Percorrer por autor "Silva, Samara Cristina"
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- Developing High-Coloring Natural Systems Using Double Emulsions with Daucus carota L. Extract to Meet High-Performance RequirementsPublication . 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.
- Development of colloidal lignin particles through particle design strategies and screening of their Pickering stabilizing potentialPublication . Colucci, Giovana; Santamaria-Echart, Arantzazu; Silva, Samara Cristina; Teixeira, Liandra Gracher; Ribeiro, Andreia; Rodrigues, Alírio; Barreiro, M.F.Colloidal lignin particles (CLPs) have increased interest as green and sustainable materials for Pickering stabilizers, with particle design being an important step towards their effective use. In this context, the antisolvent precipitation method was selected to conduct a study aiming at understanding the effect of process variables (initial lignin concentration, antisolvent pH, final ethanol concentration, and antisolvent addition rate) on particle size, zeta potential, color parameters, and contact angle. Moreover, their Pickering stabilizing potential was preliminarily screened. The evaluation using a Fractional Factorial Design revealed that the particle size is significantly influenced by the initial lignin concentration (as it increases, larger particles are obtained) and the final ethanol concentration (as it increases, smaller sizes result). The zeta potential is significantly affected by the antisolvent pH and the initial lignin concentration; the increase in both parameters results in higher negative values. The color is significantly dependent on the used initial lignin concentration (as it increases, particles become lighter and the yellowish accentuates) and the antisolvent pH (as it increases, particles become darker). Both initial lignin concentration and final ethanol concentration increase promote hydrophobicity, whereas increasing the antisolvent pH and its addition rate turns particles more hydrophilic. Through this strategy, it was possible to achieve CLPs with promising Pickering stabilizing potential, putting in evidence the importance of understanding the production process to design effective particles for target applications.
- Development of water-in-oil emulsions as delivery vehicles and testing with a natural antimicrobial extractPublication . Colucci, Giovana; Santamaria-Echart, Arantzazu; Silva, Samara Cristina; Fernandes, Isabel P.; Sipoli, Caroline C.; Barreiro, M.F.Water-in-oil (W/O) emulsions have high potential for several industrial areas as delivery systems of hydrophilic compounds. In general, they are less studied than oil-in-water (O/W) systems, namely in what concerns the so-called fluid systems, partly due to problems of instability. In this context, this work aimed to produce stable W/O emulsions from a natural oil, sweet almond oil, to be further tested as vehicles of natural hydrophilic extracts, here exemplified with an aqueous cinnamon extract. Firstly, a baseW/O emulsion using a high-water content (40/60, v/v) was developed by testing di erent mixtures of emulsifiers, namely Tween 80 combined with Span 80 or Span 85 at di erent contents. Among the tested systems, the one using a 54/46 (v/v) Span 80/Tween 80 mixture, and subjected to 12 high-pressure homogenizer (HPH) cycles, revealed to be stable up to 6 months, being chosen for the subsequent functionalization tests with cinnamon extract (1.25–5%; w/v; water-basis). The presence of cinnamon extract leaded to changes in the microstructure as well as in the stability. The antimicrobial and antioxidant analysis were evidenced, and a sustained behavior compatible with an extract distribution within the two phases, oil and water, in particular for the higher extract concentration, was observed.
- Microalgae-derived pigments: a 10-year bibliometric review and industry and market trend analysisPublication . 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.
