Supercritical CO(2) recovery of caffeine from green coffee oil: New experimental solubility data and modeling

The caffeine solubility in supercritical CO(2) Was studied by assessing the effects of pressure and temperature on the extraction of green coffee oil (GCO). The Peng-Robinson(1) equation of state was used to correlate the solubility of caffeine with a thermodynamic model and two mixing rules were evaluated: the classical mixing rule of van der Waals with two adjustable parameters (PR-VDW) and a density dependent one, proposed by Mohamed and Holder(2) with two (PR-MH, two parameters adjusted to the attractive term) and three (PR-MH3 two parameters adjusted to the attractive and one to the repulsive term) adjustable parameters. The best results were obtained with the mixing rule of Mohamed and Holder(2) with three parameters.31613191323Fundacao de Amparo Pesquisa do Estado de Sao Paulo [02/07753-0]Conselho Nacional de Desenvolvimento Cientifico e TccnologicoFundacao de Amparo Pesquisa do Estado de Sao Paulo [02/07753-0

Influence of a Lipid Phase on the Physical Properties of Spray-Dried Maltodextrin Powders

Maltodextrin powders containing 5, 10, 15, 20 and 25 % from three different palm oil fractions were produced by spray-drying emulsions with 30 wt% total solids content. The effect of the lipid phase on the characteristics of the particles was evaluated. Oilless spray-dried particles presented a smaller average size and reduced wettability as compared to the commercial product. An increase in fat content resulted in a decrease in true density while the Hausner Ratio and average diameter of the particles increased. The powders containing palm olefins (melting points, 14 degrees C and 18 degrees C) were stickier than the product containing stearin (melting point, 51 degrees C).33229229

PHYSICAL EVALUATION OF BIODEGRADABLE FILMS OF CALCIUM ALGINATE PLASTICIZED WITH POLYOLS

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)The influence of different polyols as plasticizers of alginate films on their physical attributes like moisture content, soluble mass in water, water uptake, water vapor permeability, opacity and mechanical properties were determined and the results discussed based on scanning electron microscopy observations and glass transition temperature. The alginate films were obtained by casting, using three different gramatures. Calcium crosslinked and non-reticulated films were considered. The films plasticized with glycerol and xylitol were more hygroscopic than the films with mannitol. The lowest water vapor permeability values were found for films plasticized with mannitol, at all studied thicknesses. The films plasticized with glycerol and xylitol showed very similar functional attributes regarding their application as food wrappings. The Ca2+ crosslinked mannitol films showed the highest tensile strength at rupture (> 140 MPa).304835845Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Viscoelasticity of frozen/thawed egg yolk as affected by salts, sucrose and glycerol

Based on dynamic rheological measurements, sucrose, glycerol and magnesium chloride (MgCl2) prevented egg yolk gelation at concentrations of 2% and higher, These additives showed improved cryoprotectant effects as their concentrations were increased, Sodium chloride (NaCl) at higher than 2% also prevented gelation but at 10%, it caused a considerable increase in viscosity of unfrozen yolk, Calcium chloride (CaCl2) showed an opposite effect, promoting protein coagulation before freezing, Samples with 2% CaCl2 gelled completely after 36h at -24 degrees C, Before freezing, potassium chloride (KCl) in the range 2-10% had an effect similar to that of NaCl, However, after freezing its effect changed, Yolk with 2% KCl, frozen 36h at -24 degrees C, showed very elastic behavior.631202

Release of Potassium Sorbate from Active Films of Sodium Alginate Crosslinked with Calcium Chloride

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)The release of potassium sorbate from alginate films was evaluated considering different active agent concentrations in the film and three levels of alginate crosslinking. The mechanism involved in the diffusional process was investigated using the Power Law Model. The results indicated that potassium sorbate diffusion in alginate films has characteristics of Fickian and non-Fickian behaviour. Effective diffusion coefficients obtained using the solution in series derived from Fick's Second Law are close to values obtained by the short-time solution, indicating that the influence of swelling on effective diffusivity, although perceptible, is small, allowing the use of an average effective diffusivity. The values of effective diffusivity found indicate that alginate films have a potential use as systems for release of active substances. Copyright (C) 2009 John Wiley & Sons, Ltd.226349358Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)FAPESP [01/13811-9

Dimensional analysis applied to the identification of flow regimes during sterilization in spin-cooker

During the heat treatment of canned liquid foods in a spin-cooker, the cylindrical can is horizontally positioned and made to rotate around its longitudinal axis. Though a headspace of about 15% in volume is used, the air bubble is continuously displaced to the top affecting the internal level of turbulence in the liquid phase. For relatively high rotations all liquid is adhered to the cylinder rim (Rimming Flow regime), and the level of turbulence and the heat transfer are diminished. This experimental observation stimulates the identification of the flow regime. A dimensionless model to compute the transition speed to rimming flow in horizontal, partially filled cylinders is extended to take into account the effect of the cylinder length and to cover a wide range of liquid loads. Experiments supported the optimization of the coefficients of the dimensionless model, whose mean deviations in the computation of the critical rimming speed are less than 5.0% (C) 2003 Elsevier Science Ltd. All rights reserved.59443543

