Rafael Gomes Dionello

Secagem de fatias de abacaxi in natura e pré-desidratadas por imersão-impregnação: cinética e avaliação de modelos

The effect of glucose and invert sugar impregnation on the convective drying rate of pineapple and the suitability of nine mathematical models to describe the drying curves were investigated. Tests were conducted using fresh pineapple rings and samples which were pre-treated by osmotic dehydration in sucrose solutions (0.40, 0.44, and 0.47 g mL-1) and in invert sugar syrup. Osmotic pre-treatments were performed at 40 and 50 oC for 2 hours at 60 min-1. The convective drying was performed in a tray cabinet dryer using heated ambient air at 60 oC and 1.25 m.s-1. The adjustment levels of the models were based on the correlation coefficient, the root mean square error, mean absolute percentage error, and residual plot analysis. The highest rates of convective drying were obtained for the fresh samples. In the osmotically pre-treated fruits, with both temperatures, an increase in the solution concentration was followed by a decrease in the convective drying rate. The Wang and Singh model was considered the most adequate in describing the convective drying of pineapple rings.

Avaliação nutricional e sensorial de caqui cv Fuyu submetido à desidratação osmótica e secagem por convecção

A crescente preocupacao com a saude humana tem promovido o aumento da demanda pelo consumo de frutas, tanto in natura como processadas. Neste trabalho, foram realizadas as avaliacoes nutricional e sensorial de caqui Fuyu submetido a desidratacao osmotica e secagem por conveccao. Cilindros de caqui com diâmetro de 15 mm e altura de 40 mm foram imersos por 2 horas em solucao com concentracao de sacarose de 0,47 g.mL-1, a 40 oC, utilizando-se relacao fruta/xarope de 1:10 e grau de agitacao de 60 min-1. A reducao do teor de agua ate 17% b.u. foi realizada a 60 oC, empregando-se velocidade do ar de 1,25 m/s. Apos a secagem, foram realizadas as seguintes analises fisico-quimicas: acidez, pH, oBrix, carboidratos, proteinas, lipidios, vitamina C, cinzas, fibras insoluveis e analise sensorial. Os resultados mostraram incremento em todas as caracteristicas fisico-quimicas avaliadas para o caqui desidratado em comparacao ao caqui in natura. A analise sensorial evidenciou que o produto obteve elevado indice de aceitacao, correspondendo ao segundo e terceiro niveis da escala hedonica (gostei muito e gostei regularmente). A caracteristica que influenciou predominantemente a aceitacao do produto foi a textura (88%), seguida do sabor (84%). A aparencia foi o atributo que menos influenciou a aceitacao (80%).

Thin-layer drying of passion fruit seeds

The original mathematical drying model proposed by Page (1949) was used to derive a thin-layer drying equation to describe the drying of seeds of yellow passion fruit (Passiflora edulis L.). With this purpose, experimental drying data were collected using a fixed-bed prototype drier, using three levels of drying-air temperature (30, 37 e 40oC); three levels of specific airflow rate (24, 48 e 71 m3 min-1 m2), and one level of initial moisture content (30.4±2.0% w.b.). All tests were conducted in an Agricultural Engineering Laboratory where the average temperature and humidity ratio were 28.4±1.0oC, and 0.0138±0.0016 kg kg-1, respectively. The values of errors produced by the equation derived by non-linear regression analyses were considered unacceptable for engineering purposes; this may suggest the need to evaluate other theoretical or empirical models to describe the thin-layer drying of yellow passion fruit seeds. Experimental data revealed, as expected, that as the drying air increased, the total time of drying decreased. Nonetheless, specific airflow rate appears to have no influence on drying time to reduce the initial moisture content of seeds of yellow passion fruit to a final value of 9.9±0.4% w.b.

PAHs in corn grains submitted to drying with firewood.

Grain drying using firewood as fuel for air heating, with direct fire, is still widely used in Brazil. The combustion of organic material, such as wood, can generate polycyclic aromatic hydrocarbons (PAHs) which are known to have carcinogenic potential. In the present work corn grain drying was carried out at three drying air temperatures: 60°C, 60/80°C and 80°C. Following the drying process, the presence and quantification of PAH in the corn grains was investigated. After extracting the PAHs of the matrix, the material was subjected to analysis by gas chromatography with mass detector. he results showed the presence of seven compounds: fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benzo(a)anthracene and chrysene.

Desidratação por imersão-impregnação de abacaxi em soluções de sacarose e em xarope de açúcar invertido

This work consisted of evaluating the effect of the type of osmotic agent, degree of stirring, and temperature and concentration of the hypertonic solution on the kinetics of osmotic dehydration of sliced pineapple. The osmotic agents used here were sucrose in solutions with concentrations of 0.40, 0.44 and 0.47 g.mL-1, and undiluted inverted sugar syrup. Osmotic dehydration was carried out using a fruit to syrup weight ratio of 1:10, and employing two levels of temperature of the solutions, 40 and 50 °C, two shaking rates, 0 and 60 min-1, and a total immersion time of 2 hours. The results showed that immersion in undiluted inverted sugar caused a greater increase in the total soluble solids content in sliced fruit. The parameters characterizing the kinetics of osmotic dehydration showed higher values in the sliced fruit dehydrated in syrup at 40 to 50 °C under shaking.

