Use of electrospinning to develop antimicrobial biodegradable multilayer systems: encapsulation of cinnamaldehyde and their physicochemical characterization

In this work, three active bio-based multilayer structures, using a polyhydroxybutyrate-co-valerate film with a valerate content of 8 % (PHBV8) as support, were developed. To this end, a zein interlayer with or without cinnamaldehyde (CNMA) was directly electrospun onto one side of the PHBV8 film and the following systems were developed: (1) without an outer layer; (2) using a PHBV8 film as outer layer; and (3) using an alginate-based film as outer layer. These multilayer structures were characterized in terms of water vapour and oxygen permeabilities, transparency, intermolecular arrangement and thermal properties. The antimicrobial activity of the active bio-based multilayer systems and the release of CNMA in a food simulant were also evaluated. Results showed that the presence of different outer layers reduced the transport properties and transparency of the multilayer films. The active bio-based multilayer systems showed antibacterial activity against Listeria monocytogenes being the multilayer structure prepared with CNMA and PHBV outer layers (PHBV + zein/CNMA + PHBV) the one that showed the greater antibacterial activity. The release of CNMA depended on the multilayer structures, where both Fick's and Case II transport-polymer relaxation explained the release of CNMA from the multilayer systems.Acknowledgments: Miguel A. Cerqueira (SFRH/BPD/72753/2010) andAnaI.Bourbon(SFRH/BD/73178/2010)arerecipientofafellowship from the Fundação para a Ciência e Tecnologia (FCT, POPH-QREN and FSE Portugal). J.L. Castro-Mayorga is supported by the Administrative Department of Science, Technology and Innovation (Colciencias) of Colombian Government. M. J. Fabra is a recipient of a Ramon y Cajal contract (RyC-2014-158) from the Spanish Ministry of Economy and Competitiveness. This study was supported by 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 of the Project RECI/BBB-EBI/ 0179/2012 (FCOMP-01-0124-FEDER-027462). The support of EU Cost Action MP1206 is gratefully acknowledged

Utilization of galactomannan from Gleditsia triacanthos in polysaccharide-based films : effects of interactions between film constituents on film properties

The objective of this work was to evaluate the effect of the concentrations of Gleditsia triacanthos galactomannan and glycerol and the presence of corn oil in the physical properties of edible films. The influence of interactions between those constituents on films' permeability to gases (water vapour, CO2 and O2), solubility in water, mechanical properties and colour was evaluated. The effects of those variables were analysed according to a 23 factorial design; regression coefficients were used to understand the influence of each variable (factor) on the studied properties, and a multifactor model was developed. Results show that galactomannan concentration is the most significant factor affecting the studied properties; moreover, the increase of plasticizer concentration and the presence of oil showed to be the most influent in the particular cases of solubility and transport properties (water vapour permeability and O2 permeability), respectively. These results show that galactomannan films' properties can be tailored to allow their use as alternative to non-biodegradable, non-edible packaging materials.The author M. A. Cerqueira is recipient of a fellowship from Fundacao para a Ciencia e Tecnologia (FCT, SFRH/BPD/72753/2010) and B. W. S. Souza is a recipient of a fellowship from the Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior, Brazil (Capes, Brazil)

Towards fairer conservation: Perspectives and ideas from early‐career researchers

The Black Lives Matter Movement, which gained unprecedented global momentum in mid-2020, triggered critical reflection on systemic discrimination of disadvantaged groups across many domains of society. It prompted us, as early-career researchers (ECRs) in conservation science, to examine our own awareness of ongoing injustices within our field, the role we play in perpetuating or countering these injustices, and how to move forward. Colonialist ideologies and power dynamics throughout the history of conservation practice and research have left a long-lasting legacy of inequality and systemic racism. While improvements have been made, these legacies continue to influence teaching and practice today. In this perspective piece, we reflect on the impacts of conservation’s colonial past and how the sector has developed. We then explore how current traditional routes into conservation, and the dominance of these approaches, can leave ECRs underprepared to address modern-day conservation issues due to a limited understanding of conservation’s history and key theories from other fields. We end by offering a set of suggestions encouraging others to learn and practise fairer and more inclusive conservation practices

