Three-dimensional (3D) printing offers a promising pathway to a more sustainable food system, as it enables the valorisation of food by-products that are typically discarded, transforming them into novel, nutritious ingredients. The objective of this study was to use an alginate-based ionic gelation approach to valorise various food sources, including carrot and fish by-products as well as Ulva rigida . Alginate was incorporated into the formulations, which, after 3D printing, were stabilised through Ca 2+ spraying. The impact of this process was assessed in terms of visual resolution, colour, capacity of being submerged in water and texture at the time of printing (day 0) and after 24 h (day 1). Samples without Ca 2+ were used as control. As expected, the use of Ca 2+ increased the hardness and decreased the adhesiveness of the samples. On day 1, the tendency remained, except for the alga with Ca 2+ where the hardness decreased when compared with the control. Ca 2+ samples demonstrated good capacity to withstand water immersion and lead to less colour changes specially with alga (ΔE = 5.77). This study demonstrated the potential of using an ionic gelation approach to valorise food by-products without the need for temperature to stabilize the 3D printed structure. • Food waste is a drain in the world’s resources and thus its reduction is urgent. • 3D printing and alginate/Ca 2+ gelation can be used to valorise various food sources. • Alginate/Ca 2+ increased the hardness and decreased the adhesiveness of the samples. • Ca 2+ samples demonstrated good capacity to withstand water immersion. • It also led to less colour changes than the controls.
Pereira et al. (Sun,) studied this question.