Rheological and mechanical behavior of soy protein-polysaccharide composite paste for extrusion-based 3D food printing: Effects of type and concentration of polysaccharides

Abstract

Soy protein isolate (SPI)-based pastes are widely employed for 3D printing of food materials. However, their rheological properties often do not meet the 3D printing requirements. To enhance the 3D printing characteristics of SPI pastes, this study combined SPI with carrageenan and sodium alginate to form composite materials. The effect of polysaccharide type and concentration on the rheological and textural properties of the ink was investigated to elucidate the mechanism of interaction between proteins and polysaccharides. The results demonstrated that the addition of carrageenan (1.5%, wt %) and sodium alginate (1.5%, wt %) effectively improved the mechanical properties of the paste, such as hardness and adhesiveness, enhanced thus the quality of 3D printed products. With the increase of polysaccharide proportion, the apparent viscosity and storage modulus (G′) of the composite paste increased significantly. Fourier-transform infrared spectroscopy (FT-IR), protein solubility measurement, X-ray diffraction (XRD), and differential scanning calorimetry (DSC) were employed and the results revealed notable interactions among SPI and two kinds of polysaccharides, with electrostatic interactions and hydrophobic interactions being the primary driving forces. The addition of polysaccharides induced changes in the paste crystalline state and improved its thermal stability. Scanning electron microscopy (SEM) confirmed a uniform and compact microstructure due to the incorporation of polysaccharides. Consequently, the SPI-polysaccharide paste can be considered as novel material for 3D printing food materials, and the results of this study provides a theoretical foundation for its application in the field of plant-based food products.