CAPES; Fundação Araucária / Tendo em vista evitar limitações de aplicação de ingredientes funcionais à alimentos, por modificação de sabor, diferenças de textura, bem como por instabilidade, durante o processamento e armazenamento, a microencapsulação é uma alternativa cada vez mais utilizada. Neste trabalho foi avaliada a adição de óleo de chia (Salvia hispanica), conhecido pela sua composição rica em ácidos graxos ômega-3, em cookies. Para isso, foram produzidas três formulações: cookies controle, cookies adicionados de micropartículas lipídicas sólidas de óleo de chia (1% com relação à farinha de trigo OC-E) e cookies adicionados óleo de chia puro (na mesma proporção presente nas microcápsulas, OC-P). Micropartículas de cera de carnaúba contendo óleo de chia foram produzidas por homogeneização a quente com tamanho médio de 20,8 µm com morfologia esférica e com larga distribuição de tamanhos e com cristalinidade reduzida em comparação à cera de carnaúba pura (micropartículas branco). Análises farinográficas foram realizadas para verificar o efeito da adição das micropartículase do óleo na processabilidade da massa. Os resultados demonstraram diferença significativa (p < 0,05) na absorção de água, sem afetar o tempo de desenvolvimento da estabilidade da massa Os cookies produzidos não apresentaram diferença com relação à umidade e cinzas, porém quanto à análise de cor, durante o armazenamento (30 dias) a luminosidade dos cookies OC-E aumentou significativamente com o tempo de armazenamento de 69,51 para 71,75. Possivelmente este comportamento se deve ao fato da matriz lipídica apresentar instabilidade ao longo do tempo de armazenamento, levando à expulsão de parte do óleo de chia microencapsulado. Os cookies OC-E também tiverem seu parâmetro b* significativamente maior (p<0,05) que o controle e OC-P, devido à coloração das micropartículas, mais amarelada. Dos parâmetros da análise de perfil de textura o único que apresentou diferença significativa entre os tratamentos e entre os dias de armazenamento (0, 15 e 30 dias) (p < 0,05) foi a dureza, possivelmente devido à gordura livre presente nas amostras OC-E e OC-P desestabilizarem a rede de glúten resultando em massas mais suaves. Já no teste de três pontos de flexão (probe de bigorna tripla) os resultados de fratura por estresse e tensão na fratura mostraram condições estatisticamente iguais para todos os tratamentos. A avaliação da oxidação lipídica dos cookies foi feita por meio da extração da gordura dos mesmos com método Bligh-Dyer e análise dos coeficientes de extinção específicos (K232, K270 e Δk). Os resultados mostraram que a amostra OC-E foi a que sofreu maior oxidação, seguido de OC-P e controle. Possivelmente alguns componentes da cera de carnaúba, composta por mistura de ésteres de ácidos de alto peso molecular e de hidroxiácidos, sofreram oxidação, bem como o óleo de chia puro, devido as insaturações dos ácidos graxos. Os cookies foram avaliados quanto a sua atividade de água por isoterma de sorção a 25 e 35°C onde foram determinadas os modelos que apresentaram maior ajuste e menor erro, sendo para as amostras controle (25°C e 35°C) o modelo GAB, para as amostras OC-E (25°C e 35°C) o modelo BET e para as amostras OC-P a 25°C o modelo de Peleg epara 35°C o modelo BET. Por fim, a avaliação sensorial foi realizada pelo teste de aceitação global onde foi possível concluir que, para todos os atributos avaliados, as amostras de CO-P e CO-E não diferiram da amostra controle, o que é um resultado satisfatório. / In order to avoid limitations of application of functional ingredients to food, by modification of flavor, differences in texture, as well as instability, during processing and storage, microencapsulation is an increasingly used alternative. In this work the addition of chia oil (Salvia hispanica), known for its composition rich in omega-3 fatty acids, was evaluated in cookies. For this, three formulations were produced: control cookies, cookies added solid lipid microparticles of chia oil (1% with respect to wheat flour OC-E) and cookies added pure chia oil (in the same proportion present in microcapsules, OC -P). Carnauba wax microparticles containing chia oil were produced by hot homogenization with a mean size of 20.8 μm with spherical morphology and wide size distribution and with reduced crystallinity compared to pure carnauba wax (white microparticles). Farinographic analyzes were performed to verify the effect of the addition of the oil microparticle in the processability of the mass. The results showed a significant difference (p <0.05) in the water absorption, without affecting the time of development of the mass stability. The cookies produced did not present difference with regard to moisture and ashes, however, regarding color analysis during storage (30 days) the brightness of OC-E cookies increased significantly with storage time from 69.51 to 71.75. Possibly this behavior is due to the fact that the lipid matrix presents instability throughout the storage time, leading to the expulsion of part of the microencapsulated chia oil. The OC-E cookies also had their parameter b * significantly larger (p <0.05) than the control