Construction of 3D printable Pickering emulsion gels using complexes of fiber polysaccharide-protein extracted from Haematococcus pluvialis residues and gelatin for fat replacer

Structural fat replacers that can meet the requirements of various forms of reduced-fat foods are essential for the application of fat replacement, and emulsion gels emerge as a potential alternative for fat replacers. In this study, fiber polysaccharide-protein extracted from Haematococcus pluvialis residues (FPHRs) formed FPHRs-Gelatin complexes with gelatin. Fourier transformed infrared spectroscopy confirmed the formation of hydrogen bonds between FPHRs and gelatin, the secondary structure order of the protein was enhanced. Three-phase contact angle determination showed that the contact angle of FPHRs-Gelatin complexes was 104 degrees -114 degrees. By exploring the effect of FPHRs concentration, gelatin concentration, and oil-water ratio on the emulsion gels, the Pickering emulsion gels were formed when the FPHRs and gelatin concentration were 2 wt% and 3 wt%, respectively. What's more, these emulsion gels had shear thinning phenomenon, low frequency dependence as well as excellent thixotropy when the oil-water ratio was 0.6, which indicated that they had strong structural support and great recovery capacity to be used as 3D printed materials. The 3D objects printed by the FPHRs-Gelatin complexes emulsion gels had superior print resolution and shape fidelity. This study provides a new type of emulsion gel with structure that can be used as an ideal fat replacer in food processing, the construction of a new 3D emulsion gel material is of great significance for broadening the applications of gelatin-based gels and microalgal food.

Automated summary

In this study, fiber polysaccharide-protein extracted from Haematococcus pluvialis residues (FPHRs) formed FPHRs-Gelatin complexes with gelatin, which exhibited strong structural support and great recovery capacity, making them suitable as fat replacers and 3D printed materials. The Pickering emulsion gels formed when the FPHRs and gelatin concentration were 2 wt% and 3 wt%, respectively, and showed shear thinning phenomenon, low frequency dependence, and excellent thixotropy. The 3D objects printed with FPHRs-Gelatin complexes emulsion gels had superior print resolution and shape fidelity.