Search

This work assesses the influence of the plasticizer polyethylene glycol (PEG) on the compatibilization of poly(butylene adipate-co-terephthalate) (PBAT) and thermoplastic whey protein isolate (WPIT) blends. To prepare the blends, WPI was denatured at 90 oC, in the presence of PEG, to become a thermoplastic material. Dried WPIT was later mechanically blended with PBAT using a torque rheometer at 160 oC and 80 rpm. Two blends were prepared: 90% of PBAT/10% of WPIT (90_10) and 70% of PBAT/30% of WPIT (70_30). Scanning electron microscopy (SEM) analyses showed a homogenous blend morphology and good interaction between the dispersed phase and the matrix. Atomic force microscopy-based infrared spectroscopy (AFM-IR) showed PBAT and WPIT bands in all studied regions of both blends, which suggests that these materials presented partial miscibility. The viscosity ratio of the PBAT/WPIT system was less than 3.5 in the high shear rate region in complex viscosity curves, which indicates that droplet break-up of WPIT may occur by the drop fibrillation mechanism. The addition of WPIT reduced the degree of crystallinity of PBAT in the blends in comparison to pristine PBAT as shown by X-ray diffraction (XRD). Mechanical tests showed that blend tensile strength and elongation at break decreased with the addition of WPIT. Elastic modulus of the blends increased compared to pristine PBAT. Barrier properties were also evaluated showing that the oxygen permeability coefficient reduced by 20% for the blend with 30% of WPIT and vapor water permeability increased with the addition of WPIT.

The development of clay polymer nanocomposites has been presented as an interesting alternative for design of new active food packaging materials. In this work, low density polyethylene (LDPE) nanocomposites with cetylpyridinium bromide (CPB) – modified montmorillonite (Mt) were developed. In a first stage, Mt. was modified with different CPB proportions based on cation exchange capacity (1:1 and 2:1), resulting in two different organoclays. These modified clays were hydrophobic and presented a good thermal stability that favored their capacity for extrusion to develop LDPE nanocomposites. Based on the incorporated organoclay, nanocomposite films showed important changes in morphology, and differences in mechanical properties, crystallinity, and gas permeability in comparison to polyethylene. All nanocomposites showed greater opacity than LDPE, however, their color changes did not exceed the visual perception limit. Finally, electrical conductivity (EC) measurements showed that CPB was able to migrate from the nanocomposite films to an aqueous food simulant. This behavior was dependent on the availably of free CPB in the matrix, its disposition in the organoclay and the organoclay distribution into the polymer matrix. These results highlight the migration of the surfactant from LDPE nanocomposites with Mt./CPB organoclays, making montmorillonite a potential surfactant carrier that increases compatibility and function in polymers allowing the generation of novel materials that could be used in the design of food packaging.

An experimental spray coater was used to coat writing and printing (W&P) paper substrate with cellulose nanofibrils (CNFs) suspensions. The effects of spraying variables (i.e. concentration of suspension, spray pressure, distance and time of spray) on the coated sheets were analyzed in terms of the tensile strength, water vapor transmission rate (WVTR), and oxygen transmission rate (OTR). Basis weight and the thickness of coated layers in the different treatments were measured. In addition, image analysis of the microstructure examined the coating adhesion. The WVTR of the papers decreased, while tensile strength increased with one layer of CNF coating. The OTR was not changed with the CNF coating. The tensile strength and microstructure images of the coated papers indicate good adhesion between the CNF coating and the paper substrate when using the spray coater.

The objective of this paper was evaluate the effects of spray time, nanoclay content and corona discharge on oxygen transmission rate (OTR), water vapor transmission rate (WVTR), basis weight, thickness and tensile strength of the coated papers. An aqueous slurry base, a mixture of cellulose nanofibrils (CNF) and nanoclay particles, was sprayed on a kraft writing & printing paper surface as base substrate. Upon drying, the suspension on the paper surface formed a hybrid nanocomposite layer with CNF (matrix) and nanoclay (mineral filler). Paper substrate was coated by a laboratory-assembled spray coater. Corona discharge enhanced the wetting of paper surfaces, improving adherence between paper and hybrid composite. Increased spray time improved tensile strength and barrier properties i.e. OTR and WVTR. Higher nanoclay content in coated paper enhanced its barrier properties but reduced its tensile strength. Tensile strength and morphological properties demonstrated effective adhesion between base substrate and hybrid composite.

O periodico Brazilian Journal of Food Technology - BJFT resulta da evolucao e da abertura a autores e corpo editorial externos da revista Coletânea do ITAL, um periodico endogeno do Instituto de Tecnologia de Alimentos - ITAL, vinculado a Agencia Paulista de Tecnologia dos Agronegocios da Secretaria de Agricultura e Abastecimento do Estado de Sao Paulo, criado em 1965, o mais antigo periodico cientifico especifico da area de tecnologia de alimentos no Brasil. Durante varios anos a Coletânea do ITAL foi praticamente o unico veiculo nacional de divulgacao de trabalhos cientificos de pesquisa em tecnologia de alimentos. Durante as decadas de 60 e 70, o ITAL foi uma instituicao de pesquisa quase unica em sua area de pesquisa. Na decada de 80, gradativamente aumentou a demanda de pesquisas na area de alimentos no Brasil e, na decada de90, inumeras instituicoes de pesquisa passaram a atuar na area de tecnologia de alimentos. Concomitantemente a este crescimento, aumentou o numero de periodicos brasileiros nesta area. Na criacao do BJFT, no final da decada de 80, a revista foi aberta a contribuicao de pesquisadores do Brasil e de paises vizinhos, recebendo artigos em portugues, espanhol e ingles, com foco na aplicacao de resultados de pesquisa para evolucao da tecnologia de alimentos na America Latina.

Peel yellowing and loss of fruit mass reduce the useful life of acid limes and limit their commercialization. The goal of the present study was to prolong the post-harvest preservation of acid limes using wax and packaging. Fruits were harvested, selected, disinfected, treated with fungicide, coated with Carnauba wax and placed in cardboard boxes wrapped with different plastic packaging. A fruit lot treated only with wax coating was used as a control. The fruits were stored at 10°C for 24 days followed by 6 days at 20°C. The gas atmosphere inside the packages was analysed during storage. The loss of mass, color index, titratable acidity, and total chlorophyll, ascorbic acid, soluble solids, acetaldehyde and ethanol concentrations of the fruits were measured. The combined use of wax coating and plastic Cryovac® D-955 (Cryovac Brasil Ltda, Sao Paulo, Brazil) and Vegetal Pack® (Eletropolimeros do Brasil Ltda, Sao Paulo, Brazil) films resulted in better post-harvest preservation of acid limes compared with only wax coating because the combined treatment maintained the green peel color following 30 days of storage in addition to resulting in lower loss of mass and maintaining chemical characteristics adequate for commercialization. The LDPE (low density polyethylene) and Xtend® packaging (Stepac Brasil Ltda, Sao Paulo, Brazil), although they prevented peel degreening, did not result in an adequate atmosphere to maintain the quality of limes due to the accumulation of high concentrations of acetaldehyde and ethanol, especially for the LDPE packaging. LDPE drastically changed the atmosphere surrounding the fruit, resulting in loss of the characteristic pulp color, in addition to conferring an alcohol odor. Copyright © 2015 John Wiley & Sons, Ltd.

