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Projeto de investigação
Lignin-based Pickering Stabilizers for Innovative Cosmetic Applications
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Saponin-based natural nanoemulsions as alpha-tocopherol delivery systems for dermal applications
Publication . Schreiner, Tatiana B.; Santamaria-Echart, Arantzazu; Colucci, Giovana; Plasencia, Paula; Costa, Patrícia Santos; Dias, Madalena M.; Pinho, Simão; Barreiro, M.F.
Nanoemulsions can be produced using simple methods and compounds from natural sources. They can increase
water dispersibility and bioavailability and optimise active ingredient dispersion in particular skin layers.
Lipophilic compounds of the vitamin E family (tocopherols and tocotrienols) are well-known for their high
antioxidant activity and capacity to protect the skin from oxidative stress. In this context, oil-in-water (o/w)
nanoemulsions with and without α-tocopherol (Vitamin E, VE) were formulated with two emulsifier alternatives,
Quillaja saponin (QS), and a combination of QS with Tribulus terrestris (QSTT) (50/50, w/w). The emulsions were
evaluated concerning stability, microstructure, droplet size, colour attributes, encapsulation efficiency, UV
photostability, antioxidant activity, and in vitro permeation studies to assess the delivery potential. Results
showed highly stable systems, with round-shape droplets of 80–121 nm size. QS and QSTT samples’ colours were
close to white and light brownish, respectively. The topical nano cream had the capacity to entrap VE, producing
a protective effect from UV degradation, and very significant antioxidant activity, with IC50 values around 0.01
%wt. The skin permeation profiles showed the efficiency of the formulations in the delivery of VE, with permeabilities
between 64 and 74 μg/cm2, while the control sample showed no VE permeation.
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, Filomena
Anthocyanins (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.
Lignin–Quercetin Hybrid Colloidal Particles as Sustainable Pickering Emulsifiers: A Bio-Based and Functional Approach
Publication . Oliveira, Barbara Miqueletti de; Colucci, Giovana; Schreiner, Tatiana B.; Preegel, Gert; Silva, Lucimara Lopes da; Santamaria-Echart, Arantzazu; Barreiro, Filomena
Lignin, the second-most-abundant polymer on Earth, has attracted attention for its value-added applications. Colloidal lignin particles can overcome handling and compatibility issues, offer antioxidant, antimicrobial, and UV-protective properties, and serve as Pickering stabilizers. Plant extracts rich in bioactive compounds, such as polyphenols and flavonoids (e.g., quercetin), can further enhance lignin-based formulations. In this context, colloidal lignin–quercetin particles (CLQPs) were produced for the first time via antisolvent precipitation and used as Pickering emulsion stabilizers. CLQP dispersions (30 g/L) were prepared by solubilizing lignin and quercetin in 80% (v/v) aqueous acetone solution, followed by precipitation with a pH 8 buffer. A quercetin content of 50% (w/w) (CLQP-50) resulted in predominantly round-shaped lignin–quercetin particles (<1 µm) with a small fraction of quercetin crystals. Both structures contributed to emulsion stabilization, as evidenced by confocal microscopy, a three-phase contact angle of 91.6 ± 0.1°, and a zeta potential of −52.8 ± 2.7 mV. CLQP-50 successfully stabilized Pickering emulsions at a 60/40 oil/water ratio, showing high physical stability (stability index 0.01) and shear-thinning behavior with gel-like consistency. These findings demonstrate the pioneering development of lignin–quercetin hybrid colloidal particles as sustainable and functional Pickering stabilizers, opening new opportunities for advanced cosmetic and pharmaceutical formulations.
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.
Modulation of physicochemical and antioxidant properties of Pickering emulsions using colloidal lignin particles based on kraft softwood and hardwood acetone fractions
Publication . Colucci, Giovana; Gigli, Matteo; Sgarzi, Massimo; Rodrigues, Alírio; Crestini, Claudia; Barreiro, M.F.
Colloidal lignin particles (CLPs) emerge as a sustainable alternative to traditional, fossil-based emulsion stabilizers. However, effectively outperforming the conventional ingredients requires addressing the challenges posed by lignin heterogeneity and structural complexity. In this study, one-step acetone fractionation was applied to softwood and hardwood kraft lignins to tackle the issue. The resulting soluble (AS) and insoluble (AI) fractions, along with the pristine lignins, underwent thorough characterization and were used to create CLPs through the hydrotropic precipitation. The acetone fraction-derived CLPs were tested for the first time as Pickering stabilizers. Notably, a strong correlation emerged between the structural traits of each lignin sample and the properties of the resulting Pickering emulsions. Such correlation allowed for a fine-tuning of their physicochemical and antioxidant features. The AS fractions, characterized by higher phenolic OH content and lower molecular weight, led to CLPs with larger sizes and reduced hydrophilic character compared to those derived from AI- and pristine lignins. The fraction-derived CLPs exhibited superior emulsifying capacity and imparted long-term stability to the formed emulsions. Moreover, the resulting Pickering emulsions showed high potential as antioxidant agents, proving their ability as multifunctional systems. Overall, this work demonstrates how the unique properties of lignin can be selectively enhanced through acetone fractionation method and seamlessly transferred to Pickering emulsions. This advancement promotes the use of lignin in high-value-added sectors such as cosmetics and personal care.
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Entidade financiadora
Fundação para a Ciência e a Tecnologia
Programa de financiamento
projetos financiados com o apoio do Programa Operacional Regional do Norte (POR Norte/Norte 2020).
Número da atribuição
2021.05215.BD