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- Biosynthesis of antioxidant xanthan gum by Xanthomonas campestris using substrates added with moist olive pomacePublication . Crugeira, Pedro Jorge Louro; Almeida, HeloĆsa H.S.; Marcet, Ismael; Rendueles, Manuel; Pires, Marcella Golini; Rafael, Helder Martins; Rodrigues, Ana Isabel G.; Santamaria-Echart, Arantzazu; Rafael, Helder; Barreiro, M.F.; Pires, Marcella GoliniMoist olive pomace (MOP) is a high moisture content by-product of the olive oil industry. Managing this recalcitrant residue (transport, storage, and drying) is a priority demanding investment in finding alternative valorisation routes. In this context, the biosynthesis of xanthan gum (XG) incorporating MOP in the substrate (0.0 %, 5.0 %, 10.0 %, 15.0 %, 20.0 %, 25.0 %, 30.0 % and 50.0 %) to induce bacterial stress was attempted. XG biosynthesis yield was quantified, and the product was characterised by structural analysis (FTIR), thermal behaviour (TG), rheology and antioxidant capacity. Relative to the control (sample with no added MOP), a significant increase in XG biosynthesis was found for concentrations up to 30.0 % MOP. In particular, for XG produced with 15 % MOP, a 50.91 % (p < 0.0001) increase was achieved, together with 395.78 % for viscosity. In general, XG produced with MOP presence showed antioxidant activity, a value-added property, especially for applications in the food, pharmaceutical and cosmetic areas. The results indicated that the stress imposed by the MOP induced a microbial response leading to XG production increase, structural and viscosity modifications, and antioxidant properties incorporation. Overall, this work points out a new MOP application contributing to the sustainability of the olive oil productive chain from a biobased circular economy perspective.
- Propriedades bioativas de formulaƧƵes hidrofĆlicas de curcumina: aplicaĆ§Ć£o em iogurtePublication . Leimann, Fernanda VitĆ³ria; Almeida, HeloĆsa H.S.; Roriz, CustĆ³dio Lobo; Barros, Lillian; Barreira, JoĆ£o C.M.; Calhelha, Ricardo C.; Barreiro, M.F.; Ferreira, Isabel C.F.R.A curcumina tem reconhecidas propriedades bioativas e corantes. PorĆ©m, a sua aplicaĆ§Ć£o em produtos alimentares Ć© dificultada pela sua baixa solubilidade em meios hidrofĆlicos. De forma a ultrapassar esta limitaĆ§Ć£o, foram preparadas nanopartĆculas de poli(vinil-pirrolidona) (PVP, 40.000g/mol)/curcumina com base na tĆ©cnica de dispersĆ£o sĆ³lida, utilizando Tween 80 como estabilizante e etanol como solvente. As nanopartĆculas foram caracterizadas quanto Ć morfologia (microscopia eletrĆ³nica de transmissĆ£o) indicando forma esfĆ©rica e tamanho (dispersĆ£o dinĆ¢mica de luz) com Ćndice de polidispersĆ£o = 0,050Ā±0,009 e diĆ¢metro mĆ©dio em intensidade = 377Ā±15 nm. As propriedades tĆ©rmicas (anĆ”lise termogravimĆ©trica, TG), interaƧƵes quĆmicas (Espectroscopia de Infravermelho com Transformada de Fourier, FTIR). As anĆ”lises por TG revelaram que as nanopartĆculas nĆ£o apresentaram perda de humidade (nĆ£o se observou nenhuma transiĆ§Ć£o antes dos 100 ĀŗC), justificada pelo facto de os pontos de ligaĆ§Ć£o da PVP Ć Ć”gua terem dado origem a interaƧƵes com a curcumina na sequĆŖncia da encapsulaĆ§Ć£o [1]. A anĆ”lise por FTIR comprovou este facto