23 research outputs found

    Couscous manufacture in fluidized bed by wet agglomeration of wheat semolina

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    Agglomeration is a key unitary operation in a number of industries (pharmaceutical, chemical, food, civil engineering). The agglomeration process controls the structural characteristics and final properties of agglomerates. One of the activities involving food agglomeration is the production of  couscous by agglomeration of durum wheat semolina. Couscous is considered the most important traditional dish among the Maghreb people. The industrial process of couscous production includes various stages, the most important of which is wet granulation of semolina, which contributes to the quality of the final product. The agglomeration of cereal powders from different origins (durum wheat, maize and barley) has been performed in a variety of equipment such as high shear mixers, drum mills and fluidized beds. However, the agglomeration of semolina in fluidized beds has had very limited study. The purpose of this research is, therefore, to study couscous production using durum wheat semolina in a fluidized bed equipped with a spray nozzle. The fluidized bed has the advantage of generating strong particle movement and intense mixing to increase the size of the granules evenly throughout the mass used.The efficiency of this process is determined by the couscous yield defined as the mass ratio of couscous to raw material. The results showed that couscous can be produced from semolina by wet fluidized bed agglomeration with a specific effect of fluidification air flow, liquid flow, bed temperature and spray liquid properties on the couscous quality (size, brittleness and morphology) as well as on yield. The latter rose by 60% when the water containing flour was sprayed. Furthermore, the results of this study showed that granules size changes directly with the liquid flow rate, while temperature and air flow have an opposite effect. It was also found that changing binder components have an effect on the quality of the agglomeration of the product. Key words: Couscous, agglomeration, fluidization, semolina, friability, granulation, atomization, size enlargement, dryin

    Modelling of Heat Transfer in a Fluidized Bed Reactor Irradiated Indirectly by Concentrated Solar Energy

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    AbstractA two phases model of air heating in bubbling fluidized bed of sand particles with concentrated solar radiation as source of energy is developed. This model is based on the Kato and Wen's model (1969) for the hydrodynamic aspect which was modified to take account the thermic aspect. Nine algebraic equations were established in permanent regime for different heat and mass balances as well as heat losses against surrounding media. The Newton Raphson's method was used to solve this system of equations. Results have shown that the model developed is able to predict the temperature profiles of gas and particles in the bubble and emulsion phases, the wall temperature along the reactor, the heat flux transferred to the bed and heat losses by forced convection and radiation to surrounding air. The effects of the fluidizing air velocity, total mass of particles and the wind velocity on the thermal behaviours were examined. Model predictions seem reasonable looking for its comparison agreement with bibliographical data

    Passiflora incarnata attenuation of neuropathic allodynia and vulvodynia apropos GABA-ergic and opioidergic antinociceptive and behavioural mechanisms

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    Background: Passiflora incarnata is widely used as an anxiolytic and sedative due to its putative GABAergic properties. Passiflora incarnata L. methanolic extract (PI-ME) was evaluated in an animal model of streptozotocininduced diabetic neuropathic allodynia and vulvodynia in rats along with antinociceptive, anxiolytic and sedative activities in mice in order to examine possible underlying mechanisms. Methods: PI-ME was tested preliminary for qualitative phytochemical analysis and then quantitatively by proximate and GC-MS analysis. The antinociceptive property was evaluated using the abdominal constriction assay and hot plate test. The anxiolytic activity was performed in a stair case model and sedative activity in an open field test. The antagonistic activities were evaluated using naloxone and/or pentylenetetrazole (PTZ). PI-ME was evaluated for prospective anti-allodynic and anti-vulvodynic properties in a rat model of streptozotocin induced neuropathic pain using the static and dynamic testing paradigms of mechanical allodynia and vulvodynia. Results: GC-MS analysis revealed that PI-ME contained predominant quantities of oleamide (9-octadecenamide), palmitic acid (hexadecanoic acid) and 3-hydroxy-dodecanoic acid, among other active constituents. In the abdominal constriction assay and hot plate test, PI-ME produced dose dependant, naloxone and pentylenetetrazole reversible antinociception suggesting an involvement of opioidergic and GABAergic mechanisms. In the stair case test, PI-ME at 200 mg/kg increased the number of steps climbed while at 600 mg/kg a significant decrease was observed. The rearing incidence was diminished by PI-ME at all tested doses and in the open field test, PI-ME decreased locomotor activity to an extent that was analagous to diazepam. The effects of PI-ME were antagonized by PTZ in both the staircase and open field tests implicating GABAergic mechanisms in its anxiolytic and sedative activities. In the streptozotocin-induced neuropathic nociceptive model, PI-ME (200 and 300 mg/kg) exhibited static and dynamic anti-allodynic effects exemplified by an increase in paw withdrawal threshold and paw withdrawal latency. PI-ME relieved only the dynamic component of vulvodynia by increasing flinching response latency. Conclusions: These findings suggest that Passiflora incarnata might be useful for treating neuropathic pain. The antinociceptive and behavioural findings inferring that its activity may stem from underlying opioidergic and GABAergic mechanisms though a potential oleamide-sourced cannabimimetic involvement is also discussed
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