Dissertations / Theses on the topic 'Cassava – Processing'

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Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

The aim of this research was to widen the knowledge of the physicochemical properties of cassava starch and flour and to understand the factors which influence their functional characteristics, including both genetic and environmental effects as well as processing procedures. A range of chemical and physical techniques which included the Brabender viscoamylograph, Bohlin CS rheometer, Brabender farinograph, WAXS, GPC, SEHPLC and Coulter counter have been used to examine the structural and behavioural characteristics of both cassava starch and flour. The results suggested that the functional behaviour of native cassava starches of different origins varies widely and appeared to be associated with molecular structure and the architecture of the starch granule. The viscosity and the mechanical properties of the pastes produced by gelatinization were determined by the degree of swelling and the amount and proportion of amylose and amylopectin in the solvent phase of the pastes. The amylopectin was present in the solvent phase in substantial quantities which varied between 37 and 57% of the total starch solubilized. In native cassava starches, the amylose appeared to have a high molecular weight (M, 19 x 105 - 11 x 105 ). The constituent chains of the amylopectin molecule did not vary in length with cassava starches of different origins, but their relative population did which was reflected in minor differences in the chromatographic profiles. Starch granules containing long chain amyloses and amylopectin with a high degree of branching were found to release reduced amounts of molecules into the liquid phase of the pastes, and vice versa Where the pastes contained a high proportion of amylopectin and long amylose molecules the resultant gel was surprisingly weak. Cassava starch processed to produce "sour" starch, or fermented, and sun dried starch, was found to have suffered degradation to an extent where 77-86 % of the starch was solubilized during aqueous heating. The extent of the degradation was influenced by the cassava cultivar. The "sour" starch proved superior to unfermented and fermented, oven dried starches in the production of baked baked products with an expanded texture. Starch extracted from cassava roots which had been stored for a short period, during which physiological deteriorative processes could have occurred, was found to show a slight reduction in the pasting viscosity which was not related to granular or molecular size or organization. Rural, factory-extracted starch was found to have a reduced paste viscosity as a consequence of fermentation and contamination with peel residues from the roots. Cassava flour properties were influenced by the conditions of preparation. Drying temperature, milling procedure and particle size could be selected and controlled to give cassava flours of the desired functional properties.

O impacto ambiental causado pelo descarte indevido de embalagens a base de polímeros sintéticos, desperta interesse na necessidade de desenvolvimento de embalagens a partir de materiais biodegradáveis. O objetivo deste trabalho foi desenvolver e caracterizar bandejas a base de espuma de amido de mandioca para embalagem de alimentos, obtidas pelo processo de expansão térmica. Foram testadas diferentes proporções de amido e água, como agente expansor, na formulação das espumas de amido. Como plastificantes, foram utilizados o glicerol, sorbitol e poli (álcool vinílico) (PVA), nas concentrações de 2,5; 5,0 e 7,5% m/m sob a massa de amido. A fim de melhorar as características de hidrofilia das espumas, foi aplicado revestimento a base de poli (ácido lático) (PLA) na superfície das bandejas. Testou-se a aplicação das bandejas como embalagem no armazenamento de morangos. A caracterização das embalagens foi realizada através de análises de espessura e densidade, MEV, capacidade de absorção de água (CAA), solubilidade, isotermas de sorção, resistência à tração, ângulo de contato e degradação enzimática. A proporção amido:água que produziu espumas com a melhor combinação entre as características de densidade, capacidade de absorção de água e aspecto visual foi 47,5:52,5. O aditivo que resultou em espumas de amido com a maior possibilidade de aplicação como embalagem para alimentos, por apresentar a menor CAA, ser menos solúvel e com os valores mais baixos de umidade de equilíbrio, foi o PVA em concentração de 5%. A aplicação de revestimento a base de PLA na superfície das bandejas de espuma de amido resultou em diminuição de 86% na CAA das bandejas e ângulo de contato de 84,4° (maior hidrofobia). Os modelos que melhor se ajustam a isoterma de sorção das bandejas sem revestimento são os de GAB e Oswin. Enquanto que para bandejas com revestimento de PLA, o modelo de Oswin apresenta o melhor ajuste. O ensaio de degradação enzimática por amilases microbianas revelou ocorrência da hidrólise do amido nas primeiras 8 horas do teste, indicando característica de biodegradabilidade das bandejas. Os resultados do presente estudo, obtidos através do teste de aplicabilidade das bandejas, comprovam a possibilidade da utilização da embalagem à base de amido de mandioca revestidas com PLA em alimentos com alta atividade de água.
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Fundação de Amparo à Pesquisa do Estado do Rio Grande do Sul.
The environmental impact caused by improper disposal of packaging materials based on synthetic polymers, arouses interest in development packaging from biodegradable materials. The objective of this study was to develop and characterize trays base of cassava starch foam for food packaging, obtained by the thermal expansion process. Different proportions of starch and water, as blowing agent, in the formulation of the starch foams was tested. As plasticizers were used glycerol, sorbitol, and poly (vinyl alcohol) (PVA) at concentrations of 2.5; 5.0 and 7.5% w/w on starch weight. In order to improve the hydrophilic characteristics of the foams, coating was applied of poly (lactic acid) (PLA) in the surface of the trays. The application of the trays as packaging strawberries in storage was tested. Packaging characterization was performed by thickness and density analysis, SEM, water absorption capacity (WAC), solubility, sorption isotherms, tensile strength, angle of contact and enzymatic degradation. The ratio starch:water who produced foams with the best combination of density, water absorption capacity and visual aspect characteristics was 47.5:52.5. The starch additive resulted in foams with the highest possibility of application as packaging for food for presenting the lowest WAC be less soluble and lowest values equilibrium moisture, was PVA concentration of 5%. The use of PLA-based coating on the surface of the starch foam trays resulted in a decrease of 86% in WAC trays and contact angle of 84.4 ° (higher hydrophobicity). The models that best fit the sorption isotherm of uncoated trays are the GAB and Oswin models. While for trays with PLA coating, Oswin model presents the best fit. The assay of enzymatic degradation by microbial amylases revealed the occurrence of the hydrolysis of starch in the first 8 hours of the test, indicating the biodegradability characteristics of the trays. The results of this study, obtained through the applicability of the test trays prove the possibility of the use of tapioca starch-based packing covered with PLA foods with high water activity.

