The Experimental Development of Emulsions Enriched and Stabilized by Recovering Matter from Spirulina Biomass: Valorization of Residue into a Sustainable Protein Source

Abstract

Spirulina consists of a cluster of green-colored cyanobacteria; it is commonly consumed as a food or food supplement rich in bioactive compounds with antioxidant activity, predominantly C-phycocyanin (C-PC), which is related to anti-inflammatory action and anticancer potential when consumed frequently. After C-PC extraction, the Spirulina residual biomass (RB) is rich in proteins and fatty acids with the potential for developing food products, which is interesting from the circular economy perspective. The present work aimed to develop a vegan oil-in-water emulsion containing different contents of Spirulina RB, obtaining a product aligned with current food trends. Emulsions with 3.0% (w/w) of proteins were prepared with different chickpea and Spirulina RB ratios. Emulsifying properties were evaluated regarding texture and rheological properties, color, antioxidant activity, and droplet size distribution. The results showed that it was possible to formulate stable protein-rich emulsions using recovering matter rich in protein from Spirulina as an innovative food ingredient. All the concentrations used of the RB promoted the formulation of emulsions presenting interesting rheological parameters compared with a more traditional protein source such as chickpea. The emulsions were also a source of antioxidant compounds and maintained the color for at least 30 days after production.

Keywords: antioxidant activity; food industry; residual biomass; technological ingredient; vegan emulsion.

Figure 1

Firmness (N) (a) and adhesiveness (N.s⁻¹) (b) of emulsions with 3% (w/w) of different combinations of proteins (chickpea protein and Spirulina residual biomass—RB). R0CPP100 (100% chickpea), R25CPP75 (25% RB and 75% chickpea), R50CPP50 (50% RB and 50% chickpea), R75CPP25 (75% RB and 25% chickpea) and R100CPP0 (100% RB without chickpea). According to the Tukey test, different letters indicate significantly different results (p < 0.05). The vertical bars indicate the standard deviation.

Figure 2

Mechanical spectra of emulsions with 3% (w/w) of different combinations of proteins (chickpea protein and Spirulina residual biomass—RB). R0CPP100 (100% chickpea), R25CPP75 (25% RB and 75% chickpea), R50CPP50 (50% RB and 50% chickpea), R75CPP25 (75% RB and 25% chickpea) and R100CPP0 (100% RB without chickpea). G′ corresponds to the elastic modulus, and G″ corresponds to the viscous modulus.

Figure 3

Elastic modulus G′ (a) and viscous modulus G″ (b) at 1 Hz, and plateau module G⁰_N (c) of the emulsions with 3% (w/w) of different combinations of proteins (chickpea protein and Spirulina residual biomass—RB). R0CPP100 (100% chickpea), R25CPP75 (25% RB and 75% chickpea), R50CPP50 (50% RB and 50% chickpea), R75CPP25 (75% RB and 25% chickpea) and R100CPP0 (100% RB without chickpea). According to the Tukey test, different letters indicate significantly different results (p < 0.05). The vertical bars indicate the standard deviation.

Figure 4

Flow curves of emulsions with 3% (w/w) of different combinations of proteins (chickpea protein and Spirulina residual biomass—RB). R0CPP100 (100% chickpea), R25CPP75 (25% RB and 75% chickpea), R50CPP50 (50% RB and 50% chickpea), R75CPP25 (75% RB and 25% chickpea) and R100CPP0 (100% RB without chickpea). Lines represent Williamson’s model adjustment.

Figure 5

Determination of droplet size distribution and microscopy of the emulsions with 3% (w/w) of different combinations of proteins (chickpea protein and Spirulina residual biomass -RB) and De Brouckere diameter (d4,3) obtained from the droplet size distribution analysis. R0CPP100 (100% chickpea), R25CPP75 (25% RB and 75% chickpea), R50CPP50 (50% RB and 50% chickpea), R75CPP25 (75% RB and 25% chickpea) and R100CPP0 (100% RB without chickpea). According to the Tukey test, different letters (a, b, c, d and e) indicate significantly different results (p < 0.05).