Development and characterization of a nanomultilayer coating of pectin and chitosan : evaluation of its gas barrier properties and application on 'Tommy Atkins' mangoes

A nanomultilayer coating made of food-grade, bio-based materials (consisting of five nanolayers of pectin and chitosan) was produced. This coating was firstly characterized in terms of the water vapor, oxygen and carbon dioxide permeabilities; these parameters exhibited values of 0.019 ± 0.005 × 10−11, 0.069 ± 0.066 × 10−14 and 44.8 ± 32 × 10−14 g m/(Pa s m2), respectively, and are of the same order of magnitude of those found in other nanomultilayer systems. The nanomultilayer system was applied on whole ‘Tommy Atkins’ mangoes and the layers’ adsorption was confirmed by changes in the contact angle of the coated fruits’ skin. After 45 d of storage, uncoated mangoes presented a higher mass loss, higher total soluble solids and lower titratable acidity in comparison with coated mangoes. Uncoated mangoes had also a damaged and wrinkled appearance, showing evidence of microbial spoilage, and the flesh exhibited a slightly brownish color, in comparison with the coated mangoes. These results suggest a positive effect of the coating on gas flow reduction and on the consequent extension of the shelf-life of mangoes.The author Bartolomeu G.S. Medeiros was recipient of a scholarship from de Project Isac (Isac Mundus Cooperation, European Union) and is also a recipient of a scholarship from Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (Capes, Brazil). The author Ana C. Pinheiro is recipient of a fellowship (SFRH/BD/48120/2008) from the Fundacao para a Ciencia e Tecnologia (FCT, Portugal). The present work was supported by CAPES/PROCAD/NF/1415/2007

Polysaccharide/protein nanomultilayer coatings: construction, characterization and evaluation of their effect on 'Rocha' pear (Pyrus communis L.) shelf-life

Nanolayered coatings of κ-carrageenan, a polysaccharide with good gas barrier properties, and lysozyme, a protein with antimicrobial action, were in a first stage assembled on aminolysed/charged polyethylene terephthalate (PET) pieces, which acted as a support, by alternate five-layer deposition. This was performed to allow the characterization of the nanomultilayer system. PET aminolysis was confirmed by Fourier transform infrared spectroscopy and contact angle, and the subsequent layer adsorption on aminolysed PET surface was confirmed by absorbance, contact angle and SEM images. The water vapour permeability and the oxygen permeability (O2P) of the five layers were found to be 0.013 ± 0.003 × 10−11 and 0.1 ± 0.01 × 10−14 g m−1 s−1 Pa−1, respectively. The nanomultilayer system was subsequently applied (without PET support) directly on ‘Rocha’ (Pyrus communis L.) fresh-cut pears and whole pears. Uncoated fresh-cut pears and whole pears presented higher mass loss, higher total soluble solids (TSS) and lower titratable acidity when compared with coated fresh-cut pears and whole pears. Uncoated fresh-cut pears also presented a darker colour. These results showed that the nanolayered coating assembled on the fruits’ surface has a positive effect on fruit quality and contributed to extend the shelf-life.Author Bartolomeu G. de S. Medeiros was a recipient of a scholarship from the project Isac (Isac Mundus Cooperation, European Union) and is also a recipient of a scholarship from Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (Capes, Brazil). Author A. C. Pinheiro is recipient of a fellowship (SFRH/BD/48120/2008) from the Fundacao para a Ciencia e Tecnologia (FCT, Portugal)

Development and characterization of hydrogels based on natural polysaccharides : policaju and chitosan

