Effect of temperature, pH and ionic strength on hydroxyapatite stabilised Pickering emulsions produced in batch and continuous mode

Oil-in-water (O/W) Pickering emulsions are attracting attention as carriers of lipophilic active compounds with clear advantages over traditional systems. Having in view their effective use it is important to study their stability against environmental stresses impacting manufacture, storage, and application conditions. In this work, hydroxyapatite nanoparticles (n-HAp) Pickering emulsions produced in continuous mode using a mesostructured reactor (average size ~ 7, 11 and 18 μm) and in batch mode using a rotor–stator device (average size ~ 18 μm) were studied concerning their behaviour at different temperatures (5–90 ºC), pH (2–10) and ionic strength (0–500 mM), conditions with relevance for food applications. Droplet size, morphology, and zeta-potential were analysed after 1 and 7 days under storage. In general, and despite the droplet size, the n-HAp Pickering emulsions were stable within the tested ionic strength range, at relatively high pH environments (6–10), and at temperatures up to 70 ºC. Pickering emulsions undergo complete phase separation at very low pH (2) due to n-HAp particle's disruption. A clear tendency to aggregation and coalescence was observed for high temperatures (70–90 ºC). Results indicate no significant differences related to the used production method. From an industrial perspective, this work also corroborates that the scale-up to a continuous process using a mesostructured reactor, NETmix, from a batch laboratorial process is feasible without impacting stability.This work was financially supported by LA/P/0045/2020 (ALiCE), UIDB/50020/2020 and UIDP/50020/2020 (LSRE-LCM), and UIDB/00690/2020 (CIMO) funded by national funds through FCT/ MCTES (PIDDAC). Andreia Ribeiro acknowledges her PhD fellowship funded by Project NORTE-08–5369-FSE-000028, supported by N2020, under PT2020, through ESF. Authors thank Fluidinova S.A. for providing samples of nanoXIM-CarePaste.info:eu-repo/semantics/publishedVersio

Continuous production of hydroxyapatite Pickering emulsions using a mesostructured reactor

Emulsions are used in a wide range of applications, including food and cosmetics. Nowadays, the demand for sustainable products has increased with Pickering emulsions emerging as clean alternatives. To achieve the industrial implementation of Pickering emulsions, continuous production and less intensive energy devices are required. In this context, a mesostructured reactor based on an innovative static mixer, NETmix, was tested to produce Pickering emulsions from a previously developed formulation in batch mode. The effect of the number of cycles (2–35) and Reynolds number (200–500), parameters that influence the residence time and the quality of mixing, on the Pickering emulsion properties (average droplet size, droplet morphology, and stability) was studied. The obtained results pointed out the feasibility of using NETmix to produce Pickering emulsions. It is a versatile technique to control in a tailor-made way the droplet size and generate small droplets at short times. Results show a decrease of the droplet size with increasing number of cycles and Reynolds. Under the tested conditions, stable dispersions with droplet size of ∼7 μm were produced using 17 cycles and Re = 400. Microscopy images show an oil core and nano-hydroxyapatite shell morphology.This work was financially supported by: Base Funding - UIDB/50020/2020 of the Associate Laboratory LSRE-LCM - funded by national funds through FCT/MCTES (PIDDAC), and Base Funding - UIDB/00690/2020 of CIMO - Centro de Investigação de Montanha - funded by national funds through FCT/MCTES (PIDDAC). Andreia Ribeiro acknowledges her PhD fellowship funded by Project NORTE-08-5369-FSE- 000028, supported by N2020, under PT2020, through ESF. Authors thank Fluidinova S.A. for providing nanoXIM-CarePaste, and the Centro de Materiais da Universidade do Porto (CEMUP) and Instituto de Investigação e Inovação em Saúde (i3S) for the services provided with cryo-SEM and CLSM analysis, respectively.info:eu-repo/semantics/publishedVersio

Development of water-in-oil pickering emulsions from sodium oleate surface-modified nano-hydroxyapatite