dado a ausĆŖncia da banda caracterĆstica a 3510 cm-1 na zona do estiramento dos OHs. As propriedades bioativas (atividade antioxidante, atividade anti-inflamatĆ³ria e citotoxicidade) das nanopartĆculas de PVP/curcumina (NC) foram comparadas Ć s da curcumina pura utilizada no procedimento de nanoencapsulaĆ§Ć£o (PC) (Sigma Aldrich) e Ć s de uma amostra comercial dispersĆ”vel (DC) (CHR Hansen, Vegex Tumeric WS5). Os valores de EC50 (Ī¼g/mL) para a atividade antioxidante (DPPH, poder redutor, Ī²-caroteno e TBARS) evidenciaram o seguinte perfil de atividade: PC>NC>DC, similarmente Ć resposta anti-inflamatĆ³ria (concentraĆ§Ć£o responsĆ”vel por 50% da inibiĆ§Ć£o da produĆ§Ć£o de Ć³xido nĆtrico em comparaĆ§Ć£o com o controlo negativo). Quanto Ć citotoxicidade, a PC revelou uma atividade superior em todas as linhas celulares, tendo os valores de GI50 (Ī¼g/mL) indicado atividade NC>DC apenas nos casos das linhas HeLa, HepG2 e PLP2 e indistinta nas MCF-7 e NCI-H460. Na etapa seguinte, as formulaƧƵes PC, NC e DC foram aplicadas em iogurtes, para os quais se avaliou o perfil nutricional (humidade, cinzas, gordura, proteĆnas, hidratos de carbono e energia) e os parĆ¢metros de cor (L*, a* e b*) ao longo do tempo de armazenamento (TA = 0, 7 e 15 dias, 4 ĀŗC). Independentemente de TA, os iogurtes com DC apresentaram os teores de cinza, gordura, energia e L* superiores, enquanto os valores a* e b* foram superiores para os com PC. O teor mĆ”ximo de proteĆna foi registado para os iogurtes com NC e o teor mĆ”ximo de hidratos de carbono para as amostras controlo. Quanto a TA, as amostras armazenadas durante 7 dias caracterizaram-se por teores superiores de proteĆna, cinza (tal como as amostras armazenadas durante 15 dias), hidratos de carbono e energia, enquanto as amostras analisadas no dia de preparaĆ§Ć£o registaram os valores mais elevados para gordura e a*. O efeito do tempo de armazenamento nĆ£o foi significativo nos parĆ¢metros L* e b*. Em sĆntese, e apesar de se terem observado algumas diferenƧas significativas nos indicadores nutricionais e parĆ¢metros de cor, pode concluir-se que as nanopartĆculas de PVP/curcumina sĆ£o uma boa estratĆ©gia para coloraĆ§Ć£o do iogurte, nĆ£o se tendo registado sem alteraƧƵes relevantes do seu valor nutricional e aparĆŖncia. Adicionalmente, e dado a bioatividade evidenciada, a sua utilizaĆ§Ć£o resultarĆ” em benefĆcios adicionais nĆ£o conseguidos com a PC (baixa solubilidade em meio hidrofĆlico).
- Estudo de formulaƧƵes hidrofĆlicas do corante natural curcumina para aplicaĆ§Ć£o em iogurtesPublication . Almeida, HeloĆsa H.S.; Barreiro, M.F.; Ferreira, Isabel C.F.R.; Leimann, Fernanda VitĆ³riaA utilizaĆ§Ć£o de aditivos naturais estĆ” em expansĆ£o na indĆŗstria alimentar, devido Ć maior exigĆŖncia dos consumidores que procuram produtos com qualidade diferenciada e benefĆcios para a saĆŗde. Entre os vĆ”rios aditivos, a utilizaĆ§Ć£o de corantes em alimentos tem a finalidade de deixar o produto com melhor aparĆŖncia tornando-o mais apelativo. A curcumina (E100) Ć© um corante natural que, alĆ©m de conferir cor, possui atividades biolĆ³gicas, servindo de alternativa a alguns corantes sintĆ©ticos que apresentam efeitos alergĆ©nicos, carcinogĆ©nicos ou de dĆ©fice de atenĆ§Ć£o e aumento de hiperatividade em