Chitosan Tailor-Made Films: The Effects of Additives on Barrier and Mechanical Properties

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)With the aim of achieving 'tailor-made' chitosan films, the effects of several variables on the properties of chitosan films were studied. These variables were chitosan concentration and molecular weight of thermally depolymerized chitosan, addition of lipids (palmitic acid, beeswax or carnauba wax) and plasticizer (glycerol). The water vapour transmission rate (WVTR) and mechanical properties of these films were measured. The innovative feature of this study is that it provides specific information to support the design of tailor-made films. These can only be formulated when the effects of the important variables are well understood. It was found that WVTR was reduced by 57% in film made from chitosan that had been thermally treated for 7 h at 100 degrees C (molecular mass 13.7 kDa), while in the emulsion films, the WVTR was increased by incorporation of palmitic acid, beeswax or carnauba wax incorporation. The mechanical properties (tensile strength and elongation at break) were improved when glycerol was used as plasticizer, resulting in more elastic films (increasing the elongation at break by 62%). Copyright (C) 2008 John Wiley & Sons, Ltd.223161170Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)ALFAProgramme [II-0259-FA-FDC]Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)ALFAProgramme [II-0259-FA-FDC

Agronomic cultivation, chemical composition, functional activities and applications of Pereskia species – A mini review

The exploration of the plant biodiversity as a natural source to obtain sustainable food products and new bioactive pharmaceutical compounds has been growing significantly due to their abundance, safety and economy. Natural pharmaceutical and edible compounds present some advantages when compared to synthetic ones, such as being chemically inert and widely available. In this sense, plants of the genus Pereskia belonging to the Cactaceae family, have been studied. It is an unconventional wild edible plant that contains a large amount of protein and minerals. Studies have demonstrated their biological activities and potential application in different areas such as pharmaceutical, medicinal and food. Objective: This review is focused on the chemical composition, functional properties, applications on pharmaceutical, nutraceutical and food areas and formulation techniques to enhance the stability and bioavailability of bioactive compounds from the underutilized wild edible plant known as ora-pro-nobis (Pereskia aculeata or Pereskia grandifolia). Conclusion: The latest studies involving ora-pro-nobis demonstrated its great potential due to its biological activities, which could stimulate further investigations. The utilization of this plant as a natural source to supplement the diet, or to prepare new food products and pharmaceutical formulations is an attractive approach to explore and fully realize the potential of the rich biodiversity found in Brazil and in other countries

Moisture adsorption by milk whey protein films

Edible films, using whey protein as the structural matrix, were tested for water vapour diffusion properties. Whey protein films were prepared by dispersing 6.5% whey protein concentrate (WPC) in distilled water with pH kept at 7.0. Glycerol was the plasticizer agent. Film slabs (13.5 x 3.5 cm) were put in a chamber at 25degreesC and 75% relative humidity, being held in vertical planes for different periods of time. The mass gain was determined throughout the experiment. We show that moisture adsorption by milk whey protein films is well described by a linear diffusion equation model. After an adsorption experiment was performed the solution of the diffusion equation was fitted to the data to determine the diffusion coefficient of the material.37332933

Modeling of potassium sorbate diffusion through chitosan films

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)The mechanism of potassium sorbate (K-sorbate) release from chitosan films was studied as a function of immersion time in aqueous solution. Fick's law was applied to calculate the diffusion coefficient and the power law defining the type of diffusion mechanism. The novelty in this study is the compound diffusion mechanisms comparison through chitosan film (CF) and chitosan emulsion film Initially, the lipid was selected to obtain the emulsion films The evaluation was based oil the water vapor permeability (WVP) The lower WVP (32.45% less than chitosan film) Was found using 0 5 g/100 g of palmitic acid for 2.0 g/100 g of chitosan Then, active chitosan films (ACF) were obtained incorporating K-sorbate on CF at 0 1 and 0 5 g/100 g of K-sorbate Also, active palmitic acid-chitosan films (APEF) were obtained, incorporating 0 1 g/100 g of K-sorbate The mechanisms of K-sorbate diffusion through ACF and APEF were mainly non-Fickian. However, the K-sorbate diffusion coefficient did not reduced in lipid presence (C) 2009 Elsevier Ltd All rights reserved.434584589Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)ALFA [II-0259-FA-FDC]Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)ALFA [II-0259-FA-FDC

