CARBOXYLATED-CELLULOSE NANOCRYSTALS PRODUCED FROM LIGNOCELLULOSIC SOURCES AND USED AS BARRIER COATING FOR PET FILMS

The obtainment of Cellulose nanocrystal (CNC) from different cellulosic sources recently gained a great attention due to their physical and mechanical properties. CNC can be extracted from variety of bio-based and renewable sources, such as wood, cotton, bacterial cellulose, tunicate cellulose and softwood cellulose and used as reinforced nanocomposites, functional materials and oxygen-barrier layers. The most important factor affecting the nanocellulose production is the relative proportion of cellulose, hemicellulose, and lignin in the source material. The extraction of CNC from cellulosic materials started with a pre-treatment of biomass involving the complete or partial removal of hemicelluloses, lignin, etc. and isolation of cellulose component. After the separation of matrix materials, controlled hydrolysis of the cellulosic fibers is performed in order to produce colloidal suspensions of cellulose crystals. Using of ammonium persulfate (APS) has recently achieved the obtainment of CNC from different cellulose sources without any pre-treatment. APS, a strong oxidizing agent with high water solubility, is able to produce carboxylated CNC having high crystallinity and active carboxyl groups. The conversion of the carboxylic acid groups to the carboxylate form offers active sites for surface modification and templates for the synthesis of nanoparticles. Incorporation of carboxylated–CNC as a functional layer on different substrates have enhanced the barrier (oxygen permeability), mechanical, optical, and antifog properties of the nanocomposites. The aim of this work was to obtain the CNC from two lignocellulosic sources and to characterize them in terms of morphology, crystallinity, charge density and coating properties in order to use CNC as barrier coating for PET films

Evidence and Open Questions for the Use of Video-Feedback Interventions With Parents of Children With Neurodevelopmental Disabilities

The Video-Feedback Intervention (VFI) is a technique aimed at promoting positive parenting that has been found to be supportive of child development and parent–child interaction in different at-risk and clinical populations. The application of VFI with parents of children with neurodevelopmental disabilities (ND; e.g., cerebral palsy, sensory and/or psychomotor delay, and genetic syndromes) is growing. Nonetheless, no systematic review is currently available documenting whether this type of intervention improves children’s developmental outcomes (e.g., behavioral stability and cognitive abilities), parental caregiving skills (e.g., responsive parenting), and parental emotional well-being (e.g., depressive symptomatology). In the present mini-review, 212 VFI records were retrieved from three databases (i.e., PubMed, Scopus, and Web of Science), and 10 papers were finally included. Abstracted information included age, diagnosis, methodological aspects (timing, setting, and themes), and child/parent outcomes. Significant improvements from pre- to post-VFI were observed in all studies. Specifically, the VFIs were significantly associated with better children developmental outcomes and parental caregiving skills. Inconsistent findings emerged for the VFI effects on parental emotional well-being. Overall, the current mini-review supports the potential effectiveness of parent-focused VFI interventions for parents of children with ND, despite the presence of open questions that need to be addressed in future clinical trials

Posidonia Oceanica And Green Tea Extract As Active Agents For Shelf Life Extension Of Fresh Cut Peach