In waste water, phosphorous (P) can exist in inorganic or organic forms. Depending on the concentration, P can cause eutrophication and severe environmental pollution. Microorganisms have the ability to use and accumulate P, so microorganisms are studied to treat P in waste water in general and wastewater from cassava starch processing plants in particular. Research results show that in the 20 samples of waste water and sludge of the plant has selected three strains of bacteria that can accumulate P in the form of granules in the cell. Among them, SHV22 has the highest P accumulation capacity, reaching 3.05x10-11 mg/cell, P removal efficiency in wastewater from cassava starch processing factory is 82.1%. The strain was identified as Bacillus amyloliquefaciens.
Trong nước thải P có thể tồn tại dưới dạng vô cơ hoặc hữu cơ. Tùy thuộc vào nồng độ, P có thể gây phú dưỡng và ô nhiễm môi trường nghiêm trọng. Vi sinh vật có khả năng sử dụng và tích lũy P, do đó vi sinh vật là đối tượng được nghiên cứu để xử lý P trong nước thải nói chung và nước thải của nhà máy chế biến tinh bột sắn nói riêng. Kết quả nghiên cứu cho thấy, trong 20 mẫu nước và bùn thải của nhà máy đã chọn lựa được 3 chủng vi khuẩn có khả năng tích lũy P dưới dạng hạt trong tế bào. Trong số đó, chủng SHV22 có khả năng tích lũy P cao nhất, đạt tới 3,05x10-11 mg/tế bào, hiệu quả loại bỏ P trong nước thải của nhà máy chế biến tinh bột sắn đạt 82,1%. Chủng đã được định danh là Bacillus amyloliquefaciens.

Cassava is the main staple crop in Nigeria. Using primary data from four south eastern states in Nigeria, the study assessed the gender impacts of improved cassava varieties. Comparative statistical analysis reveals that total female labor is higher than total male in cassava production, processing and marketing. Women spend more labor days than males for planting, weeding, harvesting, marketing and processing. The total female family labor is higher for adopters of new improved cassava varieties. There is however lower family labor input for both male and female adopters for clearing and plowing which are normally done by men. Significant determinants of female labor supply are number of children in the household, percent of females in the household providing labor on the farm, area under improved cassava varieties and total land area. There is a positive unexpected relationship between total female labor supply and number of children. For each of the decision making variables, there is a significant association between the gender of the spouse and the decision made except for the decision on family labor allocation. Probit results show a significant decrease in the probability that the wife makes the decision for family labor allocation, what inputs to buy and borrowing and traditional cassava income control with adoption. Results indicate that both men and women spend their income on services directly linked to the householdâ s welfare. More than half of the women ranked food as number one.
Master of Science

As mandiocas utilizadas na produção da farinha contêm elevadas concentrações de glicosídeos cianogênicos, compostos que, após degradação, liberam cianeto na forma de ácido cianídrico (HCN) conferindo toxicidade à raiz. O processamento adequado da mandioca, para produção da farinha, resulta na degradação dos glicosídeos cianogênicos e na obtenção de um alimento com baixo teor de cianeto, o que gera a hipótese de liberação de HCN durante o processo. Neste contexto, o presente estudo objetivou avaliar a exposição de trabalhadores de casas-de-farinha ao HCN proveniente da mandioca, assim como identificar possíveis alterações clínicas e laboratoriais associadas a tal exposição. Foram incluídas no estudo 4 casa-de-farinha localizadas no Agreste Alagoano, microrregião de Arapiraca. A determinação de HCN em amostras de ar foi realizada de acordo com o método analítico 6010 recomendado pelo NIOSH. Cada casa foi monitorada em três pontos: dois em zona respiratória e um em ponto estático. Um total de 36 trabalhadores voluntários do sexo masculino distribuídos nas 4 casas-de-farinha foram selecionados para o estudo. Cada participante foi submetido à coleta de urina, sendo uma amostra pré-jornada e outra amostra pós-jornada e a uma coleta de sangue pré-jornada. O teor de tiocianato (SCN-) urinário foi quantificado espectrofotometricamente, enquanto que as outras avaliações bioquímicas foram realizadas em laboratório clínico. Os resultados indicam que os trabalhadores de casas-de-farinha estão expostos, cronicamente, a níveis atmosféricos de HCN dentro de um intervalo de 0,464±0,02 a 3,328±3,85 mg/m3 no ambiente de trabalho. A comparação entre os níveis atmosféricos determinados e os Limites de Exposição Ocupacional estabelecidos pelo NIOSH e ACGIH indica que trabalhadores de casas-de-farinha, podem estar expostos a níveis de HCN capazes de causar efeitos adversos à saúde. Os níveis médios de tiocianato urinário em mg/g de creatinina (10,62 - pré- jornada e 8,76 pós - jornada), foram significativamente superiores ao valor de referência para não fumantes e à média obtida no laboratório contratado para análise de SCN-, referente ao período de 2008 a 2010. Os resultados dos exames laboratoriais indicaram aumento nos níveis séricos de fosfatase alcalina nos trabalhadores de casas-de-farinha expostos ao HCN, com uma prevalência de 93,3%. Os trabalhadores foram submetidos ao exame clínico e não foram detectadas alterações características de exposição ao HCN.
Cassava used for flour production contains high amounts of cyanogenic glycosides, compounds that, after degradation, release hydrogen cyanide (HCN) which provide toxicity to these type of root. A suitable cassava processing results in the degradation of cyanogenic glycosides and in the production of a safety flour for consumption as food, which generates the hypothesis of HCN release during the process. In this context, the present study aimed to evaluate the HCN exposure of workers engaged in cassava processing, as well as, to identify possible clinical and laboratory alterations related to this exposure. It was included in the study 4 cassava processing facilities placed on Alagoas state, Brazil. It was conducted the determination of HCN in air samples according to the method 6010 proposed by NIOSH. Each industry was monitored in three points: two on workers respiratory zone and one static. A total of 36 male volunteers, distributed between the 4 facilities were included in the study. Each participant was submitted to urine sampling, been one before and other after work shift, and to one blood sampling before work shift. Urinary thiocyanate (SCN-) was spectrophotometrically determined, whereas the remaining biochemical evaluation was conducted in a commercial clinical laboratory. The results indicated that the cassava processors are chronically exposed to HCN at levels between 0,464±0,02 and 3,328±3,85 mg/m3, in the work environment. The comparison between the levels determined at the present study with the Occupational Exposure Limits (OEL) established by NIOSH and ACGIH indicated that cassava processors may be exposed to HCN levels capable of causing adverse health effects. The mean levels of urinary thiocyanate (10,62 - before shift and 8,76 - after shift), were significantly higher than the reference value for non smokers and also for the history mean obtained from the laboratory employed for SCN- analysis, during 2008-2010. The results of laboratorial evaluation indicated increase in the serum activity of alkaline phosphatase in cassava processors exposed to HCN, with a prevalence of 93,3%. The workers were submitted to clinical evaluation and it was not detected any alteration typical of HCN exposure.