Influence of a lipid phase on steam jet agglomeration of maltodextrin powders

The contribution of an oil phase to the agglomeration mechanisms of food powders was evaluated. Maltodextrin (DE 10), palm oil stearin and two palm oil oleins (up to 25% dry mass) were used as food models. Granulation runs were carried out in a pilot plant steam jet agglomerator. The powders containing oleins were more cohesive than those with stearin and the presence of oil changed the agglomeration mechanisms. The size increase mechanism of pure maltodextrin powder was controlled by surface plasticization and agglomerates with suitable instant properties were obtained. Small amount of oil degenerated drastically the rate of dispersion in water of the powders and their agglomerates but the average size and the mechanical resistance of the agglomerates increased when the oil content of the powders increased. SEM micrographs of agglomerates indicated that higher lipid content in the powders produced compact granules, favoring sinkability but hindering their disintegration. Agglomeration enhanced considerably the flowability of the particles containing oil. The dispersion behavior of the powders with higher lipid content could be correlated with the Hausner Number. A pre-agglomeration step favored the blend of the more cohesive powders producing larger and more resistant agglomerates. (C) 2007 Elsevier B.V. All rights reserved.185325826

Glass transition control of the detachment of food pastes dried over glass plates

A drying chamber with a device that allows the spreading of a uniform film of food paste over glass plates was developed with the purpose of evaluating the drying of paste-like materials assisted by the movement of solid bodies. The chamber temperature and the water content of the dried film made of maltodextrin, gum arabic or sugar cane molasses, were determined at the instant of detachment from the solid surface and compared with an empirically determined glass transition temperature curve. The results indicated that the detachment mechanism was controlled by the glass transition of the material. The lower the glass transition temperature of the film, the drier the film should be for detachment to occur. Thus the glass transition phenomenon can be used as a reference for the optimization of drying processes of paste-like material, as a guide for the design of dryers or in the formulation of food pastes. (C) 2003 Elsevier Ltd. All rights reserved.61226126

Xylanase mass transfer studies in aqueous two-phase systems using spray and sieve plate columns

Aqueous two-phase systems (ATPSs) have long been used for biomolecule partitioning; these systems offer the possibility of using continuous or semicontinuous extraction processes. They require relatively simple equipment like spray or sieve plate columns that can be adapted for use in ATPSs. The aim of this work was to study the semicontinuous extraction of a model enzyme, xylanase, in spray and sieve plate columns, since, unlike centrifugal contactors. the cost of construction and maintenance of this equipment is low and it is easy to operate. For the spray column, the dispersed phase hold-up and overall mass transfer coefficients K-D a were evaluated for different column heights and for different superficial velocities of the dispersed phase (light phase). Results indicated that an increase in superficial velocity in the range of 0-0.18 mm/s of the dispersed phase had a positive effect on K-D a and on hold-up in all column heights studied, 75, 161 and 246 min. For the same superficial velocity of the dispersed phase, the larger the hold-up was, the shorter the column. For the sieve plate column, the effects of the superficial velocity of the dispersed phase and the number of plates were also studied. Results showed that the K-D a and hold-up increased with an increase in both parameters. The selectivity of separation of xylanase and BSA (model contaminant) was very high, since 60% of the enzyme was extracted in the light phase, whereas no significant amount of BSA was extracted. The possibility of using the sieve plate column in continuous operation for enzyme extraction was studied because previous work had only addressed the semicontinuous extraction of enzyme. The residence time distribution of the PEG phase using different superficial velocities of the salt phase was studied in continuous operation. The time required to reach the steady state was 40 min, and 70% of the xylanase was recovered. It was found that the Modified Power Spline software was well adjusted to the experimental results.26315115

Morphological and Physicochemical Characterization of Commercial Maltodextrins with Different Degrees of Dextrose-Equivalent

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Maltodextrins show increasing industrial applications depending on the extent of the starch hydrolysis. This paper reports a relationship between morphological and physico-chemical characteristics of different maltodextrins (A, B, and C) in order to establish appropriate uses. The moisture content of the maltodextrins varied from 2.82 to 6.47% and true and bulk density, average particle size, and porosity of the maltodextrins ranged from 1.14-1.44 g/mL, 0.33-0.49 g/mL, 39.44-289.17 m, and 59.70-67.58%, respectively. Spherical, irregular, and filamentous shapes conduct to low values of wetting times. The increase in the DE level of maltodextrins from the same botanical source caused a decrease in the dissolution time. Results demonstrated that products obtained by supplier B showed the best performance and regularity in the dissolution/dispersion characteristics in water meanwhile maltodextrins manufactured by supplier A would be favored by an agglomeration process.132411425Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)FAPESP [03/08377-4, 03/001105-9