Espumas à base de amido possuem limitações para utilização como embalagens na indústria alimentícia, principalmente, devido à alta hidrofilicidade e fragilidade. Para melhorar essas propriedades, torna-se necessário o uso de plastificantes e outros aditivos, como proteínas e fibras lignocelulósicas, ou ainda um aditivo fonte desses recursos, como a torta de gergelim obtida como resíduo do processamento do gergelim. Sendo assim, o objetivo deste trabalho foi desenvolver e caracterizar espumas à base de amido de mandioca adicionadas de 0 – 40 % (m/m) de resíduo de gergelim, produzidas pelo processo de expansão térmica, a fim de avaliar a influência do aditivo nas propriedades físicas, morfológicas e mecânicas dos materiais obtidos para utilização como embalagens para alimentos. A adição do resíduo resultou em espumas com menores espessuras e densidade aparente, bem como, maior capacidade de expansão dos materiais. Além disso, apresentaram melhores propriedades mecânicas e, em geral, menores capacidade de absorção de água e adsorção de água em baixas umidades relativas, em relação aos materiais compostos somente por amido. Embora as propriedades mecânicas das espumas sejam influenciadas pelas condições de umidade relativa de armazenamento, as espumas contendo 20 % de resíduo (20R) apresentaram uma combinação de propriedades no ensaio de tração (resistência à tração e módulo de elasticidade) que podem ser consideradas comparáveis às amostras de bandejas comercias de poliestireno expandido (EPS), nas três umidades relativas avaliadas (33, 53 e 90 %). Os resultados obtidos nos ensaios de flexão dessas espumas indicaram que as mesmas foram mais rígidas e menos flexíveis do que as amostras de EPS. A adição de 20 % de resíduo resultou em importantes melhorias nas propriedades físicas e mecânicas em comparação às espumas à base de amido de mandioca, além de apresentarem menos defeitos morfológicos do que os observados em espumas com maiores teores do resíduo (30 e 40 %). Foram realizados testes de aplicação das espumas 20R no acondicionamento de dois tipos de alimentos com diferentes teores de umidade: bolo (23 %) e brócolis (91 %), em comparação ao armazenamento em embalagens comerciais de EPS. A partir dos resultados obtidos para a variação de umidade, perda de massa e propriedades mecânicas na flexão das embalagens, foi observado que as espumas propostas não foram adequadas para o acondicionamento das amostras de brócolis, apresentando alta absorção de umidade e deformações após três dias de contato com o alimento. Por outro lado, as espumas 20R mostraram bom desempenho no acondicionamento das amostras de bolo, não apresentando mudanças significativas nas propriedades mecânicas no período de 3 a 9 dias de armazenamento. Dessa forma, o resíduo de gergelim em combinação com o amido de mandioca mostrou elevado potencial para o desenvolvimento de espumas que podem ser utilizadas como embalagens para alimentos com baixos teores de umidade, sendo necessários estudos mais detalhados, considerando principalmente aspectos de segurança para utilização de resíduos em produtos em contato direto com alimentos. / Starch based foams have limitations for use as food packaging, mainly due to high hydrophilicity and fragility. In order to improve these properties it is necessary the use of plasticizers and others additives, such as lignocellulosic fibers and proteins, or an additive source of these constituents like sesame cake, which it is obtained from sesame processing. In this way, the main objective of this work was to develop and characterize starch based foams added with 0 – 40 % (w/w) of sesame residue to evaluate the influence of this additive on physical, morphological and mechanical properties of materials for using as food packaging. The foams were produce by thermal expansion process. Residue addition resulted in foams with smaller thickness and density, as well as greater expansion capacity of the materials produced. In addition, foams incorporated with residue exhibited better mechanical properties and, in general, lower water capacity absorption and water adsorption at low relative humidities compared to foams made only with starch. Although mechanical properties of the foams are affected by storage humidity conditions, foams added with 20 % of residue (20R) showed tensile properties (tensile strength and tensile elasticity modulus) that can be considered comparable to expanded polystyrene (EPS) commercial trays for different relative humidities evaluated (33, 53 and 90 %). Flexural properties indicated that starch foams produced was tougher and less flexible than EPS commercial trays. Addition of 20 % of sesame residue on cassava starch-based foams resulted in relevant improvements compared to foams without residue. Besides that, fewer morphological defects were noted, as observed in foams with higher residue content (30 and 40 %). Thus, 20R formulation was selected to carrying out applicability tests of starch-based foams in packaging of two types of food with different moisture content: cake (23 %) and broccoli (91 %) compared to EPS commercial packaging. From the results obtained for moisture variation, loss of weight and flexural properties of the foams, it was found that the material proposed was not applicable to package broccoli samples. Due to high water absorption by the foams alterations on the shape were noted in the materials after 3 days in contact with this food. Nonetheless, foams based on cassava starch and 20 % of sesame residue exhibited a good performance during storage time of cake samples (9 days). It was not observed any effect on flexural mechanical properties for 3 to 9 days of storage. Thereby, sesame cake added to cassava starch showed high potential to developing foams that could be used as packaging for low moisture food. Additionally, more detailed studies are necessary, especially considering safety aspects mainly for using agricultural residues directly in contact with food products.