crianƧas, por exemplo. Por ser um corante hidrofĆ³bico Ć© necessĆ”rio proceder Ć sua modificaĆ§Ć£o e/ou compatibilizaĆ§Ć£o com o meio aquoso para melhorar a sua estabilidade e possibilitar a sua aplicaĆ§Ć£o em matrizes alimentares hidrofĆlicas. Assim, mĆ©todos como a encapsulaĆ§Ć£o e a preparaĆ§Ć£o de emulsƵes sĆ£o exemplos de metodologias que podem ser usadas para a incorporaĆ§Ć£o de agentes ativos em diversos produtos, garantindo a compatibilidade com a matriz alimentar onde sĆ£o incorporados, tornando-os solĆŗveis e estĆ”veis, aumentando a sua biodisponibilidade e melhorarando a libertaĆ§Ć£o no meio desejado. Neste contexto, o objetivo deste trabalho consistiu na realizaĆ§Ć£o de um estudo visando a aplicaĆ§Ć£o de formulaƧƵes de curcumina (E100) em iogurtes (matriz hidrofĆlica). Para tal, selecionaram-se diferentes formas de curcumina (comerciais e preparadas em laboratĆ³rio), nomeadamente curcumina em pĆ³ (PC, comercial, conteĆŗdo em curcumina 65%, hidrofĆ³bica), curcumina dispersĆ”vel em Ć”gua (DC, comercial, conteĆŗdo em curcumina 4,7-5,3%, hidrofĆlica) e curcumina nanoencapsulada (NC, laboratorial, conteĆŗdo em curcumina 8,3%, hidrofĆlica). Foi ainda desenvolvida uma formulaĆ§Ć£o hidrofĆlica de curcumina que teve por base a sua emulsificaĆ§Ć£o em Ć”gua por dissoluĆ§Ć£o numa fase Ć³leo apropriada (curcumina emulsificada, EC), utilizando para o efeito a tĆ©cnica de emulsificaĆ§Ć£o de alta pressĆ£o. As diferentes formulaƧƵes apresentaram propriedades bioativas nomeadamente, atividade antioxidante, antibacteriana e citotĆ³xica em cĆ©lulas tumorais, de acordo com a seguinte ordem PC>NC>DC. A cor conferida pelas diferentes formulaƧƵes manteve-se durante a vida Ćŗtil dos iogurtes. No entanto, houve diferenƧas na tonalidade conseguida pela aplicaĆ§Ć£o de cada uma das formulaƧƵes, demostrando potencial de utilizaĆ§Ć£o em iogurtes com diferentes aromas/sabores (caracterĆsticas sensoriais que o consumidor associa Ć cor). O perfil nutricional dos iogurtes preparados manteve-se de acordo com as especificaƧƵes do rĆ³tulo da amostra controlo, cumprindo o ingrediente corante xvi adicionado apenas a funĆ§Ć£o de conferir cor. Quanto Ć preparaĆ§Ć£o da curcumina emulsificada, apĆ³s ensaios preliminares foi possĆvel chegar Ć seleĆ§Ć£o de um sistema quĆmico hidrofĆlico estĆ”vel sendo este composto por um Ć³leo de grau alimentar (Miglyol 812, triglicerĆdeo com Ć”cidos gordos de cadeia mĆ©dia e com um conteĆŗdo de curcumina de 10,0 mg/10 ml de Miglyol). Os estudos de preparaĆ§Ć£o de uma formulaĆ§Ć£o hidrofĆlica emulsionada realizados mostraram que a melhor opĆ§Ć£o corresponde Ć utilizaĆ§Ć£o do Miglyol como fase Ć³leo, quando se usa uma razĆ£o Ć³leo/Ć”gua (O/A) 50/50. A utilizaĆ§Ć£o de 6 ciclos de passagem a alta pressĆ£o originam emulsƵes estĆ”veis durante o perĆodo de armazenamento e com tamanho de gotĆcula inferior. No geral, os resultados demonstraram a viabilidade de aplicaĆ§Ć£o do corante natural curcumina (E100), sob diferentes formulaƧƵes, em matrizes alimentares. O estudo efetuado para desenvolver o novo produto (curcumina emulsificada), embora preliminar, valida a estratĆ©gia utilizada. Apresenta como desvantagens o baixo conteĆŗdo em curcumina incorporado e como vantagens o uso de concentraƧƵes de emulsionante baixas.
