Alexandre José de Melo Queiroz

Caracterização físico-química de méis produzidos no Estado do Piauí para diferentes floradas

The objective of this work was to evaluate the physical-chemical composition of honeys produced in the Piaui State, located in semi-arid region of Northeast Brazil. The honeys produced from marmeleiro (Croton sonderianus Mull. Arg.), jitirana (Hyptis suaveolens), camaratuba (Cratylia mollis Mart. ex Benth), silvestre (Serjania glabrata) and angico de bezerro (Piptadenia moniliformis), were analysed following the methods recommended by the Brazilian Ministry of Agriculture and Normative Instruction of October 2000. the following analyses were performed: moisture, hydroxymethylfurfural (HMF), reducing sugars, apparent sucrose, ash, free acidity, insoluble solids in water, diastatic activity, oBrix and pH. The individual values of each analyzed parameter were compared with the standards established by Ministry of Agriculture and Suplies and presented satisfactory results, matching the standards cited by the Normative Instruction.

Armazenamento da polpa de acerola em pó a temperatura ambiente

This work had for objective, to study the storage of the pulp of powdered West Indian cherry wrapped in sacks of polyethylene for 60 days, under atmosphere it adapts. The West indian cherry powder was obtained by the drying of a solution containing 90% of West Indian cherry pulp and 10% of maltodextrin, in a dryer of the type spouted bed, with temperature of the air of drying of 70oC. Every 10 days were made evaluations of the parameters ascorbic acid, humidity, pH and color. The results a decrease in the tenor of ascorbic acid of 29.72%; an increase of 51.31% in the humidity; the value of the pH stayed practically unaffected oscillating between 3.7 and 3.8 units of pH and it was observed alterations in the color of the West Indian cherry powder at the end of the storage, with increment in the values of the intensity of red and yellow and decrease of the brightness

Microbiologia de farinhas de mandioca (Manihot esculenta Crantz) durante o armazenamento

This work was accomplished with the aim of evaluating the microbiological characteristic in cassava flours (Manihot esculenta Crantz) simple and temperate, stored during 180 days. The materials consisted of five samples, being one of cassava flour without mixture (simple) and the others of temperate cassava flours. The simple flour was packed in polyethylen bags of low density with capacity of 1,0kg and the temperate flours were packed in colored polipropilen bags, with capacity of 0.5kg. In all the samples fecal coliformes, Staphylococcus aureus, mesophile bacterias, yeasts counting and Salmonella sp research were accomplished. The analyses were accomplished in intervals of 30 days. Differences were not detected among the microbiological characteristic of the simple samples and the temperate ones. The storage didnx92t affect the microbiological standard of the samples. The samples presented sterility for fecal coliformes, Salmonella sp. and Staphylococcus aureus. The values found for fecal coliformes, Salmonella sp., Staphylococcus aureus, mesophile bacterias and yeasts were inside the patterns fastened by the Brazilian legislation.

Armazenamento de umbu-cajá em pó

The influence of the packing type on umbu-caja powder stored during 60 days was studied. The samples stored in two packing types, laminated and polyethylene materials, were evaluated each 10 days through the moisture content, ascorbic acid, pH, titratable acidity, soluble solids, reducers sugars and color (brightness, red and yellow intensity) parameters. It was verified that the laminated packing protected with higher efficiency the stored samples, preserving better the titratable acidity, the moisture and the brightness, red and yellow intensity color parameters. The reducers sugars contents, pH and ascorbic acid were not affected by packing type, and the time of storage didnt modify the pH.

Caracterização termofísica de polpas de bacuri

SUMMARY THERMOPHYSICAL CHARACTERIZATION OF BACURI PULP. Thermophysical properties, specific heat, density, thermal diffusivity and thermal conductivity of bacuri pulps at different concentrations were studied. The specific heat was determined by the mixture calorimeter method; the density was determined by the pycnometer; the thermal diffusivity was obtained by using the infinite cylinder method; the thermal conductivity was determined from the experimental results obtained for density, specific heat and thermal diffusivity. All the properties were also theoretically determined using proposals equations and regressions. Among the experimental results the specific heat varied from 3.616 to 2.986 kJ/kgoC; the density varied from 1,008.40 to 1,048.36 kg/m 3 ; the thermal diffusivity varied between 1.637x10-7 and 1.787x10-7 m2/s; the thermal conductivity varied from 0.50 to 0.64 W/moC. Except for the density, the value of all the properties decreased, whereas the concentration increased. The thermal conductivity was fitted

Avaliação sensorial e da atividade de água em farinhas de mandioca temperadas

Este trabalho foi realizado com o objetivo de avaliar sensorialmente quatro amostras de farinhas de mandioca temperadas e verificar o comportamento da atividade de agua ao longo de um periodo de cento e oitenta dias de armazenamento. As farinhas consistiram de cinco amostras, sendo uma de farinha de mandioca seca embalada em sacos plasticos de polietileno de baixa densidade, capacidade 1.000 g e quatro de farinhas de mandioca temperadas, obtidas a partir da primeira, embaladas em sacos plasticos de polipropileno pigmentado, capacidade 500 g, tendo sido utilizada como embalagem secundaria sacos de polietileno de baixa densidade, capacidade 10.000 g. A analise quanto a atividade de agua foi realizada logo apos o processamento e durante todo o periodo de armazenamento, com intervalos de trinta dias. Com relacao a analise sensorial as amostras obtiveram aceitacao acima de 5,5 pontos, superando o valor intermediario da escala hedonica. A atividade de agua aumentou com a temperatura e com o tempo de armazenamento, porem, com valores inferiores a 0,6.

