Continuous-flow precipitation of hydroxyapatite at 37 °C in a meso oscillatory flow reactor

Continuous-flow precipitation of hydroxyapatite (HAp) was investigated in a meso oscillatory flow reactor (meso- OFR) and in a scaled-up meso-OFR, obtained by associating in series eight vertical meso-ORFs. Experiments were carried out under near-physiological conditions of temperature and pH, using fixed frequency ( f = 0.83 Hz) and amplitude (x0 = 4.5 mm), and varying the residence time from 0.4 to 6.7 min. It has been shown that the mean particle size and the aggregation degree of the prepared HAp particles decrease with decreasing residence time. HAp nanoparticles with a mean size (d50) of 77 nm, narrow size distribution, and uniform morphology were obtained at the lowest residence times, τ = 0.4 and 3.3 min in the meso-OFR and the scaled-up meso-OFR, respectively. These results show the capability of the meso-OFR and the scaled-up meso-OFR for continuous production of uniform HAp nanoparticles, while also confirming the possibility of OFR scale-up by in series association of individual OFRs

Characterization of intermediate stages in the precipitation of hydroxyapatite at 37°C

Precipitation of hydroxyapatite Ca 5(PO 4) 3OH (HAp) was carried out by mixing a saturated calcium hydroxide aqueous solution with an orthophosphoric acid aqueous solution at 37°C. In order to promote optimal conditions for the production of HAp with high yields, mixing of the reaction medium was assured by a novel metal stirrer. Different experimental conditions were studied varying the mixing Ca/P molar ratio from 1 to 1.67. After process optimization, a suspension of HAp particles with pH close to 7 was obtained for a mixing molar ratio Ca/P=1.33. The precipitation process was then characterized as a function of pH and calcium concentration, revealing the existence of three different stages. The precipitate formed in each stage was characterized by scanning electron microscopy and X-ray diffraction.This work was supported by the Portuguese Foundation for Science and Technology (SFRH/BD/42992/2008) through the MIT-Portugal Program, Bioengineering Systems Focus Area. The authors are thankful to Dr. Jorge Ferreira from LNEG (Laboratorio Nacional de Energia e Geologia) for carrying out the X-ray measurements and their help with the interpretation of results

Biodegradation of PHB/PBAT films and isolation of novel PBAT biodegraders from soil microbiomes

Polyhydroxyalkanoates (PHAs) are important candidates for replacing petroleum-based plastics. This transition is urgent for the development of a biobased economy and to protect human health and natural ecosystems. PHAs are biobased and biodegradable polyesters that when blended with other polymers, such as poly(butylene adipate-co-terephthalate) (PBAT), acquire remarkable improvements in their properties, which allow them to comply with the requirements of packaging applications. However, the biodegradation of such blends should be tested to evaluate the impact of those polymers in the environment. For instance, PBAT is a compostable aliphatic-aromatic copolyester, and its biodegradation in natural environments, such as soil, is poorly studied. In this work, we evaluated the biodegradation of a bilayer film composed of PHB and PBAT, by a soil microbiome. The bilayer film reached 47 ± 1 % mineralization in 180 days and PHB was no longer detected after this period. The increased crystallinity of the PBAT residue was a clear sign of biodegradation, indicating that the amorphous regions were preferentially biodegraded. Seven microorganisms were isolated, from which 4 were closely related to microorganisms already known as PHB degraders, but the other 3 species, closely related to Streptomyces coelicoflavus, Clonostachys rosea and Aspergillus insuetus, were found for the first time as PHB degraders. Most remarkably, two fungi closely related to Purpureocillium lilacinum and Aspergillus pseudodeflectus (99.83 % and 100 % identity by ITS sequencing) were isolated and identified as PBAT degraders. This is very interesting due to the rarity of isolating PBAT-degrading microorganisms. These results show that the bilayer film can be biodegraded in soil, at mesophilic temperatures, showing its potential to replace synthetic plastics in food packaging.info:eu-repo/semantics/publishedVersio

Factors affecting polyhydroxyalkanoates biodegradation in soil

Polyhydroxyalkanoates (PHAs) are polymers with widespread applications, from medical devices to packaging. PHAs can be biodegradable in natural environments, such as soil, but the blend of PHA with other materials can change the polymer properties and consequently affect the biodegradation process. The composition of the microbial communities in soil also significantly affects the biodegradation, but other factors such as temperature, pH, and soil moisture, can also be determinant. These ecological and physic/chemical factors change in different seasons and in different soil layers. It is essential to know how these factors influence the PHAs biodegradation to understand the impact of PHAs in nature. This review compiles the results on PHA polymers and PHA blends biodegradation, with focus on laboratory tests. The main factors affecting PHA's biodegradation in soil, both in laboratory tests and in the environment are also discussed.Miguel Fernandes acknowledges the grant PD/BD/146195/2019 provided by the Portuguese Foundation for Science and Technology (FCT). This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UIDB/04469/2020 unit and BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020–Programa Operacional Regional do Norte.info:eu-repo/semantics/publishedVersio