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / O objetivo desse trabalho foi desenvolver filmes biodegradÃveis à base de amido e goma de cajueiro, acrescidos ou nÃo de montmorilonita. Em uma primeira etapa, foi feito um delineamento experimental composto central a partir de misturas entre amido e goma de cajueiro (1:1, m:m) adicionadas de diferentes concentraÃÃes da argila montmorilonita (0 a 15% - MMT) e tempos de ultrassom (0 a 5 min), onde foi realizado um estudo das variaÃÃes de desempenho de filmes produzidos por deposiÃÃo (casting), em funÃÃo das variÃveis. Os filmes foram avaliados em termos de propriedades Ãticas, mecÃnicas, de barreira e tÃrmicas e analisados por Microscopia eletrÃnica de varredura (MEV) e Ãngulo de contato. Em uma segunda etapa do trabalho, as formulaÃÃes dos filmes amido e goma de cajueiro (AGC) e os de amido, goma de cajueiro e montmorilonita AGC-MMT foram testadas como revestimentos para amÃndoas de castanhas de caju. As amÃndoas revestidas com AGC e AGC-MMT, assim como um controle (amÃndoas sem revestimento), foram acondicionadas em sacos plÃsticos de polietileno de baixa densidade, estocadas em temperatura e umidade ambiente e tiveram sua estabilidade avaliada. Os testes de estabilidade realizados foram baseados em medidas de absorÃÃo de umidade, atividade de Ãgua e do grau de oxidaÃÃo das amÃndoas (determinado por Ãndice de perÃxido e Ãndice de acidez). O incremento de MMT interferiu nas propriedades Ãticas dos filmes, aumentando sua opacidade. A permeabilidade ao vapor de Ãgua dos filmes produzidos foi significativamente (p < 0,05) reduzida pela MMT. A resistÃncia à traÃÃo e o mÃdulo elÃstico apresentaram valores mÃximos em uma faixa intermediÃria de concentraÃÃo de MMT. O tempo de ultrassom favoreceu a dispersÃo da argila em concentraÃÃes baixas de MMT, porÃm em concentraÃÃes maiores favorece a formaÃÃo de aglomerados, o que tambÃm à visualizado nas micrografias obtidas por MEV. Com o aumento do tempo de ultrassom, a resistÃncia à traÃÃo e o mÃdulo tenderam a aumentar. As curvas de DSC do amido, goma de cajueiro e do filme produzido sem MMT apresentaram picos endotÃrmicos similares em torno de 110ÂC, que podem estar relacionados à superposiÃÃo de eventos como vaporizaÃÃo da Ãgua e fusÃo da fase cristalina dos componentes. A medida do Ãngulo de contato comprovou que os filmes produzidos sÃo altamente hidrofÃlicos. Os testes de estabilidade realizados mostram que os revestimentos AGC e AGC-MMT conferem menor acidez e Ãndice de perÃxidos quando comparados a um controle podendo ser uma alternativa para aumento da vida de prateleira das amÃndoas de castanhas de caju, servindo como embalagem primÃria. / The purpose of this study was to develop biodegradable films based on starch and cashew gum, added or not with montmorillonite. At a first stage, a central composite experimental design was carried out from mixtures of starch and cashew gum (1:1, m: m) added with different concentrations of montmorillonite (0-15% - MMT) and submitted to variable ultrasound times (0-5 min), In a study of variations in the performance of films produced by casting. The films were evaluated in terms of optical properties, mechanical, barrier and thermal. As well as scanning electron microscopy (SEM) and contact angle. In a second stage of the work, the formulations of the films based on starch and cashew tree gum (SCG) and starch cashew tree gum and montmorillonite (SCG-MMT) were tested as coatings for cashew kernels. The kernels coated with SCG and SCG-MMT, as a control (uncoated kernels) were placed in plastic bags of low density polyethylene, stored at room temperature and relative humidity and their stability were evaluated. Stability tests were based on measurements of moisture absorption, water activity and the degree of oxidation of almonds (determined by peroxide value and acid value). The increase of MMT concentration interfered with the optical properties of the films, increasing its opacity. The water vapor permeability of films was significantly (p <0.05) reduced by the MMT. The tensile strength and elastic modulus showed a peak in an intermediate range of concentration of MMT. The time of ultrasound favors the dispersion of clay in low concentrations of MMT, but at higher concentrations et led to formation of agglomerates, which also appeared in SEM micrographs. With the increase of ultrasound times tensile strength and modulus tended to increase. DSC curves of starch, cashew gum and the film produced without MMT the endothermic peaks had similar MMT about 110  C, that may be related superposition events such as the vaporization of water and melting of the crystalline phase of the components. The contact angle measurement showed that the films are highly hydrophilic. Stability tests performed show that the coatings AG and AG-MMT give less acidity and peroxide value when compared to a control, may be an alternative of the use to increase the shelf life of almonds cashew nuts serving as primary packaging.