This study aimed to evaluate the quality changes of the minimally processed escarole under passive modified atmosphere, packaged in different flexible plastic packages, which included polyvinyl chloride (PVC) stretch film, low‐density polyethylene (LDPE) bag, polypropylene (PP) bag, and bi‐oriented polypropylene (BOPP) bag, during storage for 20 days at 0°C and 90%–95% RH. The atmosphere of 16% O₂and 3% CO₂ formed in the PVC overwrap package provided the lowest browning index and the best conservation of ascorbic acid, chlorophyll, and carotenoids. During the experiment, no differences in phenolic compounds and polyphenol oxidase activity among the treatments were observed, while the activity of peroxidase showed peaks in different analysis days. Weight loss of all samples did not exceeded 1%. The minimally processed escarole showed sensitivity to high CO₂ concentrations. Thus, a simple PVC stretch film provided the best visual and nutritional preservation of the minimally processed escarole. PRACTICAL APPLICATIONS: Escarole is one of the most consumed leafy vegetable as a minimally processed product, however, there is no information about its quality changes associated with the package. This produce is widely commercialized in the same package of other leafy vegetables. This research has focused on application of passive modified atmosphere technology for quality preservation of escarole during storage, in order to indicate the most adequate package for its quality and nutritional conservation. The results implied that the quality of minimally processed escarole is better‐maintained using PVC stretch film, which is quite different from the usual plastic bags used for minimally processed leafy vegetables. This information is quite interesting at processer and market levels in order to standardize the packaging of this product and prolong its visual and nutritional quality.

O copolímero Etileno Acetato de Vinila (EVA) é uma poliolefina utilizada principalmente em filmes para embalagens, onde a sua flexibilidade, tenacidade, elasticidade e transparência são atributos desejáveis. As propriedades mecânicas, térmicas e de barreira do EVA podem ser melhoradas pela incorporação de cargas inorgânicas. O EVA apresenta polaridade variável de acordo com o teor de Acetato de Vinila, o que promove a viabilidade para obtenção de nanocompósitos com argilas organicamente modificadas, tornando desnecessária a adição de agentes compatibilizantes. Neste trabalho foram preparados nanocompósitos de EVA e montmorilonita organofílica comercial pelo método de intercalação do fundido em um reômetro de torque, com rotores tipo roller, a 150°C durante 10minutos, com monitoramento do torque em função do tempo. A fim de investigar a influência da polaridade do EVA, da concentração da argila e das condições de processamento nas características dos nanocompósitos, variou-se a concentração de Acetato de Vinila (19% e 28%), o teor de argila (2% e 5%) e a velocidade de rotores (60 rpm e 100 rpm). Foram avaliadas a estrutura da argila, a estabilidade térmica e as propriedades mecânicas e de barreira dos nanocompósitos, mediante as técnicas de difração de raios X, análise termogravimétrica, ensaio de tração e análises de taxa de permeabilidade ao oxigênio e ao vapor d’água. A partir dos dados de permeabilidade foi aplicado o modelo de Nielsen para avaliar o grau de esfoliação da argila. Dentre os principais resultados com o planejamento fatorial destacam-se: (a) o aumento da polaridade do EVA aumentou a permeabilidade ao oxigênio e ao vapor d’água dos materiais; (b) o teor de argila não modificou a estabilidade térmica dos nanocompósitos e a estrutura da argila; (c) o aumento da concentração da argila aumentou o módulo elástico, reduziu a deformação de ruptura e reduziu significativamente o coeficiente de permeabilidade ao oxigênio e ao vapor d’água; (d) o fator rotação não implicou em alterações significativas em nenhuma das respostas avaliadas. The copolymer Ethylene Vinyl Acetate (EVA) is a polyolefin used mainly in packaging films, where its flexibility, toughness, elasticity and transparency are desirable attributes. The mechanical, thermal and barrier properties of EVA can be improved by the incorporation of inorganic fillers. Its polarity varies according to the content of Vinyl Acetate, which allows for nanocomposites to be obtained with organically modified clay, with no need to add compatibilizing agents. In this work nanocomposites of EVA and commercial organophilic montmorillonite were prepared by melt intercalation in a torque rheometer with rotors roller type, at 150°C for 10 minutes, monitoring the torque versus time. The concentration of Vinyl Acetate (19% and 28%), clay content (2% to 5%) and the rotors rotation (60 rpm to 100 rpm) were varied in order to investigate their influence on the characteristics of the nanocomposites. The clay structure, thermal stability, mechanical and barrier properties of the nanocomposites were evaluated by X-ray diffraction, thermal analysis, tensile testing, oxygen and water vapor transmission rates. Based on the permeability data, Nielsen´s model was applied to assess the degree of clay exfoliation. The main results obtained from the factorial design are: (a) increasing the polarity of EVA led to an increase in the permeability to oxygen and water vapor of the material, (b) the clay content did not change the clay structure or the thermal stability of the nanocomposites, (c) increasing the concentration of clay increased the elastic modulus, decreased the elongation at break and significantly reduced the coefficient of permeability for oxygen and water vapor, (d) the rotation factor did not result in significant changes in any of the evaluated responses.

The purpose of this study was to evaluate the changes in concentrations of O2 and CO2 inside packages of minimally processed Pera orange. Previously selected oranges that were washed, sanitized, and chilled were peeled using hydrothermal treatment (immersion of fruits in water at 50 °C for 8 minutes). The peeled oranges were then packed in five different plastic packages under passive and active modified atmosphere (5% O2 + 10% CO2 + 85% N2). The fruits were stored at 6 °C and 12 °C. The package headspace gas composition was evaluated for twelve days at 6 °C and nine days at 12 °C. The polypropylene film (32 µm) promoted modified atmosphere similar to that initially injected (5% O2 + 10% CO2 + 85% N2) at 6 °C and 12 °C. With regard to the atmosphere modification system, the injection of a gas mixture anticipated achieving an equilibrium atmosphere inside the packages at 12 °C. At 6 °C, the gas composition inside the packages was kept close to that of the injection, but the equilibrium was not verified.O objetivo deste trabalho foi avaliar as mudanças nas concentrações de O2 e CO2 do interior de embalagens contendo laranja Pera minimamente processada. Laranjas previamente selecionadas, lavadas, sanitizadas e resfriadas foram descascadas por meio de tratamento hidrotérmico (imersão dos frutos em água a 50 °C por 8 minutos). Laranjas descascadas foram acondicionadas em cinco materiais de embalagem sob atmosfera modificada passiva e atmosfera modificada ativa (5% O2 + 10% CO2 + 85% N2). O armazenamento dos frutos foi realizado a 6 °C e 12 °C. A composição gasosa no interior das embalagens foi avaliada durante doze dias a 6 °C e durante 9 dias a 12 °C. O filme de polipropileno (32 µm) propiciou atmosfera modificada semelhante injetada inicialmente (5% O2 + 10% CO2 + 85% N2) a 6 °C e 12 °C. Em relação ao sistema de modificação da atmosfera, a injeção de mistura gasosa antecipou a atmosfera de equilíbrio, dentro das embalagens a 12 °C. A 6 °C, a composição gasosa dentro das embalagens foi mantida próxima dos níveis de injeção, mas o equilíbrio não foi verificado.

The purpose of this study was to evaluate the changes in concentrations of O2 and CO2 inside packages of minimally processed Pera orange. Previously selected oranges that were washed, sanitized, and chilled were peeled using hydrothermal treatment (immersion of fruits in water at 50 °C for 8 minutes). The peeled oranges were then packed in five different plastic packages under passive and active modified atmosphere (5% O2 + 10% CO2 + 85% N2). The fruits were stored at 6 °C and 12 °C. The package headspace gas composition was evaluated for twelve days at 6 °C and nine days at 12 °C. The polypropylene film (32 µm) promoted modified atmosphere similar to that initially injected (5% O2 + 10% CO2 + 85% N2) at 6 °C and 12 °C. With regard to the atmosphere modification system, the injection of a gas mixture anticipated achieving an equilibrium atmosphere inside the packages at 12 °C. At 6 °C, the gas composition inside the packages was kept close to that of the injection, but the equilibrium was not verified. O objetivo deste trabalho foi avaliar as mudanças nas concentrações de O2 e CO2 do interior de embalagens contendo laranja Pera minimamente processada. Laranjas previamente selecionadas, lavadas, sanitizadas e resfriadas foram descascadas por meio de tratamento hidrotérmico (imersão dos frutos em água a 50 °C por 8 minutos). Laranjas descascadas foram acondicionadas em cinco materiais de embalagem sob atmosfera modificada passiva e atmosfera modificada ativa (5% O2 + 10% CO2 + 85% N2). O armazenamento dos frutos foi realizado a 6 °C e 12 °C. A composição gasosa no interior das embalagens foi avaliada durante doze dias a 6 °C e durante 9 dias a 12 °C. O filme de polipropileno (32 µm) propiciou atmosfera modificada semelhante injetada inicialmente (5% O2 + 10% CO2 + 85% N2) a 6 °C e 12 °C. Em relação ao sistema de modificação da atmosfera, a injeção de mistura gasosa antecipou a atmosfera de equilíbrio, dentro das embalagens a 12 °C. A 6 °C, a composição gasosa dentro das embalagens foi mantida próxima dos níveis de injeção, mas o equilíbrio não foi verificado.

