Caracterização físico-química da manga 'Tommy Atkins' submetida a aplicação de cloreto de cálcio pré-colheita e armazenamento refrigerado

Avaliou-se a qualidade pós-colheita de manga 'Tommy Atkins' submetida a aplicação pré-colheita de CaCl2 e armazenamento refrigerado. Os fatores estudados foram concentrações de CaCl2 (1% e 2%) e números de aplicações (2,3 e 4 vezes). Houve ainda um tratamento adicional, que funcionou como controle. As pulverizações foliares foram iniciadas cerca de 35 dias após antese, num intervalo de 15 dias. do total de 280 frutos colhidos, 175 foram levados para análise imediata, enquanto que 105 permaneceram em câmara fria (10ºC) por 30 dias, sendo posteriormente analisados. As concentrações de CaCl2 testadas não resultaram em incremento do teor de cálcio no fruto e também não influenciaram as características de qualidade avaliadas. Houve efeito do número de aplicações de CaCl2 sobre a textura, sólidos solúveis (após 30 dias) e açúcares solúveis totais (após a colheita). A incidência de colapso interno não foi associada a aplicação de cálcio.

Sinterização de filmes finos de LiNbO3 em forno microondas: estudo da influência da direção do fluxo de calor

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Armazenamento refrigerado de banana 'Prata Anã' proveniente de cachos com 16, 18 e 20 semanas

Conduziu-se este trabalho, com o objetivo de verificar a influência da temperatura de refrigeração e idade do cacho sobre a conservação e qualidade pós-colheita da banana 'Prata Anã', produzida no Norte de Minas Gerais, visando a exportação. Utilizaram-se frutos de bananeira 'Prata Anã' provenientes do município de Nova Porteirinha, MG. A colheita foi realizada na 16ª, 18ª e 20ª semanas após a emissão floral. Dos cachos colhidos, utilizou-se às segundas pencas, separadas em buquês com 5 frutos, lavados e pesados (18 kg). em seguida, os frutos foram revestidos com embalagens de polietileno de baixa densidade, com 50m de espessura, sob vácuo parcial, acondicionados em caixas de papelão e distribuídos em paletes. Depois de embalados e paletizados, os frutos foram transportados para a EPAMIG/CTNM, onde foram armazenados em câmaras de refrigeração (10 e 12ºC) e umidade relativa de 95%, por um período de 35 dias, sendo analisados antes e após a refrigeração. O armazenamento de bananas 'Prata Anã', provenientes de cachos com 16, 18 e 20 semanas, por 35 dias a temperaturas de 10 e 12ºC, não promoveu chilling nos frutos. A temperatura de 10ºC foi mais eficaz em prevenir a evolução da coloração da casca de bananas provenientes de cachos com 18 semanas, que à temperatura de 12ºC, enquanto as temperaturas de 10 e 12ºC foram igualmente eficientes na contenção da mudança de cor de bananas provenientes de cachos com 16 semanas. Frutos provenientes de cachos com 20 semanas amadureceram desuniformemente, ao longo do armazenamento refrigerado.

Armazenamento refrigerado de pomelos variedades flame e henderson revestidos com cera

Objetivou-se, neste trabalho, estudar a conservação de pomelos (Citrus paradisi Macfad.) varieties 'Flame' e 'Henderson' revestidos com cera Sparcitrus e mantidos sob refrigeração (8º C ± 1º C e 95% ± 5% UR). Para cada variedade estudada, utilizou-se delineamento inteiramente casualizado, disposto em esquema fatorial 2 x 5, com 3 repetições, onde o primeiro fator correspondeu aos tratamentos com e sem a aplicação de cera (controle) e o segundo, ao tempo armazenamento (0, 10, 20, 30 e 40 dias). Cada parcela experimental foi composta por cinco frutos. Foram estudadas as seguintes variáveis: perda de massa, rendimento do suco, pH, sólidos solúveis (SS), acidez titulável (AT), SS/AT, açúcares redutores, açúcares não redutores, açúcares solúveis totais, vitamina C e aparência externa. A aplicação de cera é efetiva na preservação da aparência de pomelos 'Flame' e 'Henderson', não afetando sua qualidade interna.