and OC-P, due to the more yellowish microparticle staining. From the parameters of the texture profile analysis, the only one that presented significant difference between the treatments and between storage days (0, 15 and 30 days) (p <0.05) was the hardness, possibly due to the free fat present in the samples OC-E and OC-P destabilize the gluten network resulting in softer masses. In the three-point bending test (triple anvil probe) the fracture stress and fracture stress results showed statistically equal conditions for all treatments. The evaluation of the lipid oxidation of the cookies was done by means of the extraction of the fat of the same ones with Bligh-Dyer method and analysis of the specific extinction coefficients (K232, K270 and Δk). The results showed that the OC-E sample underwent the highest oxidation, followed by OC-P and control. Possibly some components of carnauba wax, composed of mixture of esters of high molecular acids and hydroxy acids, underwent oxidation, as well as pure chia oil due to unsaturations of fatty acids. Cookies were evaluated for their water activity by sorption isotherm at 25 and 35 ° C where they were determined (25 ° C and 35 ° C) the GAB model, for the OC-E samples (25 ° C and 35 ° C) the BET model and for the samples OC-P at 25 ° C the Peleg model and at 35 ° C the BET model. Finally, the sensorial evaluation was carried out by the global acceptance test, where it was possible to conclude that for all attributes evaluated, CO-P and CO-E samples did not differ from the control sample, which is a satisfactory result.

Orientador: Roberto Herminio Moretti / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-04T02:30:32Z (GMT). No. of bitstreams: 1 Freitas_DanielaDeGrandiCastro_D.pdf: 989026 bytes, checksum: c9f4c5d7a467d08716626299b2917043 (MD5) Previous issue date: 2005 / Resumo: Nutrientes são necessários para o desenvolvimento e crescimento dos indivíduos. No entanto, uma nutrição preventiva pode proteger, minimizar ou mesmo protelar riscos a saúde que podem ser causados por pré-disposições genéticas, maus hábitos alimentares e até agressões do meio ambiente. As evidências epidemiológicas estão continuamente providenciando recomendações para que as pessoas consumam mais frutas e vegetais como medida preventiva para reduzir o risco de diversas doenças degenerativas. É notável o aumento do consumo de alimentos saudáveis devido à crescente preocupação com a melhoria da qualidade de vida, porém, o ritmo da vida moderna exige alimentos práticos. Dentro deste contexto, do crescimento visível do desenvolvimento de alimentos para fins especiais, da necessidade de combinar saúde e praticidade, e de reunir alguns ingredientes que vem recebendo grande atenção para a aplicação nestes alimentos funcionais, é que se elaborou o estudo de desenvolvimento e estabilidade de barra de cereais a base de proteína de soja, gérmen de trigo e aveia, incluindo como ingrediente a lecitina de soja, e suplementada com vitaminas C e E. Este trabalho teve por objetivo o desenvolvimento da formulação da barra de cereais e a avaliação das características físico-químicas, vitamínicas, enzimáticas, sensoriais e de textura durante o seu armazenamento. Um estudo preliminar de inativação enzimática no gérmen de trigo foi realizado devido à susceptibilidade a rancidez, fator adverso de qualidade de cereais desidratados. Amostras de aveia laminada integral e gérmen (produto natural inalterado da moagem do trigo) foram caracterizadas e a atividade de lipase e peroxidase medidas. Foi utilizado um delineamento fatorial completo para estudar os efeitos dos fatores ¿temperatura¿ e ¿tempo¿ na inativação das enzimas e para a determinação das condições ótimas de redução de atividade no gérmen de trigo. Foram determinadas como condições ótimas tratamentos térmicos à temperatura na faixa de 180 a 190°C, com duração de 4,8 a 8,0 minutos e obtidas reduções significativas (p£0,5) na atividade residual da lipase e peroxidase. O gérmen de trigo teve seu teor de umidade ajustado para 28% e a torração foi realizada em estufa a 180°C por 8,0 minutos, para que pudesse ser utilizado como ingrediente da barra de cereais. Desenvolveu-se então uma formulação de barra de cereais funcional sabor banana com alto teor protéico, à base de proteína de soja, gérmen de trigo e aveia, e enriquecida de vitaminas C (ácido ascórbico) e E (acetato de a-tocoferol 50%). A barra de cereais e seus principais ingredientes foram submetidos a análises físico-químicas para caracterização e três formulações variando o teor de ácido ascórbico foram avaliadas quanto à aceitação sensorial e intensidade ideal de doçura e acidez. A proteína de soja texturizada utilizada apresentou elevados teores dos oligossacarídeos rafinose e estaquiose (1,92 g/100g e 4,66 g/100g) e de isoflavonas totais (283,49 mg/100g) se comparados ao grão, farinha integral e isolado protéico. A formulação final da barra de cereais apresentou 15,31% de proteína e elevado teor de vitamina E (118,0 mg/100g) e minerais como fósforo (P), cálcio (Ca), cobre (Cu), ferro (Fe), manganês (Mn) e zinco (Zn). A formulação adicionada de 1,1g/100g de ácido ascórbico obteve maior aceitação