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- Evaluating the potential of natural polymers for water-dispersible curcumin-based solid dispersion colourant systems for food applicationsPublication . Rezende, Stephany; Ferreira, Olga; Santamaria-Echart, Arantzazu; Dias, Madalena M.; Barreiro, M.F.Solid dispersion (SD) technology, a strategy through which a hydrophobic compound is molecularly dispersed into a hydrophilic carrier, is raising interest in food applications to surpass natural colourants’ low water solubility. Motivated by the importance of using natural solutions, five natural polymers (k-carrageenan (KC), maltodextrin (MD), Arabic gum (AG), potato starch (PS), and pectin (PC) were evaluated against the synthetic benchmark polyvinylpyrrolidone (PVP)). Targeting a stable yellow hue, pH 6 was used, and the effect of salt addition on crystallinity was evaluated. Comparatively with PVP, used as a synthetic polymer reference, SDs based on MD, AG, and PC presented a deeper orange shade. Similar size distributions were achieved for the produced samples except for PS-based SDs, which showed higher sizes in volume. For all systems, polymer-curcumin hydrogen bonding was perceptible and reflected in the curcumin crystallinity modification/reduction, particularly if produced under natural pH conditions. The water solubility was significantly improved compared to free curcumin, from 1 μg/mL to 25–37 μg/mL (pH 6, PVP - 24.54 μg/mL) and 18–86 μg/mL (without pH control, PVP - 28.34 μg/mL), highlighting the favourable effect of natural polymers.
- 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.
- Water-in-oil-in-water double emulsions as protective carriers for Sambucus nigra l. coloring systemsPublication . Teixeira, Liandra Gracher; Rezende, Stephany; Fernandes, Ângela; Fernandes, Isabel P.; Barros, Lillian; Barreira, João C.M.; Leimann, Fernanda Vitória; Ferreira, Isabel C.F.R.; Barreiro, M.F.The use of natural colorants is needed to overcome consumer concerns regarding synthetic food colorants0 safety. However, natural pigments have, in general, poor stability against environmental stresses such as temperature, ionic strength, moisture, light, and pH, among others. In this work, water-in-oil-in-water (W1/O/W2) emulsions were used as protective carriers to improve color stability of a hydrophilic Sambucus nigra L. extract against pH changes. The chemical system comprised water and corn oil as the aqueous and oil phases, respectively, and polyglycerol polyricinoleate (PGPR), Tween 80, and gum Arabic as stabilizers. The primary emulsion was prepared using aW1/O ratio of 40/60 (v/v). For the secondary emulsion,W1/O/W2, different (W1/O)/W2 ratios were tested with the 50/50 (v/v) formulation presenting the best stability, being selected as the coloring system to test in food matrices of different pH: natural yogurt (pH 4.65), rice drink (pH 6.01), cow milk (pH 6.47), and soy drink (pH 7.92). Compared to the direct use of the extract, the double emulsion solution gave rise to higher color stability with pH change and storage time, as corroborated by visual and statistical analysis.
- Development of double emulsions from Sambucus nigra L. berry extract as ph stable colorant formulationsPublication . Teixeira, Liandra Gracher; Fernandes, Isabel P.; Rezende, Stephany; Reis, Filipa S.; Barros, Lillian; Leimann, Fernanda Vitória; Ferreira, Isabel C.F.R.; Barreiro, M.F.Anthocyanins are flavonoids, one of the largest groups of water-soluble vegetable pigments, having also sweetening and antioxidant properties. They are characterized by different colors, such as red, purple, blue and violet. However, their color stability is compromised by variations in pH, temperature, moisture, and luminosity conditions. 1 The berries of Sambucus nigra L. have high contents of anthocyanins (cyanidin-3-O-sambubioside and cyanidin-3-Osambubioside-5-O-glucoside), being a promising option as food coloring agents. 2 Therefore, this work aims to stabilize the natural hydrophilic colorant obtained from S. nigra through the preparation of double emulsions (water/oil/water, W/O/W). The S. nigra berries were extracted by crushing the fruits to obtain the juice, followed by spray drying to obtain the dry extract. For the preparation of the double emulsions, the procedure was the one described by Paula D. A. et al. with some modifications. 3 Briefly, for the first emulsion, the water phase comprised 55 mg/L of the extract and 5% Polyglycerol polyricinoleate (PGPR), homogenized under stirring (20000 rpm, 5 min). This phase was dispersed into corn oil at a W/O ratio of 0.4. (Figure 1 – (A)). Thereafter, the second emulsion was prepared by dispersing the previous emulsion in a water phase comprising Tween 80 and gum Arabic, tested at different concentrations. The final W/O/W emulsion was prepared at different primary emulsion/water ratios and stirred at 6000 rpm during 2 min using an Ultra-Turrax system. The produced emulsions were analyzed by optical microscopy (OM) using a Nikon eclipse 50i microscope to assess size and morphology. This analysis showed the presence of spherical and individualized droplets with an estimated particle size between 13 and 16 μm. (Figure 1 – (B)). The role of these emulsions as pH stable colorants were tested using different buffers (pH 4-7), as shown in (Figure 1-(C)), which also presented the comparison with solutions prepared from the original S. nigra extract. The obtained results pointed out for an improved stability and color homogeneity among samples in the tested pH range.