Resinas para facetas estéticas de próteses fixas. III. Análise conjunta das variáveis alteração dimensional e alteração de peso em função de materiais, condição de armazenamento e tempos.

The authors analysed the simultaneous effects of the dimensional and weight alteration of resins utilized for esthetic facets submitted to warehousing conditions and periods of time. The resins showed different behaviour and a neat correlation between dimensional alteration and weight. The condition of immersion promoted dimensional alteration 50% lower and an alteration of weight three times higher.

Simulação numérica de trocadores de calor multitubulares equipados com fitas helicoidais externamente aos tubos

Classical shell-and-tube heat exchangers are usually equipped with segmental baffles. These baffles serve two basic functions: (a) they provide tube supports, thereby preventing or reducing mechanical problems, such as sagging or vibration; (b) they direct the fluid flow over the tubes so as to introduce a cross-flow component, thereby increasing the heat transfer. Segmented baffles have several sources of performance loss, some due to various leakage flows and others caused by stagnation zones. A new concept of longitudinal flow heat exchanger - based on placing twisted tapes along the tube bundle subchannels - was developed to mitigate drawbacks of other types of tubular heat exchangers. In this paper, a numerical model has been implemented in order to simulate the thermal-hydraulic feature of tubular heat exchangers equipped either with segmental baffles or with subchannel twisted tapes. The tube bundle has been described by means of an equivalent porous medium type model, allowing a macroscopic description of the shell-side flow. The basic equations - continuity, momentum and energy - have been solved by using the finite volume method. Typical numerical results have been compared with experimental data, reaching a very good agreement. A comparative analysis of different types of heat exchangers has been carried out, revealing the satisfactory thermal-hydraulic efficiency level of the twisted tapes heat exchangers.

Efeito do Nível de Energia da Dieta e da Exposição Prévia ao Calor sobre a Respiração Mitocondrial do Músculo Cardíaco de Frangos de Corte

This work was conducted aiming to evaluate the effect of dietary energy level and the previous heat exposure on the respiratory activity of the mitochondria from the cardiac muscle of broiler chickens. It was used broiler chickens (Hubbard) from both sexes and fed with diet containing 2900 kcal ME/kg or 3200 kcal ME/kg. The birds were heat stressed (35°C/4h) in the 1 st, 21 st and 42 nd days of age. The respiratory activity of mitochondria from cardiac muscle was evaluated in a Gilson oxygraph, model 5/6, by using alpha-ceto-glutaric as substrate and the ADP (adenosine-di-phosphate) to stimulate the respiratory activity. There was not effect of dietary energy level and previous heat exposure on the respiratory activity of the mitochondria from cardiac muscle. However, the females presented higher respiratory activity than males. By reason of the low oxidative capability of the heart muscle fiber of the male broiler chickens, these could be more sensitive to cardiac disease than females.

Atividades de peroxidase e polifenoloxidase durante o armazenamento pós - Colheita de yacon (polymnia sonchifolia poep & endl)

The purpose of this study was to investigate the peroxidase and polyphenoloxidase activities during the refrigeration at 4oC of yacon tuberous roots with and without polyethylene packing and compared with untreated roots at regular conditions. It was concluded that refrigeration treatment maintains a low activity of these enzymes and keeps good appearance of the roots.

