Development and characterization of whole-grain buckwheat biscuit formula based on extruded 3D printing technology

Cereal-based or starch-based materials are commonly used ingredients for three-dimensional (3D) food printing to fabricate customized products. Tartary buckwheat (TB) is recognized as a nutrition-sensitive and climate-resilient crop that supports sustainable agri-food systems. In this study, we investigated the rheological and printing properties of TB-based dough inks formulated with varying amounts of sugar, butter and milk. The addition of milk had a more significant impact on dough printability compared to sugar and butter. Then, the formula of TB-based dough was optimized via response surface analysis to achieve the optimal dough recipe comprising 50 g of TB flour, 15.86 g of sugar, 15.88 g of butter, and 49.29 g of milk. Based on the optimized dough formula, we explored the effects of variations in key printing parameters, including printing speed (10 mm/s, 30 mm/s, 50 mm/s, 70 mm/s and 90 mm/s), nozzle diameter (0.4 mm, 0.6 mm, 0.8 mm, 1.0 mm, and 1.2 mm), and infilling density (15%, 30%, 45%, 60%, and 75%). The best printing performance was achieved using a 0.8 mm nozzle diameter, 30 mm/s printing speed, and 45% infilling density. Furthermore, a series of complex models were implemented, in conjunction with the optimized dough formula to validate the reproducibility of the optimal printing parameters, affirming the efficacy of our approach. In summary, this study provides important guidance on optimizing the formula and printing process of food inks derived from sustainable cereal resources and also greatly contributes to the advancement of 3D printing in the customization of healthy snacks.