Strawberry is a very sensitive fruit and presents a short post-harvest shelf-life. Among the factors responsible for strawberries' quality loss are high metabolic activities and mold decay. To increase product shelf-life, cassava starch–based edible coatings (3%), added or not with potassium sorbate (0.05%), were applied on minimally processed strawberries. Uncoated minimally processed strawberries were used as control samples. Physical and chemical properties, respiration rate and sensorial acceptance of uncoated and coated strawberries stored up to 15 days at 5°C were monitored. The results showed that coatings had no significant effect on soluble solids, titrable acidity, pH and colour of strawberries. Besides reducing the respiration rate of samples, cassava starch edible coatings were efficient in delaying weight and firmness loss of strawberries during storage. In the studied conditions, potassium sorbate was not efficient in controlling microbial growth. Strawberries coated with cassava starch without the antimicrobial agent showed good conditions for consumption and good sensorial acceptance up to 12 days of storage, whereas the control samples and the samples treated with the coating containing potassium sorbate achieved a shelf-life of 9 days because of microbial spoilage. Copyright © 2011 John Wiley & Sons, Ltd.

The aim of this work was to investigate the influence of osmotic dehydration and pectin edible coating on quality parameters of fresh-cut melon. Fruits were osmodehydrated in 40°Bx sucrose solution containing 0.5% calcium lactate or dipped in 0.5% calcium lactate solutions. Then, samples were coated with 1% pectin. Melon pieces dipped in sanitizing solution (nontreated sample) were used as control. Weight loss, respiration rate, firmness, color parameters (lightness, chroma, and whiteness index), sensory acceptance, microbial growth, and structural changes of fruits were evaluated during storage at 5 °C for 14 days. The shelf life of the control sample was limited to 9 days due to microbial growth and sensory rejection, while treated samples showed a shelf life of 14 days. Higher preservation of firmness in coated samples was attributed to the action of calcium salt on melon structure, causing a strengthening of the cell wall. Calcium lactate also inhibited microbial growth along storage, improving microbiological stability of fresh-cut melon. The use of calcium lactate dips and pectin edible coatings hindered weight loss and maintained fruit color characteristics during the storage time. However, these pretreatments probably masked melon taste, reducing the sensory acceptance scores at the end of shelf life study. The combination of osmotic dehydration and pectin coatings was a good preservation alternative for fresh-cut melon, since it improved fruit sensory acceptance, promoting the reduction of product respiration rate, as well as the maintenance of quality parameters during 14 days. CNPq (301761/2004-3) FAPESP (2006/03263-9, 2009/51420-4)

This work aimed to evaluate quality parameters of ‘Tommy Atkins’ mango slices pre-treated with citric acid and cassava starch or sodium alginate edible coatings, with or without glycerol. Samples only treated with citric acid were also evaluated. Mango slices dipped in sanitising solution were used as control. Colour parameters, mechanical properties, weight loss and respiration rate were analysed during 15 days at 5 °C. Cassava starch coating, with or without glycerol, provided higher stress at failure and lightness values than control sample throughout storage (p ≤ 0.05). The citric acid promoted colour preservation, but increased significantly samples weight loss during storage. Sodium alginate coatings did not maintain quality characteristics, showing stress at failure and lightness values lower than control after 15 days. All coatings reduced respiration rate, but citric acid dipping and cassava starch coating without glycerol treatments were more effective, reaching values around 41% lower, when compared to control sample. Industrial Relevance Fresh-cut mangoes are appreciated world-wide for its exotic flavour and nutritional composition. However, their shelf life is limited by changes in colour, texture, appearance and microbial growth. The edible coatings act as gas and water vapour barrier, extending the storage time of fresh-cut fruit and vegetables. Thus, cassava starch and alginate are alternatives to preserve minimally processed mangoes, maintaining the quality parameters of fresh fruit. This work is useful for the minimal processing industry in order to increase shelf life of fresh-cut mangoes, which can be considered an alternative to fast food and other ready-to-eat products, attending the demand for healthy and convenient foodstuffs.

O objetivo do trabalho foi avaliar as propriedades de barreira e a solubilidade de biofilmes obtidos a partir de amido de ervilha de alto teor de amilose em associação à goma xantana e glicerol. Soluções filmogênicas (SF) com diferentes teores de amido de ervilha (3, 4 e 5%), goma xantana (0, 0,05 e 0,1%) e glicerol (proporção glicerol-amido de 1:5 P/P) foram estudadas. As SF foram obtidas por ebulição (5 minutos), seguida de autoclavagem por 1 hora a 120 ºC e os filmes foram preparados por casting. O aumento da concentração de amido e de glicerol na composição causou aumento da espessura e da solubilidade dos filmes em água. O plastificante gerou ainda elevação dos coeficientes de permeabilidade ao vapor d'água e ao oxigênio. O aumento da concentração da goma xantana não interferiu nas propriedades estudadas. Os biofilmes obtidos a partir de amido de ervilha verde, associado ou não à goma xantana e glicerol, se comparados com filmes de amido de ervilha amarelas e outras fontes de amido, apresentaram boa barreira ao oxigênio e ao vapor d'água e baixa solubilidade em água.

'Douradão' peach is a perishable product and when cold stored is subject to chilling injury. The objective of the experiment was to evaluate the effect of modified atmosphere packaging (MAP) and cold storage on quality and storage life of these peaches. Fruits were packed in polypropylene (PP) trays and placed inside low density polyethylene (LDPE) bags (30, 50, 60, 75 μm thickness) with active modified atmosphere (10 kPa CO2 + 1.5kPa O2, balance N2). The control was made with peaches held in nonwrapped PP trays. Fruits were kept at 1 ± 1 °C and 90 ± 5% relative humidity (RH) for 28 days and CO2 and O2 within packages was monitored every two days. After 14, 21 and 28 days, samples were withdrawn from MAP and kept in air at 25 ± 1 °C and 90 ± 5% RH for ripening. On the day of removal from the cold storage and after 4 days, peaches were evaluated for weight loss, decay incidence, flesh firmness, woolliness incidence, soluble solids content (SSC), titratable acidity (TA) and juice content. The results showed that MAP had influence on reducing weight loss and prevented postharvest decay. MAP of 1-2 kPa O2 and 3-6 kPa CO2 at 1 °C (from 50 and 60 μm LDPE films) were effective for keeping good quality of 'Douradão' peaches during 28 days of storage, the ripe fruits showed reduced incidence of woolliness, adequate juiciness and flesh firmness. Packages of 30 and 75 μm LDPE films were ineffective for reducing woolliness during cold storage. MAP fruits showed lower SSC and no relevant effect on TA. Control fruits did not present marketable conditions after 14 days of cold storage. RESUMO O pêssego 'Douradão' é um produto perecível e quando armazenado sob refrigeração está sujeito à injúria pelo frio, o objetivo deste trabalho foi avaliar o efeito da embalagem de atmosfera modificada (AM) na qualidade e na extensão da vida de estocagem destes pêssegos refrigerados. Os frutos foram acondicionados em bandejas de polipropileno (PP) e colocados dentro de sacos plásticos de polietileno de baixa densidade (PEBD) com espessuras de 30, 50, 60 e 75 μm e com modificação ativa da atmosfera (10 kPa CO2 + 1.5 kPa O2, balance N2). O tratamento controle foi feito com pêssegos acondicionados em bandejas de PP sem embalagem plástica. Os frutos foram mantidos em câmara a 1 ± 1 °C e 90 ± 5% de umidade relativa (UR) por 28 dias, e as concentrações de CO2 e O2 dentro das embalagens foram avaliadas a cada dois dias. Após 14, 21 e 28 dias, as embalagens plásticas foram retiradas e as amostras foram mantidas em ar a 25 ± 1 °C e 90 ± 5% UR para amadurecimento. No dia da remoção e após 4 dias, os pêssegos foram avaliados quanto a perda de massa, incidência de podridão, firmeza da polpa, incidência de lanosidade, conteúdo de sólidos solúveis (CSS), acidez titulável (AT) e teor de suco. Os resultados mostraram que as embalagens de AM tiveram influência na redução da perda de massa e preveniu a podridão dos frutos. As embalagens de AM que mantiveram concentrações de 1-2 kPa O2 e 3-6 kPa CO2 a 1 °C (provenientes dos filmes de PEBD de 50 e 60 μm) foram efetivas para manter a boa qualidade dos pêssegos 'Douradão' durante 28 dias de estocagem, os frutos maduros mostraram baixa incidência de lanosidade, adequada suculência e firmeza da polpa. As embalagens dos filmes de PEBD de 30 e 75 μm foram ineficientes para reduzir a lanosidade nos frutos durante a estocagem refrigerada. Os frutos oriundos das embalagens de AM mostraram menor CSS e efeito não relevante sobre a AT. Os frutos controle não apresentaram condições de comercialização após 14 dias de estocagem refrigerada.

