Percorrer por autor "Schreiner, Tatiana B."
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- Bacterial cellulose biosynthesis in the presence of raw moist olive pomace: A green sustainable approach that enhances biopolymer production and propertiesPublication . Crugeira, Pedro; Khelifa, Halima; Barreira, Luísa; Halla, Noureddine; Barreiro, Filomena; Rodrigues, Paula; Peres, António M.; Schreiner, Tatiana B.; Schreiner, Tatiana B.In this study, the biosynthesis of bacterial cellulose (BC) by Komagataeibacter intermedius strain isolated from Kombucha tea in the presence of raw moist olive pomace (MOP) (concentration up to 40 % in the fermentation media) was studied. The BC membranes were characterized by their antioxidant activity, structural character- istics, crystallinity, thermal stability, and mechanical behavior. Using raw MOP activated the inherent activity of the phenolic compounds, leading to cellular adaptation under unfavorable conditions and increased BC pro- duction for all tested MOP concentrations (p < 0.0001). This led to a 166.61 % increase for the 20 % MOP group compared to the control (HS medium). For this sample, enhanced antioxidant activity (~40-fold higher than the control) was found, which might be associated with the molecular interactions established between hydroxyls of BC and phenolic compounds. Moreover, an increase of 603.03 % in strain capacity, and a 376.01 % improvement in stress at break compared to the control was observed. The study confirmed that BC can be synthesized using MOP in its natural state, supporting a sustainable circular economy while enhancing the biosynthesis of a value- added product. By reducing synthetic media and utilizing MOP, a greener bioprocess can be achieved, and BC’s applicability can be expanded.
- Emulsions preparation based on ternary phase diagrams: comparative study using two oils (Miglyol and sweet almond) with two distinct surfactants (Tween 80 and Saponin)Publication . Schreiner, Tatiana B.; Dias, Madalena M.; Pinho, Simão; Barreiro, M.F.An emulsion is a colloidal dispersion composed by a mixture of two immiscible liquids, being one the dispersed phase, as droplets, and the other one the continuous phase. In this work, a comparative study comprising the surfactants Tween 80 (synthetic surfactant) and Saponin (natural surfactant) and the oils Miglyol 812 and Sweet Almond was performed. The development of emulsions based on ternary phase diagrams showed that different phases can be formed giving rise to different formulations: microemulsions, gels, and mixtures with 1, 2 and 3 phases. The application of the HPH technique produced stable nanoemulsions with narrow distributions. Considering Tween 80, and comparing the two oils, Miglyol 812 gave rise to emulsions with lower particle size (0.023μm), comparatively to Sweet Almond Oil (1.009μm). This difference can be related with the oil viscosity, which is lower for Miglyol 812. Comparing the two surfactants, natural Saponin was very effective in the o/w composition range.
- Evaluation of saponin-rich extracts as natural alternative emulsifiers: A comparative study with pure Quillaja Bark saponinPublication . Schreiner, Tatiana B.; Colucci, Giovana; Santamaria-Echart, Arantzazu; Fernandes, Isabel P.; Dias, Madalena M.; Pinho, Simão; Barreiro, M.F.Due to synthetic surfactants' environmental impact, their replacement by natural alternatives has gained relevance, with saponins emerging as sustainable approaches. In this work, three saponin-rich extracts from different sources (Tribulus terrestris (TT), Trigonella foenum-graecum (FG), and Ruscus aculeatus (RA)) were tested as emulsifiers, and their performance compared with Quillaja Bark saponin (PS). Characterisation comprised FTIR, solubility studies, CMC assays, and emulsifying properties (emulsifying capacity (EC) and foaming capacity (FC)). For all samples, solubility assays indicated high solubility in water and low in apolar solvents (e.g., n-hexane), compatible with their O/W emulsifier character. In general, the saponin content ruled extracts' performance (PS > TT > FG > RA). EC values (without pH adjustment) were found to be 82.5, 55.0, 47.5, 36.3%, respectively. When pH changed for 7 and 9, a shift in FG and RA order was observed. The pseudo-ternary diagrams, constructed to map emulsion's composition zones, indicate the formation of single-phase systems in the region of low oil and high extract content. Except for RA extract, gel samples were formed, which are interesting technological solutions for several applications. Among the studied samples, and in alternative to PS, TT extract showed the best performance.