Qualidade fisiológica de sementes de Sebastiania commersoniana (Baill.) Smith & Downs (branquilho - Euphorbiaceae) durante o armazenamento

This paper aims to evaluate the physiological quality of Sebastiania commersoniana seeds stored in cloth bag, plastic bag and glass container and kept in two conditions: laboratory workbench and cold chamber (4 ± 2°C e 80% relative humidity - RH) for 531 days. Periodically, samples were taken in order to determine the moisture content and to perform germination tests. The experimental design was completely randomized, in factorial scheme of 3 × 2 (wrappings × conditions), for each period of storage evaluated (0, 158, 271, 389 and 531 days of storage). Supplementary, a polynomial regression was adjusted in order to describe the physiological quality of the seeds for the different conditions during the experimental period. The results lead to the following considerations: a) storage under variable temperature and air humidity (laboratory workbench) can be used for periods of over five and a half months, with the seeds stored in cloth bag, plastic bag or glass container; b) the physiological quality of the seeds was not hardly altered when stored in cold chamber in cloth bag, plastic bag and glass container for over 18 months.

Atividade antioxidante e antimicrobiana do alecrim (Rosmarinus officinalis L.) em filés de tilápia (Oreochromis ssp) salgados secos durante o armazenamento congelado

Rosemary (Rosmarinus officinalis L.) is a spice from Lamiaceae family known since ancient times because its medicinal effects and, currently, several studies have pointed its antioxidant and antimicrobian effects. Lipid oxidation is a problem in food production because proceed the lost of organoleptical and nutritional qualities so required in Market. Fish salting is an ancient conservation method that expect reduce water activity and, consequently, microorganism growth in food, except halophillic bacteria. In the meantime, the inconvenient of this procedure is that the salt accelerates tissue's lipid oxidation. The aim of this work was evaluate the antioxidative and antimicrobian effects by treatment and pre treatment with rosemary (Rosmarinus officinalis L.) aqueous extract in dry salted tilapia fillets, storaged in freezing temperatures. To follow the oxidative, dry salted tilapia fillets were treated or pre treated with rosemary natural extract and storage at -18°C for 240 days. Analisys of 2-thiobarbituric acid reactive substances (TBARS), soluble nitrogen in trichloroacetic acid (TCA), water activity and microbiology were done. The pre treatment (3.39±0,53) and the treatment with rosemary (3.31±0.79) had oxidative index twice lower than the control treatment (6.14±1.21) in the last time of the research. The microbiological rosemary analisys showed count levels of resistant microorganisms to salt (2.0×103CFU/g of sample), whom causes the initial fillets contamination. The microbiological counts remained invariable in all groups during storage periods.

Qualidade de mangas cv. palmer após armazenamento sob baixas temperaturas

This study aimed to evaluate the quality of 'Palmer' mangoes previously stored at low temperatures, after their transference to the environmental condition. Fruits harvested at physiological maturity were carefully transported to the Laboratory where they were selected, standardized as the color, size and absence of injuries and treated with fungicide before they were stored at 2°C (75.7% RH), 5°C (73.8% RH) e 12°C (82% RH) for 7, 14 and 21 days. At the end of each period, the fruits were transferred to environmental condition (22.9°C; 62.3% RH), where they were kept for 1, 3, 5 and 7 days, simulating the trading period, and evaluated for the occurrence of injuries and rottenness; peel and pulp color; firmness; contents of soluble solids, titratable acidity and ascorbic acid, as well as, the activities of the enzymes peroxidase, polyphenoloxidase and phenylalanine ammonia-lyase. The results indicated that 'Palmer' mangoes can be stored at 12°C for 21 days without damage to ripening, but with limitations due to the occurrence of decay. The storage at 2°C and 5°C was limited by the occurrence of injuries in the peel, but at the temperature of 2°C these symptoms were more severe and compromised the development of the characteristic color of the peel. However, the ripening of the pulp was not harmed, but this process occurred with less intensity than in mangoes maintained at 12°C.

Posição do racemo, do fruto e armazenamento na qualidade de sementes de mamona (Ricinus communis L.)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Sistema de armazenamento de imagens comprimidas através da transformada wavelet

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Efeito da radiação solar e temperatura na emissão de metano associado à produção e perda de calor em bovinos

Pós-graduação em Zootecnia - FCAV

Avaliação de caracteristicas físico-químicas e bioquímicas do pequi (Caryocar brasiliense Camb.) em suas diversas formas de armazenamento

Pós-graduação em Biotecnologia - IQ