Development of an integrated approach to produce phycocyanin and valorize co-bioproducts from Spirulina Arthrospira platensis

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New trends in natural emulsifiers and emulsion technology for the food industry

Publication . Santamaria-Echart, Arantzazu; Fernandes, Isabel P.; Silva, Samara Cristina; Rezende, Stephany; Colucci, Giovana; Dias, Madalena M.; Barreiro, M.F.

The food industry depends on using different additives, which increases the search for effective natural or natural-derived solutions, to the detriment of the synthetic counterparts, a priority in a biobased and circular economy scenario. In this context, different natural emulsifiers are being studied to create a new generation of emulsion-based products. Among them, phospholipids, saponins, proteins, polysaccharides, biosurfactants (e.g., compounds derived from microbial fermentation), and organic-based solid particles (Pickering stabilizers) are being used or start to gather interest from the food industry. This chapter includes the basic theoretical fundamentals of emulsions technology, stabilization mechanisms, and stability. The preparation of oil-in-water (O/W) and water-in-oil (W/O) emulsions, the potential of double emulsions, and the re-emerging Pickering emulsions are discussed. Moreover, the most relevant natural-derived emulsifier families (e.g., origin, stabilization mechanism, and applications) focusing food applications are presented. The document is grounded in a bibliographic review mainly centered on the last 10-years, and bibliometric data was rationalized and used to better establish the hot topics in the proposed thematic.

2021Book part

Open access

Spirulina (Artrhospira platensis) protein extract: techno-functional properties and potential application as a natural emulsifier

Publication . Silva, Samara Cristina; Almeida, Thayná Domingues; Colucci, Giovana; Santamaria-Echart, Arantzazu; Manrique, Yaidelin A.; Dias, Madalena M.; Barros, Lillian; Fernandes, Ângela; Colla, Eliane; Barreiro, M.F.

Microalgae are valuable sources of proteins (20-70%) and have emerged as great alternatives to animal-based proteins (e.g., whey protein, egg yolk)1. This work aimed to obtain a microalga protein extract (SpE) from Artrhospira platensis (Spirulina) and evaluate its techno-functional properties and emulsion formation capability. The SpE was obtained by ultrasound and conventional mechanical stirring under an alkaline medium (pH 9.0) followed by acid precipitation (pH 3.0)2. In addition, the SpE techno-functional (protein solubility; oil and water absorption capacities) and structural properties (FTIR analysis) were investigated. Moreover, an emulsion (oil/water ratio (30/70); pH 7.0; SpE concentration (3.5%)) was prepared according to two sequential steps: i) high-shear homogenization (UltraTurrax; 11,000 rpm; 3 min) and ii) high-pressure homogenization (100MPa; 6 cycles)3. Then, it was analysed by optical microscopy, zeta potential and particle size. The SpE (66.6%±0.31 protein) presented the lowest solubility at pH 3.0 and the highest at pH 8.0. The protein extract showed higher absorption capacity in oil (21.7±0.10 g oil/ g SPE) than in water (10.3±0.50 g water/ g SPE). From the FTIR analysis (Figure 1a), the SpE showed two peaks at 1635 cm-1 and 1535 cm-1 (red circle in Figure 1a) attributed to the presence of characteristic protein groups, amide I and amide II, respectively. The oil-in-water emulsion (ESp) presented a light blue-green colour due to the presence of SpE (Figure 1a) and remained stable for 30 days (Figure 1b). The SpE presented a zeta potential of -47.20 mV and a particle size of 330 nm (D50, volume distribution) on the 30th storage day. Small and spherical droplets were observed, evidencing the particle size and stability over the storage time (Figure 1c). Thus, the SpE showed the ability to form emulsions with stability for up to 30 days, being a great alternative to replace animal-based and synthetic emulsifiers.

2021Conference object

Open access

Developing High-Coloring Natural Systems Using Double Emulsions with Daucus carota L. Extract to Meet High-Performance Requirements

Publication . Teixeira, Liandra Gracher; Silva, Samara Cristina; Colucci, Giovana; Santamaria-Echart, Arantzazu; Peres, António M.; Dias, Madalena M.; Barreiro, M.F.

Daucus carota L. extract is attracting interest as a natural colorant alternative. However, the presence of anthocyanins (ACNs), which are sensitive to pH changes, limits its application. To tackle this issue, water-in-oil-in-water (W1/O/W2) double emulsions are emerging as innovative solutions. Nevertheless, the problem of reaching robust colorant systems for industrial use still needs to be overcome. One important target is to reach a high coloring power, minimizing its impact on the final product. In this context, the effect of colorant concentration and the volume of the primary emulsion, two routes to increase the colorant power, on color attributes and stability, an important feature to reach a marketable product, was studied. The optimal experimental design was conducted to two optimal solutions, whether through heightened colorant concentration or primary emulsion volume: a 41/59 (W1/O)/W2 ratio with 11 wt.% colorant, and a 48/52 (W1/O)/W2 ratio with 6 wt.% colorant, respectively. A subsequent assessment of color and physical emulsion stability over 30 days pointed out the solution with the lower colorant concentration (6 wt.%) as the one with better performance (L*: 44.11 ± 0.03, a*: 25.79 ± 0.01, D4;3: 9.62 ± 0.1 μm, and CI: 14.55 ± 0.99%), also minimizing the permeability of the colorant to the outer aqueous phase. Overall, these optimized emulsions offer versatile coloring solutions suitable for various industrial applications, such as food matrices and functional cosmetics.

2024Journal article

Open access

Spirulina (Arthrospira platensis) protein-rich extract as a natural emulsifier for oil-in-water emulsions: optimization through a sequential experimental design strategy

Publication . Silva, Samara Cristina; Almeida, Thayná Domingues; Colucci, Giovana; Santamaria-Echart, Arantzazu; Manrique, Yaidelin A.; Dias, Madalena M.; Barros, Lillian; Fernandes, Ângela; Colla, Eliane; Barreiro, M.F.

Spirulina (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.

2022Journal article

Open access

Microalgae-derived pigments: a 10-year bibliometric review and industry and market trend analysis

Publication . Silva, Samara Cristina; Ferreira, Isabel C.F.R.; Dias, Madalena M.; Barreiro, M.F.

Microalgae productive chains are gaining importance as sustainable alternatives to obtain natural pigments. This work presents a review on the most promising pigments and microalgal sources by gathering trends from a 10 year bibliometric survey, a patents search, and an industrial and market analysis built from available market reports, projects and companies’ webpages. The performed analysis pointed out chlorophylls, phycocyanin, astaxanthin, and β-carotene as the most relevant pigments, and Chlorella vulgaris, Spirulina platensis, Haematococcus pluvialis, and Dunaliella salina, respectively, as the most studied sources. Haematococcus is referred in the highest number of patents, corroborating a high technological interest in this microalga. The biorefinery concept, investment in projects and companies related to microalgae cultivation and/or pigment extraction is increasingly growing, particularly, for phycocyanin from Spirulina platensis. These pieces of evidence are a step forward to consolidate the microalgal pigments market, which is expected to grow in the coming years, increasing the prospects of replacing synthetic pigments by natural counterparts.

2020Journal article

Open access