- Microencapsulação como estratégia para a compatibilização da microalga Spirulina platensis em matrizes hidrofílicas (iogurtes).Publication . Silva, Samara Cristina; Fernandes, Isabel P.; Fernandes, Ângela; Barros, Lillian; Colla, Eliane; Ferreira, Isabel C.F.R.; Barreiro, M.F.Spirulina platensis (spirulina) é uma microalga azul esverdeada certificada pela FDA (Food and Drug Administration) como segura para ser adicionada em alimentos. Ê uma matriz rica em nutrientes como proteínas e aminoácidos, vitaminas, minerais, ácidos gordos e pigmentos [l]. No entanto, a sua adição na forma pura apresenta algumas limitações, nomeadamente presença de compostos que conferem sabor e odor indesejáveis [2] e dificuldade de dispersão em matrizes hidrofílicas. A microencapsulação é uma tecnologia que pode solucionar estes problemas sendo capaz de mascarar compostos indesejáveis e melhorar a solubilidade. Assim, o objetivo deste trabalho consistiu na caracterização de uma amostra comercial de spirulina quanto ao valor nutricional e energético, açúcares livres, ácidos gordos, tocoferóis e pigmentos e sua posterior microencapsulação pela técnica de spray-drying. Realizaram-se dois ensaios de encapsulação: i) spirulina/maltodextrina (SM) e ii) spirulina/maltodextrina reticulada com ácido cítrico (SMA), tendo-se feito a caracterização quanto ao rendimento (a eficiência e carga foram estimadas), características de degradação térmica (análise termogravimétrica (TGA/DTG)) e tamanho de partícula. Posteriormente, efetuou-se a incorporação das microesferas em iogurtes naturais, tendo-se comparado com a spirulina livre quanto à sua capacidade de homogeneização no iogurte. A microalga analisada apresentou alto teor em proteínas e cinzas. Foram identificados ácidos gordos essenciais (y-linolénico) e tocoferóis e ainda pigmentos como: β-caroteno, clorofila e a ficocianina. Esta microalga apresentou temperatura máxima de degradação de 304°C e resíduo de 27,65% a 600°C. Para a microencapsulação foi possível obter rendimentos relevantes, sendo 66% para SM e 75% para SMA'. Pela análise de TGA/DTG notou-se que as microesferas SM apresentaram duas zonas de degradação mais definidas comparativamente com SMA onde a primeira zona não é tão pronunciada. Esta situação é justificada pela ocorrência da reação de reticulação para a SMA, resultando numa melhor homogeneidade do material e um efeito de proteção superior. Notou-se que a distribuição do tamanho de partícula em volume e em número apresentaram comportamentos semelhantes para SM e SMA. Relativamente aos iogurtes observou-se uma melhor homogeneidade quando a spirulina foi adicionada na forma microencapsulada, tendo os iogurtes adicionados com spirulina livre apresentado heterogeneidade (um aspeto de efeito pontilhado) (Fig. l). Em síntese, conclui-se que a microencapsulação da bionÍassa de spirulina melhorou a compatibilidade desta microalga em matrizes hidrofílicas, tornando estes produtos de elevado valor nutricional mais atrativos para o consumidor.
- New trends in natural emulsifiers and emulsion technology for the food industryPublication . 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.
- Optimisation of stability and colouring power of double emulsion systems loaded with Daucus carota L.Publication . Teixeira, Liandra Gracher; Silva, Samara Cristina; Colucci, Giovana; Santamaria-Echart, Arantzazu; Peres, António M.; Dias, Madalena M.; Barreiro, FilomenaAnthocyanins (ACNs) are water-soluble bioactive flavonoids found in flowers, roots, leaves, seeds, and stalks. ACNs cover a wide palette of colours, from blue and purple through orange to red1,2. They are used in the food industry (food colourant with E163 code), namely in fruit juice concentrates, nectars, jellies, yoghurts, marmalades, potato chips, ice creams, and soft drinks, replacing the synthetic Red 40 colourants. They also have diversified pharmaceutical and cosmetic uses due to their colouring and antioxidant attributes. However, their instability due to pH, light, and temperature is a major concern. This study used a double water-in-oil-in-water (W1/O/W2) emulsion technique to prevent rapid colour loss and colour variability with pH of a commercial black carrot extract (Fig. 1). A Central Composite Rotatable Design (CCRD) 22 was used to examine the effects of colourant concentration (wt%) and emulsion ratio ((W1/O)/W2) on stability parameters (droplet size (D4,3), creaming index (CI), and colourimetric values (L*, a*). The main objective was to find an optimised formulation in terms of colourant potential and emulsion stability. Measurements were taken at 1, 7, 15, and 30 days. The optimal experimental design revealed two optimal solutions: 1) 48/52 (W1/O)/W2 ratio with 6 wt.% colorant, and 2) 41/59 (W1/O)/W2 ratio with 11 wt.% colourant. These formulations showed lower creaming index and droplet sizes with higher colourant potential. After accounting for the effect of time, the optimal condition was 6 wt% colourant concentration and 48/52 v/v (W1/O)/W2 emulsion ratio. A stable colour was maintained after 30 days (L*: 44.11±0.03, a*: 25.79±0.01, D4;3: 9.62 ± 0.1 µm, and CI: 14.55±0.99%). These findings are promising and might be applicable to produce novel colourants to be applied in several industries, such as food and cosmetics.
