• Journal of Life Science
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• v.15 no.1 s.68
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• pp.9-14
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• 2005

Batch enzymatic hydrolysis of egg yolk protein by protease was carried out at laboratory scale coupled to an ultrafiltration module. Effect of ethanol concentrations on the performance of enzymatic hydrolysis was studied to determine the optimum condition of recovery of hydrolysate. The enzymatic hydrolysis was conducted stepwise with following conditions, $50^{\circ}C$, pH 10.0 and pH 6.5. Ethanol concentration was changed from 10 to $40\%$ (w/w). As ethanol concentration was increased, the recovery yield of total solid and protein in enzymatic hydrolysate was also increased. The content of sialic acid and protein in hydrolysate was independent of ethanol concentration. We also investigated the effect of ethanol concentration on the performance of ultrafiltration. As the concentration of ethanol in yolk protein was increased, the recovery yield of product was increased. Ultra­filtration of egg yolk protein hydrolysate was conducted to increase the content of sialic acid. Four ultrafiltation modules were used in this study, and we evaluated the performance of the UF modules. When Amicon module was used, the recovery percentage of total solid in retentate was $6.0\%$, which is the highest among the modules used. In spite of the difference in the recovery yield of total solid, the purity of sialic acid in retentate was about $2.0\%$, which was 5 times higher than that in feed. It was concluded that the recovery yield and the purity of sialic acid did not correlate with the types of modules and the size of MWCO.

• Membrane Journal
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• v.21 no.3
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• pp.256-262
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• 2011

This study describes the performance of PSF and PC membranes for separation and recovery of $SF_6$ from gas mixtures (10% $SF_6$/70% $N_2$/19% $O_2$/1% $CF_4$) containing low concentration of $SF_6$. The $SF_6$ concentration in retentate, recovery efficiency and selectivity of mixed gases were measured as a function of retentate flow rate and temperature. The concentration of $SF_6$ in the gas recovered from PSF and PC membrane respectively decreased with increase of retentate flow rate and increased with increase of temperature. The values of $SF_6$ concentration in retentate of PSF membrane were higher than those of PC membrane at constant experimental conditions. The maximum value of recovery efficiency of PSF and PC membranes are 95.9% and 67.8%, respectively, under 298.15 K and 150 cc/min of retentate flow rate. With the exception of $CF_4/SF_6$, the real selectivities of $N_2/SF_6$ and $O_2/SF_6$ at PSF membrane were higher than those of PC membrane.

• Korean Chemical Engineering Research
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• v.53 no.3
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• pp.295-301
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• 2015

A theoretical analysis was carried out to examine the concentration behavior of methane from a biogas using a polysulfone membrane. After the governing equations were derived for the cocurrent flow mode in a membrane module, the coupled nonlinear differential equations were numerically solved with the Compaq Visual Fortran 6.6 software. At the typical operating condition of mole fraction of 0.7 in a feed stream, the mole fraction of methane in the retentate increased to 0.76 while the normalized retentate flow rate to the feed flow rate decreased from 1 to 0.79. When either the mole fraction of methane in a feed increased or the pressure of the feed stream increased, the methane mole fraction in the retentate increased. On the other hand, it was found that as either the membrane area decreased or the ratio of the permeate pressure to the feed pressure increased, the methane mole fraction in the retentate decreased. In case that the stage cut increased, the methane mole fraction in the retentate increased while the recovery of methane slightly decreased.

• Korean Chemical Engineering Research
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• v.52 no.6
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• pp.775-780
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• 2014

Micellar enhanced ultrafiltration (MEUF) was used to remove cadmium from an aqueous solution using sodium dodecyl sulfate (SDS) as a surfactant. Operational parameters such as initial permeate flux, retentate pressure, initial cadmium concentration, pH solution, molecular weight cut-off (MWCO), and molar ratio of cadmium to SDS were investigated. Removal efficiency of cadmium from an aqueous solution increased with an increase of retentate pressure, pH solution and molar ratio of cadmium to SDS, and decreased with an increase of initial permeate flux. Higher removal efficiency of cadmium from the aqueous solution was achieved using lower MWCO (smaller membrane pore size). Under optimized experimental condition, cadmium removal efficiency reached 74.6 % within an hour. Using MEUF-ACF hybrid process the removal efficiency of both cadmium and SDS was found to be over 90%.

