Lemon juice gel an ideal building block for 3D food printing

A new three-dimensional printing material based on lemon juice and potato starch has exhibited a consistency and flow, which could aid in creating nutritionally enhanced food material formulations. Experiments that use various quantities of these foods to form an optimal gel recipe found that adding 15 grams (g)/ 100g potato starch proved optimal for a three-dimensional (3D) food object. This material, which exhibits a translucent, flexible and chewy texture, is according to the Chinese researchers a “gel-type fudge” which “provides some guidance for other gel and starch products in 3D printing.” Compared with the traditional technology, 3D food printing is touted as a simple, time saving production technique customisable in the whole manufacturing process. 3D printing has therefore found applications for the elderly, who may have difficulty biting or swallowing or find the unappetising appearance of certain foods too much to stomach. The team, based at the Laboratory of Food Science and Technology, Jiangnan University, China, took varying quantities of potato starch (10, 12.5, 15, 17.5 and 20 g/100g) and mixed it with lemon juice. The samples were then moved to glass containers and steam cooked for 20 minutes and allowed to cool to room temperature to form a weak gellike structure, which was then stored at 4°C. Nuclear magnetic resonance (NMR), rheological and texture profile analysis (TPA) was carried out to determine the sample’s water and printing behaviour. Besides the gel’s properties, the influence of printing parameters (nozzle height, nozzle diameter, extrusion rate and nozzle movement speed) on the quality of printed products were also studied. The team, led by Dr Fanli Yang, found a 1 mm nozzle diameter, 24 mm3/s extrusion rate and 30 mm/s nozzle movement speed were the ‘optimal parameters to print 3D constructs matching the target geometry with fine resolution, more smooth surface texture, and fewer point defects with no compressed deformation.” Some food materials such as chocolate, dough and meat paste has already been used to print 3D objects to varying success. Sometimes, the printed objects have had to be processed or cooked post-printing with transglutaminase and bacon fat used as additives to make printable scallop and turkey meat-puree. The researchers also point to the production of 3D printed wheat-based snacks enriched with insect powder (Tenebrio molitor) with the aim to improve the quality and the content of proteins.