• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.8
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• pp.1051-1056
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• 2006

Response surface methodology was used to investigate the quality of clarified mixed apple and carrot juices using ultrafitration. Apple and carrot juices were blended at the ratio of 1:3, 1:1, and 3:1. A three-variable, three-level central composite design was employed where the independent variables were the blend ratio, temperature and average transmembrane pressure (ATP). With increasing temperature and pressure, flux linearly increased regardless of blending ratio. Blend juice with 75% apple showed the highest soluble sugar and total sugar content in apple and carrot blend juices. Soluble solid contents were more affected by blending ratio than temperature and ATP. Total sugar contents were greatly affected by temperature; increasing temperature led to higher total sugar content up to $25^{\circ}C$. Higher carrot ratio led to higher vitamin C content. In general, higher acidity was achieved by higher apple content and acidity was increased with increasing temperature. Turbidity increased for all samples as APT increased, with the blending ratio of 1:1 (apple:carrot) showing the highest turbidity. Viscosity was greatly changed in the blending ratio of 3:1 (apple:carrot) juice. The polynomial models developed by RSM were satisfactory to describe the relationships between the studied factors and the responses. Analytical optimization gave $flux=0.216\;L/m^2.h$, soluble $solids=10.39^{\circ}Brix$, total sugar=71.32 mg/mL, vitamin C=315.18 mg%, acidity=7.78 mL, turbidity=0.017, and viscosity=1.44 cp, when using a $temperature=44.97^{\circ}C$, ATP=113.57 kPa, and blend ratio=28.50%.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.7
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• pp.881-888
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• 2007

For the use of skipjack tuna cooking drip (STC) as a source of functional seasoning, the STC was hydrolyzed with various commercial enzymes, such as Alcalase, Flavourzyme, Neutrase and Protamex, and its hydrolysate was also investigated on the food component characteristics. The hydrolysate incubated with Alcalase for 30 min (HA30) showed 56.8% for angiotensin I converting enzyme (ACE) inhibitory activity and 1.18 for antioxidative activity, which were high or similar compared to the other enzymatic hydrolysates. There were no differences in ACE inhibitory activity and antioxidative activity among HA30, two-step enzymatic hydrolysates, and ultrafilterates (molecular weight cut off, 10 kDa). The HA30 was very stable on the digestive enzymes, such as chymotrypsin, pepsin, trypsin according to the TCA (trichloroacetic acid) soluble index. The results suggested that skipjack tuna cooking drip could be used as a source for preparing functional seasoning sauce.

• Food Science and Preservation
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• v.20 no.1
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• pp.111-120
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• 2013

Sprassis crispa was cultivated using soybean curd whey, and its antimicrobial activities were examined against those of eight microorganisms that were foodborne pathogens or food-poisoning bacteria. The culture broth of soybean curd whey was superior in mycelium content (17.76 g/L) to that of the defined culture broth, and the ${\beta}$-glucan content was about 10.64 percent (w/w). The antimicrobial activities of the culture broth were confirmed against those of B. cereus, St. aureus, L. monocytogenes and S. typhimurium using the paper disk method. The antimicrobial activity was also maintained after the heat treatment and alcalase treatment. The filtrate with less than 3 kDa M.W. also showed the antimicrobial activity against four strains: B. cereus, St. aureus, L. monocytogenes and S. typhimurium. The minimum inhibitory concentration (MIC) was about 1.26 mg/mL in the B. cereus and 12.6 mg/mL in the St. aureus and L. monocytogenes. The S. typhimurium showed a MIC of 62.8 mg/mL. Thus, the culture of Sparassis crispa using soybean curd whey provides a thermally stable antimicrobial agent that can be used as a natural preservative in the biofood industry.