- Formation and stabilisation of oil-in-water nanoemulsions using binary emulsifier mixtures of Tribulus terrestris extract and Quillaja bark saponinPublication . Schreiner, Tatiana B.; Santamaria-Echart, Arantzazu; Peres, António M.; Dias, Madalena M.; Pinho, Simão; Barreiro, FilomenaEmulsifiers are used in many industrial fields, with the natural origin ones gaining increasing relevance. Identifying diversified sources as natural emulsifiers is a pertinent topic for sustainability principles
- Formation and stabilisation of oil-in-water nanoemulsions using binary emulsifier mixtures of Tribulus terrestris extract and Quillaja bark saponinPublication . Schreiner, Tatiana B.; Santamaria-Echart, Arantzazu; Peres, António M.; Dias, Madalena M.; Pinho, Simão; Barreiro, FilomenaEmulsifiers are used in many industrial fields, with the natural origin ones gaining increasing relevance. Identifying diversified sources as natural emulsifiers is a pertinent topic for sustainability principles. Saponin-rich extract Tribulus terrestris (TT) was evaluated as a viable alternative to Quillaja bark saponin (QS). An experimental design using binary emulsifier mixtures of TT with QS was carried out by varying their composition, content, and processing conditions (HPH cycles). Emulsions were characterised by zeta potential, morphology, droplet size, and stability. Zeta potential indicated stable emulsions; even creaming was observed in samples with a low emulsifier and high TT%. Diameter of emulsions was between 78-921 nm, with smaller sizes agreeing with the higher stability. Statistical analysis revealed an optimum composition range of emulsifier (3.9-4.5%wt.) and TT content(50-56%wt.) to reach stable products. Overall, TT can provide an effective solution combined with QS.
- Formulation and optimization of nanoemulsions using the natural surfactant saponin from Quillaja barkPublication . Schreiner, Tatiana B.; Santamaria-Echart, Arantzazu; Ribeiro, Andreia; Peres, António M.; Dias, Madalena M.; Pinho, Simão; Barreiro, M.F.Replacing synthetic surfactants by natural alternatives when formulating nanoemulsions has gained attention as a sustainable approach. In this context, nanoemulsions based on sweet almond oil and stabilized by saponin from Quillaja bark with glycerol as cosurfactant were prepared by the high-pressure homogenization method. The e ects of oil/water (O/W) ratio, total surfactant amount, and saponin/glycerol ratio on their stability were analyzed. The formation and stabilization of the oil-in-water nanoemulsions were analyzed through the evaluation of stability over time, pH, zeta potential, and particle size distribution analysis. Moreover, a design of experiments was performed to assess the most suitable composition based on particle size and stability parameters. The prepared nanoemulsions are, in general, highly stable over time, showing zeta potential values lower than 40 mV, a slight acid behavior due to the character of the components, and particle size (in volume) in the range of 1.1 to 4.3 m. Response surface methodology revealed that formulations using an O/W ratio of 10/90 and 1.5 wt% surfactant resulted in lower particle sizes and zeta potential, presenting higher stability. The use of glycerol did not positively a ect the formulations, which reinforces the suitability of preparing highly stable nanoemulsions based on natural surfactants such as saponins.
- Lignin–Quercetin Hybrid Colloidal Particles as Sustainable Pickering Emulsifiers: A Bio-Based and Functional ApproachPublication . Oliveira, Barbara Miqueletti de; Colucci, Giovana; Schreiner, Tatiana B.; Preegel, Gert; Silva, Lucimara Lopes da; Santamaria-Echart, Arantzazu; Barreiro, FilomenaLignin, 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.
- Optimization of nanoemulsion formulations using saponin from quillaja bark, a natural surfactantPublication . Schreiner, Tatiana B.; Peres, António M.; Dias, Madalena M.; Pinho, Simão; Barreiro, M.F.Nanoemulsions are systems comprising three constituents, hydrophilic, lipophilic and amphiphilic compounds, forming a single macroscopic phase with reduced particle size. Nowadays, an important topic under study is the introduction of natural products as surfactants. This is partly motivated by consumer’s demands for more sustainable products, leading industry and researchers to search for alternatives with natural-friendly connotation, avoiding the large utilization of the synthetic forms. In this context, recent studies have focused the use of saponins, highlighting its physicochemical properties, and commercial potential for the development of natural-based emulsions [1,2]. Thus, the objective of this work is to optimize a nanoemulsion formulation incorporating saponin as surfactant, through response surface methodology (RSM). The systems were formed with the natural surfactant, pure saponin from Quillaja Bark, and glycerol as co-surfactant. Sweet almond oil was used as the lipophilic component. To produce the nanoemulsions, a high energy technique was chosen, namely high-pressure homogenization (HPH). The produced emulsions were characterized by measuring the zeta potential, droplet size (by laser diffraction) technique), pH and viscosity. In order to select the best formulation, a 2k full-factorial design with 3 factors and 3 replicates at the central point was implemented. The chosen parameters were oil/water ratio (10/90, 20/80, 30/70, w/w), surfactant content in the mixture (0.5, 1 and 1.5%, w/w) and the surfactant/co-surfactant ratio (50/50, 75/25, 100/0, w/w). The results obtained with the produced formulations showed zeta potential to vary between -40.3 and -46.0 (evidencing high stability) and a particle size in volume comprised in the range 111.9-431.4 nm. These two parameters were selected to perform the experimental design to find the most stable systems. Nanoemulsions with pure saponin were successfully produced, where the formulations with better long term stability were those prepared with the lower amount of oil, which is 10%. It is important to point out that taking into consideration final product applications, to have less than 10% of the lipophilic component it is not suitable. Regarding the amount of surfactant, smaller droplet sizes, and consequently lower zeta potentials, were achieved at its highest content. The co-surfactant glycerol showed to have no significant impact in zeta potential, even it showed to slightly increase droplet’s size.
