Novas tendências em embalagens alimentares funcionalidades e materiais

Motivada pela crescente preocupação com a qualidade e a segurança dos alimentos, a utilização de embalagens alimentares é uma prática de há muito enraizada na sociedade. As funções solicitadas aos materiais utilizados para produzir embalagens alimentares estão relacionadas com as tendências de consumo e com as evoluções tecnológicas adotadas ao longo dos anos pela indústria alimentar e pela distribuição, o que implica um esforço adicional para encontrar soluções de embalagem que respondam a essas solicitações. Por outro lado, mais recentemente, tem emergido uma grande polémica relacionada com a pegada ambiental deixada pelos materiais plásticos não biodegradáveis, muito comumente utilizados no fabrico de embalagens alimentares, a que urge dar resposta. Estes desafios originaram o aparecimento de novos materiais de embalagem, com novas funcionalidades, que poderão chegar ao mercado mais cedo do que possamos imaginar.info:eu-repo/semantics/publishedVersio

Genetic diversity of Lusitano horse in Brazil using pedigree information

This study aimed to evaluate population parameters and to describe the genetic diversity of the Lusitano breed in Brazil using pedigree data. Two populations were evaluated: total population (TP) containing 18,922 animals, and reference population (RP) composed of a part of TP containing 8,329 animals, representing the last generation. The generation interval (10.1 ± 5.1 years) was in the range for horse populations. Pedigree completeness in RP shows almost 100% filling in the three most recent generations, indicating improvement in the pedigree data and accuracy of the results, and the inbreeding coefficient (4.46%) and average relatedness (5.97%) for RP, indicating control on the part of breeders. The effective population size was 89 (TP) and 90 (RP). The effective number of founders (fe) were 33 and 29, effective number of ancestors (fa) were 30 and 26, and effective number of founder genomes (fg) were 19 and 15 for TP and RP, respectively, indicating a reduction of genetic variability in the last generations. The total number of ancestors that explains 100% of the genetic diversity in the Lusitano breed in Brazil was 427 (TP) and 341 (RP). The reproductive parameters, probabilities of gene origin showing loss of variability in the last generations, and the genetic contributions of ancestors suggest the need to monitor genetic diversity over time in breeding programs to allow control of the next generations and to increase their variability.info:eu-repo/semantics/publishedVersio

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

Conformational dynamics of soy protein isolate under ohmic heating

Ohmic heating (OH) brings a promise of sustainable thermal processing by assuring high levels of heating efficiency and reduction of water consumption. It is important to gather fundamental knowledge about the way how this emerging heating method technology can affect the biological, functional, and technological properties of important molecules such as proteins during food processing. Vegetable proteins are attracting scientific interest in the food arena, mostly due to the need of a protein transition but also the most recent consumer trends. This work describes the effects of OH on structural aspects of soy protein isolate (SPI). OH was applied at different electrical frequencies (i.e. from 50 Hz to 20 kHz) and moderate electric fields (i.e. from 0 V/cm to 20 V/cm) at the onset denaturation temperature of SPI (95ºC). Different SPI fractions, such as legumins and vicilins, were identified through non-denaturing SDS-PAGE. Through fluorescence spectroscopy it was observed that frequencies below 500 Hz quenches tryptophan emission, suggesting structural rearrangements of the protein folding behavior; this effect is more pronounced with increasing electric field intensity. OH at 50 Hz resulted in a decrease of maximum intrinsic fluorescence intensity (p <0.05) of 27 % and 21 % when compared with the non-heated SPI and heated sample without the presence of an electric field, respectively. At the same time, treatments at 20 kHz presented a higher intrinsic fluorescence intensity than the other treatments (p < 0.05). The exposition of hydrophobic pockets appears to be less dependent on the electrical treatments applied. By reducing the thermal load, OH induces fewer changes on the protein´s structure, but the inherent electrochemical reactions and release of metals from the electrodes surface (confirmed by inductively coupled plasma mass spectrometry) can promote complexation reactions, thus changing protein folding dynamics. OH processing parameters when properly controlled result on differentiated protein binding properties which may be of essential importance regarding their functional properties but also for different applications in bioscience fields.info:eu-repo/semantics/publishedVersio