The performance of oxygen scavengers can be influenced by several conditions, such as temperature (T) and relative humidity (RH), which are considered to be the two major factors. Therefore, the development of new scavengers requires the study of their performance, with these conditions varied. In this paper, the response surface methodology (RSM) was used to study the performance of a newly developed oxygen scavenger sachet and to model the influences of T and RH and their interaction on the absorption capacity and rate constant of the developed sachet. Commercial oxygen scavenger sachets were used for comparison purposes. The oxygen absorption capacity and rate constant were evaluated with a 22 factorial design with a central point. The results showed that each absorber sachet presented a different behaviour and there were significant interactions between T and RH; so, the RSM was the most appropriate for these studies. The developed sachet presented a better performance compared with the commercial ones at 23°C and 53% RH, which represents the condition for commercialization at room temperature of foods of intermediary water activity, while in the extreme conditions (100% RH and 37°C) all sachets present a similar absorption capacity. Copyright © 2010 John Wiley & Sons, Ltd.

This work investigates the influence of some ammonium quaternary compounds as coupling agent in polyethylene/clay nanocomposites to improve the performance of polyethylene used as packaging barrier material. The 3 wt % of vermiculite used as a nanofiller was added to linear low-density polyethylene (LLDPE) and to linear low-density polyethylene grafted with maleic anhydride (LLDPE-g-MA). The analysis results revealed that the influence of both the clay exfoliation in a polymer matrix and the coupling agents on the barrier properties were significant. Among the coupling agents used, cetylpropyldimethylammonium chloride yielded the best result for vermiculite exfoliation. A reduction of up to 18% in the oxygen-permeability coefficient was observed in the nanocompounds with exfoliated vermiculite. The nanocomposite produced with vermiculite did not prove to be efficient as a moisture barrier against according to the analysis performed. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Edible coatings can represent an alternative for extending post-harvest life of perishable fruits, as strawberries. In this work, the effect of cassava starch edible coatings, added or not of potassium sorbate, on mechanical properties, surface color, sensory acceptance, and respiration rate of strawberries was evaluated in order to choose the best coating conditions to minimally processed strawberries. Integrity and water-vapor resistance of the coatings were also evaluated. Three different concentrations of cassava starch (1%, 2%, and 3%) and two concentrations of potassium sorbate (0.05% and 0.10%) were used in the coatings formulations. Minimally processed strawberries without coating were used as control samples. The strawberries treated with different coatings and control fruits did not present differences regarding mechanical properties, surface color, and all the sensory attributes evaluated. A good integrity of cassava edible coatings on strawberries surface was observed for 2% and 3% starch concentration and the use of coatings, in these concentrations, reduced the strawberries respiration rate, representing a possibility to extend the shelf life of fruits. All coatings showed beneficial effects on increasing the water vapor resistance of the samples, but a significant increase was obtained only with the use of coating with 3% of starch. The potassium sorbate improved significantly the resistance to water vapor, but no differences were observed between the two concentrations studied. Based these results, the coatings with 3% of cassava starch and 3% of cassava starch +0.05% of potassium sorbate were those selected for future shelf life study of minimally processed strawberries.

Avaliou-se a estabilidade de repolho minimamente processado acondicionado em embalagens de polietileno de baixa densidade com atmosfera modificada ativa e passiva, e em bandejas de poliestireno expandido revestidas com filme de policloreto de vinila. O produto foi armazenado por 16 dias em câmara frigorífica na temperatura de 5 ± 1 °C e 95 ± 5 % de umidade relativa, e em um balcão refrigerado similar aos utilizados em lojas de conveniência, com o intuito de representar os locais de comercialização no varejo, com temperatura média de 2,7 ± 3,3 °C. Analisou-se a concentração de oxigênio e dióxido de carbono no interior das embalagens, e no repolho minimamente processado o incremento no escurecimento, luminosidade, atividade da polifenoloxidase e peroxidase, pH, acidez titulável, sólidos solúveis, perda de massa fresca e teor de ácido ascórbico. A estabilidade do repolho minimamente processado mostrou-se superior na temperatura de 5 °C quando comparada ao armazenamento no balcão refrigerado. A atmosfera modificada ativa não foi efetiva no aumento da vida útil do repolho minimamente processado quando comparada aos outros tratamentos. A embalagem de PEBD foi a mais adequada ao acondicionamento do repolho minimamente processado. No entanto, a embalagem de PVC também apresentou resultados satisfatórios.Stability of fresh-cut cabbage packed in low density polyethylene under active modified atmosphere and in expanded polyestyrene trays wrapped with PVC was evaluated. The fresh-cut product was stored for 16 days in a cold room at 5 ± 1 °C and 95 ± 5% RH and in a refrigerated display case similar to those found in grocery stores. The following variables were analyzed: content of oxygen and carbon dioxide inside the package headspace; browning, luminosity, polyphenoloxidase and peroxidase activities, pH, titratable acidity; soluble solids, fresh mass loss, and ascorbic acid content. The stability of fresh-cut cabbage was higher at the temperature of 5 °C compared to those stored in the refrigerated displays. The active modified atmosphere was not effective in extending the shelf life of fresh-cut cabbage compared to other treatments. LDPE packaging was more adequate for fresh-cut cabbage storage. However, PVC wrapping also presented satisfactory effects.

This study evaluates the potential of using non-irradiated barrier-shrink bags containing ethylene-vinyl alcohol copolymer (EVOH), polyamide (PA) and ethylene ionomer in their structures to preserve vacuum-packaged fresh beef as an alternative to traditional gamma-ray cross-linked bags containing polyvinylidene chloride (PVDC). Boneless beef rib eye roll cuts were vacuum-packed in an industrial processing plant using EVOH 44% mol, EVOH 32% mol and a control PVDC barrier shrink bags. The cuts were evaluated during storage at 0.5 °C. The EVOH films presented similar performance compared to control PVDC barrier shrink bags related to bacteria growth and purge loss. Packages with EVOH 32% mol film presented better performance than control bag with respect to the meat sensorial attributes, including fewer bubbles and better adhesion. EVOH 44% mol bags presented the highest rate of colour loss. The EVOH 32% mol non-irradiated and chlorine-free film is as effective for the preservation of fresh beef as traditional PVDC-irradiated shrink bags.