• Food Science and Preservation
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• v.13 no.1
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• pp.88-94
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• 2006

This study was carried out to produce antimicrobial peptides from casein using various proteases. To examine whether the hydrolysis of casein would produce antimicrobial substance and the application as natural antimicrobial material, casein was hydrolyzed by five different proteases. The casein hydrolysate was fractionated with regenerated membrane filter (molecular weight cut-off 30,000 10,000 and 3,000) and antimicrobial activity was measured for each fraction. Antimicrobial activity appeared great in the fraction below 3,000 molecular weight The fraction was re-fractionated by high performance liquid chromatography and substance of main peak (retention time: 13.2 min) collected was used as a sample to measure antimicrobial activity. Among the casein hydrolysates produced by protease, antimicrobial activity was observed the greatest in hydrolysate treated with Aspergillus oryzae protease. The minimum inhibition concentrations of the Asp. oryzae protease hydrolysate were 1.0-1.5 mg/mL. This hydrolysate was a heat stable peptide since antimicrobial activity was maintained after treating with heat for 20 min at $121^{\circ}C$.

• Journal of Soil and Groundwater Environment
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• v.9 no.3
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• pp.12-19
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• 2004

Binding mechanisms of polycyclic aromatic hydrocarbons (PAHs) with a purified Aldrich humic acid (PAHA) and its ultrafiltration (UF) size fractions were investigated. Organic carbon normalized binding coefficient ($K_oc$) values were estimated by both a conventional Stern-Volmer fluorescence quenching technique and a modified fluorescence quenching method. Pyrene $K_oc$ values depended on PAHA concentration as well as freely dissolved pyrene concentration. Such nonlinear sorption-type behaviors suggested the existence of specific interactions. Smaller molecular size PAH (naphthalene) exhibited higher $K_oc$ value with medium-size PAHA UF fractions whereas larger size PAH (pyrene) had higher extent of binding with larger PAHA UF fractions. The inconsistent observation for naphthalene versus pyrene was well explained by size exclusion effect, one of the previously suggested specific mechanisms for PAH binding. In general, the extent of pyrene binding increased with lower pH likely due to the neutralization of acidic functional groups in HS and the subsequent increase in hydrophobic HS region. However, pyrene $K_oc$ results with a large UF fraction (>100K Da) corroborated the existence of the size exclusion effect as demonstrated by an increase in $K_oc$ values at a certain higher pH range. The size exclusion effect appears to be effective only for the specific conditions (HS size or pH) that render HS hole st겨ctures to fit a target PAH.

• Journal of Food Hygiene and Safety
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• v.34 no.4
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• pp.396-403
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• 2019

Ion-exchange chromatography and ultrafiltration were used to extract anserine from salmon (Oncorhynchus keta). The salmon anserine showed DPPH radical scavenging activity in the range of 7.30% to 31.05% in a dose-dependent manner. This reducing power of salmon anserine also increased as the concentration increased. Metal chelate activity, superoxide dismutase - like activity, and thiobarbituric acid reactive substances assay showed similar results. The anserine also suppressed the increment of the peroxide value and linoleic acid during storage periods. These results suggest that salmon anserine might be useful as a natural antioxidant in various foodstuffs.

• Membrane Journal
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• v.33 no.4
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• pp.191-200
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• 2023

Polyethersulfone (PES) is a widely employed membrane material for water and industrial purification applications owing to its hydrophilicity and ease of phase separation. However, PES membranes and filters prepared using the nonsolvent induced phase separation method often encounter significant flux decline due to pore clogging and cake layer formation on the dense membrane surfaces. Our investigation revealed that tight microfiltration or loose ultrafiltration membranes can be subject to physical fouling due to the formation of a dense skin layer on the bottom side caused by water intrusion to the gap between the shrank membrane and the substrate. To investigate the effect of the bottom surface porosity on membrane fouling, two membranes with the same selective layers but different sub-layer structures were prepared using single and double layer casting methods, respectively. The double layered PES membrane with highly porous bottom surface showed high flux and physical fouling tolerance compared to the pristine single layer membrane. This study highlights the importance of physical optimization of the membrane structure to prevent membrane fouling.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.49 no.4
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• pp.299-306
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• 2023