Orientador: Miriam Dupas Hubinger
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
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Resumo: No mundo atual é crescente a demanda dos consumidores por produtos frescos, devido a sua qualidade nutricional, além de oferecer benefícios para a saúde como, por exemplo, na prevenção de algumas doenças. Frente a esta demanda, o presente trabalho estudou o uso de coberturas comestíveis de fécula de mandioca na manutenção da qualidade dos frutos de morango (Fragaria ananassa Duch.). Os frutos de morango receberam tratamentos combinando o processamento mínimo com a utilização de cobertura comestível de fécula de mandioca, cuja finalidade foi prolongar a vida útil destes em temperaturas de refrigeração. Os frutos após o processamento foram mergulhados por 10 minutos em suspensão de 3% (p/v) de fécula de mandioca e submetidos à secagem naturalmente à temperatura ambiente e armazenados em temperaturas de 10 ?C e 15 ?C. Na primeira etapa, o objetivo foi avaliar as características da cobertura aplicada nos morangos (propriedades mecânicas: forças de ruptura e penetração, cor dos morangos, taxa de respiração e resistência ao vapor de agua) depois de 24 horas do tratamento. A aplicação da cobertura nos morangos não alterou significativamente as propriedades mecânicas (forças de ruptura e penetração), cor dos morangos, taxa de respiração e resistência ao vapor de água em comparação aos morangos sem coberturas. Na segunda etapa foi realizado o estudo da vida útil dos morangos com e sem cobertura, armazenados a temperaturas de 10 ?C e 15 ?C. Na perda de peso verificou-se diferença significativa ao longo do tempo de armazenamento diferença significativa, e no tempo fixo não se observou diferenças significativas entre os tratamentos, a taxa de respiração mostrou um incremento significativo em todos os tratamentos ao longo no tempo de armazenamento e para tempo fixo não presentaram diferenças significativo entre os tratamentos exceto no dia 1 se observou que o tratamento 15 ?C com cobertura diminui significativamente com respeito a 15 ?C sem cobertura. O teor de antocianinas apresentou uma diminuição significativa ao longo do tempo de armazenamento para os tratamentos 10 ?C sem cobertura e 15 C sem e com cobertura em ambas temperaturas são não significativo nos dia 5 e 8. As amostras 10 ?C com e sem cobertura e 15 ?C com e sem cobertura foram avaliadas sensorialmente os morangos com cobertura apresentaram notas acima do limite de aceitação (4,5), o fator que determinou o tempo de vida útil foi a contaminação microbiológica observada nas amostras. As amostras armazenadas a 10 ?C com e sem cobertura apresentaram 8 dias de vida útil e as amostras armazenadas 15 ?C com e sem cobertura apresentaram 5 dias de vida útil
Abstract: Nowadays there is a growing consumer demand for fresh products, due to their nutritional quality and the health benefits they provide, for example, in the prevention of some diseases. Faced with this demand, the present work analyzed the use of edible cassava starch coating for preserving the quality of strawberry fruits (Fragaria ananassa Duch.). Strawberries underwent treatment combining minimal processing with the use of edible cassava starch coating, aiming to extend the lifetime of these fruits at refrigerated temperatures. To this aim, after the processing stage, the fruits were immersed for 10 minutes in a 3% (w/v) cassava starch suspension; then they were naturally dried at room temperature and stored at temperatures of 10?C and 15?C. During the first stage, the objective was to evaluate the characteristics of the starch-based coating applied to strawberries ¿ that is, mechanical properties (compression and penetration strengths) strawberry color, respiration rate and water vapor resistance ¿ after a 24-hour treatment. The application of the coating on the strawberries did not significantly modify the mechanical properties (compression and penetration strengths), strawberry color, respiration rate and resistance to water vapor, when compared to uncoated strawberries. During the second stage we studied the lifetime of coated and uncoated strawberries stored at temperatures of 10?C and 15?C. In the weight loss treatments, we were able to verify significant differences during the storage time, and in the fixed time no significant differences were observed, the respiration rate showed significant increase in all treatments during storage time, and in the fixed time, no significant differences among treatments were seen, except for day 1, when it was observed that the coated fruits under treatment at 15 ?C showed a significant decrease with regard to the uncoated fruits treated at 15?C. The anthocyanin content showed significant decrease during storage time for uncoated fruits at 10?C and for coated and uncoated fruits at 15?C; at both temperatures there were no significant results on days 5th and 8th. Sensory analysis was performed on samples at coated and uncoated stored at 10?C and 15?C . Coated strawberries showed numbers above the acceptance limit (4.5). The factor that determined the lifetime was the microbiological contamination observed in the samples. Coated and uncoated samples stored at 10?C had an 8-day lifetime and the coated and uncoated samples stored at 15?C had a 5-day lifetime
Mestrado
Engenharia de Alimentos
Mestra em Engenharia de Alimentos

