Tesi sul tema "Sun drying"

Abstract There is concern whether cabbage and beetroot wastes from the Fresh Produce Market are safe for feeding animals given the fact that some will have been discarded at the onset of putrefaction. This study evaluated the effects of sun-drying on microbiological load (E. coli, coliform, yeast and moulds and total bacterial count) in waste vegetables from the fresh produce market, since smallholder farmers tend to use the by-products without processing given the opportunity. Cabbage and beetroot wastes were sun dried to 14% moisture and micro-organisms were enumerated on both wet and dried samples. The results showed that sun drying reduced the level of micro-organisms significantly in both cabbage and beetroot. Although microbial load varied from batch to batch in the wet samples, coliforms were significantly more abundant in wet beetroot than in the dried samples. However, dried beetroot contained significantly more yeast and moulds. Wet cabbage contained more coliform and yeast and moulds compared to sun-dried cabbage. The sun drying process is thus an efficient processing method for resource poor farmers to reduce the microbial load in these animal feed sources and improve their shelf life.

Tomato (Lycopersicon esculentum L.var) is one of the most important vegetables in our diet and dried tomato products are becoming popular for the preparation of various food items. Though sun drying has been used for the preservation, it is a slow process and the quality of the dried product is often inferior due to contaminations. Therefore, a lab model solar cabinet and vacuum assisted solar dryers were developed to study the drying kinetics of tomato slices (4, 6 and 8 mm thicknesses) and the results were compared individually with open sun drying under the weather conditions of Montreal, Canada. The drying kinetics using thin layer drying models and the influence of weather parameters such as ambient air temperature, relative humidity, solar insolation and wind velocity on drying of tomato slices were evaluated. During drying, it was observed that the temperatures inside the solar cabinet and vacuum chamber were increased to 63 and 48oC when the maximum ambient temperature was only 30oC. The tomato slices of 4, 6 and 8 mm thicknesses could be dried from 94.0 to 11.5% wet basis moisture content, respectively in 300, 420 and 570 min using solar cabinet, in 360, 480 and 600 min using vacuum assisted solar dryer and it took 435, 615 and 735 min under open sun drying method. The quality of tomato slices in terms of physicochemical parameters such as colour retention, water activity, rehydration capacity and ascorbic acid retention were evaluated and the overall study concluded that good quality dehydrated tomato slices could be produced by using vacuum assisted solar dryer compared to solar cabinet and open sun drying methods. The Page model was found to be better in describing the drying kinetics of tomato slices in all the drying methods studied.
La tomate (Lycopersicon esculentum L. var) est une importante source nutritive de notre alimentation et les tomates séchées gagnent en popularité dans de nombreuses préparations alimentaires. Le séchage naturel est la méthode traditionnelle utilisée pour la production de tomates séchées, cependant c’est un processus lent et la qualité du produit séché est variable et sujette à la contamination. Un séchoir solaire et un séchoir solaire sous-vide furent donc développés afin d’étudier le séchage solaire de tranches de tomates (4, 6 et 8 mm d’épaisseur) en comparaison au séchage naturel sous les conditions météorologiques de Montréal, Canada. La cinétique du séchage des tranches de tomates suivant des modèles en couches minces a été établie en fonction de l’influence des conditions météorologiques telles que la température ambiante, l’humidité relative, le rayonnement solaire et la vitesse du vent. Lors du séchage dans le séchoir solaire et le séchoir solaire sous-vide, la température interne des deux séchoirs a atteint 63° et 48°C respectivement alors que la température ambiante était de 30°C. Les tranches de tomates de 4, 6 et 8 mm d’épaisseur ont pu être séchées d’un taux d’humidité de 94% à 11.5% (état humide) et ce après 300, 420 et 570 minutes en utilisant le séchoir solaire, en 360, 480 et 600 minutes grâce au séchoir solaire sous-vide, alors qu’il en a pris 435, 615 et 735 minutes par séchage naturel. La qualité des tranches de tomates a été évaluée en fonction de certains paramètres physico-chimiques tels que la stabilité de la couleur, l’activité de l’eau, la capacité de réhydratation, et la conservation de l’acide ascorbique. Des tranches de tomates séchées de meilleure qualité peuvent être produites par séchage solaire sous-vide en comparaison avec le séchage solaire et le séchage naturel. La modélisation de Page offre une très bonne représentation$

The main objective of this study was the application of solar energy for drying of parboiled wheat, corn and pea. Drying experiments were performed under open sun and also in the solar-spouted bed drier in which air heated by solar energy was used. The effects of these drying methods on drying rate and quality parameters were investigated for drying of parboiled wheat, corn and pea. The quality parameters evaluated were color, shrinkage, bulk density, apparent density, bulk and internal porosity, microstructure, pore size distribution, sphericity and rehydration ratio. For peas, ascorbic acid content was also measured. In solar-spouted bed drying, drying rates and effective diffusivity values for all samples were determined to be higher and therefore drying time was significantly lower as compared to open sun drying. Effective diffusivities were in the range of 0.30x10-10 m2/s - 0.65x10-10 m2/s for open sun and 1.35x10-10 m2/s - 3.65x10-10 m2/s for solar-spouted bed drying of different samples. In general, better quality parameters for solar-spouted bed dried samples were observed such as less shrinkage, higher rehydration capacities, more homogenous pore size distribution and higher ascorbic acid retention.