- Palm oil improves UV-block, elongation, and water vapor resistance in biodegradable κ-carrageenan/starch filmsPublication . Costa, Joice Camila Martins da; Alves, Eloize da Silva; Campos, Talita Aparecida Ferreira de; Monteiro, Johny Paulo; Costa, João Carlos Martins da; Martins, Alessandro Francisco; Schreiner, Tatiana B.; Barreiro, Filomena; Bonafe, Elton GuntendorferIn view of the environmental contamination caused by plastic waste, this work proposes the development of sustainable and efficient active packaging based on kappa-carrageenan/starch films added with palm oil. The films were produced by casting and extensively characterized. The incorporation of palm oil via emulsification resulted in a heterogeneous polysaccharide-lipid system, as evidenced by XRD, DSC, and SEM analysis. These structural rearrangements within the matrix led to higher localized organization. Consequently, the films exhibited enhanced mechanical and barrier performance. The formulation containing 1.5% palm oil exhibited 20% higher elongation than the control film (43.18% vs. 23.38%), and water vapor permeability reduced from 8.27 & times; 10- 11 to 6.70 & times; 10- 11 g & times; m-1 & times; s-1 & times; Pa- 1. Furthermore, the presence of carotenoids in palm oil allowed the film to effectively block ultraviolet radiation, extending the shelf life of cherry tomatoes. The produced films not only demonstrated efficiency in UV blocking and improvements in mechanical and barrier properties, but also confirmed their biodegradability, with mass loss exceeding 50% within 60 days. In conclusion, the new polysaccharide-based active film, produced using sustainable, environmentally friendly technology, efficiently extends the shelf life of cherry tomatoes.
- Polimorfismo e solubilidade de sais na presença de solventes mistosPublication . Schreiner, Tatiana B.; Pinho, Simão; Duarte, Elis Regina; Thomsen, KajA representação experimental e teórica de propriedades termofísicas, e do equilíbrio de fases de sistemas contendo eletrólitos é ainda muito limitada, apesar da sua elevada importância. Isso ocorre devido às dificuldades na representação das interações eletrostáticas, além daquelas que derivam da utilização de diferentes estados padrão, escalas de concentração e coeficientes de atividade. Assim, no presente trabalho foi realizado o estudo do equilíbrio sólido-líquido em sistemas de solventes mistos contendo eletrólitos, medindo solubilidades e desenvolvendo a modelação termodinâmica. Os sais estudados foram o brometo de sódio e o cloreto de lítio, nos sistemas água/metanol, água/etanol e metanol/etanol às temperaturas de 298.15 e 323.15 K, e em toda a gama de composições. Para a determinação da solubilidade, o método dos frascos agitados foi usado em combinação com dois métodos analíticos distintos, a gravimetria e medição de índice de refração. Ambos mostraram serem fiáveis, estando em geral concordantes com os encontrados na literatura. No entanto, há indicadores que as solubilidades obtidas por gravimetria são mais consistentes. Os novos dados obtidos de solubilidade, junto a informações publicadas na literatura, sobre equilíbrio sólido-líquido, coeficientes de atividade médios iónicos e coeficientes osmóticos constituíram uma base de dados relevante para o desenvolvimento do modelo termodinâmico. O modelo Extended UNIQUAC foi o selecionado, permitindo a representação da solubilidade de fases sólidas hidratadas com elevada qualidade, obtendo erros relativos entre 1.1 e 6.7%. Foram identificadas maiores dificuldades no cálculo da solubilidade quando as fases sólidas são anidras e também na descrição dos coeficientes de atividade médios iónicos ou osmóticos. Portanto, sugere-se reestimar os parâmetros do modelo quer usando propriedades como entalpia e capacidade calorífica, bem como incluindo na base de dados outros sais contendo os iões Li+ e Br-.