sensorial diferindo significativamente (p£0,5) das demais amostras. Esta formulação, preferida pela equipe sensorial, foi então submetida ao estudo de estabilidade durante o seu armazenamento. Foram utilizados como embalagens três filmes (A: PET/PEBD; B: PETmet/PEBD; C: PET/PEBD/AL/PEBD) com diferentes propriedades de barreira. As barras de cereais foram armazenadas em condições de temperatura e umidade relativa ambiente por um período de 180 dias. Durante o armazenamento, estudou-se a estabilidade das vitaminas C, vitamina E, e a atividade de lipase e peroxidase. No período de 180 dias, as barras de cereais acondicionadas nos três materiais testados apresentaram uma retenção de vitamina C menor que 50%. No entanto, a embalagem com folha de alumínio proporcionou menor velocidade de reação e maior tempo de meia vida de 146 dias. Os teores de vitamina E (acetato de a-tocoferol) nas barras de cereais apresentaram pequenas variações durante o armazenamento. Houve um aumento significativo (p£0,5) da atividade de peroxidase durante o período de 90 dias de estocagem nas embalagens testadas, provavelmente devido à regeneração dessa enzima, enquanto que a atividade de lipase não demonstrou aumento significativo durante os 180 dias de estocagem. Foram acompanhados também a umidade, atividade de água, pH, acidez total e medidas físicas associadas à textura como resistência ao corte, dureza e coesividade. A avaliação sensorial foi realizada através de teste de aceitação e intenção de compra durante o armazenamento. As barras de cereais formuladas com os ingredientes alternativos apresentaram variações na atividade de água (Aa), umidade e acidez total durante o armazenamento. A umidade das barras de cereais tendeu a um aumento, o que acarretou influência significativa (p£0,5) nas características de textura de resistência ao corte e dureza. As barras de cereais formuladas com proteína texturizada de soja, gérmen de trigo e aveia obtiveram boa aceitação sensorial perante consumidores nos atributos de sabor e aspectos visuais, porém, a aceitação tendeu a um declínio ao longo do tempo, associado à diminuição da intenção de compra do produto. O efeito das diferentes propriedades de barreira dos filmes de embalagens testados foi significativo (p£0,5) na estabilidade das barras de cereais ao longo do período de estocagem / Abstract: Nutrients are required for development and growth of individuals. However a preventative nutrition could be protected, minimized or delayed by way from health risks arising from genetic aggressions, the environment and also eating habits. Epidemiological evidence is constantly providing recommendations that people should consume more fruits and vegetables as a preventative measure to reduce the risk of various degenerative diseases. The increase in consumption of health foods is notable, due to the increasing concern with the improvement of life quality, although the pace of modern life demands practical foods. Within this context of a visible growth in the development of foods for special ends, of the need to combine health and practicality and aiming to bring together some ingredients which have received special attention for application in such functional foods, a study of the development and stabilization of a cereal bar based on soy protein, wheat germ and oat was elaborated, with the addition of soy lecithin and supplemented with vitamins C and E. Thus the objective of this study was the development and formulation of a cereal bar and an evaluation of its physicochemical, vitamin, enzymatic, sensory and texture characteristics during storage. A preliminary study of the enzymatic inactivation of wheat germ was carried out due to its susceptibility to rancidity, a process reducing the quality of dehydrated cereals. Samples of whole rolled oats and wheat germ (natural, unaltered product from wheat milling) were characterized and their lipase and peroxidase activities determined. A complete factorial design was used to study the effects of time and temperature in the inactivation of the enzymes and to determine the optimal conditions to reduce their activity in wheat germ. The optimal conditions were shown to be a temperature in the range from 180 to 190°C for between 4.8 and 8.0 minutes, obtaining significant (p£0,5) reductions in the residual activities of lipase and peroxidase. The moisture content of the wheat germ was adjusted to 28%, which was then roasted at 180°C for 8.0 minutes such that it could be used as an ingredient in cereal bars. A functional, banana flavored cereal bar was formulated with high protein content, based on soy protein, wheat germ and oat, and enriched with vitamins C (ascorbic acid) and E (50% a-tocopherol). The cereal bar and its main ingredients were characterized by way of physicochemical analyses, and three formulations, varying in their ascorbic acid contents, prepared and submitted to a sensory acceptance test and ideal test for the intensity of sweetness and acidity. The textured soy protein used showed high contents of the oligosaccharides raffinose and stachyose (1.92 g/100g and 4.66 g/100g) and of total isoflavones (283.49 mg/100g) as compared to