The objective of the study was to reveal the effect of RF heating at different power densities and time combinations as pre-conventional kiln treatment on the drying characteristics and quality of sub-alpine fir lumber. As a consequence of this objective, the study hypothesis was formulated as: “if RF heating improves the permeability of sub-alpine fir, then upon kiln drying, final moisture content variability between and within lumbers as well as drying defects will decrease”. In this research, thirteen groups of one meter long, 51 x 102 mm sub-alpine fir lumbers were RF heated with two power densities (27 and 72 kW/m³) and eight time combinations (15, 30, 45, 60, 75, 90, 105 and 120 minutes), but all to the same final temperature level (100°C) before kiln drying in a two-phase experimental design. Two groups (one for each phase) served as controls. Permeability tests were also performed in the second phase of the study. The effect of RF heating on permeability, drying rates, moisture content gradient, final moisture content variability between pieces and drying defects was evaluated and analyzed. Treatment effect on total energy consumption (sum of RF heating and kiln drying energies) was also assessed to ascertain the feasibility of applying this technology in industrial setting. Data analysis revealed in phase 1 that, not all treatments reduced moisture content variability within and between specimens and improved drying rates above and below fiber saturation point, compared to the control. Defect appearance also did not significantly reduce, and all except two treatments increased total energy consumption. In phase 2 however, permeability improved in all except one treatment but was found not to be statistically significant. Treatments also improved moisture gradient as well as drying rates above and below fiber saturation point but the moisture gradient was found not to be statistically significant. Compared to the control, not all treatments reduced moisture content variability between wood samples. Defects did not significantly improve between treatments and control, and total energy consumption was relatively higher in treatments. Results obtained within the limitations of this study led to the rejection of the hypothesis.

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Fundação de Amparo à Ciência e Tecnologia do Estado de Pernambuco
Kalanchoe brasiliensis Cambess é uma das espécies pertencentes à família Crassulaceae. Pode ser encontrada com freqüência em regiões tropicais. No Brasil encontra-se predominantemente na zona litorânea. Sua sinonímia popular é vasta, sendo conhecida como saião, coirama branca, folha da costa e folha grossa. O uso medicinal de Kalanchoe brasiliensis é relevante em várias partes do mundo. O objetivo deste trabalho foi avaliar o potencial farmacológico do extrato seco de K. brasiliensis, obtido através da tecnologia spraydrying, frente às atividades anti-inflamatória e antiulcerogênica e avaliar sua toxicidade durante a gestação em ratas Wistar. Para tanto, os efeitos do extrato seco foram investigados em modelos de inflamação aguda (edema de pata induzido por carragenina) e de úlcera induzida por etanol a 70% e indometacina, utilizando as doses de 100, 200 e 400 mg/Kg. A toxicidade reprodutiva foi realizada durante as fases de pré-implantação (1º ao 6º dia de gestação) e organogênese (7º ao 14º dia de gestação), administrando-se as mesmas doses farmacológicas. No 20º dia as ratas foram sacrificadas para avaliação dos parâmetros reprodutivos. Os resultados confirmaram a ausência de atividade anti-inflamatória durante a época de floração da K. brasiliensis. Ocorreu uma redução significativa da área da lesão gástrica induzida por etanol em cerca de 40; 47 e 71%, respectivamente, em relação ao grupo controle; e proteção de 25, 29 e 32% nas lesões induzidas por indometacina. A análise estatística empregada (ANOVA) revelou não haver alterações no peso, ganho de peso, consumo de ração e na ingestão hídrica das ratas durante o tratamento, em relação ao grupo controle, que receberam apenas água. Da mesma forma, não houve diferenças significativas no número de filhotes vivos e mortos, relação feto/mãe, peso dos filhotes, ovários e placenta, número de sítios de implantações, reabsorções, corpos lúteos e taxas de perda de pré e pósimplantação. Assim, pode-se concluir que o extrato seco de K. brasiliensis possui atividade antiulcerogênica e não apresenta efeito antiinflamatório na floração, assim como, não promove efeitos tóxicos durante a gestação em ratas Wistar

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This work describes the preparation of nanoparticles of spinel structure, made from oxides of Manganese, Nickel and Cobalt, via lyophilization process, which was compared to the process of obtaining conventional mixture of oxides, in order to analyze different forms of preparation and its influence on electrical properties (characteristic resistance, temperature coefficient, stability of the thermistor), through the measures obtained by applying a voltage of 5 volts on pads and subjecting them to a temperature range of 20 C to 300 C, measured with a thermocouple type K The microstructures were analyzed by scanning electron microscopy (SEM), the average particle size ranged from 60 to 93 nm. X-ray spectroscopy to determine the phases present in the samples and analysis of infrared to identify in the process, organic waste and the organic phase transitions were completely volatilized during the controlled heating pad on high-temperature furnace (with resistance molybdenum silicide) (Lindenberg). Through the obtained results it was noted a certain advantage at all temperatures of the samples had the composition Ni Mn and Co on the Mn Ni which had only giving larger values between 4335 and 4571 for samples made from the process liofilization.
Este trabalho descreve a preparação de nanoparticulas de estrutura espinélio, feitas a partir de óxidos de Manganês, Níquel e Cobalto, via processo de liofilização, o qual foi comparado ao processo de obtenção convencional, mistura de óxidos, afim de se analisar diferentes formas de preparação e sua influência nas propriedades elétricas (resistência característica, coeficiente de temperatura, estabilidade do termistor), através das medidas obtidas aplicando-se uma tensão de 5 volts nas pastilhas e submetendo-as a uma variação de temperatura de 20C a 300C, aferidos com um termopar tipo K. As Microestruturas foram analisadas por microscopia eletrônica de varredura (MEV), o tamanho médio das partículas ficaram entre 60 a 93 nm. Espectroscopia de raios X para determinação das fases presentes nas amostras e análise de infravermelho para se identificar em que fase do processo os resíduos orgânicos e as transições de fases orgânicas foram totalmente volatilizados ao longo do aquecimento controlado das pastilhas em forno de alta temperatura (com resistência de siliceto de molibdênio) (Lindenberg). Através dos resultados obtidos notou-se uma certa vantagem em todas as temperaturas das amostras que tinham na composição Mn Ni e Co sobre as que tinham apenas Mn Ni dando valores de maiores, entre 4335 e 4571 para as amostras feitas a partir do processo de liofilização.