Orientador: Miriam Dupas Hubinger
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
Made available in DSpace on 2018-08-12T23:34:18Z (GMT). No. of bitstreams: 1 Garcia_LorenaCosta_M.pdf: 2190843 bytes, checksum: 5ad33001b49609c1c60d7c79efdf0586 (MD5) Previous issue date: 2009
Resumo: O morango é um pseudofruto não climatérico e que possui uma curta vida útil após a colheita. Dentre os fatores responsáveis pela perda de qualidade dos morangos estão a alta atividade metabólica e alta susceptibilidade ao ataque microbiano, principalmente fungos. O objetivo no presente trabalho foi estudar o efeito da aplicação de coberturas comestíveis a base de fécula de mandioca, adicionadas ou não do antimicrobiano sorbato de potássio, nas características físico-químicas e microbiológicas determinantes da vida útil de morangos minimamente processados, armazenados a 5ºC. Primeiramente, foram aplicadas aos morangos coberturas contendo 1%, 2% e 3% de fécula de mandioca, adicionadas ou não de 0,05% e 0,1% de sorbato de potássio com o objetivo de verificar alguma alteração significativa nas características da fruta 24h após o tratamento. A aplicação das coberturas não alterou significativamente as propriedades mecânicas (força máxima de penetração e ruptura) e a cor dos morangos; todos os tratamentos foram bem avaliados sensorialmente (todas as notas acima de 4,5), indicando que não houve rejeição do consumidor pelas coberturas. Verificou-se que coberturas com maiores concentrações de fécula de mandioca foram eficientes em reduzir a taxa de respiração e aumentar a resistência à difusão de água das amostras. O sorbato de potássio teve efeito significativo apenas na resistência à difusão de água, e, entre as duas concentrações estudadas, não foram observadas diferenças significativas. Com base nestes resultados e visando o menor custo, coberturas contendo 3% de fécula de mandioca e 3% de fécula de mandioca + 0,05% de sorbato de potássio foram selecionadas para o estudo da vida útil. Neste estudo verificou-se que, ao longo de 15 dias de armazenamento a 5ºC, as coberturas foram eficientes em reduzir a perda de peso, a taxa de respiração e a perda firmeza das amostras. O teor de antocianinas das amostras com cobertura não sofreu alterações significativas ao longo do armazenamento; no entanto, para a amostra controle, um aumento significativo foi observado no 15º dia. Todos os tratamentos foram bem avaliados sensorialmente, com notas acima do limite de aceitabilidade (4,5). O fator determinante da vida útil dos morangos minimamente processados foi a contaminação pontual observada nas amostras. As amostras controle e as tratadas com 3% de fécula de mandioca + 0,05% de sorbato de potássio apresentaram vida útil de 9 dias, em função da contaminação fúngica. Já morangos tratados com 3% fécula de mandioca obtiveram vida útil de 12 dias, indicando que apenas a cobertura sem sorbato de potássio permitiu um prolongamento da vida útil dos morangos minimamente processados
Abstract: Strawberry is a non climacteric fruit and presents a short postharvest shelflife. Among the main factors for quality loss of strawberries are the high metabolic activity and mold decay. The aim of this work was to study the effect of the application of cassava starch edible coatings, with or without of the antimicrobial potassium sorbate as additive, on the physical-chemical and microbiological characteristics, responsible for the shelf life of minimally processed strawberries, stored at 5ºC. Initially, strawberries were treated with edible coatings containing 1%, 2% or 3% of cassava starch, with or without 0.05% or 0.1% of potassium sorbate, in order to verify any significant change on strawberry characteristics, after 24h of the coating application. Mechanical properties (maximum penetration and rupture forces) and strawberry color were not affected by the coating application and all treatments received good grades on the sensory analyses (all scores above 4,5). It was observed that coatings with higher starch concentrations efficiently reduced the respiration rate and increased water vapor resistance. The addition of potassium sorbate in the coating increased water vapor resistance but no statistical differences were observed between the two concentrations employed. Considering these results and seeking the lower coating cost, coatings containing 3% of cassava starch and 3% of cassava starch + 0.05% of potassium sorbate were the selected conditions to be used in the shelf life study of minimally processed strawberries. During the shelf life study, it was observed that edible coatings were efficient in reducing weight loss, respiration rate and firmness loss of samples for 15 days of storage at 5ºC. Changes in anthocyanin content were not observed on coated samples during storage; for the control samples, a significant increase was observed on the 15th day. All treatments presented good sensory acceptance. Control samples and the samples treated with the coating containing potassium sorbate showed a reduced shelf life of 9 days due to microbial spoilage. A shelf-life of 12 days was obtained for samples coated with 3% of cassava starch, indicating that the coating without the antimicrobial was efficient in increasing the shelf life of minimally processed strawberries
Mestrado
Mestre em Engenharia de Alimentos