Persimmon production in Brazil is concentrated from February to June. The large amount of this fruit available in the market influences its price during this period. This study was carried out to evaluate the effect of different packaging plastic materials on extending the storage life of ‘Fuyu’ persimmons kept under refrigeration. ‘Fuyu’ persimmon fruits were harvested on the mature-green stage and enclosed in groups of three (750 ± 30 g) in different packaging materials: 58-μm multilayer polyolephynic film (PO); 50-μm low density polyethylene film (LDPE) and 38-μm microperforated PO. Unpacked fruit stored in corrugated cardboard boxes were used as control. Fruit were stored at 1 ± 1 °C/90 ± 5% RH for 90 d. Every 7 d, five replicates of each treatment were evaluated for headspace gas composition (O2, CO2) and then transferred to 25 ± 1 °C/70 ± 5% RH for five more days. Then they were evaluated as to headspace gas composition (O2, CO2, acetaldehyde and ethanol), firmness, weight loss, skin and flesh color, total soluble solids, titratable acidity, pH, decay, discoloration and sensory attributes. The gas composition in the steady-state established in the 58-μm PO and 50-μm LDPE films extended the storage period up to 84 d at 1 °C plus 5 d at 25 °C differing significantly (P ≤ 0.05) from the control fruit as well as from those in the 38-μm microperforated PO, which were stored for 21 and 28 d, respectively. Off-flavors were not detected by sensory analysis. These results suggest that the 58-μm PO and 50-μm LDPE films are suitable for atmosphere modification and packaging of ‘Fuyu’ persimmon fruit stored under refrigeration with an additional period of time at ambient temperature.

Papaya pieces were osmotically dehydrated in a 50°Brix sucrose solution containing calcium lactate (0.05 M) and lactic acid (0.02 M) as additives for 1 h at 25C, packed in polyethylene terephthalate (PET) containers and stored at 5C for 15 days. Fresh fruit pieces packed in PET containers and under atmosphere condition were used as control samples. Sensory acceptance, microbiological count, CO2 and O2 content inside the packages, color, mechanical properties and weight loss of the product were evaluated. PET containers prevented weight loss during storage. The utilization of calcium lactate as additive was effective in maintaining fruit hardness during refrig- erated storage. The use of passive modified atmosphere associated with refrig- eration was adequate to preserve the osmotically dehydrated fruit for 15 days, showing a good sensory acceptance by the consumers during the storage time.

Retail-packed rump (Gluteus medius, GM) and striploins (Longissiumus dorsi, LD) steaks were masterpackaged under carbon dioxide (CO2) and stored at 1 °C ± 1 °C for 14, 28, 35, and 42 d. A commercial oxygen (O2) scavenger (ATCO HV1000®, Standa Industrie, Caen, France) was used in the masterpacks to achieve an O2-free atmosphere. Similar packages without the O2 scavengers were also prepared. At each storage time, 2 masterpacks of each treatment were opened and the retail trays were placed in a display case at 4 °C ± 2 °C for 1 and 48 h for microbiological and sensorial evaluations. The low growth rate of aerobic psychrotrophic flora on the stored beefsteaks demonstrated the bacteriostatic effect of CO2 during storage. The maximum level of psychrotrophic aerobic bacteria reached during storage was approximately 106 CFU/g. The steaks stored in masterpacks with scavengers bloomed to the desirable red color associated with freshly cut meat in the display case for all of the storage periods, except in the case of GM steaks, which showed a cycle of transient discoloration. GM and LD steaks were well accepted (65% and 82%, respectively) after 42 d under CO2 at 1 °C ± 1 °C. The GM and LD steaks stored without the O2 scavenger showed variable fractions of discoloration that significantly detracted from the appearance of the samples.

The objective of this study was to evaluate the influence of package materials on the preservation of cold-stored ‘Kumagai’ guavas. The treatments were: PO2, co-extruded polyolephinic film with gas injection (5% O2/5% CO2/N2); PO3, co-extruded polyolephinic film with gas injection (5% O2/5% CO2/N2); LDPE, linear low density polyethylene film; LDPE-gas, linear low density polyethylene film with gas injection (3% O2/8% CO2/N2); PVC, polyvinylchloride stretch film; PO1, co-extruded polyolephinic film and control: non-packaged guavas. Guavas were stored at 10 ± 1°C/80–90% RH for 21 days, and then transferred to room temperature. Gas composition within the package headspace was analysed during storage and the physical and chemical characteristics of the guavas were evaluated daily during ripening. The modified atmosphere provided by PO1 film was insufficient to promote the benefit of senescence control. Although PVC provided an atmosphere close to that recommended, it did not preserve the colour and pulp firmness. PO2, PO3, LDPE and LDPE-gas retarded the senescence process of the guavas during 21 days at 10°C plus 2 days at room temperature, but harmed the normal ripening of guavas in some aspects. This can be explained by reduced O2 and elevated CO2 levels within these four packages. None of the packages influenced the titratable acidity and the soluble solids, but they did harm ascorbic acid synthesis. Copyright © 2005 John Wiley & Sons, Ltd.

L.M. PEREIRA, A.C.C. RODRIGUES, C.I.G.L. SARANTOPOULOS, V.C.A. JUNQUEIRA, R.L. CUNHA, AND M.D. HUBINGER ABSTRACT: The quality of minimally processed guavas (Psidium guajava L.), osmotically dehydrated and packed under passive modified atmosphere, was evaluated during 24 d of storage at 5 °C. Modified atmosphere packaging (MAP) in polyethylene terephthalate (PET) containers had a strong influence on color preservation and weight loss of the guavas. Significant changes in the texture were found due to osmotic dehydration, but the color of the fresh fruit remained unchanged. Osmotically dehydrated guavas stored in MAP showed good microbial conditions during stor- age. The combination of storage temperature, modified atmosphere packaging, and the osmotic dehydration process

The use of PET bottles for edible oil in Brazil is increasing but there is a trend to reduce bottle weight for economic reasons, which decreases the oxygen barrier of the package. The barrier performance of a 20 g PET bottle for 900 ml soya oil, submitted to gas flushing with gaseous N2 and pressurization with liquid N2, was compared with a 27 g PET conventional bottle. During 8 months storage at 25°C the internal pressure, dissolved oxygen and oxygen in the headspace were evaluated and did not change significantly. Liquid N2 pressurization did not improve the efficiency of reducing O2 in the headspace compared to N2 gas flushing. Copyright © 2001 John Wiley & Sons, Ltd.

Cashew and passion fruit juice drinks were aseptically filled in cartons and in three types of plastic packages (with oxygen transmission rate-OTR of 1,40; 2,96 and 13,74 cm3 (STP)/m2/day at 25 °C, 75% RH and 1 atm), with nitrogen gas flushing. No adverse effect on product sterility was found, neither were any significant changes in pH and acidity detected during storage at 25 ± 2°C. A decrease of the oxygen concentration in the headspace of the cashew juice drink plastic packs was observed, which appears to be caused by consumption of that gas in oxidation reactions. The shelf-life of the cashew juice drink was limited to 45–70 days, after which period sensory changes attained objectionable levels (development of dark colours and deterioration of the typical fruit flavour). Passion fruit juice drink proved to be less sensitive to oxygen than cashew, since an increase of the oxygen concentration was detected in the headspace of the three plastic packs. The shelf-life of passion fruit juice drink was limited to 70–90 days, due to deterioration of the typical passion fruit flavour and colour. Copyright © 2001 John Wiley & Sons, Ltd.