- Optimisation of stability and colouring power of double emulsion systems loaded with Daucus carota L.Publication . Teixeira, Liandra Gracher; Silva, Samara Cristina; Colucci, Giovana; Santamaria-Echart, Arantzazu; Peres, António M.; Dias, Madalena M.; Barreiro, FilomenaAnthocyanins (ACNs) are water-soluble bioactive flavonoids present in flowers, fruits and vegetables, ACNs cover a wide palette of colors, from blue and purple through orange to red.
- Perfil cromatográfico de ácidos orgânicos e tocoferóis de Umbilicus rupestris (Salisb.) e Raphanus raphanistrum LPublication . Iyda, Júlia Harumi; Fernandes, Ângela; Silva, Samara Cristina; Ferreira, Flávio Dias; Barros, Lillian; Amaral, Joana S.; Ferreira, Isabel C.F.R.A utilização de plantas silvestres na dieta alimentar esteve em declínio, no entanto, a globalização estimulou a recuperação do uso de espécies tradicionalmente consumidas [1]. Por outro lado, o interesse dos consumidores por uma alimentação cada vez mais saudável, leva ao estudo de plantas silvestres variadas onde se incluem as espécies Umbilicus rupestris (Salisb.) Dandy e Raphanus raphanistrum L., preferencialmente consumidas em saladas. Assim, no presente trabalho fez-se a caracterização do seu perfil cromatográfico em termos de tocoferóis e ácidos orgânicos. As amostras de U. rupestris e R. raphanistrum foram colhidas em 2016 e 2017, respetivamente, na região de Trás-os- Montes. A determinação dos tocoferóis foi realizada por cromatografia líquida de alta eficiência acoplada a um detetor de fluorescência (HPLC-FL) e dos ácidos orgânicos por cromatografia líquida ultra rápida acoplada a um detetor de díodos (UPLC-DAD). Em ambas as amostras foram identificadas os quatro vitâmeros do tocoferol (α-, β-, γ- e δ-tocoferóis), sendo o γ-tocoferol o mais abundante na amostra de U. rupestris (13,24±0,09 mg/100 g matéria seca), e o α-tocoferol o maioritário na amostra de R. raphanistrum (8,8±0,1 mg/100 g). Foram identificados cinco ácidos orgânicos na amostra de U. rupestris e sete na amostra de R. raphanistrum, entre os quais os ácidos oxálico, quinico, málico, ascórbico e cítrico; na amostra de R. raphanistrum foram identificados também os ácidos sucínico e fumárico. O ácido cítrico (7,258±0,004 g/100 g matéria seca) e o ácido quínico (7,1±0,2 g/100 g) foram os compostos maioritários na amostra de U. rupestris, enquanto que a amostra de R. raphanistrum apresentou os ácidos oxálico (7,01±0,01 g/100 g), quínico (6,1±0,2 g/100 g) e cítrico (6,09±0,05 g/100 g) como compostos maioritários. Este trabalho permitiu verificar que as espécies U. rupestris e R. raphanistrum são uma fonte de ácidos orgânicos e de tocoferóis com importante função antioxidante, podendo ser incorporadas na dieta contemporânea.
- Spirulina (Arthrospira platensis) protein-rich extract as a natural emulsifier for oil-in-water emulsions: optimization through a sequential experimental design strategyPublication . 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.