The development of hydrogels based on natural polysaccharides was investigated by preparing mixtures of policaju/chitosan at weight ratios of 1:4 and 2:3. Utilizing dynamic light scattering (DLS) techniques for these mixtures, an increase on the hydrodynamic particle radius was observed varying their pH from 3.0 to 12.0. Furthermore, a reduction of ζ-potential was also observed for the same pH interval. Following rounds of drying/hydration cycles at a specific pH value, hydrogel matrices were formed. The pore size distribution of these formed hydrogels was examined using scanning electron microscopy. Further FT-IR analyses confirmed a physical interaction between the polysaccharides policaju and chitosan. Swelling experiments revealed water uptake values, after 24h of immersion in water, close to 270% for 1:4, and 320% for 2:3 hydrogels. Finally, rheological measurements were then conducted in order to confirm hydrogel viscoelastic features. These results indicate a promising road to biomaterials fabrication and biomedical applications. Copyright © 2014 Elsevier B.V. All rights reserved.Paulo A.G. Soares is a recipient of a scholarship from Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES) and the author Ana I. Bourbon is a recipient of a fellowship from the Fundacao para a Ciencia e Tecnologia, POPH-QREN and FSE (FCT, Portugal) through grant SFRH/BD/73178/2010. Maria G. Carneiro-da-Cunha, Maria T.S. Correia, Cesar AS, Andrade and Adalberto Pessoa Jr express their gratitude to the Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq) for research grants. The authors are grateful to the Centro de Tecnologias Estrategicas do Nordeste (CETENE) of the Ministerio da Ciencia e Tecnologia for technical assistance and the Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES/PROCAD) for financial suppor

Quercetin-loaded lecithin/chitosan nanoparticles for functional food applications

This study aimed at the encapsulation of quercetin into lecithin/chitosan nanoparticles using the electrostatic self-assembly technique, followed by evaluation of their functionality (antioxidant activity) and stability at different environmental conditions. These nanoparticles were characterized in terms of: average size, morphology, zeta potential, encapsulation efficiency, loading, and spectroscopic characteristics. Quercetin has been successfully encapsulated in lecithin/chitosan nanoparticles with an efficiency of 96.13 ± 0.44 %. Nanoparticles presented a spherical morphology with an average size of 168.58 ± 20.94 nm and a zeta potential of 56.46 ± 1.94 mV. Stability studies showed that nanoparticles are stable to temperatures ranging between 5 and 70 °C and a pH variation from 3.3 to 5.0. Moreover, encapsulated quercetin showed improved antioxidant properties when compared to free-quercetin. Our results suggest that quercetin-loaded lecithin/chitosan nanoparticles can be used in the manufacture of functional foods.Author Marthyna Pessoa de Souza thanks Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES/PDEE-Brazil) and Fundacao de Amparo a Ciencia e Tecnologia do Estado de Pernambuco (FACEPE, Brazil) for granting her scholarships. Miguel A. Cerqueira is recipient of a fellowship from the Fundacao para a Ciencia e Tecnologia (SFRH/BPD/72753/2010, FCT, POPH-QREN, and FSE Portugal). This research was financially supported by research grants and fellowships from the Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq), as well as the Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES) and Fundacao de Amparo a Ciencia e Tecnologia do Estado de Pernambuco (FACEPE).The support of EU Cost Actions FA0904 and FA1001 is gratefully acknowledged

Physical properties of edible coatings and films made with a polysaccharide from Anacardium occidentale L.

The effect of the concentrations of the polysaccharide from Anacardium occidentale L. (Policaju) and a surfactant (Tween 80) on relevant properties of edible coatings/films, in view of their application on apples (cv. Golden) was evaluated. The influence of the interactions between those two constituents on apples’ surface properties and on the coating/film’s wettability, water vapor permeability, opacity and mechanical properties was evaluated. The effects of the studied variables (polysaccharide and surfactant concentrations) were analyzed according to a 2² factorial design. Pareto bar charts were used to understand the most significant factors on the studied properties. The addition of surfactant reduced the cohesion forces, therefore reducing the surface tension and increasing the wettability; this resulted in an improved compatibility between the solution and the fruit skin surface. The opacity was also reduced. The results of each of the analyzed properties were adjusted to a polynomial, multifactor model, which provided a good fitting accuracy. This model is important once it will reduce the characterization work needed in subsequent applications of these coatings/films on foods.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (Capes, Brazil)Fundação para a Ciência e a Tecnologia (FCT)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Brazi

Molecular fragmentation of wheat-germ agglutinin induced by food irradiation reduces its allergenicity in sensitised mice

