3D-printed functional cookies fortified with A. platensis: evaluation of its antioxidant potential and physicalchemical characterisation

info:eu-repo/semantics/publishedVersio

3D printed functional cookies fortified with Arthrospira platensis: Evaluation of its antioxidant potential and physical-chemical characterization

In the last few decades, consumers' growing attention to the close relationship between health and nutrition is emerging as a new trend, mostly regarding the incorporation of natural ingredients into food. Among those ingredients, microalgae are considered as innovative and promising compounds, rich in valuable nutrients and bioactive molecules. In the present work, 3D printed cookies were fortified with the microalga Arthrospira platensis aiming at developing a new functional food with antioxidant properties. A. platensis antioxidants were recovered using ultrasound-assisted extraction in hydroalcoholic solutions. Ethanol/water and biomass/solvent ratios were optimised through a Design of Experiments (DOE) approach, using the antioxidant activity (ORAC and ABTS) and total phenolic content (TPC) as response variables. The highest ORAC, ABTS and TPC values were observed in the extract obtained with 0% ethanol and 2.0% biomass; thus, this extract was chosen to be incorporated into a printable cookie dough. Three different incorporation approaches were followed: (1) dried biomass, (2) freeze-dried antioxidant extract and (3) antioxidant extract encapsulated into alginate microbeads to enhance the stability to heat, light, and oxygen during baking and further storage. All dough formulations presented shape fidelity with the 3D model. The cookies had aw values low enough to be microbiologically stable, and the texture remained constant after 30 days of storage. Moreover, the extract encapsulation promoted an improvement in the ORAC value and colour stability when compared to all other formulations, revealing the potential of A. platensis for the development of a functional 3D food-ink.This work was funded by the European Union INTERREG Atlantic Area Programme and the European Regional Development Fund (ERDF) through the project “Enhance Microalgae: High added-value industrial opportunities for microalgae in the Atlantic Area” (Ref. EAPA_338/2016).info:eu-repo/semantics/publishedVersio

How additive manufacturing can boost the bioactivity of baked functional foods

The antioxidant activity of baked foods is of utmost interest when envisioning enhancing their health benefits. Incorporating functional ingredients is challenging since their bioactivity naturally declines during baking. In this study, 3D food printing and design of experiments are employed to clarify how the antioxidant activity of cookies enriched with encapsulated polyphenols can be maximized. A synergistic effect between encapsulation, time, temperature, number of layers, and infill of the printed cookies was observed on the moisture and antioxidant activity. Four-layer cookies with 30% infill provided the highest bioactivity and phenolic content if baked for 10 min and at 180 °C. The bioacitivity and total phenolic content improved by 115% and 173%, respectively, comparing to free extract cookies.Moreover, the proper combination of the design and baking variables allowed to vary the bioactivity of cooked cookies (moisture 35%) between 300 and 700 ?molTR/gdry. The additive manufacture of foods with interconnected pores could accelerate baking and browning, or reduce thermal degradation. This represents a potential approach to enhance the functional and healthy properties of cookies or other thermal treated bioactive food products.The research leading to these results has received funding from FODIAC – Food for Diabetes and Cognition, funded by European Union, under the call Marie Skłodowsk-Curie Research and Innovation Staff Exchange (Ref. H2020-MSCA-RISE-778388); PhD grantship from Fondazione di Piacenza e Vigevano (Doctoral School on the Agro-Food System, Università Cattolica del Sacro Cuore); Fondazione Cariplo through the project ReMarcForFood – Biotechnological strategies for the conversion of Winemaking by-products and their recycling into the food chain: development of new concepts of use, 2016-0740 grant.info:eu-repo/semantics/publishedVersio

Zn-Fe flower-like nanoparticles growth by gas condensation

Bimetallic nanoparticles have gained attention in the last decade due to their unusual characteristics compared to monometallic counterparts. However, production of such particles with controlled morphologies and composition need to be explored and the mechanisms understood. In this work, we demonstrate a fast and simple process to obtain flower-like Zn-Fe (Zinc-Iron) nanoparticles (NPs) using a hybrid system based on the combination of conventional magnetron sputtering and a cluster beam source. The morphology and structure were characterized by Scanning transmission electron microscopy (STEM), while the chemical composition was evaluated by simultaneous acquisition of Energy-dispersive X-ray spectroscopy (EDS) and Electron energy loss spectroscopy (EELS). Besides, molecular dynamic simulations were used to model the nanoparticle collisions during the simultaneous production, revealing the formation mechanisms of the flower-like nanoparticles.The authors thank the financial support by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UIDB/04650/2020 and by project NANOXYPACK cofinanced via FEDER (PT2020) POCI-01-0145-FEDER-030789.info:eu-repo/semantics/publishedVersio

Cellulose nanocrystals from grape pomace: production, properties and cytotoxicity assessment

