Use of low concentration factor ultrafiltration retentates in reduced-fat Minas Frescal cheese manufacture: effect on yield and sensory properties

The yield and sensory properties of reduced-fat Minas Frescal cheese made from low concentration factor (CF) retentates were studied. Three different CFs were tested (1.2, 1.5 and 1.8). The chemical compositions of the milk, retentate, whey and cheese were determined, as well as the cheese yield. The cheese moisture content decreased with increasing CF. The cheese yield was significantly dependent on the CF in the same direction as the moisture content. Despite compositional differences among the samples, only the cheese made with a CF of 1.8 presented low sensorial acceptance. CF 1.2 was found to be the optimum value for reduced-fat Minas Frescal cheese manufacture in the CF range studied.57423123

Drying of sicilian lemon residue: influence of process variables on the evaluation of the dietary fiber produced

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)In this study, the effect of the process variables of the air-drying of Sicilian lemon residues on some technological properties of the fibers produced was studied. The determination and modeling of desorption isotherms were used to establish the equilibrium moisture content at 60, 75, and 90 degrees C using the static method with 8 saturated salt solutions. The best fit was obtained with BET and GAB models. The drying process was conducted in a vertical tray dryer and delineated according to a central composite experimental design (2(2)) using the following as factors: air velocity (0.5, 0.75 and 1 m/s) and temperature (60, 75, and 90 degrees C), and it presented a good fit to the exponential model (R(2) > 99.9%). The experimental design responses evaluated were the technological properties of the fibers: water-holding, oil-holding, and swelling capacity. Since these properties were present in high levels, the lemon residues could be used to increase content of fibers in foods resulting in the addition of nutritional benefits for the consumers.302421428Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Microfiltration of umbu (Spondias tuberosa Arr. Cam.) juice

Umbu (Spondias tuberosa Arr. Cam.) diluted pulp, at mass ratio of one part of pulp to two parts of water, was microfiltered in a pilot plant containing a 0.2 mu m polypropylene membrane. A clarified juice free of pulp and with low pectin content was obtained. Effects of enzyme treatment (0-100ppm), crossflow velocity (4-6 m/s) and transmembrane pressure (0.5 x 10(5)-1.1 x 10(5) Pa (0.5-1.1 bar)) were evaluated using permeate flux and flux resistances (total, due to fouling and polarized layer formation) as parameters. Crossflow velocity was the major variable responsible for flux increase, since it reduced polarized layer. Enzyme treatment also presented a positive effect. On the other hand, transmembrane pressure increased fouling and did not influence permeate flux in most cases, except when no enzyme was added and high velocity was applied, in which flux was reduced. (c) 2006 Elsevier B.V All rights reserved.28841671616

Degumming and production of soy lecithin, and the cleaning of a ceramic membrane used in the ultrafiltration and diafiltration of crude soybean oil

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)The optimization of the cleaning process, aiming to recover the permeate flux, and diafiltration as a means to obtain and purify soybean lecithin, were analyzed in this study as a means of delaying the decrease in permeate flux during the ultrafiltration (UF) of vegetable oils and their derivatives. It also aimed to maximize the exploration of the use of this type of technology during the processing steps. Thus the influence of the transmembrane pressure, cross flow velocity, and the opening of the permeate valve during the cleaning process (hexane circulation) of a ceramic membrane with a permeation area of 0.2 m(2) and a pore diameter of 0.01 mm in a pilot unit with a processing capacity of 40 L, was studied. Four different operational cleaning conditions, associating combinations of pressure (0.5-2.0 bar) and velocity (1.0-5.0 m s(-1)), as well as the influence of opening the permeate valve, were studied. Also the production and purification of soybean lecithin was carried out by diafiltration of the retentates derived from the UF of the miscella, resulting in a product with about 90% of acetone insoluble matter. The most favorable cleaning condition was associated with a low pressure (0.5 bar) and elevated velocity (5.0 m s(-1)), with which it was possible to recover the permeate flux in about 85 min. Crown Copyright (C) 2008 Published by Elsevier B.V. All rights reserved.33041671127134Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Ultrafiltration performance of PVDF, PES, and cellulose membranes for the treatment of coconut water (Cocos nucifera L.)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Ultrafiltration (UF) inhibits the enzymatic activity which is responsible for color changes of coconut water without the need for heat treatment. In the present study, UF performance in terms of the permeate flux and enzymatic retention of the coconut water was evaluated at laboratory unit (LU) and pilot unit (PU). The membranes studied were polyethersulfone 150 kDa (UP150), polyvinylidene fluoride 150 kDa (UV150) and cellulose 30 kDa (UC030). The UP150 membrane showed the best permeate flux. The UC030 membrane showed the lowest flux, but it resulted in 100% enzymatic retention, while the other membranes showed enzymatic retentions between 71 and 85%. The application of the UC030 in the pilot unit (PU) resulted in a flux value higher than that obtained in the LU due to the tangential velocity effect. The UC030 membrane has proved adequate for industrial applications.334676684Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Solvent permeability in commercial ultrafiltration polymeric membranes and evaluation of the structural and chemical stability towards hexane