WGA, an agglutinin from wheat germ which is largely responsible for many of wheat's allergies, was used as a model to investigate the action of ionising radiation on WGA's anti-nutritive effects in sensitised mice. Based on the molecular structure, the present study also examined the structural modification of WGA in relation to the range of dose. Structural integrity was monitored using HPLC, fluorescence spectrometry and circular dichroism. Results showed a loss of intrinsic activity and the formation of insoluble amorphous aggregates with a lack of native conformational structures after irradiation. Current findings suggest that the allergenic epitopes of WGA became less active and antigenic after high-dose radiation. the reduction of cytokines typical of allergic reactions, with decreased lymphocytic infiltrate, was observed in the gut of mice given irradiated versus native WGA. Food irradiation proved effective and safe in combating immunological and allergic effects of WGA. (C) 2011 Elsevier B.V. All rights reserved.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Ministerio da Ciencia e Tecnologia (Brazilian)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundacao de Amparo a Ciencia e Tecnologia do Estado de Pernambuco (FACEPE)Univ Fed Pernambuco, Dept Bioquim, Recife, PE, BrazilUniv Fed Pernambuco, Dept Histol & Embriol, Recife, PE, BrazilUniv Fed Pernambuco, Dept Biofis & Radiobiol, Recife, PE, BrazilUniv Fed Pernambuco, Dept Antibiot, Recife, PE, BrazilUniv Estadual Oeste Parana, Ctr Engn & Ciencias Exatas, Toledo, BrazilUniversidade Federal de São Paulo, Dept Bioquim, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Bioquim, São Paulo, BrazilWeb of Scienc

Xyloglucan and Concanavalin A based dressings in the topical treatment of mice wound healing process

For medical biomaterials, xyloglucan dispersions can form films or gels to be applied as a wound dressing. For this purpose, the structural characterization of xyloglucan dressing (XG) and xyloglucan dressing containing 0.5 mg/mL of concanavalin A (XGL) was performed. The lectin release capacity and stability, cytotoxicity, and pro-wound healing effects were also investigated. XG and XGL films were prepared by mixing 0.5 % (w/v) xyloglucan with 0.3 % (v/v) glycerol. The ConA incorporated in the xyloglucan dressing maintained its biological activity for fourteen days in a controlled-release manner. The films were non-toxic, homogeneous, flexible, and accelerated the wound contraction compared with the control group, promoting less infiltration of inflammatory cells, angiogenesis, remodeling, and early epithelization. The films also alleviate the inflammation phase by reducing the production of pro-inflammatory cytokines (IFN-, TNF-, IL-1, IL-6, and IL-12), especially the XGL film, which promoted the up- and down-regulation of important proteins associated with the wound repair. All these findings suggest that XG and XGL films may represent a good therapeutic approach for wound healing applications.The authors are grateful for the financial support for research grants from the Conselho Nacional de Desenvolvimento Científico e Tecnol ´ogico (CNPq), Coordenaç˜ao de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) and the Fundaç˜ao de Amparo `a Ciˆencia e Tecnologia do Estado de Pernambuco (FACEPE). We are grateful to the Centro de Tecnologias Estrat´egicas do Nordeste (CETENE) and to the Laborat´orio de Imunopatologia Keizo Asami-LIKA at the Universidade Federal de Pernambuco (UFPE) for access to its installation and technical assistance.info:eu-repo/semantics/publishedVersio

Optimized extraction of a lectin from Crataeva tapia bark using AOT in isooctane reversed micelles

Crataeva tapia bark lectin was extracted from a crude extract into a reversed micelle phase of the anionic surfactant AOT in isooctane and back-extracted, to a final aqueous phase by addition of butanol. The effects of pH, ionic strength and surfactant concentration on the protein transfer process from the aqueous to the organic phase were characterized, being the best results obtained after 5 min of contact, under agitation, between the two phases, at pH 5.5 (10 mM citrate-phosphate buffer), 30 mM NaCl, and 5 mM AOT. Recovery to a new aqueous phase was performed with 5 min of contact, under agitation, 10 mM citrate-phosphate buffer at pH 5.5, 500 mM KCl and 5% of butanol. The overall yield obtained for the process was 80% for lectin activity and 56% for protein recovery. The efficiency of the process was confirmed by SDS-PAGE analysis.ALFA/VALNATURA; CNPq