Cellulose nanocrystals (CNCs) were obtained from grape pomace through chemical and physical pretreatments. Bleached cellulose pulp was subjected to acid hydrolysis (AH) for 30 or 60min and an ultrasound treatment to obtain CNCs (AH30Sand AH60S). Compositional analyses of untreated (UGP) and pretreated (PGP) grape pomace showed the effectiveness of pretreatment in removing non-cellulosic components, recovering 80.1% cellulose in PGP (compared to 19.3% of UGP). Scanning and transmission electron microscopies were used to evaluate the CNCs morphology. AH in combination with ultrasound treatment led to needle-shaped structures and apparently more dispersed suspensions. Crystallinity index and thermal stability were studied by X-ray diffraction and thermogravimetric analysis, respectively. The AH60S sample presented high aspect ratio, crystallinity and thermal stability. CNCs toxicity was evaluated by exposing Caco-2 cells to CNCs suspension and evaluating their viability. Results showed that CNCs are non-toxic, opening the opportunity for their use on food and pharmaceutical applications.This study was supported by the Coordenacão de Aperfeiçoamento Pessoal de Ensino Superior (CAPES), Embrapa Agroindústria de Alimentos (EMBRAPA), FP7-PEOPLE-2013-IRSES-611493 (BiValBi – Biotechnologies to Valorise the regional food Biodiversity in Latin America) and Portuguese Foundation forScience andTechnology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit and COMPETE 2020 (POCI-01-0145-FEDER-006684) 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. The work was also supported by the Norte Regional Operational Program 2014–2020 (Norte2020) through the European Regional Development Fund (ERDF) Nanotechnology based functional solutions (NORTE-01-0145-FEDER-000019). Michele Michelin is a recipient of a FCT fellowship (SFRH/BPD/100786/2014). The authors thank Paula Pereira for the technical support.info:eu-repo/semantics/publishedVersio

Neutralization Serotyping of BK Polyomavirus Infection in Kidney Transplant Recipients

Abstract BK polyomavirus (BKV or BKPyV) associated nephropathy affects up to 10% of kidney transplant recipients (KTRs). BKV isolates are categorized into four genotypes. It is currently unclear whether the four genotypes are also serotypes. To address this issue, we developed high-throughput serological assays based on antibody-mediated neutralization of BKV genotype I and IV reporter vectors (pseudoviruses). Neutralization-based testing of sera from mice immunized with BKV-I or BKV-IV virus-like particles (VLPs) or sera from naturally infected human subjects revealed that BKV-I specific serum antibodies are poorly neutralizing against BKV-IV and vice versa. The fact that BKV-I and BKV-IV are distinct serotypes was less evident in traditional VLP-based ELISAs. BKV-I and BKV-IV neutralization assays were used to examine BKV type-specific neutralizing antibody responses in KTRs at various time points after transplantation. At study entry, sera from 5% and 49% of KTRs showed no detectable neutralizing activity for BKV-I or BKV-IV neutralization, respectively. By one year after transplantation, all KTRs were neutralization seropositive for BKV-I, and 43% of the initially BKV-IV seronegative subjects showed evidence of acute seroconversion for BKV-IV neutralization. The results suggest a model in which BKV-IV-specific seroconversion reflects a de novo BKV-IV infection in KTRs who initially lack protective antibody responses capable of neutralizing genotype IV BKVs. If this model is correct, it suggests that pre-vaccinating prospective KTRs with a multivalent VLP-based vaccine against all BKV serotypes, or administration of BKV-neutralizing antibodies, might offer protection against graft loss or dysfunction due to BKV associated nephropathy

Use of metallic and bimetallic nanoparticles as constituents of active bio-based films

The use of bio-based packaging materials containing metallic and bimetallic nanoparticles is relatively modern technology. In this sense, the food packaging industry has been investigating biological and renewable resources that can replace petroleum-based materials to reduce the environmental impact and at the same time, include new functionalities using nanotechnology. Therefore, the main objective of this work was to develop bio-based poly-lactic acid (PLA) films with Zinc (Zn) and Zinc-Iron (Zn-Fe) nanoparticles (NPs), deposited by magnetron sputtering, and evaluate their effect on the structural and functional properties of the films when the NPs are oxidized to be exposed at 60 % and 96 % relative humidity (RH). The morphology and elemental analysis of the samples were determined by scanning (transmission) electron microscopy (SEM and STEM), and Inductively Coupled Plasma (ICP). The structure of the PLA was monitored before and after NPs oxidation by Fourier transform infrared spectroscopy (FTIR) analysis, and the antimicrobial and color assays were performed by using the zone of inhibition (ZOI) test and a Minolta colorimeter, respectively. Finally, the films were correlated in terms of the deposit conditions, Zn or Zn-Fe concentrations, and thickness. The results revealed PLA films with different morphologies, compositions, and sizes of Zn or Zn-Fe NPs. The samples showed a significant antibacterial and antifungal activity against E. coli, P. aeruginosa, P. fluorescens, S. aureus, and A. niger, and changes of color and opacity for the samples with the smaller thickness when stored at 95 % relative humidity. On the other hand, when the Fe in the films increases, the luminosity of the films decreased as well as their antibacterial activity when compared to the films with pure Zn. Hence, these findings are relevant to the food packaging field since intelligent and active films with multiple properties can be developed.info:eu-repo/semantics/publishedVersio