The stabilisation of water-in-oil (W/O) Pickering emulsions is still a challenge for the scientific community. In this work, sodium oleate (SO) surface modified nano-hydroxyapatite (n-HAp) particles were produced and tested as W/O stabilisers. The modified n-HAp particles presented a wettability dependent on the used SO content, switching from hydrophilic (initial state) to hydrophobic (one SO layer) and back to hydrophilic (two SO layers). The Pickering emulsions produced with the particles holding one SO layer (contact angle ~90 ◦) showed their tight adsorption at the water-oil interface (confocal analysis), and maintained the stability up to 15 days. Overall this work provides new developments in the field of W/O Pickering emulsions, a topic less studied than O/W, opening new avenues for several applications.This work was financially supported by: Base- UIDB/50020/2020 and Programmatic- UIDP/50020/2020 Funding of LSRE-LCM, funded by national funds through FCT/MCTES (PIDDAC), and Base Funding - UIDB/00690/2020 of CIMO - Centro de Investigação de Montanha - funded by national funds through FCT/MCTES (PIDDAC). Andreia Ribeiro acknowledges her PhD fellowship funded by Project NORTE-08-5369-FSE-000028, supported by N2020, under PT2020, through ESF. Authors thank Fluidinova S.A. for providing samples of nanoXIM-102Paste.info:eu-repo/semantics/publishedVersio

Nanohydroxyapatite (n-HAp) as a pickering stabilizer in oil-in-water (O/W) emulsions: a stability study

Surfactant-free emulsions, such as Pickering emulsions, have been gaining an increased interest. They constitute green alternatives to the current industrial practices in emulsion technology finding diverse technological uses. In this work, nano-hydroxyapatite (n-HAp) was tested as an oil-in-water (O/W) Pickering stabilizer using a chemical system comprising sunflower oil at different O/W ratios (10/90 to 60/40) and n-HAp at concentrations ranging from 0.5 to 15 wt%. The produced emulsions were characterized, and stability evaluated over a two-month period. Based on the results achieved for the 20/80 series, a model to predict the emulsion stability taking into account the O/W ratio, total solids content, droplet diameter, and n-HAp dimensions, was developed. Cryo-SEM evidenced the attachment of n-HAp particles at the oil surface (oil core-n-HAp shell morphology), corroborating their role as Pickering stabilizers. The experimental results, versus the predicted results were compared using a ternary phase diagram, which evidenced the formation of three zones (unstable, stable and gel) depending on the used O/W ratio and n-HAp concentration. Moreover, the comparison of the predicted with the obtained experimental data validated the model predictability.This work was financially supported by: Associate Laboratory LSRELCM - UIDB/50020/2020 - funded by national funds through FCT/ MCTES (PIDDAC). To Foundation for Science and Technology (FCT, Portugal) for financial support by national funds FCT/MCTES to CIMO (UIDB/00690/2020). Andreia Ribeiro acknowledges her PhD fellowship funded by Project NORTE-08-5369-FSE-000028, supported by N2020, under PT2020, through ESF.info:eu-repo/semantics/publishedVersio

In vitro digestion and bioaccessibility studies of vitamin E-loaded nanohydroxyapatite pickering emulsions and derived fortified foods