Comportamento reológico e efeito da temperatura da polpa de pequi em diferentes concentrações

Despite the high economic potential of pequi pulp, studies related to its physical properties for use in industrial projects and processes are still scarce. Therefore, this study aimed to assess the rheological behavior of pequi pulp with different total soluble solids contents (6, 8, 10 and 12 °Brix) and at different temperatures (25, 30, 35, 40, 45 and 50 °C). The experimental measurements were made using a Brookfield viscometer and the rheological models Ostwald-de-Waelle, Herschel-Bulkley and Mizrahi-Berk were fitted to the experimental data for shear stress and shear rate. Of the rheological models tested, the best fits were observed using the Mizrahi-Berk model. The pequi pulp showed a trend for decreasing apparent viscosity with increasing shear rate, behaving as a non-Newtonian fluid with pseudoplastic characteristics.

PRODUÇÃO E CARACTERIZAÇÃO DA POLPA DE ATEMOIA EM PÓ

A atemoia desperta cada vez mais interesse devido ao seu aroma, sabor e valor de mercado. Porem, como a maioria das frutas, e bastante perecivel, fazendo-se necessaria a aplicacao de metodos de conservacao, a exemplo da secagem por aspersao, que prolonga a vida de prateleira, reduz a atividade de agua e obtem como produto final o alimento em po. Com isso, o objetivo deste trabalho foi desidratar a formulacao elaborada com 50% de polpa de atemoia + 50% de agua destilada, adicionada de 25% de maltodextrina em secador por aspersao, com temperatura de entrada do ar de 180 oC, vazao de alimentacao da bomba de 0,5 L h-1, pressao do ar de 30 kgf cm-2 e bico aspersor de 1,2 mm de diâmetro. Como produto final, foram obtidas duas amostras em po, uma coletada na câmara de secagem e outra no ciclone, sendo estas caracterizadas fisica, fisico-quimicamente e morfologicamente. Os dados experimentais foram analisados por delineamento inteiramente casualizado. Avaliando-se os resultados, observa-se que a cor da amostra em po coletada na câmara de secagem foi mais escura do que a do ciclone; as amostras de atemoia em po, coletadas na câmara de secagem, apresentaram maior teor de agua, pH, acido ascorbico, cinzas, acucares redutores e proteinas em relacao as amostras em po coletadas no ciclone e menor atividade de agua, densidade absoluta e aparente; alem disso, o po da câmara de secagem e mais soluvel, apresenta maior porosidade e particulas maiores do que o po do ciclone, e ambas formaram aglomerados.

CINÉTICA DE SECAGEM EM CAMADA DE ESPUMA DA POLPA DE MANGA CV. KEITT

This study aimed to assess the foam-mat drying kinetics of mango pulp (cv. Keitt) adding 1% Emustab® and 1% Super Liga Neutra®, for a whipping time of 20 minutes, dried in a forced-air convection oven at different temperatures (50, 60 and 70C) and foam layer thicknesses (0.5, 1.0 and 1.5 cm). Drying kinetic data were used to build drying curves and then fit to Page, Henderson, Henderson and Pabis, Logarithmic and two-term Exponential models. Both temperature and foam layer thickness influenced drying time, which reached the shortest value at the highest temperature and smallest thickness. The Page model provided the best fit to the experimental drying curve data.

Comportamento reológico das polpas de noni integral e concentradas

The rheological behaviour of fruit pulps allows one to obtain important information about their flow under distinct conditions and at different stages of the process. Thus the present study aimed to analyse the rheological behaviour of whole noni pulp (Morinda citrifolia L.) and that concentrated to 30 and 50 °Brix. The rheological parameters determined were: shear stress, strain rate and apparent viscosity, using a Brookfield viscometer at rotational speeds of 5 to 200 rpm and temperatures from 5 to 65 °C. Of the models tested, the Mizrahi & Berk model best represented the rheograms of the whole and concentrated noni pulps with the following fittings: R2 ≥ 0.8219, X2 ≤ 0.1569 and P ≤ 2.26%. The pulps studied presented values u200bu200bfor the fluid behaviour index of less than one (n<1), characterizing them as non-Newtonian fluids with pseudoplastic behaviour. The Arrhenius equation can be used to demonstrate the effect of temperature on the apparent viscosity for the whole and 30 oBrix pulps at all speeds, and for the pulp with 50°Brix preferably at rotational speeds of 5, 10 and 20 rpm.