- Heat and pH stable curcumin-based hydrophylic colorants obtained by the solid dispersion technology assisted by spray-dryingPublication . Leimann, Fernanda Vitória; Gonçalves, Odinei Hess; Sorita, Guilherme Dallarmi; Rezende, Stephany; Bona, Evandro; Fernandes, Isabel P.; Ferreira, Isabel C.F.R.; Barreiro, M.F.Natural food colorants are on demand due to food safety concerns related with some synthetic counterparts. Health-friendly alternatives can be available from plant sources, which include curcumin extracted from Curcuma longa L. However, its industrial use is difficult to achieve due to the low water affinity, pH and thermal instability, which is particularly challenging, e.g. for baked foods. In this work, the solid dispersion technique followed by spray-drying, an emergent approach in the context of colorants, was applied to curcumin using k-carrageenan, poly(vinyl alcohol) and polyvinylpyrrolidone, as the encapsulant materials. An orthogonal central composite design with dummy-variables was applied, and principal component analysis (PCA) and hierarchical cluster analysis (HCA) carried out to identify the experimental conditions leading to the most effective formulations. In general, particles with a wide range of pH and heat stability have been produced depending on the chosen encapsulant material, used formulation (curcumin, surfactant and polymer contents), and synthesis conditions (pH). Moreover, the used mathematical approach showed to be a valuable tool to support the development of tailor-made formulations directed to specific applications where pH and temperature are relevant processing parameters.
- β-Carotene colouring systems based on solid lipid particles produced by hot melt dispersionPublication . Carvalho, Amarilis Santos; Rezende, Stephany; Caleja, Cristina; Pereira, Eliana; Barros, Lillian; Fernandes, Isabel P.; Manrique, Yaidelin A.; Gonçalves, Odinei Hess; Ferreira, Isabel C.F.R.; Barreiro, M.F.In this work, β-carotene was selected to develop a novel study, namely a food colorant system based on beeswax solid lipid particles obtained by hot melt dispersion. The obtained microparticles were characterized by optical microscopy, scanning electron microscopy, particle size analysis and Fourier Transform Infrared spectroscopy. It was observed that the obtained size can be modulated by using different amounts of emulsifier, as well as the dispersing capability. In a final stage, the obtained particles were tested concerning their colorant power by selecting a food matrix widely appreciated and consumed (mayonnaise). Moreover, the formulation providing the best hue and dispersibility (formulation containing 3% of Tween 80, and β-carotene at 5 mg/25 g of commercial mayonnaise) was analysed along a storage period of 15 days concerning colour, nutritional value and chemical composition. The results pointed out for colour stability and nutritional value maintenance, after 15 days under storage at 6 °C.
- Soluções corantes baseadas em emulsões duplas incorporando extrato de Sambucus nigra L.: desenvolvimento e teste em diferentes matrizes alimentaresPublication . Teixeira, Liandra Gracher; Rezende, Stephany; Fernandes, Isabel P.; Reis, Filipa S.; Barros, Lillian; Barreira, João C.M.; Leimann, Fernanda Vitória; Ferreira, Isabel C.F.R.; Barreiro, M.F.As antocianinas são pigmentos vegetais hidrossolúveis, pertencentes à classe dos flavonoides apresentando propriedades edulcorantes e bioativas. São caracterizadas por conferirem cor na gama do vermelho a violeta. No entanto, para aplicações industriais, estes pigmentos apresentam problemas de variabilidade da cor com o pH, temperatura, presença de humidade e luminosidade [1]. Neste contexto, estudaram-se extratos obtidos a partir de bagas de Sambucus nigra L., reconhecidas pelo seu elevado teor em antocianinas, como soluções corantes para a área alimentar. Para o efeito, procedeu-se à estabilização do extrato através da preparação de emulsões duplas (água/óleo/água, A/O/A). A obtenção do extrato corante foi efetuada por trituração das bagas, seguindo-se da secagem do sumo obtido por spray-drying para obtenção da correspondente forma em pó. A preparação das emulsões duplas foi realizada adaptando a metodologia descrita por Paula et al. [2], podendo ser descrita como dividida nas duas etapas seguintes: i) preparação da emulsão primária, por emulsificação da fase aquosa (55 mg/L do extrato e 5% de polirricinoleato de poliglicerol (PGPR)) em óleo de milho (razão A/O 0,4) utilizando uma velocidade de homogeneização de 20000 rpm durante 5 min; e ii) preparação da emulsão dupla por dispersão da emulsão primária numa fase aquosa secundária contendo Tween 80 e goma arábica, em diferentes proporções. A emulsão A/O/A final foi preparada utilizando diferentes proporções de emulsão primária/fase aquosa secundária recorrendo a um homogeneizador a 6000 rpm durante 2 min. As emulsões produzidas foram analisadas por microscopia ótica (MO) para avaliar o tamanho e morfologia das gotículas. Adicionalmente, procedeu-se ao teste das emulsões como agentes corantes estáveis ao pH, usando para o efeito matrizes alimentares com diferentes valores de pH, nomeadamente iogurte líquido natural (pH 4,65), bebida biológica de arroz (pH 6,01), leite (pH 6,47) e bebida biológica soja (pH 7,92), tendo-se feito a comparação com o uso direto do extrato de S. nigra (Figura 1). Posteriormente procedeu-se à avaliação da cor de acordo com os parâmetros L*, a* e b*. Os resultados obtidos apontam para uma melhor estabilidade da cor e menor variabilidade desta com o pH. Em síntese, a estratégia testada revelou-se promissora tendo em vista o desenvolvimento de formulações corantes, para a área alimentar, baseadas em corantes naturais ricos em antocianinas. Esta estratégia poderá ser aplicada a outros setores industriais.