Vitamin E is a lipophilic vitamin playing an essential role in human health. Due to oxidative instability, it presents fast degradation and bioactivity loss. In this study, vitamin E-loaded Pickering emulsions stabilized by nano-hydroxyapatite (n-HAp) were produced using a static mixer (NETmix), a technique enabling continuous production and droplet size tailoring. Thus, oil-in-water (O/W) emulsions containing vitamin E at a content of 1mg/mL were produced with different droplet sizes (7.53, 11.56 and 17.72m) using an O/W ratio of 20/80 (v/v). Their stability during in vitro gastrointestinal digestion and vitamin E bioaccessibility were investigated. It was observed that n-HAp particles disrupt in the stomach and subsequently aggregate as random calcium phosphates in the small intestine, leading to low vitamin E bioaccessibility due to oil entrapment. The emulsion showing the highest vitamin E bioaccessibility (3.29±0.57%, sample with the larger average droplet size) was used to produce fortified gelatine and milk, resulting in an increased bioaccessibility (10.87±1.04% and 18.07±2.90%, respectively). This fact was associated with the presence of macronutrients and the lower n-HAp content. Overall, n-HAp Pickering emulsions offer advantages for vitamin E encapsulation directed to fortified foods development, a process able to be extended to other lipophilic vitamins.This work was financially supported by Base Funding -UIDB/50020/2020 of the Associate Laboratory LSRE-LCM -funded by national funds through FCT/MCTES (PIDDAC), Base Funding -UIDB/00690/2020 of CIMO -funded by national funds through FCT/MCTES (PIDDAC), and Base Funding -UIDB/04469/2020 of the CEB funded by national funds through FCT. Andreia Ribeiro acknowledges her PhD fellowship funded by Project NORTE-08-5369-FSE-000028, supported by N2020, under PT2020, through ESF, and Raquel F. Goncalves acknowledges the Foundation for Science and Technology (FCT) for their fellowship (SFRH/BD/140182/2018). Authors thank Fluidinova S.A. for providing samples of nanoXIM-CarePaste and Instituto de Investigacao e Inovacao em Saude (i3S) for the services provided with CLSM analysis.info:eu-repo/semantics/publishedVersio

Inovação e interdisciplinaridade: um estudo de caso no desenvolvimento de competências no curso de engenharia civil

A inovação tecnológica é um processo complexo e o desempenho das organizações depende da sua capacidade de evoluir para se manter com sucesso em mercados cada vez mais globais e competitivos. A interdisciplinaridade é parte fundamental da inovação, porque as modernas soluções dependem da atuação integrada das diversas áreas do conhecimento para que os resultados sejam maximizados. A construção de uma abordagem interdisciplinar é, portanto, fundamental para promover a criação de respostas a quaisquer desafios que possam vir a confrontar as sociedades e organizações. Assim, este trabalho define esses conceitos relevantes e faz uma ligação entre o desenvolvimento de diferentes competências e habilidades de forma interdisciplinar reunindo as bases para um processo de inovação tecnológica e acadêmica orientado à solução de problemas reais, através de ampla pesquisa bibliográfica e valendo-se de um estudo de caso aplicado em uma instituição de ensino superior.  A proposta foi seguir as novas Diretrizes Curriculares Nacionais dos Cursos de Engenharia (DCN) (MEC, 2019a), pela Resolução MEC nº 2, de 24 de abril de 2019 e propor melhorias nas grades do curso de engenharia civil. Adaptando a nova consciência que o curso pode ter 25% da grade EAD (Ensino a Distância) e que a interdisciplinaridade faz parte da inovação

Inovação e interdisciplinaridade: um estudo de caso no desenvolvimento de competências no curso de engenharia civil

A inovação tecnológica é um processo complexo e o desempenho das organizações depende da sua capacidade de evoluir para se manter com sucesso em mercados cada vez mais globais e competitivos. A interdisciplinaridade é parte fundamental da inovação, porque as modernas soluções dependem da atuação integrada das diversas áreas do conhecimento para que os resultados sejam maximizados. A construção de uma abordagem interdisciplinar é, portanto, fundamental para promover a criação de respostas a quaisquer desafios que possam vir a confrontar as sociedades e organizações. Assim, este trabalho define esses conceitos relevantes e faz uma ligação entre o desenvolvimento de diferentes competências e habilidades de forma interdisciplinar reunindo as bases para um processo de inovação tecnológica e acadêmica orientado à solução de problemas reais, através de ampla pesquisa bibliográfica e valendo-se de um estudo de caso aplicado em uma instituição de ensino superior.  A proposta foi seguir as novas Diretrizes Curriculares Nacionais dos Cursos de Engenharia (DCN) (MEC, 2019a), pela Resolução MEC nº 2, de 24 de abril de 2019 e propor melhorias nas grades do curso de engenharia civil. Adaptando a nova consciência que o curso pode ter 25% da grade EAD (Ensino a Distância) e que a interdisciplinaridade faz parte da inovação