Navegando por Autor "SILVA, Diego Aires da"

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Acesso aberto (Open Access)
Hygroscopic behaviour of cassava flour from dry and water groups
(Universidade Federal do Pará, 2015-08) CHISTÉ, Renan Campos; CARDOSO, Jonnahta Monteiro; SILVA, Diego Aires da; PENA, Rosinelson da Silva
Cassava flour from dry and water groups are important starch products widely consumed in the Amazonian region of Brazil. In this study, the moisture sorption isotherms of cassava flour from dry and water groups were obtained in the water activity (aw) range from 0.09 to 0.94 (dry group) and 0.07 to 0.93 (water group) at 25°C and the applicability of eight mathematical models in data prediction was evaluated. Both cassava flour from dry and water groups exhibited type II isotherms (sigmoid) and the hysteresis effect between adsorption and desorption isotherms was shown almost over the entire range of aw. The moisture of cassava flour from dry and water groups should not exceed 11.3g H2O 100g-1(aw=0.6) to ensure the theoretical microbiological stability and the monolayer moisture value (9.0 and 7.9 g H2O 100g-1, respectively) indicated the level of moisture content to be reached during the drying process to avoid unnecessary power consumption. Finally, the data fit showed that the mathematical model of GAB were able to predict efficiently the sorption isotherms of both cassava flour from dry and water group at the entire aw range.
Acesso aberto (Open Access)
Production of medium-chain-length polyhydroxyalkanoate by Pseudomonas oleovorans grown in sugary cassava extract supplemented with andiroba oil
(2014-12) SILVA, Diego Aires da; ANTONIO, Regina Vasconcellos; ROSSI, José Márcio; PENA, Rosinelson da Silva
Pseudomonas oleovorans were grown on sugary cassava extracts supplemented with andiroba oil for the synthesis of a mediumchain- length polyhydroxyalkanoate (PHAMCL). The concentration of total sugars in the extract was approximately: 40 g/L in culture 1, 15 g/L in cultures 2 and 3, and 10 g/L in culture 4. Supplementation with 1% andiroba oil and 0.2 g/L of (NH4)2HPO4 was performed 6.5 hours after growth in culture 3, and supplementation with the same amount of andiroba oil and 2.4 g/L of (NH4)2HPO4 was performed at the beginning of growth in culture 4. The synthesis resulted mainly in 3-hydroxy-decanoate and 3-hydroxy-dodecanoate units; 3-hydroxy-butyrate, 3-hydroxy-hexanoate; and 3-hydroxy-octanoate monomers were also produced but in smaller proportions. P. oleovorans significantly accumulated PHAMCL in the deceleration phase of growth with an oxygen limitation but with sufficient nitrogen concentration to maintain cell growth. The sugary cassava extract supplemented with andiroba oil proved to be a potential substrate for PHAMCL production.