Nowadays the reduction of food waste and the availability of food all over the world areas are priority keys for society. In this context, the shelf life extension of fresh products in a sustainable way may represent one of the main goals. The aim of the present research work was to extend the shelf life of fresh cut peach slices by using extracts of Posidonia oceanica (POS) and green tea (GT), and compared to the control. Total polyphenols content was assessed by Folin-Ciocalteu method and the antioxidant capacity by DPPH (2,2-Diphenyl-1-Picrylhydrazyl) assay. Antimicrobial activity of the two extracts was initially carried out in vitro by determining the Minimal Inhibitory Concentration (MIC) against Escherichia coli, Listeria innocua, Pseudomonas putida, Staphylococcus aureus, Saccharomyces cerevisiae, Aspergillus niger and Penicillium chrysogenum. The two extracts in vivo on peach slices by dipping were applied (only water for the control), than, slices were placed into low-density polyethylene (LDPE) bag and stored at 3 ± 1°C for up to 7 days. Microbiological analyses, color (L*,a*,b*), total soluble solid (TSS) and titratable acidity (TA) on peach slices were carried out every 3 days. POS showed the highest polyphenols content (615±45 mg Gallic Acid Equivalent/g – mg GAE/g) while GT 526 ± 28 mg GAE/g. The values of EC50, for POS, was 72.42 ± 22.90 mg/L, while for GT 3.80 ± 0.11 mg/L. Trials in vitro showed MIC values of above 2 g/L for POS and above 1 g/L in GT mainly against Gram positive bacteria. POS was also found to lead a growth delay in the case of fungi, approximately 60 h compared to the control. Results related to the Total Aerobic (TAC) and yeasts and moulds (Y&M) counts highlighted that peach slices dipped with POS maintained in the first 5 days of storage the microbiota at lower or analogous levels than those found at t0 (1.80 ± 0.09 log cfu/g respect 2.30 ± 0.11 log cfu/g and 1.80 ± 0.05 log cfu/g respect 1.70 ± 0.03 log cfu/g of the control, respectively for TAC and Y&M). Regarding pomological analysis, after seven days, lightness of the peach slices decreased 28% in POS, 24% in GT and 35% in control. During shelf life TSS increased 8% in the control, 2% in POS and remained unchanged in GT, after seven days. At the same time, TA decreased 30% in POS, 20% in GT treatment and 63% in the control. During the experiment TSS increased in all treatments, more rapidly in the control; meanwhile the TA decreased slowly in treated samples compared to the control. Concluding, Posidonia oceanica and green tea extracts were found able to delay the colour and pomological parameters decay, maintaining a good fruit quality during shelf life. Data already showed evidence a better performance of the Posidonia extract, limiting the growth of microorganisms responsible for fresh fruit deterioration

INTERACTIVE POLYPHENOLS-BASED BIOPACKAGING FOR FOOD PRESERVATION: AN IN VITRO STUDY

Producing green, sustainable and renewable materials is one of the major challenge nowadays in the food-packaging sector. In this context, the aim of our study is to develop an active cellulose-based packaging, cellulose in fact is one of the most plentiful polymer on the earth. Tetrahydrocurcumin (THC), a derivative of curcuma, chosen as antioxidant and antimicrobial natural substance, was added into a cellulose matrix (1.5% w/w) and the resulting material was then studied. In addition to this active compound, the paper also contained chitosan and carboxymethylcellulose, to improve the retention of THC and the mechanical properties. Mechanical, chemical and microbiological analyses were done to completely characterize the active papers. Grammage, dry and wet strength were determined. The polyphenol content was determined by the Folin-Ciolcalteu method. Antimicrobial activity of THC, in solution and after its incorporation into the papers, was tested against Gram negative bacteria (Escherichia coli and Pseudomonas putida), Gram positive bacteria (Staphylococcus aureus and Listeria innocua) and moulds (Penicillium chrysogenum and Aspergillus niger). Antioxidant capacity was also tested through the DPPH method. THC solution presented a good antioxidant capacity: it showed an EC50 equal to 4,49 ppm ( EC50 of Trolox was 2,86 ppm). Its minimal inhibitory concentration is 0,4 g/L for Gram positive bacteria, and higher than 0,6 g/L for Gram negative. THC solution was found effective in delaying the development of moulds. THC polyphenols were quantified as 0,8% on paper weight for the paper containing THC and these quantities together with chitosan resulted able to slow down the growth of microorganism. Pseudomonas is inhibited by the presence of chitosan and THC is able to amplify the antimicrobial activity of chitosan, by inhibiting also the growth of Staphylococcus and E. Coli. The presence of THC does neither affect the mechanical properties of papers, nor the color and the odor. Based on these results, it is possible to conclude that THC exhibits good antioxidant and moderate antimicrobial properties. Paper sheets didn’t lose their mechanical properties. These data will pave the way to the use of THC for the production of an active paper-based packaging to improve the shelf life of food items