Le séchage et l’imbibition sont des phénomènes physiques indispensables, de nos jours, à la formulation de nombreux matériaux en milieu industriel. Ces phénomènes, comme on peut l’observer avec l’apparition de fissures lors du séchage d’une peinture fraichement appliquée, peuvent affecter de manière irréversible l’aspect, l’intégrité ou la durabilité du matériau concerné. De plus, dans l’industrie, la connaissance des mécanismes physiques mis en jeu lors de ces étapes de séchage ou d’imbibition reste fréquemment empirique, conduisant à de fortes consommations d’énergie. La compréhension fondamentale de ces phénomènes représente donc un enjeu industriel majeur.En utilisant des techniques de mesure telles que l’Imagerie à Résonnance Magnétique (IRM) ou la microscopie électronique, nous nous sommes intéressés à la physique des écoulements fluides dans des milieux poreux modèles, déformables ou non-déformables, dont la taille caractéristique des pores varie de l’échelle du millimètre à celle de quelques nanomètres.Le résultat essentiel de ces travaux de thèse est la démonstration que l’évolution de la distribution de liquide dans ces milieux modèles, lors du séchage, provient de la compétition entre deux phénomènes physiques, quelle que soit la taille des pores, et que le matériau fissure ou subisse du retrait. Ces phénomènes physiques sont : le ré-équilibrage capillaire, ayant lieu lors de la substitution de l’eau par l’air dans le milieu poreux, provoquant un écoulement fluide selon la direction du gradient des pressions de Laplace imposé au liquide par l’évaporation, et le développement d’une région sèche apparente depuis la surface libre de l’échantillon.Plus précisément, nous montrons que le phénomène de ré-équilibrage capillaire est permanent lors du séchage et permet de maintenir une saturation homogène dans les régions humides de l’échantillon quel que soit le régime de séchage rencontré ou la taille des pores de cet échantillon. Pour des pores de dimension supérieure à quelques nanomètres, nous montrons que le séchage s’opère en deux étapes : une première période à fort taux de séchage dont la durée décroit avec la réduction de la taille des pores, cette étape est suivie d’une seconde période présentant le développement d’une région sèche depuis la surface de l’échantillon provoquant une chute du taux de séchage. Nous démontrons aussi que les phénomènes de fracturation et de retrait peuvent influer de façon significative sur la durée de cette première période.Quand la taille des pores devient inferieure à quelques nanomètres, nous montrons que l’infime rayon de courbure de l’interface eau-air développant dans les pores du milieu poreux tend à limiter le taux d’évaporation de l’échantillon et entraine sa décroissance progressive au cours du séchage. De manière surprenante, dans ce cas particulier, la distribution d’eau à travers l’échantillon reste homogène tout au long du séchage. Cette dernière observation nous renseigne sur le fonctionnement du mécanisme de ré-équilibrage capillaire dans les nano-pores et montre que les propriétés d’écoulement liquides en milieux confinés diffèrent grandement de celles rencontrées dans des milieux plus grossiers
Drying and imbibition are widely used in industry to formulate and process materials. Familiar to anyone who ever filled a sponge with water and left it to dry, or spread a coat of paint, fluid to solid transitions may affect the aspect, the integrity and the durability of the material processing. Moreover, in industry this transitional steps frequently relies on empirical techniques for the control of both of these phenomena, resulting in an overconsumption of energy. The understanding of the mechanisms behind drying and imbibition are therefore of crucial industrial stakes.Using measurement techniques such as MRI imaging or electron microscopy, we studied the physics of fluid flow within model deformable and non-deformable porous media with pore sizes ranging from a couple of millimiters to a few nanometers, during imbibition or drying.A fundamental discovery our work features is the demonstration that during convective drying, in any case, namely even down to a nanometric pore size, and even if the material shrinks or fracture during the process, the liquid distribution within a sample evolves from the competition between two phenomena. Particularly, capillary re-equilibration caused by capillary effects inducing liquid flow to equilibrate Laplace pressure throughout the partially saturated regions of the samples, and, the inward development of an apparent dry region from the surface of the sample exposed to the airflow.In details, this manuscript shows that at all time capillary-equilibration enables to maintain a homogeneous saturation within the wet region of the porous sample and two regimes may be distinguished from considerations on the drying rate and the pore size of the material. Namely, for pore sizes superior to a couple of nano meters, a first regime exhibits a high drying rate down to lower saturation with increasing pore size, followed by a second regime where a dry region develops from the sample free surface, resulting in a falling rate period. Note that deformation such as shrinkage and crack may convey the extension of the period of high rate. However, in smaller pores the small curvature of the air-water interface limits the evaporation rate from the very beginning of the process and gives rise to a progressively decreasing drying rate while a homogeneous distribution of water is maintained throughout the sample. This last piece of information emphasizes that in nano-pores capillary equilibration still occurs in a series of instantaneous scattered rearrangements of liquid throughout the sample and finally that the flowing properties of the liquid strongly differ from standard unidirectional liquid flow

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Universidade Estadual Paulista (UNESP)
The present study to have to do as aim to determine the log steaming time its involvement on the sawing process and on the drying of Eucalyptus grandis wood. In order to do it so, were used logs with diameter of 20 at <25, 25 at <30 and 30 at <35 cm, from the Horto Florestal, Manduri, São Paulo. The logs were heated during 20 hours at 90ºC of temperature and 100% of relative humidity. For the adaptation of the logs heating general model developed by Steinhagen to make use of thermocouples fixed it logs center and a datalogger recorded the time and real temperature at each minute. Later the logs were sawing for width tangential system and measuring of the defects resulted from the growth stress were performed with intention to evaluate the effect of steaming treatment and the growth stress behavior with logs diameters. The sawn wood was dry in the dry-kiln and were available the dry defects of the sawn wood deriving as much the control logs as the steamed logs. The results indicate that: the log steaming time determination general model developed by Steinhagen don't is applied for eucalypts and that are necessary the use of the adjustment factors that provided the used them model for studied kind; the logs steaming provided the release of a great part of the growth stress, without, however, eliminate them completely, showing, nevertheless, that this treatment to be feasible and advisable for the growth stress relief; there are among the boards a difference on the growth stress magnitude with the logs diameters showing that the bigger logs to produce boards to be inclined cracks and that logs with diameter smaller to develop biggest boards opening during the sawing process; across of the drying schedules used so much boards provided of the control logs as the heated logs don't to presented collapse e that the warping and end checks were smaller in the heated material; the boards provided... (Complete abstract click electronic access below)

