Effect of drying method on post-processing stability and quality of 3D printed rose-yam paste

The addition of rose pollen to the yam paste for 3D printing could not only meet consumers' needs for nutrition and health, but also provide a new way to achieve personalized customization of healthy food. In this work, the rose-yam paste was selected as material, by comparing the post-treatment shape and color stability, bioactive substance content and hardness to explore the effect of hot air drying (HD), microwave vacuum drying (MVD) and freeze drying (FD) on the stability and quality of printed products. FD products illustrated the best post-processing stability, while HD products were the worst. FD products had a higher anthocyanin retention rate of 72.45% and a higher total phenol content of 31.33 mg/100g. However, FD products showed the lowest hardness. Although MVD products showed lower sensory score in appearance and color than FD products, their flavor score was higher than FD products, and the total sensory score of MVD products was equivalent to FD products. Moreover, MVD illustrated the highest drying efficiency, and a reduction of 84% drying time was obtained when compared with FD. Therefore, the combination of MVD and 3D printing could obtain the best quality products. This study would provide useful information on the development of post-processed high value-added 3D printed products, especially for the bio-active substances.