the bean, whole flour and protein isolate. The final formulation of the cereal bar showed 15.31% protein and high contents of vitamin E (118.0 mg/100g) and minerals such as phosphorus (P), calcium (Ca), copper (Cu), iron (Fe), manganese (Mn) and zinc (Zn). The formulation with 1.1 g/100g of ascorbic acid was the most accepted sample, differing significantly (p£0,5) from the other samples. This most accepted formulation was submitted to an evaluation during storage. Three films were used for packaging: (A: PET/PEBD; B: PETmet/PEBD; C: PET/PEBD/AL/PEBD), each with distinctive barrier properties. The cereal bars were studied under environmental conditions of temperature and relative humidity for 180 days. Vitamins C and E stabilities and the activities of lipase and peroxidase were determined during storage. The cereal bars packaged in the three materials tested showed vitamin C retention below 50% after 180 days storage. However the packaging including aluminum foil provided a lower reaction velocity and longer half life of 146 days. The vitamin E (a-tocopherol acetate) contents of the cereal bars presented slight variations during storage. There was a significant increase in peroxidase activity during the first 90 days of storage in all the types of packaging tested, probably due to regeneration, whilst lipase activity showed no significant increase during the 180 days of storage. The moisture content, water activity, pH and total acidity were also determined during storage as well as the textural measurements of cutting resistance, hardness and cohesiveness. The acceptance and intention to buy tests were used for the sensory evaluation during storage. The cereal bars formulated with alternative ingredients showed variations in water activity (Aw), moisture content and total acidity during storage. The moisture contents of the cereal bars tended to increase during storage, with a significant (p£0,5) influence on the textural characteristics of cutting resistance and hardness The cereal bars formulated with textured soy protein, wheat germ and oats were well accepted by the consumers in the sensory evaluation (flavor and visual aspect), although the acceptance tended to decline during storage, associated with a decrease in intent to buy. The effect of the different barrier properties of the packaging films tested was significant (p£0,5) in the stability of the cereal bars during storage / Doutorado / Tecnologia de Alimentos / Doutor em Tecnologia de Alimentos

Este trabalho teve como objetivo avaliar o efeito de revestimentos comestíveis na qualidade de mamão \'Formosa\' minimamente processado durante armazenamento a 5°C por 15 dias. Os tratamentos foram: o controle, e os seguintes revestimentos: amido de arroz 3%, alginato de sódio 0,5% e carboximetilcelulose 0,25%. O uso de revestimentos causou alterações nos parâmetros físicos, físico-químicos e microbiológicos do mamão minimamente processado, quando comparado ao controle. As alterações mais importantes foram: menor contagem de coliformes totais; menor respiração dos mamões tratados com amido de arroz e maior dos tratados com carboximetilcelulose, ao longo do tempo; menor descoloração da polpa dos frutos ao longo do armazenamento; maior manutenção da firmeza das amostras tratadas com carboximetilcelulose; e redução do teor de sólidos solúveis e aumento da acidez titulável. Os revestimentos não afetaram os atributos sensoriais. Como a maioria dos efeitos positivos das coberturas ocorreu no 12° e 15° dias e, considerando o custo da tecnologia relacionado ao preço dos revestimentos, a melhor opção, até 9 dias de armazenamento, consiste em fazer apenas uma boa sanitização dos frutos, como feito no controle. No entanto, se o interesse for preservar a vida útil dos mamões por um período maior, até 15 dias, os revestimentos testados podem ser utilizados com resultados satisfatórios. / This study aimed to evaluate the effect of edible coatings on the quality of minimally processed \'Formosa\' papaya during storage at 5°C for 15 days. The treatments were: the control, and the following coatings: rice starch 3%, sodium alginate 0.5% and carboxymethylcellulose 0.25%. The use of coatings caused changes in the physical, physicochemical and microbiological parameters of minimally processed papaya, when compared to control. The most important changes were: lower counts of total coliforms; lower respiration of papayas treated with rice starch and higher of those treated with carboxymethylcellulose over time; less fruit pulp discoloration during storage, increased firmness maintenance of samples treated with carboxymethylcellulose; and reduction of soluble solids and increased acidity. The coatings did not affect the sensory attributes. Since most of the positive effects of the coatings occurred at the 12th and 15th days, and considering the technology cost related to the price of coatings, the best option, until 9 days of storage, is just to do a good sanitization of fruits such as that of control samples. However, if the interest is to preserve the shelf life of papayas for a longer period, up to 15 days, the coatings tested could be used with satisfactory results.