Orientador: Miriam Dupas Hubinger
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
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Resumo: A manga é uma fruta largamente cultivada e consumida no Brasil, sendo exportada também 'in natura¿ para diversos países. Na forma minimamente processada, apesar da grande praticidade, as fatias podem apresentar escurecimento enzimático e mudanças desagradáveis de textura. Neste contexto, este trabalho visou estudar a vida útil de fatias de manga (Mangifera indica cv 'Tommy Atkins¿) pré-tratadas com ácido cítrico e/ou recobertas com fécula de mandioca ou alginato de sódio e estocadas a 5°C. Em testes preliminares, concentrações de 0,5% a 2% (p/v) de ácido cítrico e 1% a 3% (p/v) de fécula de mandioca foram analisadas quanto a: perda de peso, propriedades mecânicas (tensão e deformação na ruptura) e cor (L*, C* e H*). As concentrações de 0,5% de ácido cítrico e 1% de fécula de mandioca foram definidas como as melhores condições de tratamento. Na etapa subseqüente, foram analisadas as condições ótimas de tratamento associadas (ácido cítrico e cobertura de fécula de mandioca), fatias de manga imersas em solução de ácido cítrico (0,5%) com cobertura a base de alginato de sódio (concentração de 2% p/v) e a adição de 1% (p/v) de glicerol nos tratamentos com recobrimentos. As amostras com cobertura de alginato apresentaram maior perda de textura e escurecimento enzimático. As películas de fécula de mandioca foram mais eficientes na conservação dos parâmetros de qualidade das fatias de manga. Embora todas as coberturas tenham reduzido a taxa respiratória do produto, a adição de glicerol permitiu maior troca gasosa. Para o estudo de vida útil do produto, foram selecionados os tratamentos com cobertura de fécula, com e sem glicerol. O tratamento com película de fécula sem glicerol foi mais eficiente na manutenção da textura e coloração. Devido à imersão em ácido cítrico, essas amostras apresentaram maiores valores de acidez total titulável e menores valores de sólidos solúveis totais. As fatias com película de fécula de mandioca sem glicerol apresentaram boa aceitação sensorial e sua vida útil foi atestada em 15 dias. As fatias com película de fécula contendo glicerol apresentaram sabor amargo e, devido ao crescimento microbiano, obtiveram uma vida útil de 10 dias
Abstract: Mango is a widely grown and consumed fruit in Brazil, being also exported 'in natura¿ to many different countries. Fresh-cut mangoes, in spite of their practicity, may have enzymatic browning and unpleasant changes of texture. Thus, this work aimed to study the shelf-life of mango slices (Mangifera indica cv 'Tommy Atkins¿) pre-treated with citric acid and/or covered with cassava starch or sodium alginate and stored at 5°C. Preliminary tests with citric acid concentrations between 0.5% and 2% (w/v) and cassava starch from 1% to 3% (w/v) were made to quantify weight loss, mechanical properties (stress and strain at failure) and color (L*, C* and H*). The 0.5% citric acid and the 1% cassava starch concentrations were considered the best treatment conditions. In the following procedures, the best conditions for associated treatments (citric acid and cassava starch coating), mango slices dipped in citric acid solution (0.5%) with sodium alginate coating (2% w/v) and the addition of 1% (w/v) of glycerol on the coated treatments were analyzed. The samples with alginate coating showed the higher texture loss and enzymatic browning. Cassava starch coatings were more efficient in maintaining the quality parameters of the mango slices. Although all coatings have reduced the respiration rate of the product, the addition of glycerol promoted higher gas exchange. The treatments with cassava starch, with and without glycerol, were selected to the shelf-life study. The non-glycerol cassava starch treatment was more efficient in maintaining the texture and color. Due to the citric acid dipping, these samples presented higher values of titratable acidity and lower values of total soluble solids. The cassava starch coating slices without glycerol had a good sensorial acceptance and their shelf-life was attested to be of 15 days. The cassava starch coating slices containing glycerol presented a bitter taste and, due to microbiological growth, had a shelf-life of 10 days
Mestrado
Mestre em Engenharia de Alimentos

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
This study aimed to evaluate the use of modified atmosphere (MA) in the conservation of sweet cassava variety 'Pernambuana' minimally processed in plastic containers. In the first stage determined the chemical composition (macro and micronutrients), heavy metals, the cooking time (DTC), quality of cooking and cyanogenic compounds. Minimal processing was the subdivision into two areas, dirty areas: reception of raw materials, selection, classification and pre-wash. In the second step, the clean area: processing (peeling and cutting), rinse, sanitizing, spinning, packing, storage. We analyzed the gas concentration (O2 and CO2) inside the package by 70 pm. The experiment was conducted at temperature 10 °C and stored in polystyrene containers terephthalate (PET) without PVC (CONT), PET with PVC (AMCF), sealed polyethylene bags without vacuum (AMSV) and vacuum (AMCV) at 5 ± 0.2 º C, RH 43% for 20 days. Were performed physical and chemical analysis. The increase in browning (IE), staining of cuttings (L *, C *, H *). and enzyme activity were performed every four days until the 16th day. The microbiological analysis of fecal and total coliforms were performed on the day of processing, with eight and sixteen days. The variety 'Pernambucana‟ has got cooking time of 20 minutes, quality mass formed after cooking and low levels of cyanogenic compounds. It was observed that the pH, ascorbic acid, varied significantly during storage. There were statistical differences (P ≤ 0.05) for the values of reducing sugars, total soluble sugars during periods of storage. Packaging (AMSV and AMCV) had the highest values of L *, the lowest increment of darkening, a smaller reduction of ascorbic acid, however, had the highest pH values. The enzymes showed no statistical differences (P ≤ 0.05) for the activity of peroxidase and polyphenol in storage periods and between treatments. Considering the physico-chemical and microbial life of cassava was 12 days for treatments AMSVand AMCV and eight days for the treatment AMCF. According to the microbiological analysis of cassava breeding minimally processed showed an absence of coliform bacteria at 45 °C, however, treatment with AMCF, and AMSV AMCV showed total coliform counts considered high.
Este trabalho teve como objetivo avaliar o uso de atmosfera modificada (AM) na conservação de mandioca de mesa da variedade Pernambucana‟ minimamente processada em embalagens plásticas. Na primeira etapa determinou-se a composição química, (macro e micronutrientes), metais pesados, o tempo de cocção (DTC), qualidade de massa cozida e compostos cianogênicos. O processamento mínimo consistiu na subdivisão em duas áreas, área suja: recepção da matéria-prima, seleção, classificação e pré-lavagem. Na segunda etapa, na área limpa: processamento (descascamento e corte), enxague, sanificação, centrifugação, embalagem, armazenamento. Analisou-se a concentração gasosa (O2 e CO2) no interior das embalagens, por 70 hs. O experimento foi realizado em câmara fria a 10ºC e armazenados nas embalagens Poliestireno tereftalato (PET) sem PVC (CONT), PET com PVC (AMCF), saco de polietileno selado sem vácuo (AMSV) e com vácuo (AMCV) à temperatura de 5 ± 0,2ºC, UR 43% por 20 dias. Foram realizadas as análises físico-químicas. O incremento de escurecimento (IE), coloração dos toletes (L*, C*, H*). e atividade enzimática foram realizadas a cada quatro dias até o 16º dia. As análises microbiológicas de coliformes totais e termotolerantes foram realizadas no dia do processamento, com oito e dezesseis dias. A variedade Pernambucana apresenta obteve tempo de cozimento de 20 minutos, qualidade massa formada após cozimento e baixo teores de compostos cianogênicos. Observou-se que os valores de pH, ácido ascórbico, variaram significativamente durante o armazenamento. Houve diferenças estatísticas (P≤0,05) para os valores de açúcares redutores, açúcares solúveis totais nos períodos de armazenamento. As embalagens (AMSV e AMCV) obtiveram os maiores valores de L*, os menores valores de incremento de escurecimento, menor redução de ácido ascórbico, no entanto, obteve os maiores valores de pH. As enzimas apresentaram diferenças estatísticas (P≤0,05) para a atividade da polifenol e peroxidase nos períodos de armazenamento e entre os tratamentos. Considerando-se a análise físico-química e microbiológica, a vida útil da mandioca foi de 12 dias para os tratamentos AMSV e AMCV e oito dias para o tratamento AMCF. De acordo com as análises microbiológicas a mandioca de mesa minimamente processada apresentou ausência de coliforme a 45ºC, no entanto, os tratamentos com AMCF, AMSV e AMCV apresentaram contagem de coliformes totais consideradas altas. Palavras-