In this study, exosomes were isolated by ultrafiltration from Lactobacillus rhamnosus J2K-821 and their various effects for skin were evaluated. Their size and concentration were identified 50 ~ 200 nm and 3.22 × 10⁸ particles/mL, respectively through nanoparticle tracking analysis. In order to verify the inflammatory relief effect of Lactobacillus rhamnosus-derived exosomes (LRDEs), their nitric oxide (NO) production inhibitory ability in RAW 264.7 macrophages induced an inflammatory reaction with lipopolysaccharide (LPS) was confirmed. It was revealed that they inhibited NO production in a concentration-dependent manner. To evaluate the antioxidant activity and skin barrier improvement effect of LRDEs, their 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity and hyaluronidase inhibitory activity were confirmed. It was also revealed that their activities were increased by concentration-dependent manner. Through these results, It is believed that LRDEs can be used as a effective natural cosmetic ingredient for anti-inflammation, antioxidation and skin barrier improvement.

• Journal of Dairy Science and Biotechnology
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• v.30 no.1
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• pp.1-10
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• 2012

The objective of this study was to evaluate the rheology and sensory properties of Mozzarella cheese manufactured by the traditional method and by an ultrafiltration technique and to attempt to develop a new type of Mozzarella cheese. We noted 3 observations. (1) The initial pH observed for raw milk and retentate of ultrafiltration (CF 2 and CF 3) did not vary much. However, there was a significant difference in the pH at stretching. The initial TAwas significantly different between the raw milk and retentate obtained by ultrafiltration (CF 2 and CF 3). However, no differences were observed in TA at stretching. (2) The predicted yield (Y50), adjusted to 50% total solids (TS), was affected by the concentration factor, fat content, and addition of starter and rennet. The Y50 increased with the concentration factor. 3) Hardness, elasticity, cohesiveness, and brittleness were affected by fat content, and addition of starter and rennet. The hardness, elasticity, and brittleness of Mozzarella cheese made from the retentate of ultrafiltration (CF 2 and CF 3) were higher than in Mozarella cheese made by the traditional method; however, the cohesiveness decreased during storage at $4^{\circ}C$ over a period of 3 months. (4) Flavor, body texture, appearance, color, and firmness decreased with bacterial count, fat content, and addition of starter and rennet. The results of the sensory evaluation of the Mozzarella cheese made from the retentate of ultrafiltration (CF 2 and CF 3) changed during storage at $4^{\circ}C$ over a 3-month period.

• Analytical Science and Technology
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• v.16 no.4
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• pp.292-298
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• 2003

In this study, the photooxidation and ozonation of humic acid (HA) in aqueous solution were conducted and the treated HA samples at different reaction time were analyzed using ultrafiltration techniques to evaluate the change of their molecular size distributions with its DOC removal. Molecular size distribution of untreated HA showed 41.5% in higher molecular size fractions (>30,000 daltons) and 15.2% in much smaller molecular size fraction (<500 daltons). As UV irradiation time was increased, it was observed that the degradation of the large molecules of the fraction of >30,000 daltons into much smaller molecules was increased. In UV system, the HA molecules of the fraction of <500 daltons became significantly more and its percentage was increased from 35.3% (UV only irradiation) to 58.9% ($UV/TiO_2$) and 87.8% ($UV/H_2O_2$) in the presence of the photocatalysis. Otherwise, ozonation of HA produced mainly the fraction of medium molecular size ranging from 3,000 to 30,000 daltons with much lower portion (<~7%) in the fraction of <500 daltons. In ozone only system, the fraction of 30,000~10,000 daltons occupied in 41.5% at 60 min of ozonation time. In $O_3/H_2O_2$ system, the fraction of 30,000~10,000 daltons and 10,000~3,000 daltons occupied in 38.9% and 36.2% respectively. Based on these results, we suggested applicable treatment process which could be combined with $UV/H_2O_2$, $UV/TiO_2$ and $O_3$, $O_3/H_2O_2$ system for more effective removal of humic acid in water treatment.