Thesis (M.Sc. (Horticulture)) -- University of Limpopo, 2022 / Cold storage is commonly used to prolong papaya fruit storability. Furthermore, the optimal recommended storage temperature is below 10℃ for export and distant market. However, chilling injury (CI) occurs at 10℃ or lower during prolonged cold storage. This condition hampered consumer acceptance, resulting in economic losses for producers and exporters. Therefore, the study aimed to investigate the potential of postharvest polyamine dips and storage conditions to improve the quality and shelf life of ‘Solo’ papaya fruit. The experiment was conducted as 4 x 2 factorial arranged in a completely randomised design (CRD) with eight replications. The fruits were treated with putrescine (PUT) (0 (control), 1, 2 and 3 mM) before storage for 21 days at 7.5 and 13℃ plus 5 days storage at ambient temperature. Additionally, the PUT effect on quality attributes and shelf-life were studied. The results showed that physiological and pathological disorders increased with progressive storage, irrespective of storage temperature. However, PUT treatment reduced the incidence of chilling injury and anthracnose at both 7.5 and 13℃. Additionally, the interaction of treatment and cold storage temperature significantly affected ‘Solo’ papaya fruit physical and biochemical quality attributes. Furthermore, treatment with 2 and 3 mM PUT concentration reduced changes in colour, mass, firmness, TA, and TSS compared to control. In conclusion, postharvest PUT improved ‘Solo’ papaya fruit quality and prolonged shelf-life. / AgriSETA (Agricultural Sector Training Authority)

É muito elevado o potencial de utilização do pescado na forma de minced fish - MF, servindo de matéria-prima para outros produtos. O MF de sardinha foi avaliado quanto ao rendimento, ao efeito da lavagem sobre a melhoria da cor, à caracterização química e quanto à estabilidade química e sensorial durante estocagem sob congelamento de -17 a -18°C. O rendimento do MF de sardinha lavado com água foi de 55% em relação ao peixe inteiro e próximo do rendimento teórico da parte comestível. A lavagem do MF com água ou água + bicarbonato de sódio proporcionou a obtenção de um produto com cor vantajosamente mais clara e apreciável. Com relação à composição química básica o MF de sardinha lavado com água apresentou maior hidratação e menor teor de cinzas em relação ao controle e semelhantes quantidades de proteína e lípides. Comparado ao controle, o MF de sardinha lavado com água, não apresentou diferença quanto ao perfil de ácidos graxos e pH, o que não ocorreu com o nitrogênio das bases voláteis - N-BVT, que diminuiu, e às substâncias reativas ao ácido tiobarbitúrico - TBARS, que aumentaram. O MF de sardinha lavado com água, contendo ou não antioxidantes artificialmente adicionados, apresentou estabilidade química e sensorial quando mantido sob congelamento, com base nos parâmetros pH, N-BVT, TBARS, odor a ranço e cor, em até 26 semanas de estocagem. Os resultados do presente trabalho são favoráveis à possibilidade de obtenção de MF de sardinha lavado com água e seu emprego como matéria-prima para outros produtos pesqueiros. / The potentiality of fish\'s utilization as minced fish - MF is very high, actually turning into a raw material to other products. The sardine\'s MF was evaluated according to its yield, the washing effect improving the color, its chemical characteristic and chemical and sensorial stability, during frozen storage under -17,-18°C. The yield of sardine\'s MF washed in with water, was 55% related to the whole fish and close to the theoretic yield of eatable portion. The MF\'s washing in water or in water plus sodium bicarbonate provide a product with clearer and more desirable color. Related to the chemical basic composition, sardine\'s MF washed in water, presented better hydration and lower ashes contents than its control, and similar quantity of protein and lipids. Compared to the control, the sardine\'s MF washed in water, had not presented any difference related to the fatty acids profile and pH, that had not happened with the nitrogen of volatile bases - N-BVT, which had been decreased, and the thiobarbituric acid reactant substances - TBARS, that had been increased. The sardine\'s MF washed in water, containing or not added antioxidants, was chemical and sensorial stable when maintained frozen, based on parameters as pH, N-BVT, TBARS, rancidity odor, and color, stored for 26 weeks. The results of this work are propitious to the possibility of achieving sardine\'s MF washed in water, and your utilization as a raw material to others seafoods.