- Disclosing the potential of Cupressus leylandii A.B. Jacks & Dallim, Eucalyptus globulus Labill., Aloysia citrodora PalĆ”u, and Melissa officinalis L. hydrosols as eco-friendly antimicrobial agentsPublication . Almeida, HeloĆsa H.S.; Crugeira, Pedro Jorge Louro; Amaral, Joana S.; Rodrigues, AlĆrio; Barreiro, M.F.Antimicrobial resistance is a major global health concern, threatening the effective prevention and treatment of infections caused by microorganisms. These factors boosted the study of safe and green alternatives, with hydrosols, the by-products of essential oils extraction, emerging as promising natural antimicrobial agents. In this context, four hydrosols obtained from Cupressus leylandii A.B. Jacks & Dallim, Eucalyptus globulus Labill., Aloysia citrodora PalĆ”u and Melissa officinalis L. were studied. Their chemical composition comprises neral, geranial, 1,8-cineole, terpinen- 4-ol, and oplopanonyl acetate, compounds with recognised antimicrobial activity. Concerning antimicrobial activity, significant differences were found using different hydrosol concentrations (10ā20% v/v) in comparison to a control (without hydrosol), showing the potential of the tested hydrosols to inhibit the microbial growth of Escherichia coli, Staphylococcus aureus, and Candida albicans. A. citrodora hydrosol was the most effective one, inhibiting 90% of E. coli growth and 80% of C. albicans growth, for both hydrosol concentrations (p < 0.0001). With hydrosol concentration increase, it was possible to observe an improved antimicrobial activity with significant reductions (p < 0.0001). The findings of this work indicate the viability of reusing and valuing the hydrosols, encouraging the development of green applications for different fields (e.g., food, agriculture, pharmaceuticals, and cosmetics).
- Photodynamic inactivation of Staphylococcus aureus by ecological antibacterial solutions associating LED (Ź 450 Ā± 10 nm) with curcumin and olive leaf extractsPublication . Crugeira, Pedro Jorge Louro; Almeida, HeloĆsa H.S.; Teixeira, Liandra Gracher; Barreiro, M.F.Antimicrobial resistance is a problem in contemporary society, with Staphylococcus aureus standing out as a threat due to its ability to colonize, its pathogenicity, and its expression of several virulence factors. In this context, antimicrobial photodynamic inactivation (aPDI) emerges as an alternative to conventional microbicidal or microbiostatic systems, enabling numerous and successive applications without developing side effects and microbial resistance. In this context, an aPDI system against cultures of S. aureus based on a water-in-oil (W/O) emulsion incorporating curcumin as the photosensitizer (PS), with and without olive leaf extract (OLE), was developed and the antibacterial efficacy evaluated under LED activation (lambda 450 +/- 10 nm) by depositing an energy density of 14 J/cm(2). The produced emulsified systems showed no significant differences in the droplet size and morphology, remaining stable along the tested period of 30 days. The bacterial reduction achieved after the first aPDI application for the emulsions added with curcumin and curcumin combined with the OLE was 5 log10 CFU. mL(-1) and 6 log10 CFU.mL(-1), respectively, revealing a significant difference between the two groups (p < 0.0001). After the second aPDI application, an increased microbial reduction (7 log10 CFU.mL(-1)) was observed for both studied groups even with a low significant difference (p < 0.05). The PS loading through an emulsified system for aPDI obtained a bactericidal action against S. aureus, increased by applying two aPDI, showing a significant synergy between photodynamic inactivation, OLE delivery and antibacterial activity. In addition, the developed solutions were produced using natural products by an ecologically correct process.