• Korean journal of food and cookery science
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• v.13 no.4
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• pp.507-513
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• 1997

To separate and concentrate functional components contained in soybean curd whey, ultrafiltration was performed using regenerated cellulose or polysulphone membrane of spiral-wound type with MWCO 10,000, and the permeate and retentate solutions were analyzed. As the pH of soybean curd whey increased, the permeate flux decreased in both membranes. Treatment of 0.01 M EDTA rather decreased the permeate flux compared with control. The concentration of ionic calcium, which decreased with the pH increase, was thought to affect the permeate flux also. In case of polysulphone membrane, the permeate was efficiently purified and the retentate protein was concentrated significantly in which the membrane rejection value (MRV) for chemical oxygen demand (COD) was 79.25% and that of protein was 98.42% at the volume concentration ratio (VCR) of 10. MRV of the protein of regenerated cellulose membrane was lower than that of polysulphone membrane. To recover oligosaccharides to the permeate solution and increase the content of raffinose and stachyose, regenerated cellulose membrane was more suitable than polysulphone membrane and the optimum VCR was 4.

• Food Science of Animal Resources
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• v.30 no.4
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• pp.575-581
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• 2010

This investigation was aimed at developing a ready-to-reconstitute beverage by utilizing probiotics and whey protein hydrolysates carrying bioactive peptides. Cheddar cheese whey was ultrafiltered. The 18% protein retentate was subjected to protein hydrolysis using Neutrase. The hydrolyzed retentate was further condensed to 35% total solids and spray-dried at $75^{\circ}C$ outlet air temperature. Different levels of sugar, citric acid and stabilizer were blended for spray-dried hydrolysates. Spray-dried hydrolysate was further inoculated with different levels of probiotics grown in a whey medium and dried in fluidized-bed drier at $40^{\circ}C$ to obtain a ready-to-reconstitute beverage. Hydrolysis was greatest at an enzyme:substrate ratio of 1:25 for 3 h. Spray-dried hydrolysate reconstituted to 1% protein and blended with 15% sugar, 0.2% citric acid and 0.15% xantham gum resulted in a superior product with no sedimentation. Accordingly, sugar, citric acid and xanthum gum were dry-blended with spray-dried hydrolysates. Bifidobacterium bifidum and Lactobacillus acidophilus that was grown separately in a whey medium, blended to produce 2% spray-dried hydrolysate and dried as described above resulted in a readyto-reconstitute beverage mix. The fluidized dried product typically exhibited a probiotic count of $10^8$colony forming units (CFU)/g. However, blending of probiotic to the retentate and direct spray-drying precipitously reduced the probiotic count to $10^4$ CFU/g of powder.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.53 no.1
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• pp.112-122
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• 2020

This study investigated some enzymatic properties and bitterness improvement of an aminopeptidase retentate fraction (ARF) from common squid Todarodes pacificus hepatopancreas extract (HPE), obtained by ultrafiltration with a 10 kDa molecular weight cut off membrane. Endoprotease and aminopeptidase (AP) activity, and the purity of the ARF (>10 kDa) increased by 6.69-18.11 U/mg and 1.5-2.6 fold, respectively, compared to HPE (2.63-9.37 U/mg). The AP activity toward LeuPNA was stable at 20-55℃ and pH 5-9, but decreased slightly with increasing concentration of NaCl in the reaction mixture. The ARF was the most active MetPNA and preferentially hydrolyzed Glu, Leu and AlaPNA. The bitterness tryptic casein hydrolysates (BTCHs) were treated with ARF, and the bitterness of ARF-BTCHs significantly decreased with increasing amounts of released amino acids Ala, Val, Met, Ile and Leu, which show strong correlations with bitterness. Therefore, the ARF of T. pacificus HPE obtained by ultrafiltration may have a considerable potential for application in protein hydrolysis and appears to be ideally suited to the purpose of lowing bitterness in protein hydrolysates.