Application of chitosan emulsion as a coating on Kraft paper

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Kraft paper was coated with chitosan emulsion film. The novelty of this paper is the formation of a packaging bilayer system in only one drying step, which combines a biodegradable polymer emulsion (chitosan and palmitic acid) with Kraft paper. This system is described in detail and characterized for barrier properties (water vapor permeability rate (WVPR), air permeability and water absorption capacity (Cobb test)), mechanical properties (tensile properties, Taber stiffness and tear strength) and structural properties. The application of chitosan coating (3.5 gm(-2), wet basis) on Kraft paper sheets provides a significantly lower WVPR (by ca 43%) and water absorption capacity (by ca 35%) as compared to uncoated Kraft paper. The incorporation of palmitic acid into the chitosan film solutions at 1.8 gm(-2) improves the properties of Kraft paper even more by further reducing the WVPR and water absorption capacity by 51 and 41%, respectively. The air resistance of the coated Kraft systems is lower by 8- and 11-fold compared to uncoated Kraft paper, which could be associated with the chitosan film acting as a gas barrier and as a coating agent that fills the pores between cellulose fibers. (C) 2011 Society of Chemical Industry606SI963969Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Alpha POLYLIFEFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

An analysis of water vapour diffusion in whey protein films

The macroscopic aspects of moisture transmission in whey protein films were determined by measuring water vapour adsorption. A theoretical model was constructed in which two kinds of water vapour fluxes were considered: one originating from diffusion, whilst the other was a flux due to the gravitation drift of moisture. The comparison of theoretical and experimental results showed that only the diffusion process was present.38559560

Water vapour permeability of whey protein emulsion films

A water vapour adsorption experiment was carried out using whey protein films containing a small fraction of fatty acid. This experiment was performed in 3 different configurations. Some film samples were held in a vertical plane, and the other samples were laid on a horizontal plane. Half of these were placed with the external face upward and the other half with the external face downwards. The mass of water adsorbed was weighed for different periods of time until stationary state was reached. Finally, a linear diffusion equation model was used to fit the experimental data and determine the diffusion coefficient for each vertical and horizontal configuration.5941671485

Surface evaluation of whey protein films by atomic force microscopy and water vapour permeability analysis

The atomic force microscopy (AFM) technique is a powerful tool for studying surfaces and has been used to provide qualitative and quantitative information about nanometer-scale matter properties that are often inaccessible by any other experimental technique. In this work AFM was used to evaluate the surfaces of edible films produced with whey protein concentrate (WPC). The morphology and the roughness of the films were analysed. The effects of WPC and plasticizer concentration were characterized in terms of water vapour permeability (WVP) and roughness parameters. Roughness was calculated through the images captured with AFM. AFM can be useful to identify structural changes of the film resulting from sample preparation. The results showed a relation between water vapour permeability and area roughness, through different sample preparation. The analyses of topography through roughness obtained with AFM, demonstrated the correlation between the morphology of the film, obtained with nanometer resolution and WIT. Copyright (C) 2004 John Wiley Sons, Ltd.17526727

Iron-rich chitosan-pectin colloidal microparticles laden with ora-pro-nobis (Pereskia aculeata Miller) extract

Iron deficiency represents a global nutrition gap that calls for innovative strategies including food fortification, while overcoming the drawbacks of taste and reactivity of iron. The aim of this work was to develop iron-rich colloidal microparticles laden with a Brazilian plant food extract from ora-pro-nobis (OPN, Pereskia aculeata Miller). We formulated electrostatic self-assembled complexes of oppositely charged chitosans and pectin laden with aqueous OPN extract. After characterisation of the physical properties, selected formulations were examined in their colloidal stability (50 mM NaCl, Dulbecco's modified eagle medium (DMEM), simulated gastric fluid (SGF) and simulated intestinal fluid (SIF)), production yield, iron association efficiency, transmission electron microscopy (TEM), cellular cytotoxicity and iron uptake using Caco-2 cells. The ζ-potential varied from ~ −25 mV to ~ +23 mV regardless of the degree of acetylation (DA) of chitosan. The production yield ranged between 20 and 26%. The particles were stable at DMEM, SGF and SIF during 3 h. Iron association efficiency was ~60% for systems charge ratio (n+/n–) = 5.00. TEM analyses revealed invariably spherical morphology. OPN-laden microparticles did not present cytotoxicity against Caco-2 cells. Higher cellular ferritin levels were determined for the particles comprising OPN extract and n+/n– = 5.00. We obtained in vitro proof of concept of the efficiency of chitosan/pectin particles to delivering iron from a Brazilian edible plant extract. The industrial potential of this approach as a viable alternative for iron fortification or supplementation by the food industry is yet to be realised