Characterization of split cylinder airlift photobioreactors for efficient microalgae cultivation

An extensive characterization of photobioreactors (PBRs) must be made in order to optimize their operational conditions, operate design improvements and perform scale-up. In this work, a hydrodynamic characterization of liquid and gas phases was performed, as well as the determination of the mass transfer coefficient of three different PBRs (bubble column – BC – and two Split Cylinder Airlift Photobioreactors – SCAPBRs – featuring two different riser-to-downcomer cross sectional area ratios: SCAPBR 75 and SCAPBR 50). The effect of these parameters on biomass productivity was also evaluated. The developed SCAPBRs proved to be extremely suitable for microalgae cultivation. The design of the PBR, particularly the designed gas sparger, allowed meeting the needs of microalgae in terms of mixing and mass transfer (efficient supply and removal of CO2 and O2, respectively). SCAPBR 50 (with a superficial gas velocity of 0.0044 m s−1) showed, among the tested PBRs, the highest value of biomass volumetric productivity (0.75 g L−1 d−1). This result is probably due to a higher PBR illuminated surface area, and a more regular flow pattern between the illuminated and dark zones verified in SCAPBR 50, which allows exposing cells to regular light–dark periods.This research work was supported by the Grant SFRH/BPD/98694/2013 (Bruno Fernandes) from Fundacao para a Ciencia e a Tecnologia (Portugal). The authors thank the FCT Strategic Project PEst-OE/EQB/LA0023/2013. The authors also thank the Project "Biolnd - Biotechnology and Bioengineering for improved Industrial and Agro-Food processes, REF. NORTE-07-0124-FEDER-000028" Co-funded by the Programa Operacional Regional do Norte (ON.2 - O Novo Norte), QREN, FEDER

Antioxidant potential of two red seaweeds from the Brazilian coasts

In this work, in vitro antioxidant activity of two Brazilian red seaweeds, Gracilaria birdiae and Gracilaria cornea, was characterized. The total phenolic content, the radical-scavenging activity and the antioxidant activity were determined in two solvent extracts of the algae. Liquid chromatography mass spectrometry (LC MS/MS) allowed identification of important antioxidant compounds. The ethanol extract of G. birdiae was found to have the highest value of total phenolic content: 1.13 mg of gallic acid equiv (GAE)/g of extract.The radical-scavenging activity of G. birdiae and G. cornea extracts has been evaluated at different extract concentrations; the IC50 values of ethanolic extracts of G. cornea and G. birdiae were 0.77 and 0.76mgmL 1, respectively, while formethanolic extracts, the IC50 values of G. cornea and G. birdiae were 0.86 and 0.76mgmL 1, respectively. The antioxidant activities of these two seaweeds’ extracts as assessed by the ß-carotene linoleic acid assay were equally high, achieving values of ß-carotene oxidation inhibition of up to 40%. Finally, in the methanolic extracts, LC MS/MS allowed identification in both algae of two important antioxidants: apigenin and gallic acid.B.W.S.S. is the recipient of a fellowship from the Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES, Brazil) M.A.C. and J.T.M. are recipients of fellowships from the Fundacao para a Ciencia e Tecnologia (FCT, Portugal) (SFRH/BD/23897/2005 and SFRH/BD/32566/2006, respectively)

Development and characterization of pectin films with Salicornia ramosissima: biodegradation in soil and seawater