É muito elevado o potencial de utilização do pescado na forma de minced fish - MF, servindo de matéria-prima para outros produtos. O MF de sardinha foi avaliado quanto ao rendimento, ao efeito da lavagem sobre a melhoria da cor, à caracterização química e quanto à estabilidade química e sensorial durante estocagem sob congelamento de -17 a -18°C. O rendimento do MF de sardinha lavado com água foi de 55% em relação ao peixe inteiro e próximo do rendimento teórico da parte comestível. A lavagem do MF com água ou água + bicarbonato de sódio proporcionou a obtenção de um produto com cor vantajosamente mais clara e apreciável. Com relação à composição química básica o MF de sardinha lavado com água apresentou maior hidratação e menor teor de cinzas em relação ao controle e semelhantes quantidades de proteína e lípides. Comparado ao controle, o MF de sardinha lavado com água, não apresentou diferença quanto ao perfil de ácidos graxos e pH, o que não ocorreu com o nitrogênio das bases voláteis - N-BVT, que diminuiu, e às substâncias reativas ao ácido tiobarbitúrico - TBARS, que aumentaram. O MF de sardinha lavado com água, contendo ou não antioxidantes artificialmente adicionados, apresentou estabilidade química e sensorial quando mantido sob congelamento, com base nos parâmetros pH, N-BVT, TBARS, odor a ranço e cor, em até 26 semanas de estocagem. Os resultados do presente trabalho são favoráveis à possibilidade de obtenção de MF de sardinha lavado com água e seu emprego como matéria-prima para outros produtos pesqueiros. / The potentiality of fish\'s utilization as minced fish - MF is very high, actually turning into a raw material to other products. The sardine\'s MF was evaluated according to its yield, the washing effect improving the color, its chemical characteristic and chemical and sensorial stability, during frozen storage under -17,-18°C. The yield of sardine\'s MF washed in with water, was 55% related to the whole fish and close to the theoretic yield of eatable portion. The MF\'s washing in water or in water plus sodium bicarbonate provide a product with clearer and more desirable color. Related to the chemical basic composition, sardine\'s MF washed in water, presented better hydration and lower ashes contents than its control, and similar quantity of protein and lipids. Compared to the control, the sardine\'s MF washed in water, had not presented any difference related to the fatty acids profile and pH, that had not happened with the nitrogen of volatile bases - N-BVT, which had been decreased, and the thiobarbituric acid reactant substances - TBARS, that had been increased. The sardine\'s MF washed in water, containing or not added antioxidants, was chemical and sensorial stable when maintained frozen, based on parameters as pH, N-BVT, TBARS, rancidity odor, and color, stored for 26 weeks. The results of this work are propitious to the possibility of achieving sardine\'s MF washed in water, and your utilization as a raw material to others seafoods.

Thesis (M. Tech. (Environmental Health)) -- Central University of technology, Free State, 2013 / Malnutrition and concomitant infections are major contributing factors to child morbidity and mortality in developing countries such as South Africa. Globally, children benefiting from school feeding programmes are generally from communities with low socio-economic statuses. The meals provided through feeding schemes, such as the National School Nutrition Programme (NSNP) in South Africa, are aimed at significantly supplementing the beneficiaries’ daily energy and nutrient requirements. The possible nutrient deficiency of meals provided through such programmes compromises the nutritional well-being of children, promotes malnutrition and renders children more susceptible to infectious diseases. Furthermore, illness, particularly caused by diarrhoeal and infectious diseases, is a major factor contributing to child malnutrition as the human body is unable to efficiently digest foods and absorb nutrients during illness. Therefore, the microbiological safety of the foods served to children via feeding schemes is essential. In an effort to contribute towards the safety and wholesomeness of foodstuffs served through the NSNP, the present study was conducted with a view to assess the nutritional quality and safety of the foodstuffs. The knowledge, attitudes and practises (KAP) of food handlers and NSNP representatives/committee members at the schools were also investigated in order to assess origins of potential food contamination. Data collected via nutritional analyses of meals served to school children were compared to the nutrient-based standards set by the United Kingdom as guidelines for an average school lunch. The carbohydrate, energy, calcium and zinc contents of the school meals were below the standards, the majority of the meals met the protein and iron standards and all meals complied with the standards for lipid and vitamin C contents. During the microbiological analysis study, preparation surfaces yielded higher counts of all detected organisms (total coliforms, Escherichia coli, Staphylococcus aureus and yeasts and moulds) compared to the hands of food handlers. Therefore possible sources of contamination may be foodstuffs, animal pests and environmental elements such as dust. However, significant differences of surface microbial counts could not be established (P > 0.05) and thus cross-contamination may have resulted among surfaces, possibly augmented by shortfalls in cleaning regimes. The majority of the participants of the questionnaire survey reportedly washed their hands and cleaned all surfaces several times during the day with water and detergent. In addition, a disinfectant was used by some of the food preparers during cleaning. Furthermore, participants stated that their aprons were washed daily. These claims were in agreement with the findings of the surface microbial study with regards to the hands, however, they did not match the findings of the preparation surfaces which contained the highest counts of total coliforms, E. coli and S. aureus of the three surfaces analysed, and aprons responsible for the highest yeast and mould counts. Improper storage and food preparation methods, such as the application of high temperatures, excessive exposure to UV light and oxygen, and high moisture conditions, may result in the deterioration of nutrients. Storage conditions which may permit pest infestation may also increase the risk of food-related illnesses and risk could be further elevated by application of improper cleaning and sanitation practices. In order for the NSNP to operate effectively, it is essential that the national and provincial Departments of Basic Education, which are responsible for the overall administration of the NSNP, and schools’ personnel function in an integrated manner through support structures and effective communication. Infrastructural limitations (lack of proper kitchen facilities and ventilation) and shortage of resources while administering the NSNP were the main challenges observed during the present study. Due to these hurdles, adhering to food safety practices and maintaining nutritional quality of foods may be a challenge. Continuous training in personal and general hygiene is also a necessity in preserving food safety. Furthermore, nutritional quality of foodstuffs may be preserved through proper storage practices and application of preparation methods which minimize loss of nutrients.