Guavas cv. ‘Kumagai’ were packed in several plastic materials and stored at 10°C and 85–90% relative humidity (RH) for 7, 14, 21 and 28 days (+3 days at 25°C). The plastic materials studied were: multilayer co-extruded polyolephine film with selective permeability (PSP), low-density polyethylene film (LDPE), LDPE film with mineral incorporation (LDPEm) and heat-shrinkable polyolephine film (SHR). Guavas not packed were taken as control samples. The physicochemical characteristics of the fruits, O2 and CO2 transmission rates of the packaging materials and gas composition at the package headspace were evaluated. The LDPE film, 69 µm in thickness, with the lowest permeability to both O2 and CO2, led to anaerobiosis and high CO2 concentration inside the packages and promoted physiological disturbances and changes in fruit flavour. The SHR film, 15 µm in thickness, was the most permeable to CO2 and had quite high O2 transmission, which modified the inner atmosphere of the packages slightly. The fruits packed in this film showed a poorer quality than the controls, possibly due to the heat produced during the shrinking of the film. The LDPEm film, 24 µm in thickness, was almost as permeable to CO2 but had reduced O2 transmission, promoting an atmosphere of equilibrium of 3% O2 and 4.5% CO2. Fruits packed in this film kept their skin colour and pulp firmness, suitable for consumption up to 14 days. The PSP film, 35 µm in thickness, had the greatest O2 transmission but just over half of the CO2 transmission of LDPEm, promoting an atmosphere of equilibrium of 0.5% O2 and 4.5% CO2 inside the packages. Fruits packed in such packages kept their physicochemical characteristics up to 21 days. Copyright © 2001 John Wiley & Sons, Ltd.

Guavas cv. Kumagai fruits were packed in plastic bags and stored at 10°C and 85-90% RH during 7, 14, 21 and 28 days, followed by open exposure for 3 days at 25°C and 70-80% RH to simulate commercial handling conditions. The packaging materials used were: multilayer coextruded polyolefin film with selective permeability (PSP), low density polyethylene film (LDPE), LDPE film with mineral incorporation (LDPEm) and heat-shrinkable polyolefin film (SHR). Guavas without plastic packages were used as control samples. The concentrations of O 2 and CO 2 in the package headspace and the sensorial characteristics of the guavas (skin color, pulp texture, off-flavor and overall quality) were evaluated. The LDPE film presented the higher gas barrier and promoted the lowest O 2 level (0.1%) and the highest CO 2 concentration (19%) inside the packages. Such passive modified atmosphere induced both off-flavor and abnormal ripeness. The polyolefin heat-shrinkable film provided poor modification in the package atmosphere, so the fruits exhibited fast senescence (decay). The film incorporated with mineral provided an atmosphere of 3% O 2 and 4.5% CO 2 inside the packages, which kept the fruit with good sensorial characteristics for 14 days. The coextruded polyolefin film provided an atmosphere of 0.5% O 2 and 4.5% CO 2 that was sufficient to maintain the fruit with good sensorial characteristics for 28 days.

This study compares and evaluates the mechanical performance of two types of PET bottle of different nominal weights but identical design and filled with 900 ml vegetable cooking oil. The air in the headspace of all the bottles was replaced with liquid or gaseous nitrogen upon conclusion of the filling operation and immediately before capping. Two different closures, with an internal or external tamper-evident feature, were used on the 20 g bottles. The 27 g bottle was closed exclusively with the closure fitted with an external seal. The 20 g PET bottles prior to capping were either flushed with gaseous nitrogen or pressurized with liquid nitrogen. The air contained in the headspace of the 27 g bottle was removed by injection of gaseous nitrogen only. Corrugated fibreboard cases containing 20 bottles each were submitted to a vibration test and all the components of the packaging system were subsequently evaluated with respect to important mechanical properties, such as stacking strength, drop impact strength and package integrity. The results show that the closure with external seal provided considerably better protection against leakage. Also tests conducted with stacks of five corrugated cases each and arranged onto two pallets placed one upon the other demonstrated that reducing total bottle weight by 26% is viable in terms of mechanical performance. On the other hand, the use of pressurized liquid nitrogen was found to be unnecessary. Copyright © 2000 John Wiley & Sons, Ltd.

This paper describes the development of an analyser intended to measure the concentrations of CO 2 and O 2 present as part of the gas mixture in the head-space of food packages. The efficiency of the measuring device was evaluated by analysing the atmosphere of packages containing the following food products: grated Parmesan cheese, milk powder and fresh pasta. A comparison between the results of the analysis performed with the newly developed analyser and those obtained by gas chromatography showed good correlation between the two methods. The O 2 and CO 2 analyser presented satisfactory accuracy (absolute error smaller than 2.5%, v/v) and precision (relative standard deviation varying from 0.2% to 8.5%). In addition, final results of the levels of both gas types present in the atmosphere submitted to analysis are obtained after about 2 min. The proposed analyser constitutes an alternative solution for the analysis of gases present in the head-space of packages, especially when gas samples of very small volumes-about 200 μl-are to be used.

Portions (about 1 kg each) of chicken leg cuts packed in low density polyethylene bags were arranged in masterpack barrier bags injected with two different kinds of modified atmosphere: 80% CO 2 /20% N 2 and 70% CO 2 /30% N 2 . All the samples packed in modified atmosphere, as well as the control samples packed in air, were dark stored at 3±1°C. The shelf life of the products was evaluated on the basis of microbiological and sensory criteria. The shelf life of the samples with initial mesophilic and psychotrophic bacteria counts of 5.38 and 5.72 log CFU/g, respectively, and stored under 80% CO 2 was extended from 7 to 17 days, considerably longer than the shelf life increase achieved with the samples packed in a modified atmosphere containing 70% CO 2 , which increased from 10 to 14 days. The odour changes observed during refrigerated storage of all samples followed a uniform pattern, starting with an odour of 'old chicken meat' which gradually developed into rancid and, finally, putrid odours. The detection of putrid odours was the basic criterion for rejection of the products and correlated well with the microbiological evaluation data. At the end of the shelf life the appearance of the samples was evaluated as slightly to moderately different from their appearance at the start of the experiment.

Twelve slices of mozzarella cheese (about 174 g) were packaged in expanded polystyrene trays placed in gas-barrier bags under three different atmospheres (100% N 2 , 100% CO 2 , and 50% CO 2 /50% N 2 ). A gas headspace-to-cheese ratio of 2.5 liters/kg of cheese was initially set in the modified-atmosphere packages. Simulating conventional Brazilian packaging, some trays were wrapped in PVC stretched film. Periodically, the product stored at 7 ± 1°C was evaluated as to its sensorial quality, microbiological condition, and physical and chemical characteristics. The headspace volume and gas composition of modified-atmosphere packages were evaluated. The mozzarella cheese did not show any physical or chemical alteration in all packaging treatments. These characteristics were not factors which limited shelf life in air or in modified atmospheres. The critical parameter was sensory degradation. The shelf life of sliced mozzarella in conventional air pack was 13 days. N 2 atmospheres had only a minor effect on shelf life compared with air. Samples under N 2 were satisfactory up to 16 days. A significant shelf life increase was verified under CO 2 atmospheres compared with air, as follows : 63 days (a 385% increase) and 45 days (a 246% increase) for product under 100% CO 2 and 50% CO 2 /50% N 2 , respectively. The bacteriostatic and fungistatic effects of CO 2 were verified. The growth of psychrotrophic bacteria, molds, and yeasts was slower under CO 2 atmospheres. Mold and yeast development was inhibited under 100% CO 2 (2 liters of CO 2 per kg of cheese).

UNLABELLED This study correlated the composition of the spoilage bacterial flora with the main gaseous and volatile organic compounds (VOCs) found in the package headspace of spoiled, chilled, vacuum-packed meat. Fifteen chilled, vacuum-packed beef samples, suffering from blown pack spoilage, were studied using 16S rRNA clone sequencing. More than 50% of the bacteria were identified as lactic acid bacteria (LAB), followed by clostridia and enterobacteria. Fifty-one volatile compounds were detected in the spoiled samples. Although the major spoilage compounds were identified as alcohols and aldehydes, CO2 was identified as the major gas in the spoiled samples by headspace technique. Different species of bacteria contribute to different volatile compounds during meat spoilage. LAB played an important role in blown pack deterioration of the Brazilian beef studied. SIGNIFICANCE AND IMPACT OF THE STUDY The data generated by this study provided useful information to correlate the microbial contamination of Enterobacteriaceae, lactic acid bacteria and Clostridium with the VOC and gaseous compound production to define, in a faster manner, not only the type of contamination, but also to prevent it.

