• The Korean Journal of Food And Nutrition
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• v.17 no.4
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• pp.412-419
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• 2004

In odor to select optimum extraction methods of volatile compounds in beef extract powder(BEP) as basic data for the development of a new detection method of irradiated BEP, four extraction methods, such as solid phase microextraction with polar fiber(S-PD) and non-polar fiber(S-CD), purge and trap(P&T) and liquid liquid continuous extraction(LLCE) methods, were tested with gas chromatography/mass spectrometry method. A total of 106 volatile compounds including 22 hydrocarbons, 7 aldehydes, 6 ketones, 13 alcohols, 6 sulfur-containing compounds, 19 nitrogen-containing compounds, 6 aromatic compounds, 17 terpenes, 8 furans and 2 miscellaneous compounds were detected in BEP by four detection methods. The most compounds(62 compounds) were detected by S-PD method, followed by P&T(43), LLCE(38) and S-CD method(30). Among these methods, S-PD and P&T methods showed a complementary interrelationship to detect volatile compounds as S-PD method showed high detectabiltiy to all compound groups except hydrocarbons and ketones, which had high volatility and low molecular weight(less than RI 1200), but P&T method showed the contrary pattern to that of S-PD method. Moreover, the most of volatile compounds detected by S-CD and LLCE methods were also detectable by S-PD or/and P&T methods. Therefore, the simultaneous application of S-PD and P&T methods were selected as the optimum volatile extraction methods of BEP.

• Korean journal of food and cookery science
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• v.13 no.1
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• pp.78-85
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• 1997

To determine the optimum coagulants concentrations for preparing soybean-curds, the transmittance of soybean-curd whey using spectrophotometer has been measured. The textural properties of soybean-curds were examined by texture analyzer and sensory evaluations. The general components, oligosaccharides and amino acids in soybean-curd wheys were analyzed. Protein patterns of soybean-curd wheys comparing with soyflour and soymilk were investigated. By texture analyzer, hardness, cohesiveness, springiness, and gumminess of Cacl$_2$ soybean-curd, MgCl$_2$ soybean-curd were higher than those of CaSO$_4$ soybean-curd and GDL soybean-curd. In the sensory evaluations, CaSO$_4$ soybean-curds and GDL soybean-curds were smoother and moister than others. Glutamic acid and aspartic acid were the first two abundant amino acids in three kinds of soybean-curd wheys, but arginine was the most abundant amino acid in GDL soybean-curd whey. Total sugar content of soybean-curd wheys were about 12-13 g/l, and the main sugars among 5 kinds of sugars were sucrose and raffinose. Electrophoresis using SDS-PAGE showed that glycinin and P-conglycinin, the main proteins of soybean appeared in soy flour and soymilk, and only low molecular weight subunits appeared in soybean-curd wheys.

• Korean Journal of Food Science and Technology
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• v.34 no.4
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• pp.694-699
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• 2002

The purpose of this study is to observe the effect of bovine colostral whey fractions on proliferation of Th1 cells and to verify the effect of whey fractions that are directly related to growth of Th1 cells on macrophages activation. Whey was fractionated into 3 fractions depending on by ultrafiltration (fraction (Fr.) I; molecular weight (Mw.) 10 kDa and more, Fr. II; Mw. $1\;kDa{\sim}10\;kDa$, Fr. III; Mw. less than 1 kDa) and examined by SDS-polyacrylamide gel electrophoresis. Fr. II stimulated and proliferated Th1 cells most at 1 mg/mL concentration and the percentage of cell proliferation was 67.1%. The secretive induction of tumor necrosis $factor-{\alpha}$ $(TNF-{\alpha})$ by whey, Fr. II, protein fraction (Fr. P) and oligosaccharide fraction (Fr. O) after fractionating Fr. II into Fr. P and Fr. O on the basis of Th1 cells growth was that Fr. O had more 80% secretive induction of $TNF-{\alpha}$ than that of $1\;{\mu}g/mL$ lipopolysaccharide that was positive control. So confirmed that Fr. O induced $TNF-{\alpha}$ secretion by activating macrophages.

