Silva, Samara CristinaAlmeida, Thayná DominguesColucci, GiovanaSantamaria-Echart, ArantzazuManrique, Yaidelin A.Dias, Madalena M.Barros, LillianFernandes, ÂngelaColla, ElianeBarreiro, M.F.2018-02-192021-03-182018-01-192021-03-182022González-Arias, Judith; Sánchez, Marta Elena; Martínez, Elia Judith; Covalski, Camila; Alonso-Simón, Ana; González, Rubén; Cara-Jiménez, Jorge (2020). Hydrothermal carbonization of olive tree pruning as a sustainableway for improving biomass energy potential: Effect of reaction parameters on fuel properties. Processes. ISSN . 8:10, p.0927-7757http://hdl.handle.net/10198/23349Spirulina (Arthrospira platensis) proteins have been proven to present emulsifying properties. In this work, a Spirulina protein-rich extract obtained by ultrasound extraction (SpE) was tested to stabilize oil-in-water (O/W) emulsions. For this purpose, a sequential experimental design strategy (Fractional Factorial Design (FFD) 24–1 followed by a Central Composite Rotatable Design (CCRD) 22)) was applied. The effect of four variables, SpE concentration, O/W weight ratio, pH and storage time, on emulsions’ zeta potential and number-mean droplet diameter was considered for the FFD 24–1, indicating SpE concentration and storage time as the relevant variables for the CCRD 22. According to zeta potential and number-mean droplet diameter evaluation, for the studied SpE concentration range (2–5 wt%), quite stable emulsions were obtained along the tested 30-days period. Even so, for 5%, visual inspection revealed extract segregation after 20-days. The optimal solution comprised 4 wt% of SpE, for an O/W weight ratio of 30/70 and a pH of 7.0 (number-mean droplet diameter of 55.66 nm and zeta potential of -43.83 mV). Overall, SpE has proven to be an excellent emulsifier, offering the potential to substitute animal-based proteins and synthetic emulsifiers. In addition, no signs of contamination by microorganisms were observed, suggesting that the SpE may also act as an antimicrobial agent.engMicroalgal proteinsProtein-rich extractOil-in-water emulsionsProtein-stabilized emulsionsExperimental designSpirulina (Arthrospira platensis) protein-rich extract as a natural emulsifier for oil-in-water emulsions: optimization through a sequential experimental design strategyjournal article10.1016/j.colsurfa.2022.1292641873-4359