- Solid dispersions as effective curcumin vehicles to obtain k-carrageenan functional films for olive oil preservationPublication . Rezende, Stephany; Santamaria-Echart, Arantzazu; Almeida, HeloĆsa H.S.; Marcet, Ismael; Carpintero, Maria; Rendueles, Manuel; Lopretti, Mary; Dias, Madalena M.; Barreiro, M.F.Synthetic packaging materials offer cost efficiency and performance but pose environmental risks. This study explores sustainable alternatives by developing k-carrageenan (KC) films functionalized with curcumin, using solid dispersions (SDs) to improve curcumin's compatibility, addressing the challenge of incorporating hydrophobic functionalities into hydrophilic film matrices. Films with varying curcumin content (1ā20 wt%; KC1- KC20) were compared to a base film without curcumin (KC0) regarding water solubility, vapor permeability, water contact angle, and tensile properties. Compared to KC0, KC10 (10 % curcumin-SDs) exhibited improved water resistance, with solubility decreasing from 82.89 % to 77.18 %, while maintaining vapor permeability (2.96 Ć 10ō 10 gā m/sā m2ā Pa). KC10 demonstrated enhanced tensile properties, with a 12.51 % increase in tensile modulus (241.47 MPa), a 3.86 % increase in stress at break (3.50 MPa), and a 4.42 % increase in strain at break (2.36 %). Furthermore, it exhibited potent antioxidant activity without releasing curcumin into a simulated fatty medium (non-migratory active protection mechanism), effectively preserving olive oil by limiting lipid oxidation to a peroxide value (PV) of 14 mEq. O2/kg oil, compared to 20 mEq. O2/kg oil in unprotected samples under accelerated conditions. It demonstrated significant antimicrobial activity with bacterial reductions of 95.4 % (Escherichia coli) and 90.6 % (Listeria monocytogenes), surpassing KC0. In conclusion, k-carrageenan films functionalized with curcumin SDs are promising and sustainable alternatives to synthetic packaging materials.
- Unlocking the Potential of Hydrosols: Transforming Essential Oil Byproducts into Valuable ResourcesPublication . Almeida, HeloĆsa H.S.; Fernandes, Isabel P.; Amaral, Joana S.; Rodrigues, AlĆrio; Barreiro, M.F.The global demand for sustainable and non-toxic alternatives across various industries is driving the exploration of naturally derived solutions. Hydrosols, also known as hydrolates, represent a promising yet underutilised byproduct of the extraction process of essential oils (EOs). These aqueous solutions contain a complex mixture of EO traces and water-soluble compounds and exhibit significant biological activity. To fully use these new solutions, it is necessary to understand how factors, such as distillation time and plant-to-water ratio, affect their chemical composition and biological activity. Such insights are crucial for the standardisation and quality control of hydrosols. Hydrosols have demonstrated noteworthy properties as natural antimicrobials, capable of preventing biofilm formation, and as antioxidants, mitigating oxidative stress. These characteristics position hydrosols as versatile ingredients for various applications, including biopesticides, preservatives, food additives, anti-browning agents, pharmaceutical antibiotics, cosmetic bioactives, and even anti-tumour agents in medical treatments. Understanding the underlying mechanisms of these activities is also essential for advancing their use. In this context, this review compiles and analyses the current literature on hydrosolsā chemical and biological properties, highlighting their potential applications and envisioning future research directions. These developments are consistent with a circular bio-based economy, where an industrial byproduct derived from biological sources is repurposed for new applications.
- What is better to enhance the solubility of hydrophobic compounds in aqueous solutions: eutectic solvents or ionic liquids?Publication . Ferreira, Olga; Silva, Liliana P.; Almeida, HeloĆsa H.S.; Benfica, Jordana; Abranches, Dinis O.; Pinho, SimĆ£o; Coutinho, JoĆ£o A.P.The solubilities of benzoic acid, (S)-hesperetin, and L-tryptophan in aqueous solutions of ionic liquids (choline glycolate and choline malonate) and the analogous eutectic solvents (choline chloride:glycolic acid and choline chloride:malonic acid) were studied. It is shown that while ionic liquids (IL) and eutectic solvents (ES) were able to increase the solubility of all compounds studied in aqueous solution, ionic liquids were much more efficient for neutral and acidic compounds, while eutectic solvents showed a better performance for the alkaline substances. The results reported here show that the solubility enhancement is related, in the first instance, to the pH of the aqueous solution, which is the dominant effect on the increase in solubility and the main parameter that must be taken into account when selecting a co-solvent to successfully achieve the solubilization of ionizable hydrophobic biomolecules in aqueous solution. In addition, a hydrotropy mechanism was identified when the pH effect was removed, supporting the idea that ionic liquids and eutectic solvents behave as hydrotropes in aqueous solutions. The results here reported show that rather than a focus on the type of solvents (IL vs. ES), the molecular mechanisms such as speciation and co-solvation/hydrotropy, which in some cases may have complementary and synergetic effects, are the parameters that must be addressed in the design or selection of the best solubility enhancer.
