Protein Fortification of Millet-Based Gluten-Free Snacks Designed for 3D Printing

Abstract

The global trend in gluten-free snack innovation involves using naturally gluten-free grains as a nutrient-rich foundation, enriching formulations with multifunctional plant and microbial proteins, and optimizing ingredient interactions to balance nutritional demands with structural integrity. The study demonstrates that blending proso millet flour with yeast-derived and almond (50:50 ratio) proteins effectively produces a protein- and fiber-rich gluten-free dough suitable for 3D printing, without the need for synthetic additives. This approach aligns with the growing demand for clean-label, sustainable protein sources that enable the creation of healthy, stable, and appealing ready-to-eat snacks. The enriched dough demonstrated superior rheological behavior, characterized by a dominant elastic modulus (G′ > G″), enabling smooth extrusion and stable shape retention. Nutritional analysis revealed an increase in protein (28.16 vs. 13.26 g/100 g DB) and dietary fiber (12.17 vs. 6.22 g/100 g DB) compared to the control. The amino acid profile improved significantly, with 48% more essential amino acids and a 63% increase in non-essential amino acids. Dimensional accuracy improved, and post-processing deformation was reduced, confirming enhanced structural integrity. Texture analysis showed no significant increase in hardness, maintaining a desirable texture profile despite higher protein content. Sensory evaluation confirmed greater acceptance of the enriched snack, especially in terms of flavor, aroma, and smell, while preliminary cost assessment indicated that, despite higher ingredient costs, the enriched formulation remains economically feasible. Additional optimization of protein concentration and processing conditions could enhance the overall functionality even further.