Relationship between galactomannan structure and physicochemical properties of films produced thereof

In this work five sources of galactomannans, Adenanthera pavonina, Cyamopsis tetragonolobus, Caesalpinia pulcherrima, Ceratonia siliqua and Sophora japonica, presenting mannose/galactose ratios of 1.3, 1.7, 2.9, 3.4 and 5.6, respectively, were used to produce galactomannan-based films. These films were characterized in terms of: water vapour, oxygen and carbon dioxide permeabilities (WVP, O 2 P and CO 2 P); moisture content, water solubility, contact angle, elongation-at-break (EB), tensile strength (TS) and glass transition temperature (T g ). Results showed that films properties vary according to the galactomannan source (different galactose distribution) and their mannose/galactose ratio. Water affinity of mannan and galactose chains and the intermolecular interactions of mannose backbone should also be considered being factors that affect films properties. This work has shown that knowing mannose/galactose ratio of galactomannans is possible to foresee galactomannan-based edible films properties.The authors thank the fellowship (SFRH/BPD/ 72753/2010) from the Fundação para a Ciência e Tecnologia (FCT, Portugal). The authors also thank the FCT Strategic Project of UID/BIO/ 04469/2013 unit, the project RECI/BBB-EBI/0179/2012 (FCOMP-010124-FEDER-027462) and the project BBioInd - Biotechnology and Bioengineering for improved Industrial and Agro-Food processes, REF. NORTE-07-0124-FEDER-000028 Co-funded by the Programa OperacionalRegionaldoNorte(ON.2–ONovoNorte),QREN,FEDER. Fundação Cearense de Apoio ao Desenvolvimento Científico e Tecnológico – FUNCAP, CE Brazil (CI1-0080-00055.01.00/13)

Mineral inadequacy of oral diets offered to patients in a Brazilian hospital

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Introduction: While enteral diets for hospitalized patients normally follow nutrient composition guidelines, more than 90% of hospitalized patients receive oral diets with unknown mineral composition. Objective: To evaluate the mineral contents and adequacy of three types of oral diets (regular, blend and soft) and complementary snacks offered to patients of a Brazilian hospital. Methods: The amount of minerals was determined in two non-consecutive days in duplicate samples of breakfast, collation, lunch, snack, dinner, supper and a complementary snack meal. Dietary Reference Intakes (DRIs) were used to determine the adequacy of the daily amounts served to patients. Results and discussion: The regular diet met the RDA (Recommended Dietary Allowances) requirements only for Mn, P and Se, while the blend diet was deficient in Ca, K and Mg, and the soft diet met RDA requirements only for P and Zn. Iron was below the RDA requirement in all diets for women in fertile age, and Na was above the safe limit of intake (UL) in all the diets. The use of complementary snack was effective in meeting RDA requirements for Cu in the regular diet, and Mn and Se in the soft diet, but promoted overconsumption of Na. Conclusions: Evident nutritional imbalances have been detected at a key interphase between nutrition and public health services, but a solution does not appear to be insurmountable. A permanent nutritional evaluation of hospital oral diets should be an integral part of routine health care in order to speed the recovery of the hospitalized patient and dispel eventual risks due to critical mineral imbalances.271288297Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Functional characterisation and antimicrobial efficiency assessment of smart nanohydrogels containing natamycin incorporated into polysaccharide-based films