- Bioactive evaluation and application of different formulations of the natural colorant curcumin (E100) in a hydrophilic matrix (yogurt)Publication . Almeida, HeloĆsa H.S.; Barros, Lillian; Barreira, JoĆ£o C.M.; Calhelha, Ricardo C.; Heleno, Sandrina A.; Sayer, Claudia; Miranda, Cristiane Grella; Leimann, Fernanda VitĆ³ria; Barreiro, M.F.; Ferreira, Isabel C.F.R.Curcumin (E100) is a natural colorant that, besides conferring color, has bioactivity, serving as an alternative to some artificial colorants. As a hydrophobic colorant, its modification/compatibilization with the aqueous medium is required to improve stability and enable its application in hydrophilic food matrices. Herein, different formulations of curcumin (curcumin powder: PC, water-dispersible curcumin: DC: and nanoencapsulated curcumin: NC) were evaluated as yogurt colorants. PC showed the strongest bioactivity in all assays (EC50 values: 63Ā±2 to 7.9Ā±0.1 Ī¼g.mL-1; GI50 values: 48Ā±1 to 17Ā±1 Ī¼g.mL-1 and MIC values: 0.0625 to 0.5 mg.mL-1), which might indicate that DC and NC reduce the short-term accessibility to curcumin. The tested curcumin formulations produced yogurts with different appearance, specifically associated with their color parameters, besides presenting slight changes in nutritional composition and free sugars and fatty acids profiles. The water compatible formulations (DC and NC) showed advantages over hydrophobic (PC) having a wider industrial utilization.
- Comparison of two computational methods for solvent screening in countercurrent and centrifugal partition chromatographyPublication . Vilas-Boas, SĆ©rgio M.; Cordova, Isabella Weber; Kurnia, Kiki A.; Almeida, HeloĆsa H.S.; Gaschi, Priscilla S.; Coutinho, JoĆ£o A.P.; Pinho, SimĆ£o; Ferreira, OlgaCountercurrent and centrifugal partition chromatography are techniques applied in the separation and isolation of compounds from natural extracts. One of the key design parameters of these processes is the selection of the biphasic solvent system that provides for the adequate partitioning of the solutes. To address this challenging task, the fully predictive Conductor-like Screening Model for Real Solvents (COSMO-RS) and the semi-predictive Non-Random Two-Liquid Segment Activity Coefficient (NRTL-SAC) model were applied to estimate the partition coefficients ( K ) of four model phenolic compounds (vanillin, ferulic acid, ( S )-hesperetin and quercetin) in different solvent systems. Complementing the experimental data collected in the literature, partition coefficients of each solute in binary, or quaternary, solvent sys- tems were measured at 298.2 K. Higher deviations from the experimental data were obtained using the predictive COSMO-RS model, with an average RMSD (root-mean-square deviation) in log( K ) of 1.17 of all four solutes (61 data points), providing a satisfactory quantitative description only for the systems containing vanillin (RSMD = 0.57). For the NRTL-SAC model, the molecular parameters of the solutes were initially calculated by correlating a set of K and solubility ( x , in mole fraction) data (16 partition coefficients and 44 solubility data points), for which average RMSD values of 0.07 and 0.41 were obtained in log( K ) and log( x ) , respectively. The predictions of the remaining log( K ) data (45 partition coefficients) resulted in an average RMSD of 0.43, suggesting that the NRTL-SAC model was a more reliable quantitative solvent screening tool. Depending on the amount of available solubility and partition data, both models can be valuable alternatives in the preliminary stages of solvent screening destined to select the optimal mobile and stationary phases for a given separation.