Orientador: Elias Taylor Durgante Severo
Banca: Claudio Angeli Sansígolo
Banca: Geraldo Bortoletto Junior
Abstract: The present study to have to do as aim to determine the log steaming time its involvement on the sawing process and on the drying of Eucalyptus grandis wood. In order to do it so, were used logs with diameter of 20 at <25, 25 at <30 and 30 at <35 cm, from the Horto Florestal, Manduri, São Paulo. The logs were heated during 20 hours at 90ºC of temperature and 100% of relative humidity. For the adaptation of the logs heating general model developed by Steinhagen to make use of thermocouples fixed it logs center and a datalogger recorded the time and real temperature at each minute. Later the logs were sawing for width tangential system and measuring of the defects resulted from the growth stress were performed with intention to evaluate the effect of steaming treatment and the growth stress behavior with logs diameters. The sawn wood was dry in the dry-kiln and were available the dry defects of the sawn wood deriving as much the control logs as the steamed logs. The results indicate that: the log steaming time determination general model developed by Steinhagen don't is applied for eucalypts and that are necessary the use of the adjustment factors that provided the used them model for studied kind; the logs steaming provided the release of a great part of the growth stress, without, however, eliminate them completely, showing, nevertheless, that this treatment to be feasible and advisable for the growth stress relief; there are among the boards a difference on the growth stress magnitude with the logs diameters showing that the bigger logs to produce boards to be inclined cracks and that logs with diameter smaller to develop biggest boards opening during the sawing process; across of the drying schedules used so much boards provided of the control logs as the heated logs don't to presented collapse e that the warping and end checks were smaller in the heated material; the boards provided... (Complete abstract click electronic access below)
Mestre

Orientador: Neura Bragagnolo
Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
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Resumo: Mudanças na bebida e na cor dos grãos durante o armazenamento do café cru levam à perda do valor no mercado devido, provavelmente, a processos oxidativos nos lipídios. Durante a oxidação dos lipídios há formação de compostos muito reativos, os quais podem reagir com proteínas, ácidos clorogênicos e outros compostos presentes no grão cru. O objetivo do presente trabalho foi avaliar em café natural (CN) e café cereja descascado (CD) da cultivar IPR 98 as alterações nos lipídios, proteínas, ácido 5-cafeoilquínico, viabilidade da semente e na estrutura celular do grão, além das mudanças sensoriais na bebida e na cor do grão, verificando se a perda da qualidade sensorial durante a estocagem por 15 meses está relacionada com processos oxidativos. As modificações nos lipídios foram avaliadas pelo acompanhamento do processo oxidativo mediante análises de substâncias reativas com ácido tiobarbitúrico (TBARS) e no teor de ácidos graxos livres. A fração de ácidos graxos livres foi analisada por cromatografia gasosa após a extração com éter metil-t-butílico e fracionamento por cromatografia de permeação em gel. A oxidação de proteínas foi medida pelo método espectrofotométrico empregando dinitrofenilidrazina para a formação de osazonas. O teor do ácido 5-cafeolquínico foi medido utilizando cromatografia líquida de alta eficiência com detector de arranjo de diodos. A avaliação da viabilidade da semente foi realizada mediante imersão em sal de tetrazólio, e a análise da estrutura celular foi realizada por microscopia eletrônica de transmissão. As mudanças sensoriais avaliadas foram a qualidade global da bebida, a intensidade do sabor café descansado na bebida e a medida da cor nos grãos. No final da estocagem foi observado nos cafés CN e CD aumento do teor de ácidos graxos livres, do valor de TBARS e do número de grupos carbonilas nas proteínas, assim como diminuição do teor de ácido 5-cafeoilquínico e perda total da viabilidade da semente. A qualidade global da bebida aumentou até o nono mês da estocagem para o café CD e diminuiu nos meses seguintes, enquanto que para o café CN aumentou, mantendo-se até o final da estocagem. A intensidade do sabor café descansado aumentou durante todo o tempo da estocagem. Essas mudanças foram acompanhadas pelo branqueamento dos grãos de café. A microscopia revelou mudanças na estrutura celular durante a estocagem. A presença de grupos carbonilas e os valores de TBARS encontrados no inicio da estocagem, além de trabalhos na literatura que relatam o desenvolvimento de estresse oxidativo durante a secagem, levaram a realizar um novo estudo analisando o comportamento de algumas enzimas antioxidantes durante a secagem de outra amostra de café (cultivar Mundo Novo), processado como café natural e café cereja descascado. Nestas amostras foram quantificadas as atividades das enzimas superóxido dismutase (SOD), guaiacol-peroxidase (GOPX) e glutationa redutase (GR), além da quantificação simultânea de peróxido de hidrogênio. Durante a secagem foi observada maior atividade enzimática no café cereja descascado em comparação com o natural, e maior concentração de peróxido de hidrogênio no café natural do que no café cereja descascado. Considerando os resultados obtidos no presente estudo, pode-se concluir que as mudanças sensoriais observadas durante a estocagem são em parte decorrentes de processos oxidativos não enzimáticos, os quais podem ter sido iniciados durante a secagem do grão
Abstract: Changes in beverage and coffee beans color during storage lead to loss of commercial value probably due to the oxidative processes in lipids. Oxidation of lipids lead to formation of reactive compounds which can react with proteins, chlorogenic acids and other compounds present in raw coffee beans. The present study was initiated to determine the relationship between changes in lipids, proteins, 5-caffeoylquinic acid and sensory characteristics; in addition it was evaluated the viability of the beans and the cell structure of the coffee beans processed as natural coffee and pulped natural coffee during the storage for 15 months. Lipid oxidation was evaluated as thiobarbituric acid reactive substance (TBARS) and free fatty acids. Lipids were extrated with tertiary butyl methyl ether, fractionated by gel permeation chromatography and the fraction of free fatty acids analysed by gas chromatography. The protein carbonyl groups were quantified by following the dinitrophenylhydrazine coupling method. The 5-cafeoylquinic acid content was performed using high performance liquid chromatography. The viability of coffee beans was estimated by tetrazolium chloride test and the cellular structure was examined by transmission electron microscopy. The cup quality and rested coffee flavor using an intensity scale were used for the coffee beverage evaluation . The color was expressed in L*, a* and b*. After 15 months of storage the free fatty acids content, the TBARS values and the number of carbonyl groups increased, while the 5-cafeoilquinic acid content decreased and the coffee bean viability was lost. The cup quality increased until the ninth month of storage and declined in subsequent months to pulped natural coffee while the cup quality to natural coffee not declined during the storage. The rested coffee flavor increased during storage, these changes were accompanied by bleaching of the coffee beans. The transmission electron microscopy revealed changes in the cell structure during the storage. The number of carbonyl groups and TBARS values at the beginning of the storage and the literature reporting the possibility of oxidation stress during the drying of the coffee beans led to a new study aiming to analyze the behavior of some antioxidant enzymes in other coffee sample processed as natural coffee and pulped natural coffee during the drying. The activity of superoxide dismutase (SOD), guaicol-peroxidase (GOPX) and glutathione redutase (GR) as well as hydrogen peroxide content were evaluated. Pulped natural coffee showed more enzyme activities and lower hydrogen peroxide concentration than natural coffee. The results suggested that the sensory changes occurrence during the coffee storage are at least partly due to non enzymatic oxidative process initiated during drying of coffee bean
Doutorado
Ciência de Alimentos
Doutor em Ciência de Alimentos

