In this study, we investigated the effect of toughening treatment (55 ℃ for 0, 12, 24, 36, 48 and 60 h) on the microstructure, pasting properties, thermal properties, rheological properties and 3D printability of potato starch. The results showed that the toughening treatment roughened the surface of starch granules and increased the viscosity and pasting temperature of the starch. The toughened potato starch gel showed greater mechanical strength and a more stable and ordered internal structure than the native starch gel. It was found that toughening treatment for 36 h had a significant effect on the printing characteristics of potato starch gels, resulting in the highest printing accuracy and height as well as the best printing performance.

In this study, the changes in the amylose content, crystalline structure, Fourier transform infrared (FTIR) properties, pasting properties, and rheological properties of potato starch were explored after radio frequency (RF) treatment at different polar plate spacings (90, 100, 110, 120, and 130 mm). The appropriate RF parameters for 3D printing of potato starch gels were determined. The results revealed that under low plate spacing, the content of amylose decreased and the crystalline form of starch transformed from B-type to C-type. We found that the starch gel with RF treatment at a plate spacing of 90 mm had the best morphology in terms of transparent line uniformity and high retention rate. To sum up, we can conclude that RF treatment at low polar plate spacings is an effective method for preparing 3D printed starch gels.