Ce travail décrit les processus de production des savoirs locaux sur le manioc et leurs modes d’apprentissage et circulation par les paysans centrafricains, lesquels se confrontent à l’exécution des politiques publiques agricoles et agroalimentaires du pays. Les savoirs locaux sur le manioc constituent un ensemble de techniques et de savoir-faire construits et acquis par les paysans à travers des apprentissages qui mettent en interaction des acteurs appartenant à des mondes sociaux différents. Mes recherches s’appuient sur des enquêtes de terrain multi-situées, à Pissa, à Yaloké et à Sibut, et sur une expérience d’observation participante aux travaux agricoles et à l’apprentissage du « savoir-cultiver » qui m’ont conduit à identifier des changements socio-économiques et des mutations de connaissances induits par l’émergence de ces savoirs paysans. Ceux-ci sont des connaissances hybrides construites selon les contextes sociaux, économiques et agro-écologiques en interactions avec les savoirs scientifiques diffusés en milieu paysan. Les transferts de savoirs technico-scientifiques portés par les projets de production du manioc conduisent les agriculteurs à des réinterprétations qui adaptent les informations reçues à leurs besoins. L’exemple des pratiques de bouturages précoces et tardives comme techniques adaptatives aux changements climatiques invite à repenser la question de la considération des savoirs paysans par les scientifiques en termes de savoirs sociaux répondant aux besoins des agriculteurs
This work describes the production processes of local knowledge on cassava and their learning styles and circulation by Central African farmers, who are confronted with the implementation of agricultural policy and food of the country. Local knowledge on cassava are a set of techniques and know-how acquired and built by farmers through learning that highlight interaction of the actors belonging to different social worlds. My research is based on multi-located field surveys to Pissa at Yaloké and Sibut, and participant observation of experience in farm work and learning "know-grow" that led me to identify socio-economic changes and knowledge of mutations induced by the emergence of farming knowledge. These are hybrid knowledge built by the social, economic contexts and agro-ecological interactions in scientific knowledge broadcast on-farm. Transfers of technical-scientific knowledge carried by cassava production projects led farmers to reinterpretations which adapt the information received to their needs. The example of the practice early and late cuttings as adaptive techniques to climate change calls to rethink the question of consideration of the farmers' knowledge by scientists in terms of social knowledge to the needs of farmers