No description available.

Childhood obesity is a major public health issue. Canada has one of the highest childhood obesity rates in the world. Food advertising and marketing have contributed to the rapid rise in childhood obesity. High energy and low nutrient foods have been promoted directly to children through attractive imagery on packages, including the use of popular cartoon characters. Children’s food packaging also features a range of nutrition information targeted at parents, including nutrition claims; however, there is relatively little research on the impact of these nutrition claims and the extent to which they may interact with child-friendly imagery to influence parents’ perception of food quality. The current study used a 2 x 2 experimental design to examine the effect of four front-of-package (FOP) nutrition information and four cartoon characters on parental perceptions of children’s food products. Participants consisted of 897 parents recruited across Canada through GMI, a market research company. Participants were over 18, had at least one child between ages 4-10 and the primary shopper of their household. Participants completed an online survey in July 2011. Participants were shown images of food products with or without cartoon characters and with or without FOP nutrition information and were asked to rate the food product on appeal, nutritional quality, intention to buy and willingness to pay. Participants were also asked to rate the FOP nutrition information on believability, ease of understanding and perceived effectiveness. Linear mixed modelling examined the influence of cartoon characters, FOP nutrition information and socio-demographic factors on these outcomes. Results indicated that cartoon characters increased product appeal and FOP nutrition information increased the perceived nutritional quality of food products with low nutritional value. No significant differences were observed for intention to buy or willingness to pay. There was no consistent pattern between socio-demographic factors and product rating outcomes. For FOP nutrition information ratings, Health Check and Source of Fibre were rated more believable, easier to understand and more effective overall than Sensible Solution and Given the Thumbs Up by Kids. Overall, the findings indicate that cartoon characters can increase the perceived appeal and FOP nutrition information can increase the perceived nutritional quality of food products with low nutritional value.