Minimally processed kale leaves were packed in passive modified atmosphere and stored at 3 conditions: 1 °C in the dark and 11 °C with or without light exposure. The products were evaluated during storage in terms of headspace gas composition, sensory attributes, flavonol, and carotenoid contents. The sensory quality decreased slightly during 17 d at 1 °C in the dark. At 11 °C, the vegetable shelf life was predicted to be 6 d in the dark and 3 d with light. Quercetin and kaempferol were stable during storage for 15 d at 1 °C in the absence of light. At 11 °C in the dark, quercetin was stable during 10 d, increasing slightly on the 8th day. Kaempferol decreased up to the 5th day but increased on the 8th day, decreasing again on the 10th day. After 5 d at 11 °C under light, the flavonol levels were significantly higher than those of the initial values. Neoxanthin and violaxanthin did not change significantly after 15 d at 1 °C in the dark. Lutein and β-carotene, however, decreased 7.1% and 11.3%, respectively. At 11 °C in the dark, neoxanthin, violaxanthin, lutein, and β-carotene decreased 16.1%, 13.2%, 24.1%, and 23.7% after 10 d, respectively. At 11 °C under light, neoxanthin and lutein had a slight increase while violaxanthin and β-carotene decreased 23.1% and 16.5% after 5 d. Practical Application: Passive modified atmosphere packaging together with refrigeration can extend the shelf life of minimally processed kale, retaining the health-promoting compounds, flavonols and carotenoids. Quercetin, kaempferol, neoxanthin, and violaxanthin are stable and lutein and β-carotene slightly reduced.

Filmes de BOPP e de PET metalizados são muito utilizados em embalagens multicamadas, pois reúnem boas propriedades mecânicas e de barreira a gases e umidade, as quais, bem como a aparência e a integridade, são comprometidas quando ocorre a delaminação da estrutura multicamada. Um dos principais fatores que influem na resistência à delaminação é a força de adesão da camada de alumínio ao substrato polimérico, parâmetro para o qual não há um método de quantificação normalizado. O objetivo deste trabalho foi estabelecer e validar um método de ensaio para determinar esta força de adesão. O método foi definido usando um planejamento experimental com fatores fixos e variáveis sendo que, para cada variável, foram definidos dois níveis. O método de ensaio estabelecido mostrou-se estável, preciso, robusto e replicável. Consiste, basicamente, na termosselagem de um filme plástico à face metalizada da amostra, em condições específicas de temperatura/tempo/pressão, e medida da força para destacamento da metalização, em ângulo e velocidade específicos, em máquina universal de ensaios. OPP and OPET metallized films are widely used as substrates in multilayer packages, since they bring together good mechanical properties and barrier to gases and water vapor, which are damaged with delamination of the film layers, together with the visual appearance and package integrity. One of the main factors that affect the package delamination is the adhesion strength of aluminum layer to the polymeric substrate, a parameter for which there is no standard procedure to quantify. The aim of this work was to establish and validate a procedure to determine the adhesion strength of the aluminum to the polymer. This test procedure was carried out using experimental design with fixed and variables parameters with two levels for each variable. The test procedure was stable, robust and replicable. It consisted basically of the heat sealing of a plastic film to the metallized sample surface, under specific temperature/time/pressure conditions and the measuring of adhesion strength of metallization in a universal test machine running at specific angle and speed.

Combination of citric acid dipping (5 g/L) and cassava starch coating (10 g/L), with and without glycerol (10 g/L), was studied to verify the effectiveness of these treatments to inhibit enzymatic browning, to reduce respiration rate, and to preserve quality parameters of "Tommy Atkins" fresh-cut mangoes during storage at 5 degrees C. Color characteristics (L and C), mechanical properties (stress at failure), weight loss, beta-carotene content, sensory acceptance, and microbial growth of fruits were evaluated during 15 d. The respiration rate of fruit subjected to the treatments was also analyzed. Nontreated fresh-cut mango was used as a control sample. Cassava starch edible coatings and citric acid dipping promoted a decrease in respiration rate of mango slices, with values up to 41% lower than the control fruit. This treatment also promoted better preservation of texture and color characteristics of mangoes and delayed carotenoid formation and browning reactions during storage. Moreover, the treated fruit showed great sensory acceptance by consumers throughout the whole storage period. However, the use of glycerol in the coating formulation was not efficient in the maintenance of quality parameters of fresh-cut mangoes, promoting a higher weight loss of samples, impairing fruit texture characteristics, increasing carotenogenesis, and favoring microbial growth during storage.

Avaliou-se a estabilidade de repolho minimamente processado acondicionado em embalagens de polietileno de baixa densidade com atmosfera modificada ativa e passiva, e em bandejas de poliestireno expandido revestidas com filme de policloreto de vinila. O produto foi armazenado por 16 dias em câmara frigorífica na temperatura de 5 ± 1 °C e 95 ± 5 % de umidade relativa, e em um balcão refrigerado similar aos utilizados em lojas de conveniência, com o intuito de representar os locais de comercialização no varejo, com temperatura média de 2,7 ± 3,3 °C. Analisou-se a concentração de oxigênio e dióxido de carbono no interior das embalagens, e no repolho minimamente processado o incremento no escurecimento, luminosidade, atividade da polifenoloxidase e peroxidase, pH, acidez titulável, sólidos solúveis, perda de massa fresca e teor de ácido ascórbico. A estabilidade do repolho minimamente processado mostrou-se superior na temperatura de 5 °C quando comparada ao armazenamento no balcão refrigerado. A atmosfera modificada ativa não foi efetiva no aumento da vida útil do repolho minimamente processado quando comparada aos outros tratamentos. A embalagem de PEBD foi a mais adequada ao acondicionamento do repolho minimamente processado. No entanto, a embalagem de PVC também apresentou resultados satisfatórios. Stability of fresh-cut cabbage packed in low density polyethylene under active modified atmosphere and in expanded polyestyrene trays wrapped with PVC was evaluated. The fresh-cut product was stored for 16 days in a cold room at 5 ± 1 °C and 95 ± 5% RH and in a refrigerated display case similar to those found in grocery stores. The following variables were analyzed: content of oxygen and carbon dioxide inside the package headspace; browning, luminosity, polyphenoloxidase and peroxidase activities, pH, titratable acidity; soluble solids, fresh mass loss, and ascorbic acid content. The stability of fresh-cut cabbage was higher at the temperature of 5 °C compared to those stored in the refrigerated displays. The active modified atmosphere was not effective in extending the shelf life of fresh-cut cabbage compared to other treatments. LDPE packaging was more adequate for fresh-cut cabbage storage. However, PVC wrapping also presented satisfactory effects.

Fatias de manga fresca e osmoticamente desidratadas foram acondicionadas em bandejas de poliestireno expandido, recobertas com filme de polietileno de baixa densidade (PEBD) e estocadas à temperatura de 5 °C com o objetivo de verificar o efeito da desidratação osmótica e da embalagem com atmosfera modificada passiva na vida útil das frutas. Amostras de manga fresca, acondicionadas nas condições do ar atmosférico, foram utilizadas como controle. As mangas foram avaliadas periodicamente quanto às suas características físico-químicas e microbiológicas, composição da atmosfera interna das embalagens, perda de peso e aceitação sensorial. O processo de desidratação osmótica e o acondicionamento das frutas com atmosfera modificada influíram positivamente na manutenção das características sensoriais e na qualidade microbiológica das fatias de manga. As fatias de manga fresca acondicionadas nas condições do ar atmosférico (FR AR) e com atmosfera modificada (FR MAP) apresentaram uma vida útil de apenas 8 e 14 dias, respectivamente, sendo limitada principalmente por sua aceitação sensorial e contaminação microbiológica. Já as frutas desidratadas osmoticamente e embaladas com atmosfera modificada (OD MAP) apresentaram uma vida útil de 18 dias com boa aceitação sensorial durante toda a estocagem.