Le son et la paille de blé, riches en hémicelluloses, sont deux co-produits de la récolte de blé, abondants et renouvelables, mais qui restent à mieux valoriser. Dans le but d'extraire ces hémicelluloses, possédant plusieurs propriétés intéressantes (filmogènes, épaississantes, émulsifiantes, stabilisantes…), un procédé de fractionnement a été élaboré. Ce procédé consiste, après extraction alcaline, en la purification des extraits hémicellulosiques obtenus. Deux techniques ont été appliquées : l'ultrafiltration et la chromatographie sur résine échangeuse d'anions. L'ultrafiltration a permis de concentrer les extraits d'hémicelluloses et de les purifier en éliminant dans le perméat la plupart des molécules contaminantes, essentiellement les sucres libres et les sels minéraux. Les principales limitations de cette étape étaient la viscosité des extraits et les phénomènes de polarisation de concentration et de colmatage des membranes. La percolation sur résine, quant à elle, a permis de décolorer les extraits et de produire des poudres d'hémicelluloses plus claires en fixant certaines molécules colorées telles que les molécules possédant des groupements phénoliques. La combinaison des deux techniques a permis de produire des hémicelluloses pures à 60%. L'extrapolation du procédé à l'échelle pilote par l'utilisation d'un extrudeur bi-vis a permis d'obtenir des poudres d'hémicelluloses pures à 40%
Wheat bran and wheat straw are two by-products abundant and renewable, rich in hemicelluloses, but still not well valued. In order to extract these hemicelluloses characterized by their several interesting properties (film-forming, thickening, emulsifying, stabilizing…), a fractionation process was developed. This process consisted, after alkaline extraction, to purify the hemicellulosic extracts obtained. Two techniques were used: ultrafiltration and chromatography on anion exchange resin. The ultrafiltration allowed to concentrate the extracts and to purify them by removing in the permeate, the contaminating molecules, mostly free sugars and minerals. The main limiting factors of this stage were the extracts viscosity and the fouling of the membranes. The percolation on the resin discoloured the extracts and allowed to produce hemicellulosic powders with lighter colours and that by capturing the coloured compounds such as molecules with phenolic groups. The combination of the two techniques allowed the production of purified hemicelluloses; the purity was about 60%. The extrapolation of the process at a pilot scale using a twin-screw extruder allowed to obtain hemicelluloses with a purity of 40%