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The negative externalities caused by production activities to satisfy the consumption needs impact directly on the natural environment, for example, the emission of greenhouse gases and pollution of soil and water, requiring new approaches to decision-making processes in organizations. Among these approaches are incorporating innovations that provide reduced environmental impacts, also called eco-innovations, and the adoption of models that assess comprehensively, integrated and in different perspectives the overall performance of these innovations. Considering that the object of this research is the eco-innovation 'biodigester technology' and the research field are the processing of cassava industries in State of Paraná, this multicase study included an extensive literature review to propose a specific set of indicators to assess the overall impact caused by the eco-innovation cited, covering the classic dimensions of sustainable development (environmental, social and economic) as well as other dimensions defined for the model used (training of human resources, institutional development, introducing innovation, unexpected/unwanted occurrences and characteristics of environmental management). This set of indicators was incorporated into the INOVA-tec System Model (Jesus-Hitzschky, 2007) developed by a researcher at the Brazilian Agricultural Research (Embrapa), setting up a new model called INOVA-tec System Modified. The primary data were processed in the new model and after analysis of the results it was evident that the technology object of this research has a favorable scenario for its spread, but the performance indicators are still low. Then were then presented suggestions for improvement to optimize the overall impact of the technology and at the end, it is recommended that the model proposed in this study be applied to other activities of the agricultural industry in order to validate and improve it´s theoretical contribution.
As externalidades negativas provocadas pelas atividades produtivas para atender as necessidades de consumo impactam diretamente o meio ambiente natural, por exemplo, pela emissão de gases efeito estufa e contaminação do solo e da água, exigindo novas abordagens para os processos decisórios das organizações. Entre essas abordagens estão a incorporação de inovações que proporcionem redução dos impactos ambientais, também denominadas ecoinovações, bem como a adoção de modelos que avaliem de forma abrangente, integrada e em diferentes perspectivas a performance geral dessas inovações. Tendo como objeto de pesquisa a ecoinovação ‘tecnologia de biodigestores’ e como campo de pesquisa as fecularias do Estado do Paraná, este estudo de casos múltiplos compreendeu uma extensa revisão na literatura para propor um conjunto específico de indicadores capazes de avaliar o impacto geral provocado pela referida ecoinovação, contemplando as dimensões clássicas do desenvolvimento sustentável (ambiental, social e econômica) bem como as demais dimensões definidas para o modelo utilizado (capacitação de recursos humanos, desenvolvimento institucional, introdução da inovação, ocorrências inesperadas/indesejadas e características da gestão ambiental). Esse conjunto de indicadores foi incorporado ao modelo INOVA-tec System (Jesus-Hitzschky, 2007) desenvolvido por uma pesquisadora da Empresa Brasileira de Pesquisa Agropecuária, configurando um novo modelo aqui denominado INOVA-tec System Modificado. Os dados primários obtidos foram processados no novo modelo e após análise dos resultados ficou evidenciado que a tecnologia objeto desta pesquisa tem um cenário favorável à sua disseminação, porém a performance dos indicadores ainda é baixa. Foram, então, apresentadas sugestões de melhoria visando otimizar o impacto geral da tecnologia e, ao final, recomenda-se que o modelo proposto neste estudo seja aplicado em outras atividades da agroindústria a fim de validar e aprimorar sua contribuição teórica.

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Universidade Federal de Sao Carlos
The aim of this study was to evaluate the influence of hydraulic retention time (HRT), the origin of different inoculum (sludge from a UASB reactor for swine wastewater treatment and poultry slaughterhouse), and different carbon source (glucose, cassava processing wastewater and cheese whey) on the stability and efficiency of the anaerobic fluidized bed reactor (AFBR) for producing hydrogen. Twelve identical reactors were used, and in two reactors the mixture of glucose with cheese whey (R1S, R2S) was used as a substrate, six reactors were used with mix cassava processing wastewater and glucose (R1M, R2M, R3M and R4M). It was evaluated use of cheese whey (R3S, R4S, R5s and R6S) and cassava processing wastewater (R5M and R6M). The AFBRs were inoculated with sludge from a UASB reactor used in the treatment of swine wastewater (R1S, R3S, R1M, R3M, R5S, R6S, R5M and R6M) and sludge from a UASB reactor that treated poultry slaughterhouse wastewater (R2S, R4S, R2M, R4M), both heat treated. Variations of HRT (12-1 h) and substrate concentrations were performed (2-15 g .L -1), with temperature control at 30 ° C. The reactors that used cheese whey as substrate showed a greatest potential for hydrogen production, with yields (HY) of 3.2 mmolH2.g-1COD (R6S) and 2.6 mmolH2.g-1COD (R5S) were obtained by applying a HRT of 6 and 14 hours, with a concentration of 3 and 5 g.L-1, respectively. Both substrates showed potential for the production of ethanol with yields (EtOHY) of 4.2 mmolEtOH.g-1COD (R6M) and 3.5 mmolEtOH.g-1COD (R2S). In the comparison between the two inocula used, both showed a balance in terms of hydrogen production, but in terms of ethanol production, the sludge from poultry slaughterhouse showed highest potential. By cloning and sequencing of the 16S rRNA gene for bacteria domain reactor R4S (whey), there was a predominance of the genus Selenomonas (69 % of the sequences) and Clostridium (8 % of the sequences). For the reactor R3M (glucose and cassava) analyzes cloning and sequencing of bacterial consortium revealed similarities with Lactobaccilus. As for the archaeal domain, the sequencing of the 16S rRNA gene had highly similar to the genus Methanobacterium (98.5 % and 95 % of the sequences), for R4S and R3M, respectively reactors.
O objetivo deste estudo foi avaliar a influência do tempo de detenção hidráulica (TDH), da origem de diferentes inóculos (lodo de suínos e lodo de aves), e da fonte de carbono (glicose, manipueira e soro de queijo) sobre a estabilidade e eficiência do reator anaeróbio de leito fluidizado (RALF) na produção de hidrogênio e etanol. Foram utilizados doze reatores idênticos, sendo que em dois reatores foram utilizados mistura de glicose com soro de queijo (R1S, R2S), seis reatores foram utilizados a mistura de água do processamento da mandioca (manipueira) e glicose (R1M, R2M, R3M e R4M). Também foi avaliado o uso individual do soro de queijo (R3S, R4S, R5S e R6S) e da manipueira (R5M e R6M). Os RALFs foram inoculados com lodo proveniente do tratamento de águas residuárias de suinocultura (R1S, R3S, R1M, R3M, R5S, R6S, R5M e R6M) e de águas residuárias do abatedouro de aves (R2S, R4S, R2M, R4M), ambos tratados termicamente. Foram realizadas variações de TDH (14-1 h) e concentrações de substrato (2- 15 g. L-1), com controle de temperatura a 30°C. Os reatores que utilizaram soro de queijo como substrato apresentaram um maior potencial para a produção de hidrogênio, com rendimentos (HY) de 3,2 mmolH2.g-1DQO (R6S) e 2,6 mmolH2.g-1DQO (R5S), por meio da aplicação de um TDH de 6 e 14 horas, com uma concentração de 3 e 5 g.L-1, respectivamente. Ambos os substratos apresentaram potencial para a produção de etanol, com rendimentos (EtOHY) de 4,2 mmolEtOH.g-1DQO (R6M) e 3,5 mmolEtOH.g-1DQO (R2S). Na comparação entre os dois inóculos utilizados, ambos apresentaram um equilíbrio em termos de produção de hidrogênio, porém em termos de produção de etanol, o lodo proveniente do abatedouro de aves apresentou um maior potencial. Por meio da clonagem e sequenciamento do gene RNAr 16S para o domínio bactéria do reator R4S (soro de queijo), houve a predominância do gênero Selenomonas (69% das sequências) e do gênero Clostridium (8% das sequências). Para o reator R3M (glicose e manipueira) as análises de clonagem e sequenciamento do consórcio bacteriano revelaram semelhanças com Lactobaccilus. Já para o domínio archaea, o sequenciamento do gene RNAr 16S, teve altas similaridades com gênero Methanobacterium (98,5% e 95% das sequências), para os reatores R4S e R3M, respectivamente.

