Enhancement of PLA-PVA surface adhesion in bilayer assemblies by PLA aminolisation

Data Availability: The raw/processed data required to reproduce these findings cannot be shared at this time due to legal or ethical reasons.Poly(lactic acid) (PLA) and poly(vinyl alcohol) (PVA) present complementary barrier properties, and their combination in multilayer assemblies (laminates) could provide materials with more effective barrier capacity for food packaging purposes. However, their low chemical affinity compromises adequate polymer adhesion. Surface free energy modification of thermo-processed PLA films through treatment with 1,6-hexanediamine was used to enhance adhesion with polar PVA aqueous solutions. Treatments of 1 and 3 min increased the polar component of the solid surface tension, while treatments above 10 min provoked a corrosive effect in the films structure. Extensibility analyses of PVA solutions loaded with carvacrol (15 wt.%) and different Tween 85 ratios on PLA-activated surfaces allowed the selection of the 1-min aminolysed surface for obtaining PLA-PVA bilayers, by casting PVA solutions on the PLA films. This study revealed that despite aminolisation enhancing the PLA surface affinity for aqueous PVA solutions, casting-obtained bilayers presented limited oxygen barrier effectiveness due to heterogeneous thickness of PVA layer in the laminates.The authors acknowledge the financial support provided by the Ministerio de Economia y Competitividad (MINECO) of Spain (project AGL2016-76699-R). The author A. Tampau thanks MINECO for the pre-doctoral research grant #BES-2014-068100.info:eu-repo/semantics/publishedVersio

Perspectives on utilization of edible coatings and nano-laminate coatings for extension of postharvest storage of fruits and vegetables

It is known that in developing countries, a large quantity of fruit and vegetable losses results at postharvest and processing stages due to poor or scarce storage technology and mishandling during harvest. The use of new and innovative technologies for reducing postharvest losses is a requirement that has not been fully covered. The use of edible coatings (mainly based on biopolymers) as a postharvest technique for agricultural commodities has offered biodegradable alternatives in order to solve problems (e.g., microbiological growth) during produce storage. However, biopolymer-based coatings can present some disadvantages such as: poor mechanical properties (e.g., lipids) or poor water vapor barrier properties (e.g., polysaccharides), thus requiring the development of new alternatives to solve these drawbacks. Recently, nanotechnology has emerged as a promising tool in the food processing industry, providing new insights about postharvest technologies on produce storage. Nanotechnological approaches can contribute through the design of functional packing materials with lower amounts of bioactive ingredients, better gas and mechanical properties and with reduced impact on the sensorial qualities of the fruits and vegetables. This work reviews some of the main factors involved in postharvest losses and new technologies for extension of postharvest storage of fruits and vegetables, focused on perspective uses of edible coatings and nano-laminate coatings.María L. Flores-López thanks Mexican Science and Technology Council (CONACYT, Mexico) for PhD fellowship support (CONACYT Grant Number: 215499/310847). Miguel A. Cerqueira (SFRH/BPD/72753/2010) is recipient of a fellowship from the Fundação para a Ciência e Tecnologia (FCT, POPH-QREN and FSE Portugal). The authors also thank the FCT Strategic Project of UID/ BIO/04469/2013 unit, the project RECI/BBB-EBI/0179/2012 (FCOMP-01-0124-FEDER-027462) and the project ‘‘BioInd Biotechnology and Bioengineering for improved Industrial and AgroFood processes,’’ REF. NORTE-07-0124-FEDER-000028 Co-funded by the Programa Operacional Regional do Norte (ON.2 – O Novo Norte), QREN, FEDER. Fundação Cearense de Apoio ao Desenvolvimento Científico e Tecnológico – FUNCAP, CE Brazil (CI10080-00055.01.00/13)