This thesis addresses a new technique of foaming on polymer-paperboard composites which combines the advantages of traditional polymeric foam with the environmental benefits of paperboard. Paperboard is sandwiched between two extruded polymeric layers of different densities. On application of heat, one face is foamed by the evaporating moisture in the board; the other face serves as a barrier. This work is directed at gaining a better understanding of the fundamental processes in foaming polymers on paperboard. The ultimate goal is to be able to produce uniform bubbles of a predetermined size on the surface so as to give optimum heat insulation and good tactile properties. Bubble growth was studied as a function of paperboard properties, polymer melt index, extrusion speed, polymer thickness, temperature and moisture content. The foam quality (thickness) is also related to the cell size distribution and various factors affecting it are identified. A combination of experimental techniques such as high speed imaging, infrared thermography and scanning electron microscopy is used for this purpose. Foaming on paper-polymer composites is caused by water vapor escaping through the pores present in the paperboard substrate and then foaming the polymer. The vapor driving force which dominates foaming and overcomes the less significant viscoelastic and surface tension opposition forces depends on the paperboard properties as well as on the ability of the polymer to bond with the paperboard. It was found that the bubble size distribution directly relates to the pore size distribution on the paperboard. The bubble size was also controlled by the thickness of the polymer layer and its ability to bond with the paperboard. Coalescence subsequently led to thicker foams due to the formation of larger sized bubbles.

The major objective of this project was to evaluate the feasibility of artificial neural networks (ANNs) and genetic algorithms (GAs) for modeling and optimization of food thermal processing. The specific objectives were: (1) to develop a comprehensive computer simulation program for thermal processing, (2) to apply ANNs and GAs for modeling and optimization of constant retort temperature (CRT) thermal processing and variable retort temperature (VRT) thermal processing, (3) to develop dynamic models for thermal processing using ANNs, and (4) to explore ANN-model-based analysis of critical control points for deviant thermal processes. / As a preliminary research, neural network models were successfully developed for modeling of residence time distribution (RTD) under aseptic processing conditions. The main configuration parameters of neural networks such as the number of hidden layers and their neurons, learning runs, choice of transfer functions and learning rules were optimized. / In order to provide experimental data needed for developing and testing of ANN models and GA optimization, a comprehensive finite difference computer simulation program for thermal processing was first developed in MS Visual Basic language, which could be used for simulating different thermal processes such as constant retort temperature (CRT) and variable retort temperature (VRT) thermal processing. / The second objective was focused on developing modeling and optimization methods for CRT thermal processing using ANNs and GAs. The ANN models were developed for predicting process time, average quality retention, surface cook value, final temperature difference, lethality ratio, and equivalent energy consumption. Using this optimization program, the effects of process variables on the optimal retort temperature and the maximum average quality retention were investigated. / The final part of the thesis research was focused on applying ANN methods for the analysis of critical control points (CCPs) for deviant thermal processes, one of the important steps required for developing hazard analysis of critical control points (HACCP) program. The results indicated that ANN models could be efficiently used for the analysis of CCPs of thermal processing. Such a concept can be expanded for developing an ANN based HACCP expert system for thermal processing. (Abstract shortened by UMI.)

A granola-type, omega-3-rich breakfast cereal prototype was developed using ground flaxseed as the principal source of linolenic acid (1.8% w/w). Other ingredients included rolled oats, yellow sugar, honey, sliced almonds, and canola oil. The focus of the research investigation was to apply and study the addition of an antioxidant (AO) and the use of Modified Atmosphere Packaging (MAP) on shelf-life extension of the enriched cereal. Granola samples, both with and without AO (300ppm of 70% mixed tocopherols), were packaged in air, and under the two atmospheres achieved by nitrogen flushing (MA 1) and an oxygen scavenger (MA2). Samples were stored at either 21 or 35°C. / Shelf-life was terminated when products reached a thiobarbituric acid (TBA) value of 4.0 mg malonaldehyde/kg corresponding to a sensory score of 5 (on a hedonic scale of 10). (Abstract shortened by UMI.)

Oxygen scavengers are used in active packages to protect the food against deteriorative oxidation processes. The aim of this work was to investigate the possibilities to produce oxygen-scavenging packaging materials based on oxygen-reducing enzymes. The enzymes were incorporated into a dispersion coating formulation applied onto a food-packaging board using conventional laboratory coating techniques. Various enzymes were used: a glucose oxidase, an oxalate oxidase and three laccases originating from different organisms. All of the enzymes were successfully incorporated into a coating layer and could be reactivated after drying. For at least two of the enzymes, re-activation was possible not only by using liquid water but also by using water vapour. Re-activation of the glucose oxidase and a laccase required relative humidities of greater than 75% and greater than 92%, respectively. Catalytic reduction of oxygen gas by glucose oxidase was promoted by creating an open structure through addition of clay to the coating at a level above the critical pigment volume concentration. Migration of the enzyme and the substrate was reduced by adding an extrusion-coated liner of polypropylene on top of the coating. For the laccase-catalysed reduction of oxygen it was possible to use lignin derivatives as substrates for the enzymatic reaction. The laccase-catalysed reaction created a polymeric network by cross-linking of lignin-based entities, which resulted in increased stiffness and increased water-resistance of biopolymer films. The laccases were also investigated with regard to their potential to function as oxygen scavengers at low temperatures. At 7°C all three laccases retained more than 20% of the activity they had at room temperature (25°C), which suggests that the system is also useful for packaging of refrigerated food.