- Valorisation of brazilian pine-fruit shell residue (araucaria angustifolia) in the production of biopolyolsPublication . Rezende, Stephany; Pinto, João A.; Leimann, Fernanda Vitória; Barreiro, M.F.The valorisation of agro-forestry residues, namely the ones which do not have commercial value, have attracted the interest of academia and industrials contributing to generate new alternatives in the eld of chemicals and materials. The purpose is not only promoting their reuse to generate value- added products, but also highlight the production of bio-based products from renewable resources. Araucaria angustifolia is a coniferous tree native of South America, found in the South and Southwest of Brazil, part of a whole vegetation of the Atlantic Forest. The Brazilian pine-fruit shell (PFS) is an attractive lignocellulosic residue with potential to be used as a raw material to produce polymeric materials. In this context, this work comprises the characterization of PFS and their use to produce polyols trough oxypropylation
- Exploring oxypropylation to prepare liquid and biphasic polyols from the pine-fruit shell of Auraucaria angustifoliaPublication . Pinto, João A.; Rezende, Stephany; Leimann, Fernanda Vitória; Barreiro, M.F.This work comprises the characterization of pine-fruit shell, the residue of the edible seeds of Araucaria angustifolia, a coniferous tree native of South America with economic importance in the South and Southwest of Brazil, and their subsequent use to produce polyols trough oxypropylation. Two different alternatives have been followed: (i) total oxypropylation to produce liquid polyols and (ii) partial oxypropylation to produce biphasic polyols (liquid polyols reinforced with biomass of the same nature). The first polyols were characterized in what concerns unreacted biomass, homopolymer content, hydroxyl number and viscosity, and their properties compared with equivalent products to foresee future applications (e.g. production of rigid polyurethane foams). The second ones were subjected to homopolymer extraction and tested to produce composite materials by hot pressing.
- Pickering emulsions stabilized with curcumin-based solid dispersion particles as mayonnaise-like food sauce alternativesPublication . Ghirro, Larissa Camargo; Rezende, Stephany; Ribeiro, Andreia; Rodrigues, Nuno; Carocho, Márcio; Pereira, J.A.; Barros, Lillian; Demczuk Junior, Bogdan; Barreiro, M.F.; Santamaria-Echart, ArantzazuPickering emulsions, which are emulsions stabilized by colloidal particles, are being increasingly positioned as novel strategies to develop innovative food product solutions. In this context, the present work aims to develop Pickering emulsions stabilized by natural-based curcuminloaded particles produced by the solid dispersion technique as promising mayonnaise-like food sauce alternatives. Two particle formulations (KC1 and KC2) were produced using k-carrageenan as the matrix material and different curcumin contents, then employed in the preparation of three Pickering emulsion formulations comprising different oil fractions (') and particle concentrations (KC1 ' 0.4 (4.7%), KC2 ' 0.4 (4.7%) and KC2 ' 0.6 (4.0%)). The creaming index tests accompanied by the optical microscopy analysis evidenced the good stability of the developed products for the tested period of 28 days. The final products were tested concerning color attributes, pH, oxidative stability, textural, and nutritional composition, and compared with two commercial mayonnaises (traditional and light products). Overall, the produced emulsions were characterized by a bright yellow color (an appealing attribute for consumers), an acidic pH (similar to mayonnaise), and a considerably improved oxidative stability, implying a foreseeable longer shelf life. The sauce KC1 ' 0.4 (4.7%) showed a similar texture to the light commercial mayonnaise, being a promising alternative to conventional sauces, holding a low-fat content and potentially added benefits due to the curcumin and virgin olive oil intrinsic properties.