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

Produção de leite, gordura e proteína por lactação em cruzamentos de HVB X Guzerá.

Para caracterizar o desempenho de cruzamentos HVB X Guzerá, foram analisadas observações de primeiras lactações obtidas entre junho de 1980 e agosto de 1985 em 65 fazendas da região Sudeste, estratificadas em classes de alto e baixo nível de manejo.Resum

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

TiO2/graphene and TiO2/graphene oxide nanocomposites for photocatalytic applications: A computer modeling and experimental study

Supplementary data related to this article can be found at http://dx. doi.org/10.1016/j.compositesb.2018.03.015.This work reports a computational study, focused on graphene (G) and graphene oxide (GO) interfaces with titanium dioxide (TiO2), and an experimental assay on the photocatalytic activity of TiO2/G and TiO2/GO nanocomposites in the degradation of two different pollutants: methylene blue and ciprofloxacin. Both carbon nanostructures were compared due to their different chemical structure: GO is a G derivative with oxygen functional groups which should promote a closer chemical interaction with TiO2 nanoparticles. Computational models of the fundamental properties of the composites indicated potentially improved photocatalytic activity compared to TiO2, namely lower band gaps and charge carrier segregation at the interfaces. These fundamental properties match qualitatively experimental results on methylene blue, which was more effectively degraded by TiO2/G and TiO2/GO nanocomposites than by pure TiO2 under UV light. In contrast, the same nanocomposites were found to be less efficient to degrade ciprofloxacin than pure TiO2 under visible and UV light. Therefore, this work showcases the relevance of an efficient matching between the catalyst and the molecular properties and structure of the pollutant.This work was supported by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Project PESTC/FIS/UI607/2014 and PEST-C/QUI/UIO686/2014 and the CICECO Aveiro Institute of Materials, POCI-01-0145-FEDER-007679 (FCT ref. UID/CTM/50011/2013). Access to computing facilities provided by the Project “Search-ON2: Revitalization of HPC infrastructure of UMinho” (NORTE-07-0162-FEDER-000086) is also acknowledged. P. M. Martins and Luciana Pereira thanks the FCT for grants SFRH/BD/98616/2013 and SFRH/BPD/110235/2015, respectively. MMF for a program Ciência 2008 fellowship. The authors thank financial support from the Basque Government Industry Department under the ELKARTEK Program. P.A.A.P. Marques thanks the grant IF/00917/2013/CP1162/ CT0016. Acknowledges also to FCT under the scope of the strategic funding of UID/BIO/04469/2013 unit and COMPETE 2020 (POCI-010145-FEDER-006684) and BioTecNorte operation (NORTE-01-0145FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020 - Programa Operacional Regional do Norte.info:eu-repo/semantics/publishedVersio

Melt processability, characterization, and antibacterial activity of compression-molded green composite sheets made of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) reinforced with coconut fibers impregnated with oregano essential oil

New packaging materials based on green composite sheets consisting of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and coconut fibers (CFs) were obtained by twin-screw extrusion (TSE) followed by compression molding. The effect of varying the CF weight content, i.e. 1, 3, 5, and 10wt.-%, and the screw speed during melt processing, i.e. 75, 150, and 225rpm, on both the aspect ratio and dispersion of the fibers was analyzed and related to the properties of the compression-molded sheets. Finally, the CFs were impregnated with oregano essential oil (OEO) by an innovative spray coating methodology and then incorporated into PHBV at the optimal processing conditions. The functionalized green composite sheets presented bacteriostatic effect against Staphylococcus aureus from fiber contents as low as 3wt.-%. Therefore, the here-prepared CFs can be successfully applied as natural vehicles to entrap extracts and develop green composites of high interest in active food packaging to provide protection and shelf life extension.This research was funded by the EU H2020 project YPACK (reference number 773872), the Spanish Ministry of Economy and Competitiveness (MINECO) project AGL2015-63855-C2-1-R, the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit and COMPETE 2020 (POCI-01-0145-FEDER-006684), and the BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund (ERDF) under the scope of Norte2020 – Programa Operacional Regional do Norte. Prof. Sergio Torres-Giner wants to thank the European Cooperation in Science and Technology (COST) Action FP1405, ActInPak, for financial support during his Short Term Scientific Mission (STSM) at the University of Minho.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

Continuous production of melamine-formaldehyde microcapsules using a mesostructured reactor

A mesostructured NETmix reactor was adapted to develop a continuous process to produce microcapsules, focusing on the steps commonly used in batch formulation: the emulsion and cure. Microcapsules were formed through a polycondensation process by coating Miglyol, a skin-hydrating emollient, with melamine-formaldehyde, which is a resistant shell material with surface smoothness. Different recirculation times were tested for the cure step. Microcapsules show a spherical shape and smooth membrane. Efficiencies of encapsulation of 75%, core contents of 70%, and diameters around 20 μm, ideal range for textile impregnation, were obtained. Scanning electron microscopy shows the integrity of microcapsules on textiles after impregnation and their flexible behavior. The thermogravimetric analysis confirmed the thermal stability of microcapsules up to 210 °C. With the NETmix reactor, it is possible to reduce the cure time of traditional batch formulation in 80%, producing microcapsules with similar characteristics in a continuous process.This work was supported by Associate Laboratory LSRE-LCM UID/EQU/50020/2019 funded by national funds through FCT/MCTES (PIDDAC) and Project TexBioPro, POCI-01- 0247-FEDER-003472, funded by FEDER, through COMPETE 2020, under PT2020.info:eu-repo/semantics/publishedVersio

Evaluation of strategies for crossbreeding of Dairy Cattle in Brazil.

To compare breeding strategies, economic performance was calculated for 376 cows of six red and white Holstein-Friesian X Guzera crossbred groups, based on their accumulated dairy production and on culling or death observations of 87 nonfreshening heifers