Unravelling the behavior of nanostructures during digestion and absorption

The food industry is increasingly focused on preventing nutrition-related diseases and improving consumers’ wellbeing. As a result, there is a growing trend towards healthy foods, enriched with bioactive compounds (such as vitamins, probiotics, bioactive peptides and antioxidants) produced through the application of innovative and safe technologies. In this context, the development of novel delivery systems for food applications through the use of nanotechnology has been extensively explored [1]. In fact, the encapsulation of bioactive compounds in bio-based nanostructures have been reported as promising mean of protecting the valuable bioactive compounds and providing new functionalities (e.g. increase of bioavailability). However, the use of very small particle sizes may alter the biological fate of the ingested materials and bioactive compounds, which could potentially have adverse effects on human health [2]. Therefore, the emerging field of nanotechnology offers new challenges to food industry not only by offering novel tools to improve food quality and human health, but also by introducing questions about nanostructures’ behaviour within the human body. The challenges that must be overcome before nanotechnology can be entirely embraced by food industry, includes the optimisation of nanostructures’ formulations to increase stability and bioactive compounds’ bio availability and the risk assessment of their use in food. The understanding of the behaviour of different nano-based delivery systems (e.g. nanoemulsions, nanoparticles) under digestion conditions, assessing their efficiency and safety is therefore of utmost importance to enable its widespread application in the food industry. This evaluation can be challenging, however, there are opportunities to take advantage from the lessons learned from pharmaceutical industry and of the considerable progress in the development of more realistic in vitro models to more accurately predict the behaviour of bio-based nanostructures once ingestedinfo:eu-repo/semantics/publishedVersio

Incorporation of solid lipid nanoparticles into stirred yogurt: effects in physicochemical and rheological properties during shelf-life

The aim of this work was to develop a yogurt fortified with curcumin. Curcumin is a lipophilic compound with a wide range of biological activities; however, it presents low water solubility and low bioavailability, and therefore it was the first to be encapsulated in solid lipid nanoparticles (SLNs). Then the influence of the incorporation of curcumin-loaded SLNs on the physicochemical (i.e., pH, titratable acidity, syneresis and color) and rheological properties of yogurt during its shelf-life (30 days at 4 °C) was evaluated. SLN incorporation into yogurt did not affect pH and titratable acidity compared to the control (i.e., plain yogurt) during shelf-life, even though the yogurt with SLNs presented lower values of pH (4.25 and 4.34) and acidity (0.74% lactic acid and 0.84% lactic acid) than the control in the end, respectively. Furthermore, the yogurt with SLNs presented slightly higher values of syneresis than the control during the shelf-life; however, it did not present visual differences in whey separation. Relative to the color, the incorporation of SLNs into the yogurt imparted a strong yellow color to the sample but did not affect color stability during shelf-life. Both samples showed flow curves with yield stress and shear-thinning behavior during shelf-life, and, regarding the viscoelastic behavior, both showed a typical weak viscoelastic gel with an elastic structure. Overall, curcumin-loaded SLNs incorporation did not affect the physicochemical and rheological stability of yogurt during shelf-life, showing a promising application for the development of new functional foods.This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UIDB/04469/2020 unit and by LABBELS Associate Laboratory in Biotechnology, Bioengineering and Microelectromechanical Systems, LA/P/0029/2020.info:eu-repo/semantics/publishedVersio

Separation and purification of biomacromolecules based on microfluidics

Separation and purification of biomacromolecules either in biopharmaceuticals and fine chemicals manufacturing, or in diagnostics and biological characterization, can substantially benefit from application of microfluidic devices. Small volumes of equipment, very efficient mass and heat transfer together with high process control result in process intensification, high throughputs, low energy consumption and reduced waste production as compared to conventional processing. This review highlights microfluidics-based separation and purification of proteins and nucleic acids with the focus on liquid-liquid extractions, particularly with biocompatible aqueous two-phase systems, which represent a cost-effective and green alternative. A variety of microflow set-ups are shown to enable sustainable and efficient isolation of target biomolecules both for preparative, as well as for analytical purposes.publishe

Lipid-based nanostructures as strategies to enhance curcumins bioavailability: effect of carrier oil physical state

This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the Project PTDC/AGR-TEC/5215/2014, the strategic funding of UID/BIO/04469/2019 unit and BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020 - Programa Operacional Regional do Norte.info:eu-repo/semantics/publishedVersio

Plant-based bigels for delivery of bioactive compounds: Influence of hydrogel:oleogel ratio and protein concentration on their physicochemical properties

Bigels are a class of soft matter systems with high potential in food industry as fortified ingredient replacers or food analogs. The aim of this work was to develop plant-based bigels using potato protein-based hydrogel and candelilla wax-based oleogel. The potato protein concentration and hydrogel:oleogel ratio effects on bigels production was assessed in terms of textural and rheological properties. The incorporation of curcumin and its bioaccessibility after in vitro digestion was also evaluated. All samples presented an oleogel-in-hydrogel structure arrangement. Increasing the protein concentration led to increased hardness and G*, improving the structure and consistency of bigels. The increase of oleogel fraction altered the distribution of oleogel droplets in the hydrogel matrix, affecting the hardness and the consistency of bigels. Overall, the increase of oleogel fraction and protein concentration allowed forming bigels with stronger mechanical properties and higher thermal resistance. The bigel showed a curcumin's bioaccessibility of 16.3 % and a curcumin's stability of 43.8 %, suggesting that this type of structures is promising for the delivery of bioactive compounds at the colon or for slow release of bioactive compounds. Overall, the results showed the possibility to develop potato protein-based bigels with interesting mechanical, rheological and thermal properties by changing the protein concentration and hydrogel:oleogel ratio, expanding the application of bigels in novel food products with high nutritional value and protein content, namely plant-based products.Raquel F. S. Gonçalves acknowledge the Foundation for Science and Technology (FCT) for her fellowship (SFRH/BD/140182/2018). This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UIDB/04469/2020 unit, and by LABBELS – Associate Laboratory in Biotechnology, Bioengineering and Microelectromechanical Systems, LA/P/0029/2020