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In the productive process of the textile industry have stages that uses dye, which generates effluents that can degrade the environment. This paper looks for producing an alternative adsorbent made from Green Coconut Mesocarp (MCV) for removing the Blue Cassafix - CA 2G, a reactive dye. The adsorbent was produced by drying the MCV in air circulation oven at temperatures of 60 and 80°C, among the tested models for the drying process, the Midili model fitted at most the experimental data. The factorial planning 2^4 analyzed the influence of variables: mass, concentration, pH and time; the factors mass and concentration were statistically significant while the factors pH and time had no influence to the process within the studied levels. In the factorial planning of 2^5 the analyzed variables were mass of MCV, dye concentration, pH, time and washing or not the MCV with an albumin solution; the pH was the only factor that did not show statistically significant effect in the process within the studied levels. The adsorption kinetics tests were carried out with the in naturain natura bioadsorbent and the adsorbent washed with albumin, with a volume of 25 mL of solution and concentration of 100 mg.L^-1, the pseudo-first order and the pseudo- second order models agreed to the experimental data. The best results of qt were found in the kinetics of adsorption with experiment 4, with 3.4 mg.g^-1. In the -1 equilibrium study, 10 erlemmeyers with concentrations ranging from 10 to 100 mg.L^-1 and 0.10 g of MCV were in contact for 30 min at 200 rpm, the Sips model had the best fit for the experimental data. The MCV has potential as a bioadsorbent, has low cost and is found in plenty.
Dentro do processo produtivo da indústria têxtil, há etapas em que a utilização de corante gera efluentes com características que degradam o meio ambiente. O presente estudo busca produzir um adsorvente alternativo a partir do mesocarpo do coco verde (MCV) para remoção do corante reativo Azul Cassafix – CA 2G. O adsorvente foi produzido através da secagem em estufa de recirculação de ar forçado nas temperaturas de 60 e 80 °C, dentre os modelos testados para o processo de secagem o que melhor se ajustou aos dados experimentais foi o de Midili. O planejamento fatorial 2^4 analisou a influência das variáveis massa, concentração, pH e tempo, os fatores massa e concentração foram estatisticamente significativos e os fatores pH e tempo não influenciaram o processo dentro dos níveis estudados. No planejamento fatorial de 2^5 as variáveis analisadas foram a massa, a concentração, o pH, o tempo e a lavagem do MCV com uma solução de albumina, o pH foi o único fator que não apresentou efeito estatisticamente significativo no processo dentro dos níveis estudados. Os ensaios de cinética da adsorção foram realizados com o adsorvente in natura e após lavagem com albumina, com volume de 25 mL de solução e concentração de 100 mg.L^-1 modelo de pseudo-segunda ordem apresentou melhor concordância com os dados experimentais. Os melhores resultados de qt foram encontrados na cinética da adsorção com o experimento 4 no valor de 3,4 mg.g^-1. No estudo do equilíbrio, 10 erlemmeyers com concentrações variando de 10 a 100 mg.L^-1 e 0,10 g de MCV ficaram em contato pelo tempo de 30 min e 200 rpm, o modelo de Sips foi o que melhor se ajustou aos dados experimentais. O MCV apresenta potencial como adsorvente, tem baixo custo e é encontrado em abundância.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
A banana é a fruta com maior produção mundial, sendo plantada em quase todos os continentes. Devido à grande oferta de banana no mercado, é notável a existência de problemas com a geração de resíduos causados por desperdícios (fruta sobremadura) e material celulósico gerado no cultivar. O presente trabalho tem como objetivo principal a aplicação do processo de secagem para resíduos do cultivar da banana nanica (Mussa spp. Haploide AAB ), visando seu possível aproveitamento na indústria. Resíduos de banana tipo nanica (casca, pedicelo, pedúnculo) e polpa foram caracterizados quimicamente, encontrando valores de cinza, umidade, matéria seca, proteína, lipídeos e carboidratos totais muito próximos à literatura. A relação entre o conteúdo de umidade e a atividade de água proporciona informações uteis para a armazenagem e processamento destes resíduos. Na pesquisa foram determinadas isotermas de desorção para casca, pedicelo e polpa de banana a seis temperaturas (20, 30, 40, 50, 60 e 70°C), na faixa de conteúdo de umidade entre 0,001-6,360 kg·kg -1 e atividades de água entre 0,02-0,907. O modelo teórico de GAB foi empregado para a modelagem das isotermas de desorção. Foi proposta a segunda derivada da solução analítica da equação de Clausius-Clapeyron para calcular o calor isostérico de sorção, a entropia diferencial e, a energia livre de Gibbs, através do modelo de GAB quando o efeito da temperatura em equilíbrio higroscópico é considerado. Experimentos de secagem para casca de banana foram realizados em um secador de leito fixo, a três diferentes velocidades de ar (2.5, 1.5 e 1.0 m·s -1 ), e quatro temperaturas (40, 50, 60 e 70°C). Os modelos de Peleg, Lewis, Henderson-Pabis e difusivo, foram empregados na modelagem das curvas de secagem. Na análise gráfica, encontrou-se que a velocidade de ar não influência no tempo final secagem...
Banana is the most produced fruit in the world, being planted in every continent. Due to the large supply bananas in the market, the existence of problems with waste generation caused for overripe fruit and cellulosic material is noteworthy. The objective of this paper is the drying process implementation for banana waste, variety nanica (Mussa spp. Haploid AAB), for a possible application in the industry. Waste (peel, pedicel and peduncle) and pulp of banana nanica were characterized chemically, where values of ash, protein, fat, carbohydrates, and water were quantified, showing similar results with literature. The relationship between moisture content and water activity provides useful information for processing and storage of banana waste. The desorption isotherms of peel, pedicel and pulp of overripe bananas were determined at six different temperatures (20, 30, 40, 50, 60 and 70ºC) over wide ranges of moisture content (0,001–6,360 kg kg-1 d.b.) and water activity (0,02– 0,907). The theoretical model of GAB was used for modeling the desorption isotherms. An analytical solution of the Clausius-Clapeyron equation was proposed to compute the isosteric heat of sorption, the differential entropy, and the Gibbs’ free energy, by means of the GAB model when the effect of temperature on hygroscopic equilibrium is considered. Drying kinetics for peel banana in convective hot air forced equipment were determined, at three air velocities (2.5, 1.5 and 1.0 m·s -1 ), and four temperatures (40, 50, 60 and 70 ° C). The models of Peleg, Lewis, Henderson-Pabis, and diffusive were used to the modeling of drying curves. In the graphical analysis, for all experiments, air velocity does not influence in the final time of drying, showed a decreasing rate period of drying. Finally, acid hydrolysis of dry peel banana was performed by using a central composite design experimental with three... (Complete abstract click electronic access below)