The food packaging industry is a £300bn global industry growing at a rate of 12% per year and increasingly favouring polymer or polymer-based materials. This generates 58m tonnes of "plastic" packaging waste annually in the EU and poses significant challenges for management given existing legislative constraints and increasing concerns surrounding the environmental impacts. The government, consumers, food retailers and pressure groups are all driving the demand for biodegradable packaging from renewable resources that can be disposed of with reduced impacts to the environment. Green Peace has devised a pyramid classification system of "Poisonous Plastics", which ranks plastics in terms of their harmfulness to the environment. They are campaigning against the use of oil-based materials and advocating the take up of biodegradable materials. The market for biodegradable food packaging is expanding rapidly but is still in its early stages of development and has not reached a critical mass to achieve significant market penetration. This is predominantly due to a lack of suitable materials that meet all environmental, functional and economical requirements. Whilst the long-term solution requires continued efforts in materials research and development, in the shorter term, changing working practices can abate the environmental impact of the industry. This research project tackled the challenge of environmental packaging from several directions: A novel starch-based material was developed that would fill the current gap in the food packaging market and facilitate recovery of the used materials by home composting. Using the sponsoring organisation as a case study, it was proved that by changing working practices by increasing rework and re-processing waste material for use in lower grade applications, both manufacturing costs and environmental impact can be reduced, thus benefiting both industry and the environment. A Life Cycle Assessment of selected biopolymers and oil-based polymers confirmed Green Peace's damning view of PVC and highlighted the need to develop biopolymers further. A domestic composting study of a range of commercially available "biodegradable" polymer materials revealed that a number of biodegradable packaging materials may typically biodegrade well in industrial high-temperature composting systems but fail to biodegrade under a low-temperature home composting environment and thus alerted the potential pitfall in waste management of some biodegradable polymers.

Childhood obesity is a major public health issue. Canada has one of the highest childhood obesity rates in the world. Food advertising and marketing have contributed to the rapid rise in childhood obesity. High energy and low nutrient foods have been promoted directly to children through attractive imagery on packages, including the use of popular cartoon characters. Children’s food packaging also features a range of nutrition information targeted at parents, including nutrition claims; however, there is relatively little research on the impact of these nutrition claims and the extent to which they may interact with child-friendly imagery to influence parents’ perception of food quality. The current study used a 2 x 2 experimental design to examine the effect of four front-of-package (FOP) nutrition information and four cartoon characters on parental perceptions of children’s food products. Participants consisted of 897 parents recruited across Canada through GMI, a market research company. Participants were over 18, had at least one child between ages 4-10 and the primary shopper of their household. Participants completed an online survey in July 2011. Participants were shown images of food products with or without cartoon characters and with or without FOP nutrition information and were asked to rate the food product on appeal, nutritional quality, intention to buy and willingness to pay. Participants were also asked to rate the FOP nutrition information on believability, ease of understanding and perceived effectiveness. Linear mixed modelling examined the influence of cartoon characters, FOP nutrition information and socio-demographic factors on these outcomes. Results indicated that cartoon characters increased product appeal and FOP nutrition information increased the perceived nutritional quality of food products with low nutritional value. No significant differences were observed for intention to buy or willingness to pay. There was no consistent pattern between socio-demographic factors and product rating outcomes. For FOP nutrition information ratings, Health Check and Source of Fibre were rated more believable, easier to understand and more effective overall than Sensible Solution and Given the Thumbs Up by Kids. Overall, the findings indicate that cartoon characters can increase the perceived appeal and FOP nutrition information can increase the perceived nutritional quality of food products with low nutritional value.