Desidratação osmótica de frutos de duas cultivares de abacaxi em xarope de açúcar invertido

The objective of the present study was to investigate the kinetics of the osmotic dehydration of sliced pineapple of two cultivars, Perola and Smooth Cayenne, in undiluted inverted sugar syrup. Osmotic dehydration was carried out using a fruit to syrup weight ratio of 1:10, and employing two levels of temperature of the solutions (40 and 50 oC), two levels of agitation (zero and 60 min-1) for a total immersion time of 2 h. Results showed that the fruit to syrup ratio employed did not alter the total soluble solids content of the osmotic solution at the end of the dehydration process. A threefold increase in the total soluble solids content in pineapple slices was observed after dehydration, irrespective of cultivar and temperature of the solution. Highest values of mass reduction, water loss and solids gain were observed for fruit slices of cultivar Perola.

Efeito da dose e exposição à terra de diatomácea de diferentes insetos em milho armazenado

Sitophilus zeamais and Tribolium castaneum are important insect pests of stored grain and their damage corresponds to approximately 25% of post-harvest losses in Brazil. The methods used for the control of these pests notably include the use of post-harvest inert dusts. Therefore, the objective was to assess the mortality of adult S. zeamais and T. castaneum with the use of diatomaceous earth (DE) at different dosages and durations. The treatments with diatomaceous earth were 1,000 and 2,000 GT-1 and control (no application). Insects (10 each species) were placed in 300-ml plastic containers containing 100 g of corn kernels with different moisture contents (12, 14 and 16% wb). Infestations occurred 1 hour, 10 and 20 days after the application of TD. Mortality was evaluated at 30 and 60 days. There were five replicates per treatment. There was a higher mortality for the species S. zeamais than for T. castaneum, and this morality rate increased in direct relation to insect exposure time. It was concluded that T. castaneum has greater tolerance and that the more time the insects are in contact with treated grain the greater the mortality.

Eficiência de inseticidas durante o armazenamento de grãos de milho

O objetivo foi verificar a mortalidade de adultos de Sitophilus zeamais infestando graos de milho tratados com diferentes inseticidas ao longo de 240 dias de armazenamento. Foram utilizados dois inseticidas, um piretroide liquido da marca Starion® 25 CE (Bifentrina) e outro organofosforado liquido da marca Actellic® (Pirimifos metilico), sendo as doses de 6 e 8 mL do produto, diluido em 2 litros de agua, com aplicacao de 2 mL da solucao por quilo de graos. Para o tratamento controle usou-se 2mL de agua. Cada dosagem foi aplicada em tres lotes de 1 kg, com uso de pulverizador uni-spray, com tres repeticoes para cada tratamento, sendo avaliados em duplicata de 50 g, em delineamento inteiramente casualizado. A cada periodo de 30 dias apos as aplicacoes, ocorreram as infestacoes com 20 adultos de S. zemais , sendo a mortalidade verificada apos 15 dias de contato. As infestacoes ocorreram 30, 60, 90, 120, 150,180, 210 e 240 dias apos a aplicacao dos produtos. Ate 60 dias apos a aplicacao, ambas as dosagens de Pirimifos metilico causaram mortalidade acima de 80%, porem apos esse periodo apenas a dosagem de 8 mL ficou acima de 88%. Ja a dosagem de 8mL de Bifentrina, aos 30 dias, apresentou 51,04% de mortalidade, sendo a maior nos tratamentos com este inseticida. Resistencia e degradacao dos inseticidas sao possiveis causas da baixa mortalidade. Conclui-se que Pirimifos metilico com dosagem de 8mL representa a melhor forma de controle de S. zeamais .

Atividade Antagonista de Rizobactérias Isoladas de Plantas de Milho Ao Crescimento Micelial e Germinação de Conídios de Fusarium Verticillioides Produtor de Fumonisina B1.

Tiago Einloft, Flavio Veras, Patricia Oliveira, Rafael Dionello.Atividade Antagonista de Rizobacterias Isoladas de Plantas de Milho Ao Crescimento Micelial e Germinacao de Conidios de Fusarium Verticillioides Produtor de Fumonisina B1.. In: Anais do 12o Congresso Latinoamericano de Microbiologia e Higiene de Alimentos MICROAL 2014 [= Blucher Food Science Proceedings, num.1, vol.1]. Sao Paulo: Editora Blucher, 2014. DOI 10.5151/foodsci-microal-069 Atividade Antagonista de Rizobacterias Isoladas de Plantas de Milho Ao Crescimento Micelial e Germinacao de Conidios de Fusarium Verticillioides Produtor de Fumonisina B1.

EFICIÊNCIA DO USO DE TERRA DE DIATOMÁCEA NA PROTEÇÃO DE GRÃOS DE MILHO - DOI: 10.13083/1414-3984.v22n06a02

Among the main methods of insect control on post-harvest grain, highlighted is the use of diatomaceous earth. Thus, it was proposed to test the efficiency of different dosages of this inert powder on control of Sitophilus zeamais adults in maize grains during storage. Five repetitions were performed with 100 g of grains with different moisture contents (12, 14, and 17%), infested with 20 insects, and treated with different dosages (0, 500, 1500 and 2500 g. t-1) in h hours and 15 days after application of the product. Mortality of insects in the grains, loss of weight, humidity and technological analysis of grains was performed at 60 days after each period of infestation. There were no statistical differences between the averages of mortality regardless of the treatment and moisture content. The control treatments of all moistures presented greater weight losses in both periods of infestation. Higher moisture content was found in untreated grains with initial value of 17%. Higher values of rotten grains were obtained for untreated grains, independent of the moisture content and infestation period. It was therefore concluded that the treatment with diatomaceous earth is effective for the control of S. zeamais and reduces damage to corn grains.