Le renforcement du secteur de la transformation agroalimentaire est reconnu comme un élément moteur de développement des pays d’Afrique subsaharienne, face à une importante croissance démographique accompagnée d’un fort taux d’urbanisation. Si les entreprises agroalimentaires créent localement de la valeur ajoutée et dynamisent la production agricole, elles éprouvent des difficultés pour se doter d’équipements efficients et assurer leur fourniture énergétique.Les méthodes de conception et d’optimisation des procédés agroalimentaires sont encore peu développées, du fait de la complexité de ces systèmes (composition et propriétés de l’aliment, variabilité et évolution de sa qualité, ...) dont la modélisation n’est pas aisée car elle requiert des connaissances pluridisciplinaires.Ce travail se propose de mettre en œuvre une méthode intégrée, déjà éprouvée dans d’autres domaines industriels, la méthode « Observation-Interprétation-Agrégation (O.I.A.) », et de l’appliquer à un procédé couplant une unité de conversion biomasse énergie à un séchoir de produits céréaliers. L’apport de bioénergie pour le séchage, opération très pratiquée en Afrique de l’Ouest mais énergivore constitue un enjeu pour les entreprises. La conception de ce procédé prend en compte des objectifs variés comme la qualité du produit séché, la fabrication locale et l’efficacité énergétique des équipements et ce, pour en garantir une meilleure durabilité.Dans une première partie, les modèles de transfert de chaleur et de perte de pression associés à un turbulateur elliptique innovant sont créés. Cet élément s’insère dans les tubes d’un échangeur de chaleur et améliore nettement le transfert thermique. Dans un deuxième temps, les variables de conception et d’observation du procédé sont définies et justifiées. Les modèles de représentation des différentes opérations unitaires sont développés et assemblés dans un simulateur afin de prédire les performances du procédé. Dans une dernière partie, le simulateur est intégré dans un environnement d’optimisation multicritère apte à formaliser, interpréter puis agréger les préférences des utilisateurs finaux. Ce processus s’appuie sur un algorithme génétique. La pertinence des solutions de conception du procédé performantes produites révèle tout l’intérêt et la performance de la méthode O.I.A. Le concepteur dispose ainsi d’éléments objectifs pour faire des choix et aller vers la réalisation d’installations de séchage durables en Afrique de l’Ouest
The reinforcement of the food processing sector is recognized as a driving factor for the development of sub-Saharan African countries, faced with considerable major demographic growth accompanied by a high rate of urbanization. While the agribusiness companies generate added value locally and boost agricultural production, they find difficulties in obtaining efficient equipment and securing their energy supply.Agribusiness process design and optimization methods are still underdeveloped, due to the complexity of these systems (food composition and properties, variable and changing quality, etc.), modelling of which is not easy since it requires multidisciplinary knowledge.This work proposes to implement an integrated method, already proven in other industrial fields, the “Observation-Interpretation-Aggregation” method (OIA), and apply it to a process coupling a biomass energy conversion unit to a cereal products dryer. The bioenergy supply for drying, a very common practice in West Africa despite being energy-intensive, represents a challenge for the companies. The design of this process takes into account the various objectives such as quality of the dried product, local manufacture and the energy efficiency of the equipment, in order to guarantee better sustainability.First of all, the models for heat transfer and pressure loss associated with an innovative elliptic turbulator are created. This component is inserted into the tubes of a heat exchanger, and significantly improves heat transfer. Secondly, the process design and observation variables are defined and justified. The representation models of the various unit operations are developed and brought together in a simulator, in order to predict the process performances. Finally, the simulator is integrated into a multicriteria optimization environment able to formalize, interpret and then aggregate end user preferences. This procedure is based on a genetic algorithm. The relevance of the high-performance design solutions produced reveals the full benefit and performance of the OIA method. In this way, the designer obtains objective information on which to base their choices, and develop sustainable drying facilities for West Africa

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The growth of the sugarcane sector has enhanced the generation of large amounts of waste such as bagasse from sugar cane, a fact that has encouraged the search for new alternatives of it's use. This study aimed to kiln drying and convective dryer bagasse sugarcane and its application in the removal of metal nickel. Fluorescence spectra of X- rays detected the presence of C, O and Si in the biosorbents, and a fibrous structure and apparently fragmented. Thermal analysis has demonstrated that the bagasse has thermal stability up to 80 °C and four stages of weight loss and decomposition of its components. The point of zero charge was 5,38. The ash content of 4,4%. The kiln drying showed the best results obtained by the experimental desing 22 with 4 center points were showed the temperature of 80 °C as more suitable for balancing the end of the drying process of sugar cane bagasse in 140 minutes. In convective drying the best results were at a temperature of 80 °C and the drying air speed of 2,0 m s-1 reaching the equilibrium moisture content (Xe) in 85±8,66 minutes. Page's model represented better the kinetics, with R2 of 0,9948. The coefficient of diffusivity and activation energy for the best drying conditions investigated were 1,4340 x 10-12 m2 s-1 and 0,58 kJ mol-1. In the adsorption process optimized variables by Experimental Desing Full 23 values showed the following: pH = 5,0, temperature = 25°C, agitation rate = 75 rpm and adsorbent mass of 0,1 g. The adsorption kinetics of bagasse presented a qeq of 1,43 ± 0,024 mg g-1 in a time of 120 minutes. The sugar cane bagasse being a low cost, renewable and biodegradable agroindustrial by product, proves to be a potential adsorbent for the removal of nickel metal.
O crescimento do setor sucroalcooleiro tem potencializado a geração de grandes quantidades de resíduos como o bagaço de cana-de-açúcar, fato que tem incentivado a pesquisa de novas alternativas para sua aplicação. Este trabalho teve como objetivo a secagem em estufa e em secador convectivo do bagaço de cana-de-açúcar e sua aplicação na remoção do metal níquel. Os espectros de fluorescência de raios-X detectaram a presença de C, O e Si no biossorvente, além de uma estrutura fibrosa e fragmentada aparentemente. A análise térmica demonstrou que o bagaço possui estabilidade térmica até 80 °C e quatro estágios de perda de massa e decomposição de seus componentes. O ponto de carga zero (PCZ) do bagaço de cana-de-açúcar foi de 5,38. A secagem em estufa apresentou a temperatura de 80 °C como mais apropriada para estabelecer o equilíbrio ao final do processo de secagem do bagaço de cana em 140 minutos. Na secagem convectiva os melhores resultados obtidos pelo planejamento experimental 22 com 4 pontos centrais foram a temperatura de 80 °C e velocidade do ar de secagem de 2,0 m s-1 atingindo a umidade de equilíbrio (Xe) em 85±8,66 minutos. O modelo de Page representou melhor a cinética de secagem do bagaço de cana com coeficiente de determinação de 0,9948. O coeficiente de difusividade e a energia de ativação para as melhores condições de secagem investigadas foram de 1,4340 x 10-12 m2 s-1 e 0,58 KJ mol-1. No processo de adsorção de níquel as variáveis otimizadas pelo Planejamento Experimental Completo 23 foram pH de 5,0, temperatura de 25 °C e velocidade de agitação de 150 rpm. A cinética de adsorção do níquel pelo bagaço de cana foi de 1,43 ± 0,024 meq g-1 para um tempo de equilíbrio de 120 minutos. O bagaço de cana-de-açúcar por ser um subproduto agroindustrial de baixo custo, renovável e biodegradável, demonstra ser um adsorvente potencial para a remoção do metal níquel.