An alternative encapsulation approach for production of active chitosan-propolis beads

Encapsulation is a promising technology to carry natural active substances, preventing their loss and maintaining their stability until use. Beads of chitosan-containing propolis have been prepared using a mono-pore filter device, which permits the encapsulation of natural polyphenols avoiding heat treatments, high shear rates and the use of toxic solvents. Beads proved to be active against Bacillis cereus, Escherichia coli, Listeria innocua, Pseudomonas fluorescens, Yarrovia lipolytica and three moulds strains; the highest effect was found against Staphylococcus aureus (MIC 0.8 mg beads mL-1). Results in liquid cultures of S. aureus evidenced that beads were able to release the flavonoids from propolis: the diffusion of the active compounds is a key factor in the exploitation of the microbial activity. The obtained chitosan-propolis beads represent an example of natural antimicrobial delivery system that could be used to prevent the growth of pathogenic/spoilage bacteria in food applications

Tuning Polyamidoamine Design to Increase Uptake and Efficacy of Ruthenium Complexes for Photodynamic Therapy

Nanomedicine holds great promises to change the way drugs are delivered to their target, owing to the use of nano-sized drug carriers capable to enter cells and be trafficked intracellularly via energy dependent pathways [1, 2]. This is very different from the way most drugs arrive to their target, often based simply on their solubility and partition coefficients in lipids and water. Despite some valuable successes, drug delivery remains rather challenging and several factors are still limiting its potential. Among such factors, it has emerged, for instance, that most nano-sized carriers entering cells via endocytosis are later trafficked along the endolysosomal pathway to the lysosomes, where the low pH and abundant proteases can degrade and destroy the internalised cargo. Strategies to escape the endosomes and lysosomes are being investigated. Among the many polymer species employed as drug delivery vectors, linear polyamidoamines (PAAs) are very interesting and promising materials. In this communication it will be presented a new polycationic PAA endowed with a luminescent Ru complex (Ru-PhenAN) and its ability to target the cell nucleus. It shows unique trafficking to the cell nucleus of all the treated cells, also at polymer doses as low as cytotoxicity is very low. Also, it will be shown the efficacy of Ru-PhenAN as photosensitizers for photodynamic therapy (PDT), a treatment of pathological conditions based on the photo-activation of a bioactive compound, which is not harmful in the absence of light irradiation [3]

Evaluation of the antioxidant/antimicrobial performance of Posidonia oceanica in comparison with three commercial natural extracts and as a treatment on fresh-cut peaches (Prunus persica Batsch)

This research aimed at extending the choice of natural antimicrobials/antioxidants for food applications. Four plant extracts, Posidonia oceanica (PO), Green Tea (GT), Grape seeds (GS) and Grape skin (GK), were analyzed to determine their total phenolic content, antioxidant activity and in vitro antimicrobial performance. PO extract showed the highest total phenolic content (711 mg gallic acid/g extract) and antifungal activity against Aspergillus niger and Penicillium chrysogenum. The highest antioxidant (3.81 mg/L EC50) and antibacterial activities (bactericidal against Gram positives and bacteriostatic against Gram negatives) were found for GT extract. The best performing extracts (PO and GT) were applied by dipping on peach slices in storage trials. Microbiological and pomological parameters were evaluated during 7 d storage. Total aerobic count, Pseudomonas as well as yeasts and moulds populations, were reduced by about 0.5 log cfu/g, mainly up to 5 d in all treated samples compared to the control. Total soluble solids, titratable acidity and colour (L*a*b*) changes were also delayed in treated fruit

Study of cellulose-lysozyme interactions aimed to a controlled release system for bioactives