The potential application of polysaccharide-based films containing smart nanohydrogels for the controlled release of food preservatives is demonstrated here. Smart active packaging is the most promising alternative to traditional packaging as it provides a controlled antimicrobial effect, which allows reducing the amount of preservatives in the food bulk, releasing them only on demand. This work evaluates the usefulness of smart thermosensitive poly(N-isopropylacrylamide) (PNIPA) nanohydrogels with or without acrylic acid (AA) incorporated into polysaccharide-based films (GA) to transport natamycin and release it as a response to environmental triggers. Release kinetics in liquid medium from GA films containing PNIPA/AA nanohydrogels (GA-PNIPA(5) and GA-PNIPA-20AA(5)) presented a characteristic feature regarding the films without nanohydrogels that was the appearance of a lag time in natamycin release, able to reach values of around 35 h. Another important feature of natamycin release kinetics was the fact that the release from GA-PNIPA/AA films only occurred when temperature was increased, so that the natamycin release was restricted to when there is a risk of growth of microorganisms that cause food spoilage or the development of pathogenic microorganisms. Additionally, it could be observed that the relative fraction of natamycin released from GA-PNIPA/AA films was significantly (p<0.05) higher than that released from GA films loaded with the same amount of free natamycin. It can be hypothesised that the encapsulation of natamycin into nanohydrogels helped it to be released from GA films, creating reservoirs of natamycin into the films and, therefore, facilitating its diffusion through the film matrix when the nanohydrogel collapses. In a solid medium, the low water availability limited natamycin release from GA-PNIPA/AA films restricting the on/off release mechanism of PNIPA/AA nanohydrogels and favouring the hydrophobic interactions between natamycin and polymer chains at high temperatures. Despite the low natamycin release in solid media, antimicrobial efficiency of GA-PNIPA(5) films containing natamycin in acidified agar plates was higher than that obtained with GA films without natamycin and GA films with free natamycin, probably due to the protecting effect against degradation when natamycin was included in the nanohydrogels, allowing its release only when the temperature increased.Clara Fucinos and Miguel A. Cerqueira are recipients of a fellowship (SFRH/BPD/87910/2012 and SFRH/BPD/72753/2010, respectively) from the Fundacao para a Ciencia e Tecnologia (FCT, POPH-QREN, and FSE Portugal). The authors thank the FCT Strategic Project PEst-OE/EQB/LA0023/2013 and the project "BioInd - 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 and the project from the "Ministerio de Educacion y Ciencia" (Spain) "Nanohidrogeles inteligentes sensibles a cambios de pH y Temperatura: Diseno, sintesis y aplicacion en terapia del cancer y el envasado activo de alimentos", Ref. MAT2010-21509-C03-01

Calibration of myocardial T2 and T1 against iron concentration.

BACKGROUND: The assessment of myocardial iron using T2* cardiovascular magnetic resonance (CMR) has been validated and calibrated, and is in clinical use. However, there is very limited data assessing the relaxation parameters T1 and T2 for measurement of human myocardial iron. METHODS: Twelve hearts were examined from transfusion-dependent patients: 11 with end-stage heart failure, either following death (n=7) or cardiac transplantation (n=4), and 1 heart from a patient who died from a stroke with no cardiac iron loading. Ex-vivo R1 and R2 measurements (R1=1/T1 and R2=1/T2) at 1.5 Tesla were compared with myocardial iron concentration measured using inductively coupled plasma atomic emission spectroscopy. RESULTS: From a single myocardial slice in formalin which was repeatedly examined, a modest decrease in T2 was observed with time, from mean (± SD) 23.7 ± 0.93 ms at baseline (13 days after death and formalin fixation) to 18.5 ± 1.41 ms at day 566 (p<0.001). Raw T2 values were therefore adjusted to correct for this fall over time. Myocardial R2 was correlated with iron concentration [Fe] (R2 0.566, p<0.001), but the correlation was stronger between LnR2 and Ln[Fe] (R2 0.790, p<0.001). The relation was [Fe] = 5081•(T2)-2.22 between T2 (ms) and myocardial iron (mg/g dry weight). Analysis of T1 proved challenging with a dichotomous distribution of T1, with very short T1 (mean 72.3 ± 25.8 ms) that was independent of iron concentration in all hearts stored in formalin for greater than 12 months. In the remaining hearts stored for <10 weeks prior to scanning, LnR1 and iron concentration were correlated but with marked scatter (R2 0.517, p<0.001). A linear relationship was present between T1 and T2 in the hearts stored for a short period (R2 0.657, p<0.001). CONCLUSION: Myocardial T2 correlates well with myocardial iron concentration, which raises the possibility that T2 may provide additive information to T2* for patients with myocardial siderosis. However, ex-vivo T1 measurements are less reliable due to the severe chemical effects of formalin on T1 shortening, and therefore T1 calibration may only be practical from in-vivo human studies