Resumo: A banana é a fruta com maior produção mundial, sendo plantada em quase todos os continentes. Devido à grande oferta de banana no mercado, é notável a existência de problemas com a geração de resíduos causados por desperdícios (fruta sobremadura) e material celulósico gerado no cultivar. O presente trabalho tem como objetivo principal a aplicação do processo de secagem para resíduos do cultivar da banana nanica (Mussa spp. Haploide AAB ), visando seu possível aproveitamento na indústria. Resíduos de banana tipo nanica (casca, pedicelo, pedúnculo) e polpa foram caracterizados quimicamente, encontrando valores de cinza, umidade, matéria seca, proteína, lipídeos e carboidratos totais muito próximos à literatura. A relação entre o conteúdo de umidade e a atividade de água proporciona informações uteis para a armazenagem e processamento destes resíduos. Na pesquisa foram determinadas isotermas de desorção para casca, pedicelo e polpa de banana a seis temperaturas (20, 30, 40, 50, 60 e 70°C), na faixa de conteúdo de umidade entre 0,001-6,360 kg·kg -1 e atividades de água entre 0,02-0,907. O modelo teórico de GAB foi empregado para a modelagem das isotermas de desorção. Foi proposta a segunda derivada da solução analítica da equação de Clausius-Clapeyron para calcular o calor isostérico de sorção, a entropia diferencial e, a energia livre de Gibbs, através do modelo de GAB quando o efeito da temperatura em equilíbrio higroscópico é considerado. Experimentos de secagem para casca de banana foram realizados em um secador de leito fixo, a três diferentes velocidades de ar (2.5, 1.5 e 1.0 m·s -1 ), e quatro temperaturas (40, 50, 60 e 70°C). Os modelos de Peleg, Lewis, Henderson-Pabis e difusivo, foram empregados na modelagem das curvas de secagem. Na análise gráfica, encontrou-se que a velocidade de ar não influência no tempo final secagem... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Banana is the most produced fruit in the world, being planted in every continent. Due to the large supply bananas in the market, the existence of problems with waste generation caused for overripe fruit and cellulosic material is noteworthy. The objective of this paper is the drying process implementation for banana waste, variety nanica (Mussa spp. Haploid AAB), for a possible application in the industry. Waste (peel, pedicel and peduncle) and pulp of banana nanica were characterized chemically, where values of ash, protein, fat, carbohydrates, and water were quantified, showing similar results with literature. The relationship between moisture content and water activity provides useful information for processing and storage of banana waste. The desorption isotherms of peel, pedicel and pulp of overripe bananas were determined at six different temperatures (20, 30, 40, 50, 60 and 70ºC) over wide ranges of moisture content (0,001-6,360 kg kg-1 d.b.) and water activity (0,02- 0,907). The theoretical model of GAB was used for modeling the desorption isotherms. An analytical solution of the Clausius-Clapeyron equation was proposed to compute the isosteric heat of sorption, the differential entropy, and the Gibbs' free energy, by means of the GAB model when the effect of temperature on hygroscopic equilibrium is considered. Drying kinetics for peel banana in convective hot air forced equipment were determined, at three air velocities (2.5, 1.5 and 1.0 m·s -1 ), and four temperatures (40, 50, 60 and 70 ° C). The models of Peleg, Lewis, Henderson-Pabis, and diffusive were used to the modeling of drying curves. In the graphical analysis, for all experiments, air velocity does not influence in the final time of drying, showed a decreasing rate period of drying. Finally, acid hydrolysis of dry peel banana was performed by using a central composite design experimental with three... (Complete abstract click electronic access below)
Orientador: Javier Telis Romero
Coorientador: Vanildo Luiz Del Bianchi
Co-oreintador: Henry Alexander Váquiro Herrera
Banca: Miriam Dupas Hubinger
Banca: José Francisco Lopes Filho
Mestre

La determination de l'evolution de l'etat hygrothermique d'un toit experimental de tuiles de terre cuite durant son sechage est effectuee a partir du modele mathematique de luikov et des equations des conditions aux limites de type fourier. On determine les coefficients thermophysiques et de transfert de masse de la terre cuite. Les coefficients de transferts de chaleur et de masse, dus a la convection en surface et en sous-face de la couverture, sont etudies en fonction des donnees meteorologiques. La resolution numerique du probleme de sechage suppose unidimensionnel est effectuee par une methode de differences finies

This thesis consists of two essays that each discuss a major component of the post-harvest management of maize in sub-Saharan Africa: drying and storage. The first essay uses cross-country data about on-farm storage decisions between 2013 and 2015 to assess the severity of storage loss in the absence of improved storage technologies. We find that while losses are low, farmers report on average that they lose more than expected and sell earlier than originally intended at harvest. Additionally, we look for evidence that farmers use adaptation strategies for the purpose of mitigating storage loss and find that storage chemicals are effective at both reducing loss and increasing storage duration. The second essay introduces a third-party moisture testing service to traders in western Kenya to elicit willingness to pay for external quality verification using two moisture detection devices, a low-cost hygrometer and a commercial grade moisture meter. We find that while traders value the moisture meter service more, the hygrometer service is more profitable for potential service providers. Further, when offered a chance to purchase the hygrometer device at/around market price ($2.50), only 15% of traders accepted the offer, suggesting that a service provider model is a viable way to make moisture testing more widely accessible and standard practice in the future.