ENCAPSULATION OF AROMA COMPOUNDS IN BIOPOLYMERIC EMULSION BASED EDIBLE FILMS TO CONTROL FLAVOUR RELEASE

Flavour loss strongly affects food quality. In order to decrease flavour changes during food conservation, different strategies could be used. Aroma compound encapsulation allows the protection of food flavour from loss and degradative reactions, like oxidation. Edible films could be an encapsulation matrix: in the case of emulsified film, lipid globules incorporated can act as carriers of active molecules, such as aroma compounds. Edible films prepared from i-carrageenans are interesting for good mechanical and gas barrier properties. The aim of this study was to encapsulate different aroma compounds in an i-carrageenan emulsion based edible film. Release of ten aroma compounds was compared to that obtained from a lipid matrix, Grindsted Barrier System 2000 (GBS), was also used as an edible film formulation. Flavour release was followed by HS-SPME measurements. This study allowed the influence of both matrix and aroma compounds characteristics on flavour release to be investigated. This study presents new understanding of the role of emulsion based edible films as a matrix able to encapsulate aroma compounds. Carrageenans films were possible encapsulating matrixes because they showed better performances for retention of more polar aroma compounds than the usual lipid supports. Carrageenans films were able to retain volatile compounds during film-process formation, and to release gradually with time

Good practices of innovative management of internationalization

Through FORTHEM’s latest project, FIT FORTHEM, standing for Fostering Institutional Transformation of R&I Policies in European Universities, launched in 2021, the Alliance has made clear its willingness to put an even greater emphasis on the internationalization of the research of its members. In FIT FORTHEM, the seven partner organizations aim at making the FORTHEM Alliance a unique and united entity, a European University, not only with a strong higher education strategy, as developed within the Erasmus+ project, but also with a comprehensive research and innovation strategy and tight links to the socio-economic environment, with a view toward increasing competitiveness and the success rate of the Alliance and its partner universities, on the European and global scenes. Consequently, the real and very ambitious challenge is to make sure that all researchers within the FORTHEM alliance develop the awareness of being full members of a European university, at least as much as they feel part of their home university. Almost ten centuries ago the University was founded based on a sacred covenant between students and professors, which was sanctioned by political and religious authorities. It was a covenant for knowledge and research, devoid of borders

Effect of process temperature on gluten film properties

Gluten has been proposed as raw material to develop edible film formulation. Gluten based edible films are characterised by good mechanical and gas barrier properties but poor water vapour barrier properties. Process conditions influence final film structure and performances. In particular, heating treatment is supposed to improve protein reticulation. In this study, different temperatures from 30\ub0 to 85\ub0C were used to prepare film forming dispersions with the aim of studying the influence of temperature on mechanical and water vapour barrier properties of edible films. Differences in mechanical and barrier properties of films were observed only for samples prepared at 30\ub0 and 85\ub0C. Size Exclusion-HPLC was performed to study the effect of temperature dispersion on molecular properties of gluten based films. Protein size distribution seemed not to change when dispersion temperature increased, suggesting the absence of modifications in protein chains. Therefore, the different behaviours observed for film prepared at different temperature are not due to changes in gluten fraction on the basis of molecular weight. Probably, heating leads to a more homogeneous gluten network caused by the protein unfolding, to the increase in hydrophobic interactions and a better plasticizer distribution

EFFECT OF ULTRASOUND TREATMENT ON PROPERTIES OF GLUTEN-BASED FILM

Gluten films obtained in acid conditions display some protein dispersion difficulties. Ultrasound treatment (UT) could represent an interesting strategy for improving gluten film appearance. Different UT exposure times were applied to film-forming dispersion. The aim of this work was to investigate the effect of ultrasound treatment on gluten-based films at molecular and mesoscopic levels. Distribution in gliadin and glutenins was determined with SE-HPLC. The UT improved protein dispersion and final film appearance. Sonication did not lead to large changes in various gluten fractions, which suggests absence of important protein breakdown at the molecular level. Gluten showed high tolerance to UT. Surface properties of untreated and treated films were investigated by contact angle measurement: sonication promoted hydrophilic surface properties. Industrial relevance: Bio-based packaging has been receiving increasing attention in view of its beneficial impact on the environment. Among proteins, gluten resulted as a very interesting film-forming material. Gluten films prepared in acid conditions showed problems in protein dispersion. Sonication represents a physical strategy which allowed us to obtain gluten-based films without the addition of chemical additives, such as sodium sulphite