Rheological properties, dispensing force and printing fidelity of starchy-gels modulated by concentration, temperature and resting time

Trends in functional food development with three-dimensional (3D) food printing technology: prospects for value-added traditionally processed food products

“…Similarly to the conventional food extrusion process (W ojtowicz and Mo scicki 2014; Sobowale et al 2018), 3DFP can either be a hot extrusion (HE) process in which case; resultant products require no further post-processing or cold extrusion (CE) in which 3D printed foods (3DPF) usually requires a cooking step such as baking, frying, drying, or steaming (Anukiruthika, Moses, and Anandharamakrishnan 2019;Feng et al 2020;). The latter is applied, especially when printing is done at extrusion temperatures 50 C, the printing temperature range at which printing behavior or cooking effect (such as dehydration) on some foods may be less significantly affected (Liu, Tang, Duan, Qin, Zhao, et al 2020;Paolillo et al 2021).…”

“…The term may also be associated with the extrudability, flowability, and post-processing stability of a well-developed structure (Pulatsu and Lin 2021). These printability characteristics also affect the printed object's overall resolution, which may define its fidelity of printing, i.e., the ability to create an excellent replica of a CAD model (Kim, Bae, and Park 2018;Paolillo et al 2021). Foods of a gelly nature or containing significant amounts of starch/hydrocolloids are generally printable, relatively to the gel's quality indicated by elasticity, viscosity, and water molecule mobility (An et al 2019).…”

“…It is also vital to stress the effect of resting or storage temperature and time of food ink before 3DFP. These conditions contribute to dynamic changes in viscosity profile and rheological properties of printing inks, most especially starchy material, in terms of the starch source, retrogradation effects, and re-proportion degree of starch polymers (Maniglia et al 2019;Liu, Tang, Duan, Qin, Zhao, et al 2020;Paolillo et al 2021). There is, however, less reported information about the extent of those conditions' influence on food ink printability.…”

“…There is, however, less reported information about the extent of those conditions' influence on food ink printability. Paolillo et al (2021) investigated the effect of resting times [2, 24, and 46 hours (h)], printing temperature, and varied ingredients of starchy gels stored at room temperature. Increasing storage time at ambient temperature was found to significantly increase the ink gel's viscosity, which was suggested to be due to amylopectin chains' rearrangement, occurring at a lesser rate than amylose gelation.…”

“…Dough-like structures with higher apparent viscosity, G' and G Ã may require more mechanical force to drive through an extrusion barrel than substrate like gel, chocolate, dispersed ink suspensions, etc. Indeed, the higher ratio of a starchy component in a starchy gel increased its viscosity which necessitated higher dispensing force for 3D extrusion (Paolillo et al 2021). Therefore, considering that a food ink's required dispensing force is strongly linked to its viscosity, it is reasonable to assume that a constant interplay between timely ink flow under extrusion and higher printing speeds would produce printed structures of preferred lesser energy consumption and reduced processing time.…”