Percorrer por autor "Silva-Pituco, Samara C."
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- Spirulina (Arthrospira platensis) immobilization in calcium-alginate beads can provide a way to produce food-grade C-phycocyanin following a biorefinery perspectivePublication . Barreiro, Filomena; Silva-Pituco, Samara C.; Aquino, Leandro L.; Dias, Madalena M.C-phycocyanin (C-PC), a water-soluble blue pigment, is the primary phycobiliprotein in Spirulina. In this study, Spirulina was immobilized in calcium-alginate (SAC) beads as an innovative method to recover C-PC in the crosslinking bath while retaining the biomass within the beads. This approach simplifies the separation process and reduces costs. SAC beads were prepared via ionic gelation with alginate and CaCl2 at 2 % (PC2) and 4 % (PC4) concentrations. Different Spirulina to CaCl2 (S:CA) ratios (1:33, 1:42, 1:83, 1:125 w:v) were tested. PC4 extracts surpassed the food-grade purity threshold (≥ 0.7), achieving the highest purity of 0.83 at a 1:42 S:CA ratio. For PC2, the highest purity was 0.68, observed at a 1:83 S:CA ratio. Overall, this method effectively re- leases C-PC into the CaCl2 bath, attaining food-grade purity with significant extraction yields (> 50 mg/g biomass). Additionally, the SAC beads exhibited high protein levels (> 25 g/100 g d.w.) and can be further utilized within a biorefinery framework, either directly as a food supplement or for cascade extractions to recover the remaining lipid and protein fractions.
- Zero-Waste Hydrogel Design via Integral Biomass Valorization of Protein-Rich Spirulina MicroalgaePublication . Aquino, Leandro Lima ; Silva-Pituco, Samara C.; Hernandez-Sosa, Alejandro; Ramalhosa, Elsa; Hernandez, Rebeca; Colla, Eliane; Santamaria-Echart, Arantzazu; Barreiro, FilomenaInterest in alternative protein sources has grown, with Spirulina, a microalga belonging to the genus Limnospira (formerly Arthrospira), emerging as a key option. Guided by sustainability principles, this study explored the gelling capacity and hydrogel-forming properties of integral Spirulina biomass (SpB), targeting applications in structured foods. Two experimental designs (DoE) were employed. One to identify key factors influencing hydrogel formation, and another to optimize the formulation (22 wt%, pH 5.6, thermal gelation at 90 °C). Syneresis analysis revealed that high SpB hydrogels experienced less water loss, with the 22% sample losing just 2.51% after 14 days, due to its dense, particulate morphology as observed by means of scanning electron microscopy. Rheological analysis confirmed the optimized formulation’s superior mechanical properties, with a storage modulus (G′) 24-times higher than the low concentration reference sample (~1890 Pa), remaining dominant over the loss modulus (G″) (G′ > G″) across the analysed frequency range, corroborating a strong elastic behaviour. Although the recovery tests showed partial recovery (27.1%) after high shear, the high residual stiffness (≈515 Pa) confirmed the material’s ability to maintain its shape. These results enabled successful 3D printing tests with the optimized hydrogel, pointing out its potential for innovative food applications in structured food design.