Carnes processadas refrigeradas são produtos de alto valor agregado, tradicionalmente acondicionados a vácuo em embalagens plásticas, que minimizam o contato do produto com o oxigênio do ar e, consequentemente, prolongam sua vida útil. Neste trabalho mapearam-se os materiais utilizados no mercado nacional para embalagens termoformadas de lingüiças, salsichas e frios fatiados e para embalagens tipo cook in de presuntos e apresuntados. Basicamente são utilizadas estruturas coextrusadas ou uma combinação de coextrusão com laminação (tampas). Poliamidas, EVOH e PET-PVDC são os materiais utilizados para conferir às embalagens barreira ao oxigênio. A TPO2 dos filmes fundo para termoformação variou entre 5 e 30cm³ (CNTP)/m²/dia, com valores mais baixos para os frios fatiados. A TPO2 das tampas foi da ordem de 10 cm³(CNTP)/m²/dia, todos a 23 °C e a úmido. A resistência à perfuração ficou em torno de 25N (tampa) e 35N (fundo - linguiças/salsichas). Nos filmes fundo para frios fatiados houve grande variação na resistência à perfuração, em decorrência da ampla gama de espessuras disponíveis. Embalagens de mercado foram avaliadas quanto a integridade das selagens e distribuição de espessura do filme termoformado. Não foram detectados problemas de fechamento. A redução na espessura total do filme fundo, no canto de bandejas (região crítica) para salsichas e lingüiças, que têm maior profundidade de termoformação, variou entre 42 e 65%, o que leva a uma significativa perda de barreira a gases da estrutura e justifica o emprego de EVOH, um polímero de alta barreira a gases, a fim de não comprometer a vida útil do produto. Refrigerated processed meats are high added-value products traditionally vacuum-packed in plastic packages to minimize contact of the product with oxygen and, consequently, prolong their shelf life. This study aimed at elaborating a comprehensive and detailed overview of the packaging materials used on the Brazilian market to manufacture thermoformed packages for sausages, hot dogs and sliced processed meat, in addition to cook in-type packages for hams and restructured ham products. Basically, the materials most used are coextruded films or a combination of coextruded and laminated (top film) structures. Polyamides, EVOH and PET-PVDC are used to provide an oxygen barrier. The oxygen transmission rate (O2TR) of bottom films for thermoformed packages varied between 5 and 30 cm³ (STP)/m²/day, with lower values for the films used in the package of sliced processed meat. The O2TR of top films were of the order of 10 cm³(STP)/m²/day, determined at 23 °C under wet conditions. Perforation resistance was about 25N (top films) and 35N (bottom films-sausages/hot dogs). The bottom films for sliced processed meat varied considerably in terms of puncture resistance due to the wide range of thickness available. A series of packages currently in use on the Brazilian market were evaluated for seal integrity and thickness distribution of the thermoformed film. No sealing problems were detected. The reduction of total film thickness at the corner of flexible trays (critical area) for sausages and hot dogs, whose depth is larger than for sliced processed meat packages, varied between 42 and 65%. The reduced thickness at the corners significantly affects the gas barrier properties of the package and justifies the use of EVOH which does not cause the shelf life to decrease.

Goiabas (Psidium guajava L.), variedade vermelha "Paluma", minimamente processadas por desidratação osmótica branda, foram acondicionadas em embalagens rígidas de polietileno tereftalato (PET) e estocadas à temperatura de 5ºC, com o objetivo de avaliar a influência da embalagem sob atmosfera modificada e do processo de desidratação osmótica na vida-de-prateleira do produto. Goiabas sem o tratamento osmótico, acondicionadas nas embalagens de PET e em ar atmosférico, foram utilizadas como controle. Durante a estocagem foram avaliadas a perda de peso, a contaminação microbiológica, as características físico-químicas do produto e as concentrações de O2 e CO2 no interior das embalagens. As goiabas foram submetidas também a uma análise sensorial de aceitação, acompanhada da avaliação da intenção de compra do produto pelo consumidor. Verificou-se que a combinação da temperatura de estocagem, da embalagem sob atmosfera modificada passiva e do processo de desidratação osmótica proporcionou às goiabas minimamente processadas uma vida-de-prateleira de 24 dias, resultando num produto mais estável à contaminação microbiológica e com características sensoriais superiores às amostras controle, apresentando, também, melhor aceitação pelo consumidor. Guavas (Psidium guajava L.), var. "Paluma", minimally processed by mild osmotic dehydration, were packed in polyethylene terephthalate (PET) trays and stored at 5ºC, with the objective to evaluate the modified atmosphere package and osmotic dehydration influence on the shelf life of the product. Non-treated guavas, packed in PET trays and in atmospheric air, were used as control. Weight loss, microbial spoilage, physico-chemical characteristics of the product and oxygen and carbon dioxide concentrations inside the packages were evaluated during the shelf life of the product. The guavas were submitted to a sensory analysis and the purchase intention was also evaluated. The combination of storage temperature, passive modified atmosphere package and osmotic dehydration process provided a 24-day shelf life to the minimally processed guavas, resulting in a microbiologically more stable product with better sensory attributes than the control samples, also showing better acceptance by the consumer.

Frutos de melão do tipo, rendilhado cv. Bônus II, foram minimamente processados na forma de cubos e acondicionados em embalagens de diversos materiais sendo, em seguida, armazenados a 3ºC. Nas embalagens foram utilizados os materiais: AFG: filme poliolefínico da DuPont 15µm, HP: filme poliolefínico da DuPont 15µm, PD-900: filme poliolefínico da Cryovac 58µm, PEBD: filme de polietileno de baixa densidade 87µm, PP: filme de polipropileno 52µm, BB-200: filme multicamada da Cryovac 65µm, PET: embalagem rígida de polietereftalato de etileno. Foram determinadas as taxas de permeabilidade ao O2 e ao CO2 de cada uma das embalagens. As composições gasosas do espaço livre das embalagens foram determinadas diariamente durante 8 dias e no 9º dia as características físico-químicas e sensoriais foram avaliadas. A taxa respiratória foi determinada nos melões inteiros e nos melões minimamente processados. Os filmes utilizados não promoveram modificação efetiva da atmosfera, mas a embalagem rígida de PET proporcionou, a partir do 6º dia, uma atmosfera de equilíbrio com 12% O2 e 7% CO2. As características físico-químicas dos melões foram mantidas em todos os tratamentos, enquanto as características sensoriais foram mantidas apenas nos melões acondicionados na embalagem rígida de PET. A modificação passiva da atmosfera, para melão minimamente processado armazenado a 3ºC, não foi verificada na extensão desejada com as embalagens estudadas, provavelmente devido à baixa taxa respiratória observada nesta temperatura, associada à alta relação entre área de permeação da embalagem e massa de melão. Fruits of net melon cv. Bonus II were minimally processed as cubes, wrapped in several plastic materials and stored at 3ºC for 9 days. The following materials were used for packaging: AFG: DuPont polyolephinic film 15µm; HP: DuPont polyolephinic film 15µm, PD-900: Cryovac polyolephinic film 58µm, PEBD: low density polyethylene film 87µm; PP: polypropylene film 52µm; BB-200: Cryovac multilayer film 65µm; PET: rigid polyethylene terephtalat tray. The gas permeability of each film was determined. The gas composition within the packages was evaluated every day during 8 days and the physico-chemical and sensorial characteristics were evaluated on the 9th day. The melon respiration rate was determined before and after processing. The packaging systems did not promote effective atmosphere modification, except for the PET tray which promoted, after the 6th day, an equilibrium atmosphere of 12% O2 and 7% CO2. Physical-chemical characteristics of the processed melons were maintained in all treatments during storage, whereas sensorial characteristics were kept only for the melons in the PET tray. Passive atmosphere modification was not effective for fresh cut melons stored at 3ºC. Probably due to the low respiration rate at this temperature associated with the high relationship between permeation area of the packages and melon mass.