Study on 3D printing of orange concentrate and material characteristics

Three-dimensional (3D) food printing is a promising technology that attracted the attention of both academia and industry since it is considered as a major paradigm shift in the fabrication of intricate and personalized food design with the choices of altering the nutritional profile. In this study, 3D printing (3DP) properties of orange leather (OL) were characterized and simultaneously comparative assessment was carried out while making it from orange concentrate (OC) by adding varying proportions (15, 20, 25. and 30%) of wheat starch (WS). Rheological data suggest that steam cooking of OC-WS mixture for 16 +/- 0.5 min exhibit shear-thinning behavior, which is essential for extrusion-type 3DP of food mixtures. A variation of 5% WS with OC significantly increase the yield stress (tau(0)) and viscosity (n). Nuclear magnetic resonance (NMR) study revealed that the maximum amount of partially immobilized water was converted to bound water and developed the highest mechanical strength but poor extrudability for 30% WS containing sample. Texture profile analysis suggests that the 20% WS containing samples provide the best mastication properties among the four samples. To optimize the printing conditions and test the reproducibility of OL 3DP process effects of nozzle diameter (d(n)), nozzle tip-print bed height (h(c)), extrusion rate (v(d)), and nozzle moving speed (v(n)) were tested experimentally. It was found that, at d(n)=1.5 mm, h(c) = 1.54 +/- 0.02 mm, v(d) = 245 mm(3)/s, and v(n) = 35 mm/s the printed objects remain consistent, achieve the best resolution and maximum fidelity.