility. In summary, the ZTS-HIPEs prepared in this study could be used not only as an effective delivery carrier of ll-carotene, but also as a potential ink for 3D printing. The research findings in this study are expected to provide novel insight on HIPEs for nutrition delivery systems and future food manufacturing.