Novel active biopolymer materials for the food packaging

The presence of residual oxygen inside food packaging can significantly affect the organoleptic properties of food and increase microorganism proliferation, decreasing the shelf-life of the products. In this context, the food packaging industry has been investigating new bio-based environmentally friendly multifunctional materials that act as oxygen scavengers and antimicrobial agents. Therefore, in the present work, a new generation of bio-based active films and fibres containing metallic (Zn) and bimetallic (Zn and Fe) nanoparticles (NPs) is developed. Zinc (Zn) and iron (Fe) nanoparticles (NPs) can enhance oxygen absorption capacity, while the oxidized form of Zn, the ZnO, has relevant antimicrobial properties. The NPs were deposited on poly-lactic acid (PLA) films and PLA fibres (produced by electrospinning) by magnetron sputtering, resulting in two different architectures with dissimilar Fe NPs percentages (0, 10 and 20%). The effect of NPs on the structural and functional properties of the produced materials was evaluated at 60 % and 96 % relative humidity. The morphology and metallic composition of the samples were determined by scanning electron microscopy (SEM), and Inductively Coupled Plasma (ICP), respectively. The oxygen scavenging capacity was measured using a Piccolo sensor connected to sealed vials containing 5% oxygen. Finally, the antimicrobial assay was performed through the zone of inhibition (ZOI) test, and the Zn NPs migration was evaluated using different food simulants. The results showed all PLA films and fibres developed have significant oxygen scavenging capacity, achieving the highest decrease of oxygen with the PLA film containing Zn/Fe-10%. All the samples presented promising antimicrobial activity against E. coli and S. aureus. On the other hand, the migration tests revealed that PLA films and fibres containing Fe showed the lowest migration values when 95% ethanol was used as the food simulant, independently of the Fe percentage. Thus, the developing biopolymers prove to be active materials with multiple properties that could be used in the food packaging industry.info:eu-repo/semantics/publishedVersio

Active flexible films for food packaging: a review

Active food packaging is a dynamic area where the scientific community and industry have been trying to find new strategies to produce innovative packaging that is economically viable and compatible with conventional production processes. The materials used to develop active packaging can be organized into scavenging and emitting materials, and based on organic and inorganic materials. However, the incorporation of these materials in polymer-based flexible packaging is not always straightforward. The challenges to be faced are mainly related to active agents’ sensitivity to high temperatures or difficulties in dispersing them in the high viscosity polymer matrix. This review provides an overview of methodologies and processes used in the production of active packaging, particularly for the production of active flexible films at the industrial level. The direct incorporation of active agents in polymer films is presented, focusing on the processing conditions and their effect on the active agent, and final application of the packaging material. Moreover, the incorporation of active agents by coating technologies and supercritical impregnation are presented. Finally, the use of carriers to help the incorporation of active agents and several methodologies is discussed. This review aims to guide academic and industrial researchers in the development of active flexible packaging, namely in the selection of the materials, methodologies, and process conditions.Financed by European Regional Development Fund (ERDF), through the Incentive System to Research and Technological development, within the Portugal2020 Competitiveness and Internationalization Operational Program. IPC researchers acknowledge also funding by National Funds through FCT-Portuguese Foundation for Science and Technology, References UIDB/05256/2020 and UIDP/05256/2020

Sorting live stem cells based on Sox2 mRNA expression.

PMCID: PMC3507951This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.While cell sorting usually relies on cell-surface protein markers, molecular beacons (MBs) offer the potential to sort cells based on the presence of any expressed mRNA and in principle could be extremely useful to sort rare cell populations from primary isolates. We show here how stem cells can be purified from mixed cell populations by sorting based on MBs. Specifically, we designed molecular beacons targeting Sox2, a well-known stem cell marker for murine embryonic (mES) and neural stem cells (NSC). One of our designed molecular beacons displayed an increase in fluorescence compared to a nonspecific molecular beacon both in vitro and in vivo when tested in mES and NSCs. We sorted Sox2-MB(+)SSEA1(+) cells from a mixed population of 4-day retinoic acid-treated mES cells and effectively isolated live undifferentiated stem cells. Additionally, Sox2-MB(+) cells isolated from primary mouse brains were sorted and generated neurospheres with higher efficiency than Sox2-MB(-) cells. These results demonstrate the utility of MBs for stem cell sorting in an mRNA-specific manner