Le début du XXI siècle a été marqué par deux épisodes de flambées des prix des produits alimentaires au niveau mondial, respectivement en 2007-08 et 2010-11. Ces hausses de prix ont aggravé le niveau d’insécurité alimentaire dans de nombreux pays en développement et ont engendré des manifestations et troubles sociaux dans certains pays. Déterminer les facteurs qui contribuent à accroitre le risque d’insécurité alimentaire et comprendre les mécanismes qui sous-tendent l’éclatement d’une crise alimentaire pourraient permettre d’améliorer l’efficacité des politiques de prévention. Cette thèse contribue à cet objectif. Le chapitre 2 estime les différentes composantes de la variabilité de la disponibilité alimentaire en utilisant les données désagrégées des bilans alimentaires. Nos résultats suggèrent que plus de la moitié de la variabilité de la disponibilité alimentaire d’un pays dépend de chocs propres au pays. Les chocs globaux représentent environ 1% de la variabilité totale.Le chapitre 3 montre que l’impact du commerce international sur la variabilité de la disponibilité alimentaire dépend du portefeuille d’accords commerciaux détenu par le pays. Le chapitre 4 utilise le cadre théorique des paniques bancaires et s’appuie sur des travaux portant sur le risque perçu et sur les biais cognitifs pour modéliser le comportement d’achat alimentaire du consommateur. Nous montrons comment l’amplification sociale du risque peut conduire au stockage de précaution et à une crise alimentaire auto-réalisatrice. Nous mettons aussi en évidence l’utilité sociale d’une information publique / The beginning of the 21st century is marked by two episodes of global food price spikes in 2007-08 and 2010-11, respectively. These price increases have worsened the level of food insecurity in many developing countries and have led to social unrest in some countries. Identifying the factors that contribute to increase the risk of food insecurity and understand the mechanisms that underpin the outbreak of a food crisis could help to improve food policy management.This thesis contributes to this objective. Chapter 2 estimates the different components of food supply variability by using disaggregated data of food balance sheets. Our results suggest that more than half of food supply variability is caused by country-specific shocks. Global shocks account for about 1% of the total variability.Chapter 3 shows that the impact of international trade on food supply variability depends on the country's portfolio of trade agreements. Chapter 4 uses the theoretical framework of bank panics and builds on work on perceived risk and cognitive biases to model consumer food purchasing behavior under uncertainty. We show how social amplification of risk can lead to precautionary storage and in fine self-fulfilling food crisis. We also highlight the social utility of reliable public information. Finally, Chapter 5 examines the impact of dietary composition on the probability of occurrence of social unrest in case of soaring world food prices. Our results suggest that the cereal concentration of the diet increases significantly the probability of social unrest.