Pectin films were developed by incorporating a halophyte plant Salicornia ramosissima (dry powder from stem parts) to modify the film’s properties. The films’ physicomechanical properties, Fourier-transform infrared spectroscopy (FTIR), and microstructure, as well as their biodegradation capacity in soil and seawater, were evaluated. The inclusion of S. ramosissima significantly increased the thickness (0.25 ± 0.01 mm; control 0.18 ± 0.01 mm), color parameters a* (4.96 ± 0.30; control 3.29 ± 0.16) and b* (28.62 ± 0.51; control 12.74 ± 0.75), water vapor permeability (1.62 × 10−9 ± 1.09 × 10−10 (g/m·s·Pa); control 1.24 × 10−9 ± 6.58 × 10−11 (g/m·s·Pa)), water solubility (50.50 ± 5.00%; control 11.56 ± 5.56%), and elongation at break (5.89 ± 0.29%; control 3.91 ± 0.62%). On the other hand, L* (48.84 ± 1.60), tensile strength (0.13 ± 0.02 MPa), and Young’s modulus (0.01 ± 0 MPa) presented lower values compared with the control (L* 81.20 ± 1.60; 4.19 ± 0.82 MPa; 0.93 ± 0.12 MPa), while the moisture content varied between 30% and 45%, for the film with S. ramosissima and the control film, respectively. The addition of S. ramosissima led to opaque films with relatively heterogeneous microstructures. The films showed also good biodegradation capacity—after 21 days in soil (around 90%), and after 30 days in seawater (fully fragmented). These results show that pectin films with S. ramosissima may have great potential to be used in the future as an eco-friendly food packaging material.info:eu-repo/semantics/publishedVersio

Customization of an optical probe device and validation of a signal processing procedure to study gas-liquid-solid flows. Application to a three-phase internal-loop Gas-lift Bioreactor

The study of local hydrodynamic properties of three-phase bioreactors in biotechnology processes is of great importance, mainly because of the complex interaction between bioreactor and microorganisms. However, classical techniques used for measuring local hydrodynamic properties such as single needle probes are mainly limited to two-phase flows. In this work it was developed and validated a new system, based on the customization of an optical probe initially designed in LEGI. The necessity of a new system was due to the agglomeration of the solid-phase (spent grains which are used as the micro-organisms carrier for the targeted application) around the optical tip, which influences the measurements. This new system allows for the measurement of the main local gas-phase properties in a complex gas-liquid-solid mixture. The new system was first validated for air-water system in an internal loop gas-lift reactor and then applied to a spent grains-air-water mixture at low solid load in an internal gas lift reactor. In addition, experiments using complementary techniques (as high speed camera and PIV) were performed that allowed for the validation of the new system and the explanation of possible physical mechanisms that are underlying on this multiphase system. The system developed has the potential for improvement and use in several biotechnology applications.The authors gratefully acknowledge the financial support from FCT (Fundacao para a Ciencia e Tecnologia, SFRH/BD/37082/2007 and SFRH/BPD/45637/2008)

Uso de microsistemas na precipitação em contínuo de hidroxiapatite

Neste trabalho é apresentado o estudo de dois microreatores ultrasónicos para a precipitação em contínuo de hidroxiapatite Ca5(PO4)3OH (HAp) a 37 º C. O primeiro reator consiste num microreator tubular imerso num banho ultrasónico, onde os fluxos laminar e segmentado (gás-líquido) foram ambos avaliados. De seguida, o estudo em regime laminar foi conduzido num novo dispositivo microfluídico desenvolvido no MIT. Este é constituído por uma pilha de placas de Teflon com um elemento piezoelétrico integrado, permitindo assim a transmissão direta de ultrassons para o reator. Para todos os microsistemas estudados foram obtidas nanopartículas de HAp, em condições próximas das condições fisiológicas de pH e temperatura. Além disso, as partículas produzidas apresentam-se sob a forma de bastonetes de aproximadamente 100 nm de comprimento e 20 a 50 nm de largura. Os microreatores utilizados produziram partículas de HAp num tempo muito curto e com maior cristalinidade, comparado com as partículas produzidas num reator batch. Também foi possível reduzir significativamente a agregação das partículas nos microsistemas, ao contrário do sistema batch, onde não foi possível evitar a formação de agregados.info:eu-repo/semantics/publishedVersio