| Popis: |
3D-printing is an emerging technology advantageous in the use of alternative raw materials such as grain by-products. This study aimed to investigate dough rheology, printing quality and textural properties of 3D-printed snacks and breakfast cereals made with grain by-products. Four snack recipes consisted of oat flour, sunflower oil, salt, baking soda, glucose oxidase, water, and either of the following: 1) wheat bran and pea protein (mixture WS), 2) pumpkin seed cake (WPFS), 3) defatted flaxseed flour (WFFS), 4) amaranth bran and rice protein (AS). Two breakfast cereal recipes consisted of oat flour, rice protein, wheat bran, baking soda, glucose oxidase, water, and sugar (WSBC) or honey (WHBC). Different 3D shapes were extruded using the Createbot S3 printer and baked at 180°C for 18 min (snack) or 10 min (breakfast cereal). 3D-printing precision, shape accuracy and deformation were determined by digital image analysis. Amplitude and frequency sweep tests were performed on dough using the MCR 92 Oscillatory rheometer (Anton Paar, Austria). Cutting tests were performed on final products with the TA.HDplus texture analyser (Stable Micro Systems, UK). All properties determined were significantly dependent on the dough mixture. The most viscous mixture with the largest G' and G'' values was WS. Dough for snacks printed with higher precision (between 95 and 98%) and shape was deformed less during baking (between -12 and -48%) than dough for breakfast cereals (between 68 and 82% and 75 and 80%, respectively). Snacks shrank, while breakfast cereals spread during baking. With the exception of AS mixture, baked snacks were harder (from 1.68 to 2.84 g) than the breakfast cereals (from 0.63 to 0.78 g). Overall, the WPFS dough mixture was printed with the highest precision (98%) and showed the highest shape accuracy (98%) and the lowest deformation (12%). We can conclude that mixtures with grain by-products can be accurately 3D-printed in various shapes, but further modifications are required to avoid undesirable shape deformation in post-processing. |
