3D printed gluten-free cereal snack with incorporation of Spirulina (Arthrospira platensis) and/or Chlorella vulgaris

3D food printing is a recent technology promising to break cultural barriers by introducing new food sources such as microalgae, through innovative food shapes and textures, in a resource-scarce world whose sustainability is at stake because of the current intensive production of meat and agriculture products. The present work intends to create an innovative gluten-free cereal snack nutritionally improved by the incorporation of Chlorella vulgaris and Arthrospira platensis (“Spirulina”) biomass using 3D printing technology. Doughs without (control) or with microalgal biomass with different incorporation percentages (from 5 to 30 %) were tested and those showing the most adequate rheology (low viscoelastic moduli and apparent viscosity) and texture (low firmness, adhesiveness and high cohesiveness) properties for a correct printing process were selected and baked (control and 5 % microalgae incorporation). Nutritional characterization of the control and 5 % snacks was performed, in terms of total protein and lipid contents, ash, humidity, water activity, energy, and carbohydrates, as well as total phenolics, pigments and antioxidant activity. Physical traits of snacks, including their colour and size, were also analysed. Control snacks presented a lighter and yellow colour compared to snacks containing Chlorella and Spirulina, which had higher green chromaticity (Control: a* - 0.953, b* 21.3; Chlorella 5 %: a* - 2.20, b* 11.8; Spirulina 5 %: a* -1.05, b* 3.55). Nutritional characterization revealed that snacks containing Chlorella and Spirulina had both higher protein and essential minerals content. Overall, 5 % Spirulina snacks presented the best nutritional and sensory performance, with higher antioxidant activity, mineral and protein contents. These Spirulina-snacks deserved a positive sensory appreciation from consumers