The membrane technology application in the vegetable oil processing is associated to the hexane recovery from the miscella obtained during the extraction, degumming and subsequent refining stages, where the presence of the hexane results in higher permeate flux. However, the development of this technological alternative depends on membrane chemical stability. The objective of this work was to evaluate six flatsheet polymeric membranes in relation water affinity, permeability and flux of water, ethanol and hexane, with the purpose of characterizing their hydrophobic and hydrophilic profiles and resistance to hexane. The equipment used was a stirred cell. The following commercial flat membranes were used: 30 kDa and 50 kDa PVDF (polyvinylidene fluoride); 10 kDa PES (polyethersulfone); 0.05 mu m PC (polycarbonate); 0.05 mu m and 0.025 mu m CME (mixed cellulose esters). Membrane permeability with water, ethanol and hexane was evaluated in a laboratory unit at 4 bar, 200 rpm and 40 degrees C. Regarding flux rates with the tested solvents, the 50 kDa PVDF membrane revealed the highest permeability to water, two of the membranes were characterized as less hydrophilic (PC and PES) and the remaining ones were more hydrophobic. The membrane structural stability towards the hexane was verified by visual observation, filtering area variation (shortening or intumescence) and permeate flux assessments. The permeation with hexane was conducted for 12 h, at 1.5 bar, 200 rpm and 40 degrees C, with constant flux in all of the membranes during the experiment. Membranes untreated, submersed in hexane for 48 h and submitted to hexane permeation for 12 h were examined by scanning electron microscopy (SEM) in order to verify possible microscopic alterations. All the membranes were hexane-resistant, indicating that they are suitable for use with this solvent. (C) 2009 Elsevier B.V. All rights reserved.711132

Degumming of corn oil/hexane miscella using a ceramic membrane

The aim of the present study was to investigate the degumming (removal of phospholipids) of crude oil/hexane miscella, using an alumina multichannel ceramic membrane with an average pore diameter of 0.05 mu m. The influence of transmembrane pressure (TMP) (0.5 and 1.5 bar), tangential velocity (v) (1.4 and 2.4 m s(-1)) and percentage of corn oil on the miscella (25% and 35% w/w), in terms of the permeate flux and removal of phospholipids, were investigated. A phospholipid removal of between 65% and 93.5% was achieved, resulting in a minimum phosphorus content in the permeate of 23 mg kg(-1) and a reduction in color and waxes, besides the conservation of tocopherols and tocotrienols in the crude oil. A raised TMP and a greater percentage of oil in the miscella had a positive effect on the retention of phosphorus, while the tangential velocity had a negative influence. Under the best operational conditions used the permeate flux reached 120 kg h(-1) m(-2), at 40 degrees C. (C) 2007 Elsevier Ltd. All rights reserved.86455756

The optimisation of soybean oil degumming on a pilot plant scale using a ceramic membrane

In the present study, soybean oil degumming in an oil/hexane miscella by ultrafiltration was investigated as a substitute for the conventional degumming process. A multi-channel ceramic membrane was used with 0.2 m(2) permeation area and a pore diameter of 0.01 mu m. The response surface methodology (RSM) was used with a complete 2(2) factorial design, considering the tangential velocity and transmembrane pressure as the independent variables. The phosphorous concentration in the permeate (degummed oil) and the permeate flux represented the dependent variables. The tangential velocity varied from 2.9 to 3.9 m s(-1) and the transmembrane pressure (TMP) from 1 to 2 bar. Up to 99.7% of the phospholipids were retained, resulting in a phosphorous concentration of 2.2 mg kg(-1). The permeate flux varied from 21.5 to 40.5 L m(-2) h(-1), with a mass reduction factor (MRF) of 3.2. The only variable shown to influence the process was the TMP. The lowest phosphorous content (2.2 mg kg(-1)) in the degummed oil and the highest permeate flux (40.5 kg m(2) h(-1)) were observed at 2 bar. (c) 2008 Elsevier Ltd. All rights reserved.87451452

Solvent recovery from soybean oil/hexane miscella by polymeric membranes

In this work, solvent recovery from soybean oil/hexane miscellas (1:3, w/w) was studied. Flat sheet polymeric membranes, polysulfone and polysulfone/polyamide based, used in reverse osmosis, nanofiltration and ultrafiltration, were tested. The effects of pressure (13-27 bar) and temperature (21-49 degrees C) on permeate flux, oil retention and separation of free fatty acids (FFA) were evaluated by a 2(2) complete factorial design, with three central points and four axial points. Increased pressure resulted in a higher permeate flux though the retention of oil and free fatty acids by the membranes has decreased. However, higher temperatures showed positive effects on the permeate flux, retention of oil and free fatty acids permeation. The highest oil retention (67.12%) was observed for low pressure (15 bar) and high temperature (45 degrees C). (c) 2006 Elsevier B.V. All rights reserved.2824167132833