Physical characterisation of an alginate/lysozyme nano-laminate coating and its evaluation on ‘coalho’ cheese shelf life

This work aimed at the characterisation of a nanolaminate coating produced by the layer-by-layer methodology and its evaluation on the preservation of ‘Coalho’ cheese. Initially, five alternate layers of alginate and lysozyme were assembled in an aminolysed/charged polyethylene terephthalate (A/C PET) and physically characterised by UV/VIS spectroscopy, contact angle, water vapour (WVTR) and oxygen (OTR) transmission rates and scanning electron microscopy. Afterwards, the same methodology was used to apply the nano-laminate coating in ‘Coalho’ cheese and its shelf life was evaluated during 20 days in terms of mass loss, pH, lipid peroxidation, titratable acidity and microbial count. UV/VIS spectroscopy and contact angle analyses confirmed the layers’ deposition and the successful assembly of nano-laminate coating on A/C PET surface. The coating presented WVTR and OTR values of 1.03×10−3 and 1.28× 10−4 g m−2 s−1, respectively. After 20 days, coated cheese showed lower values of mass loss, pH, lipidic peroxidation, microorganisms’ proliferation and higher titratable acidity in comparison with uncoated cheese. These results suggest that gas barrier and antibacterial properties of alginate/lysozyme nanocoating can be used to extend the shelf life of ‘Coalho’ cheese.The author Bartolomeu G. de S. Medeiros is recipient of a scholarship from Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES-Brazil). The author Marthyna P. Souza is recipient of a scholarship from Fundacao de Amparo a Ciencia e Tecnologia do Estado de Pernambuco (FACEPE, Brazil) and was recipient of a scholarship from Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES/PDEE-Brazil). The authors Ana C. Pinheiro, Ana I. Bourbon and Miguel A. Cerqueira are recipients of a fellowship (SFRH/BD/48120/2008, SFRH/BD/73178/2010 and SFRH/BPD/72753/2010, respectively), supported by Fundacao para a Ciencia e Tecnologia, POPH-QREN and FSE (FCT, Portugal). Maria G. Carneiro-da-Cunha express is gratitude to the Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq) for research grant. The present work was supported by CAPES/PROCAD/NF/1415/2007. The support of EU Cost Action FA0904 is gratefully acknowledged

Effects of interactions between the constituents of chitosan-edible films on their physical properties

The main objective of this work was to evaluate the effect of chitosan and plasticizer concentrations and oil presence on the physical and mechanical properties of edible films. The effect of the film constituents and their in-between interactions were studied through the evaluation of permeability, opacity and mechanical properties. The effects of the studied variables (concentrations of chitosan, plasticizer and oil) were analysed according to a 2 3 factorial design. Pareto charts were used to identify the most significant factors in the studied properties (water vapour, oxygen and carbon dioxide permeability; opacity; tensile strength; elongation at break and Young's modulus). When addressing the influence of the interactions between the films' constituents on the properties above, results show that chitosan and plasticizer concentrations are the most significant factors affecting most of the studied properties, while oil incorporation has shown to be of a great importance in the particular case of transport properties (gas permeability), essentially due to its hydrophobicity. Water vapour permeability values (ranging from 1. 62 × 10 -11 to 4. 24 × 10 -11 g m -1 s -1 Pa -1) were half of those reported for cellophane films. Also the mechanical properties (tensile strength values from 0. 43 to 13. 72 MPa and elongation-at-break values from 58. 62% to 166. 70%) were in the range of those reported for LDPE and HDPE. Based on these results, we recommend the use of 1. 5% (w/w) chitosan concentration to produce films, where the oil and plasticizer proportions will have to be adjusted in a case-by-case basis according to the use intended for the material. This work provides a useful guide to the formulation of chitosan-based film-forming solutions for food packaging applications.The author MA Cerqueira is a recipient of a fellowship from Fundacao para a Ciencia e Tecnologia (FCT, SFRH/BD/23897/2005) and BWS Souza is a recipient of a fellowship from the Coordenacao Aperfeicoamento de Pessoal de Nivel Superior, Brazil (Capes, Brazil)