The potential use of cellulose based materials for active food packaging applications was explored. For this purpose, the sorption of lysozyme in a cellulose based paper pulp was optimized using the experimental design methodology. A Face-Centered Composite design was applied to investigate the effect of short/long fibers ratio and carboxymethyl cellulose concentration on linking lysozyme to the fibers surface and to optimize the cellulosic matrix composition. The related polynomial model showed good fitting ability (R2[0.9) as well as good prediction ability (Q2[0.8). The best combination of factors was 50 % short fibers, 50 % long fibers and at least 4 % carboxymethyl cellulose. Afterwards the lysozyme release was investigated using a mathematical model based on Fick\u2019s second law. It was able to describe the release kinetics of lysozyme from the paper sheets made with the optimized cellulosic matrix into water at different temperatures (between 4 and 23 C), pH (from 4 to 7) and NaCl concentrations (from 0.2 to 2 M). The apparent diffusion coefficients for the lysozyme were in the range of 3.1 X 10-16 6.6x10-14 and the Ea value was 22.1 kJ/mol at pH 5 and NaCl concentration of 0.5 M

Estudio cinético de la degradación del color en pulpa de frambuesa durante el procesamiento térmico

Las frambuesas poseen pigmentos antociánicos que les otorgan un color característico intenso, que va del rosado al rojo, el cual es una de las principales características organolépticas que presenta dicho fruto y que define la calidad y aceptabilidad de los mismos. Las antocianinas, además de ser responsables del color, le confieren propiedades nutricionales debido a su capacidad antioxidante. El procesamiento de las frambuesas para la obtención de pulpas y la posterior aplicación de un tratamiento térmico para asegurar su inocuidad, resulta en una de las alternativas que permiten generar un producto seguro, de mayor estabilidad y valor agregado. Sin embargo, durante el procesamiento térmico de la pulpa de frambuesa, las antocianinas se ven afectadas por el calor, y consecuentemente también su color. El objetivo del presente trabajo radica en evaluar la estabilidad térmica de pigmentos antociánicos presentes en pulpas mediante la medición de color y obtener modelos cinéticos que describan su variación con la temperatura y el tiempo de proceso. Para ello, se utilizaron frutos de frambuesa provistos por la empresa Yuco Frutos de Villa María, los cuales fueron procesados para obtener pulpa. Posteriormente, muestras de 3 mL de pulpa fueron dispuestas en tubos de ensayo y sometidas a calentamiento en baño termostatizado a diferentes temperaturas (70, 80, 90 y 100ºC) y tiempos (5, 10, 20, 30, 60, 90 y 180 minutos). Las medidas de color de las muestras se realizaron con un colorímetro (Minolta, Modelo CR-400, Japón) con el que se obtuvieron los parámetros L*, a* y b*, y a partir de los cuales se calculó el Índice de Pardeamiento (BI), el Croma (C*) y la Diferencia de Color Total (ΔE). La pulpa de frambuesa inicialmente presentó valores de L* (35,51±0,35), a* (34,06±0,67), b* (13,92±0,60) que corresponden a un color rojizo. Los estudios cinéticos indicaron que L* (luminosidad) no varía de manera significativa con el tiempo de calentamiento para las diferentes temperaturas analizadas. Por su parte, se observó una disminución de a* y b* con el tiempo, siendo dichas reducciones más pronunciadas a mayores temperaturas. Finalmente, luego de evaluar diferentes modelos matemáticos para describir la variación de BI, C* y ∆E con el tiempo, se obtuvo que el modelo de conversión fraccional de primer orden es el que mejor representa el comportamiento de estos parámetros de color con el tiempo (R2˃0,96). Las cinéticas obtenidas podrían resultar de interés en la industria de alimentos para diseñar y optimizar tratamientos térmicos de pulpa de frambuesa, minimizando las pérdidas de color.Centro de Investigación y Desarrollo en Criotecnología de Alimento