• Korean Journal of Food Science and Technology
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• v.30 no.1
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• pp.151-160
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• 1998

Tangerine peel is mostly discarded as waste in citrus processing. However, tangerine peel contains besides dietary fibers bioflavonoids such as naringin and hesperidin which act as antimicrobials and blood pressure depressants, respectively. A continuous membrane separation process was optimized for the production of bioflavonoids relative to feed flow rate, transmembrane pressure, temperature, and pH. The tangerine peel was blended with 7.5 times water volume and the extract was prefiltered through a prefiltration system. The prefiltered extract was ultrafiltered in a hollow fiber membrane system. The flux and feed flow rate didn't show any apparent correlation, but we could observe a mass-transfer controlled region of over 8 psi. When temperature increased from $9^{\circ}C\;to\;25^{\circ}C$, the flux increased about $10\;liters/m^2/min\;(LMH)$ but between $25^{\circ}C\;and\;33^{\circ}C$, the flux increased only 2 LMH. At every transmembrane pressure, the flux of pH 4.8 was the most highest and the flux at pH 3.0 was lower than that of pH 6.0, 7.0, or 9.0. Therefore, the optimum operating conditions were 49.3 L/hr. 10 psi, $25^{\circ}C$, and pH 4.8. Under the optimum conditions, the flux gradually decreased and finally reached a steady-state after 1 hr 50 min. The amount of dietary fibers in 1.0 g retentate in each separation step was analyzed and bioflavonoids concentration in each permeate was measured. The contents of total dietary fiber in the 170 mesh retentate and soluble dietary fiber in the prefiltered retentate were the highest. Naringin and hesperidin concentration in the permeate were $0.45{\sim}0.65\;mg/g\;and\;5.15{\sim}6.86\;mg/g$ respectively, being $15{\sim}22$ times and $79{\sim}93$ times higher than those in the tangerine peel. Therefore, it can be said that PM 10 hollow fiber membrane separation system may be a very effective method for the recovery of bioflavonoids from tangerine peel.

• Korean Chemical Engineering Research
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• v.49 no.2
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• pp.250-255
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• 2011

In this study, by using the polymeric membrane separation process, the $CO_{2}/CH_{4}$ separation and $H_{2}S$ removal from biogas were performed in order to $CH_{4}$ purification and enrichment for the fuel cell energy source application. Fibers were spun by dry/wet phase inversion method. The module was manufactured by fabricating fibers after surface coating with silicone elastomer. The scanning electron microscopy(SEM) studies showed that the produced fibers typically had an asymmetric structure; a dense top layer supported by a porous, sponge substructure. The permeance of $CO_{2}$ and $CO_{2}/CH_{4}$ selectivity increased with pressure and temperature. Mixture gas with increasing pressure and temperature, removal efficiency of the $CO_{2}$ and $H_{2}S$ were decreased while concentration of $CH_{4}$ was increased up to 100%. When retentate flow rate was increased with the decreasing of pressure and temperature the $CH_{4}$ recovery ratio in retentate side was increased while the $CH_{4}$ purity in retentate side was decreased.

• KSBB Journal
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• v.16 no.4
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• pp.403-408
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• 2001

Distillation condensate generated from downstream processing of microbial alcohol fermentation imposes a serious burden to biological wastewater treatment or anaerobic digestion due to its high contents of SS (suspended solids) and TN (total nitrogen), A pilot scale microfiltration of the stillage condensate with a stainless steel SCEPTER membrane of 0.1 ${\mu}$m pore size was carried out to remove SS which was mostly composed of microbial cell residue. A stable permeate flux was achieved when the decanter effluent containing 0.7% of SS was filtered under the conditions of X10 VCR (volume concentration ratio), 2.5 bar of TMP (transmembrane pressure), and 60$^{\circ}C$. When stillage condensate with 2.6% SS was treated directly with microfiltration, VCR below X3 was recommended for a long duration of filtration. The permeate and retentate obtained from microfiltration were recycled to make-up medium of fermentation. Adding permeate or retentate up to 30% of fermentation volume showed no distinguished undesirable influence during the course of alcohol fermentation. Although only slight improvements in the final amount of CO$_2$ evolution and alcohol content were observed, fermentation rate increased so that the required time to reach 450 L/ton of CO$_2$ evolution was shortened to 72% of that with normal media.