Submitted in fulfilment of the requirements for the Degree of Doctor of Technology: Biotechnology, Durban University of Technology, 2010.
Cassava, (Manihot esculenta Crantz), is used for the production of a variety of West African foods and ranks fourth in the list of major crops in developing countries after rice, wheat and maize. Gari is one of the most popular foods produced from cassava. Cassava may contain high levels of linamarin, a cyanogenic glucoside, which in its natural state is toxic to man. Therefore, some processing methods that can enhance the detoxification of cassava and lead to the improvement of the quality and hygienic safety of the food are vitally important for less toxic products to be obtained. Quality, safety and acceptability of traditional fermented foods may be improved through the use of starter cultures. There has been a trend recently to isolate wild-type strains from traditional products for use as starter cultures in food fermentation. A total of 74 bacterial strains and 21 yeast strains were isolated from a cassava mash fermentation process in a rural village in Benin, West Africa. These strains were assessed, together with 26 strains isolated at the CSIR from cassava samples sent from Benin previously, for phenotypic and technological properties. Twenty four presumptive lactic acid bacteria (LAB) were selected for further phenotypic, genotypic and technological characterization during a research visit to the BFE (now Max Rubner Institute of Nutrition and Food). After assessment, the strains VE 20, VE 36, VE 65b, VE 77 and VE 82 were chosen for further study as starter cultures. These L. plantarum strains were chosen on the basis of predominance and possession of suitable technological properties. The investigation of this study was complemented by further, similar studies on further Gari isolates in Germany by the BFE. That study was done independently from this study, but both studies served to select potential starter cultures for cassava fermentation for the production of Gari, as this was the common goal of the project. Thus, a wider final selection of potential starter cultures was decided on at the project level and this selection was further tested in fermentation experiments. A total of 17 strains were grown in optimized media in 2 L fermenters. These strains were freeze-dried and thereafter tested in lab-scale cassava mash fermentation trials. xiii The strains performed well in the small scale bucket fermentations. There was a rapid acidification evidenced by the increase in titratable acidity, ranging from 1.1 to 1.3 % at 24 hours, and 1.3 to 1.6 % at 48 hours. The effect of the starter was obvious in that it lowered the pH much faster and to lower levels than the control. It appeared that both the processing and starter culture addition played a role in the removal of cyanide during processing of the cassava into Gari. This was evident from the lower cyanide values obtained for fermentations that included starter cultures. The study also showed that especially the L. plantarum group strains could be produced as starter cultures at lower costs than compared to L. fermentum, W. paramesenteroides or L. mesenteroides strains. Overall the results of this study were crucial for the project in showing that a starter culture which is easy and economical to produce and which has the desired attributes is a feasible possibility for application in the field.

碩士
國立屏東科技大學
熱帶農業暨國際合作系所
96
Cassava (Manihot esculenta Cranz), originated from South America, was introduced into Africa thousands of years ago. The world production is estimated at around 195 million tones. Production from Africa (103 million tones) is more than the rest of the world combined. It is a staple food for at least 600 million people in the tropics. In Africa, it is the third most important food source after rice and maize and ranked tenth in terms of production world wide. The starch content of cassava is more than 80% but low in protein, fat and other minerals. Consumption of cassava is limited due to its high content of cyanogenic glucosides, a chemical compound that can be found in all parts of cassava and has potentials to pose health risks to human beings when continuously consumed. Cassava products such as flour and Garri are produced by application of different processing methods (drying, fermentation, boiling, soaking, roasting etc.) and some of these methods are found to be inefficient in eliminating or reducing cyanide compound to acceptable levels. The present study investigated the effects of fermentation (natural and induced for 3 days), sun drying (3 days), oven drying 40 and 60ºC for 6, 12, and 24 hours), and extrusion cooking (dry and wet) on the physicochemical properties of bitter and sweet cassava genotypes. Results of this study showed that fermentation was the most effective method of reducing cyanide to safe levels compared to sun drying, oven drying, and extrusion cooking. There was significant difference (p<0.05) on residual cyanide among fermented cassava flours, Garri and sun-dried or oven-dried flours of both bitter and sweet varieties. The cyanide levels in natural fermented flour and Garri were found 1.60 and 0.80 mg equivalent/kg dry weight from the initial cyanide content of 61.67 HCN mg/kg equivalent dry weights in fresh cassava pulp, respectively. Natural fermented flour, Garri, and Saccharomyces cerevisae fermented flour were significantly (p<0.05) lower than the sun-dried (28.60 mg HCN equivalent/kg dry weight) or oven-dried (27.70 mg HCN equivalent/kg dry weight flours, but were not significantly (p>0.05) different from each other. Wet and dry extrusion cooking had also effected cyanide reduction in both bitter and sweet cassava genotypes and they were significantly (p<0.05) different from each other. Dry extrusion had a significant cyanide reduction in both bitter (26.10 mg HCN equivalent/kg dry weight), and sweet (9.89 mg equivalent/kg dry weight) cassava extrudate and the level of reduction was comparable to the fermented flours. Preliminary study on acrylamide confirmed that it could be formed when cassava was oven-dried and then dry extruded, although the quantities were insignificant and ranged from 4.8 to 14.3 ppm.