O presente trabalho objetivou estudar o impacto das variações térmicas durante o armazenamento de carcaças de frango sobre as propriedades funcionais, especialmente a perda de umidade no descongelamento (Drip Loss). Para avaliação destas condições, foram simuladas duas situações: uma comercial, onde um lote de aves abatidas, evisceradas e resfriadas em chiller foram congeladas até -15 (±2)°C e sofreram variações térmicas em ciclos de 8 horas com retirada das mesmas da câmara de estocagem, passando de -15 (±2)°C a -3(±2)°C, momento em que eram novamente devolvidas a câmara de congelamento (situação crítica) e outro lote mantido congelado a -15(±2)°C (situação ideal). Outra condição, chamada de ensaio modelo, foram simuladas 7 faixas de temperatura de armazenamento (0°C, -3°C, -6°C, -9°C, -12°C, -15°C e -18°C) visando definir faixas críticas, baseadas em valores de Drip Loss. Foram definidas 2 faixas: -3°C e -6°C, baseadas em sua proximidade a faixa mais crítica e com valores maiores de Drip Loss (0°C). Para estudo das propriedades funcionais no ensaio comercial, amostra (n=120) de carcaças, divididas em situação ideal (n=60) e situação crítica (n=60) foram descongeladas e submetidas às análises de pH, cor e perda de umidade por descongelamento (Drip Test). Os resultados encontrados mostraram uma tendência (p<0,05) de aumento do Drip Loss com o aumento do tempo de armazenamento na situação crítica, com valores de 4,77(±1,24)% para 3 dias e 10,28(±0,87)% para 120 dias. A situação ideal não apresentou diferenças significativas entre os resultados encontrados, que foram de 5,19(±1,13)% para 3 dias e 4,86(±0,84)% para 120 dias. Para estudo das propriedades funcionais no ensaio modelo, amostras (n=70), em triplicata, de carcaças foram descongeladas e, após a definição das faixas críticas, submetidas às análises de perda umidade por descongelamento (Drip Test), capacidade de retenção de água, análise de perda de umidade no cozimento, quantificação do gel protéico, análise do teor de proteínas no exsudato, análise do perfil protéico do exsudato e análise histológica. Os resultados demonstraram não haver diferenças estatísticas (p<0,05) entre as faixas críticas estudadas (-3°C e -6°C) em relação às propriedades funcionais, com exceção das análises de perda de umidade por descongelamento (Drip Test), onde a mesma tendência de aumento do Drip Loss em relação ao tempo de armazenamento foi encontrada, com valores de 5,85 (±1,16)% para 0 dia e 12,33 (±1,12)% para 70 dias na faixa -3°C e 5,83 (±1,93)% para 0 dia e 10,15 (±0,15)% para 70 dias na faixa -6°C. Concluindo, existem evidências de que as variações térmicas promovem o aumento do Drip Loss em relação a um maior tempo de armazenamento. A constatação deste fato serve como base para estudos mais aprofundados sobre o impacto das condições de armazenamento sobre as propriedades funcionais da carne de frango, bem como para padronizar os processos de congelamento, transporte, distribuição e venda de carne de frango congelada. / The objective of this work was to study the impact of thermal variations during the storage of broiler carcasses on its functional properties, especially the moisture loss during thawing (Drip Loss). In order to evaluate these conditions, two situations were simulated: one called commercial, where a batch of slaughtered, eviscerated and chilled on water system broilers were frozen to -15(±2)°C and divided in two equal batches: one of these batches was called Critical Condition and was maintained in a 8 hour cycle of thermal variation ranging from -15(±2)°C to -3(±2)°C while the other, called Ideal Condition was maintained at -15(±2)°C during all the storage time. In another situation, named Model, seven ranges of storage temperature (0±2°C, -3±2°C, -6±2°C, -9±2°C, -12±2°C, -15±2°C , -18±2°C) were simulated in order to obtain the critical ranges based on the Drip Loss values. Two ranges were found based on its proximity to the most critical range and bigger Drip Loss values: -3±2°C and -6±2°C. For the functional properties studies on the commercial situation, a sample (n=120) of broiler carcasses, equally divided in Critical and Ideal were unfrozen and pH, color and Drip Loss analyzed. The results showed a statistical trend (p<0,05) of increase of Drip Loss values as time of storage increases in the critical condition, with values of 4,77±1,24% for 3 days of storage and 10,28±0,87% for 120 days of storage. The ideal condition didnt showed significant differences among the obtained results that were from 5,19±1,13% for 3 days of storage to 4,86±0,84% for 120 days. For the functional properties studies on the model situation, a sample (n=70), in triplicate, of broiler carcasses was thawed and, after the definition of the critical ranges, it was analyzed for Drip Loss, water holding capacity, moisture loss during cooking, Exudative cooking gel quantification, protein quantification on the exsudate, protein profile on the exudate and histological evaluation. The results showed that there were no statistical differences (p<0,05) between the studied critical ranges (-3±2°C and -6±2°C) in relation to its functional properties, except for Drip Loss values, where a trend of increase in Drip Loss as the time of storage increases was found, with values from 5,85±1,16% for 0 days to 12,33±1,12% for 70 days in range -3±2°C and from 5,83±1,93% for 0 days to 10,15±0,15% for 70 days in range -6±2°C. In conclusion, theres some evidence that the thermal variation can cause the increase of Drip Loss values in relation to an increase of the storage time. All these data can be useful as basis for new studies on functional properties of broiler meat regard to thermal variation during storage, as well as, to standard the processes of freezing, transport, distribution, and retail of frozen broiler meat.

Doctorat en philosophie et lettres / info:eu-repo/semantics/nonPublished