• Korean Journal of Food Science and Technology
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• v.34 no.4
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• pp.552-558
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• 2002

Polyphenol oxidase from Flammulina velutipes was purified and characterized. Purification of polyphenol oxidase was achieved by ammonium sulfate precipitation, Superdex G-200 gel filtration chromatography, Phenyl superose affinity chromatography, Mono-Q anion exchange chromatography and Superdex S-200 gel filtration chromatography on FPLC. After these purification steps specific activity of purified polyphenol oxidase increased to 199.1 units/mg. Polyphenol oxidase from F. velutipes was composed of a single polypeptide with molecular weight of about 40 kDa. Optimum pH and temperature for the enzyme reaction were found to be 6.0 and $25^{\circ}C$, respectively. The activity of the enzyme gradually decreased at acidic pH between 3 and 5, and the enzyme lost its activity at alkaline pH between 8 and 10. This enzyme exhibited high substrate specificity to o-diphenols. Km-values for L-DOPA and caffeic acid were found to be 3.97 mM and 1.78 mM, respectively. 2-mercaptoethanol, L-ascorbic acid, sodium bisulfite, EDTA and $Mg^{2+}$ inhibited the activity of pholyphenol oxidase and $Cu^{2+}$, $Fe^{2+}$, $Zn^{2+}$ and $Ni^{2+}$ increased enzyme activity. The activity of enzyme was well maintained at $-70^{\circ}C$ for over 4 months, and at $-20^{\circ}C$ for 1 months.

• Korean Journal of Food Science and Technology
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• v.32 no.5
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• pp.1079-1086
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• 2000

Pectinesterase inhibitor(PEI) of ripened kiwi fruit(Actinidia chinensis) was separated with affinity chromatography using CNBr-activated Sepharose 4B being covalently bound by orange pectinesterse(PE). The affinity resin strongly and selectively bound PEI, which could be eluted in high yield as a single peak by pH 9.5 without loss of inhibitory activity. The separated PEI had maintained almost inhibitory activity at $-25^{\circ}C$ and $5^{\circ}C$ during 30 days but lost it at room temperature in 4 weeks. The PEI possessed a molecular weight of 16.6 KDa, as estimated by 12.5% SDS-PAGE. PEI had optimum pH of 7.5, optimum temperature of below $10^{\circ}C$ and stability up to $70^{\circ}C$. Also, optimum inhibitory activity for PEI was obtained in 0.2 M NaCl of substrate solutions. The kind of inhibition on tomato pectinesterase was found to be noncompetitive, using citrus pectin as substrate. Fresh orange juice added with crude PEI extracts maintained almost the same cloud stability as pasteurized juice. In case of apple juice, the addition of crude PEI extracts to apple juice had decrease of L-ascorbic acid with nearly no effect on cloud loss.

• Korean Journal of Food Science and Technology
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• v.32 no.2
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• pp.312-316
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• 2000

Crude xylooligosaccharides(XO) were separated with a cellulose membrane (10,000 molecular weight cut-off). Flux variation was measured at transmembrane pressures of 5, 10, 20 and 30 psi, while flow rates were maintained at 100, 200, 300 and 400 ml/min and temperatures at 10, 20, 23-25 and $30^{\circ}C$. Optimal conditions were found at the transmembrane pressure of 20 psi, the flow rate of 300 ml/min and the temperature of $23-25^{\circ}C$, where the flux was decreasing with time by 62% after 200 min. Total sugar, total solid and ash contents were rather independent of ultrafiltration but protein was removed up to 55% from crude XO. Especially, the use of ultrafiltration was very effective for decolorization (84%) of crude XO. These results suggest that ultrafiltration is a useful method for the primary purification of XO.

• Korean Journal of Food Science and Technology
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• v.32 no.2
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• pp.461-468
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• 2000

To investigate the antigenotoxicity of Korean mistletoe using Comet assay, the crude extract was divided into 4 fractions, i.e. fraction I (MW range over 14,000), fraction II $(8,000{\sim}14,000)$, fraction III $(3,500{\sim}8,000)$, and fraction IV (below 3,500) by molecular weight fractionation. In the non-tumoral 3T3 cells, fraction IV could reduce DNA damage induced by MNNG in a dose dependent pattern while fraction I and III which were known to contain lectins and viscotoxins, respectively, did not show the activity. By heat treatment, the antigenotoxic activity of faction IV, though was gradually diminished according to heating time, was found to be maintained significantly. From the Sephadex G-25 gel filtration chromatography, a more purified fraction responsible for the activity of faction IV was obtained from the latter part of total elute. Therefore, it was concluded that the antigenotoxic components of Korean mistletoe were water soluble substances of MW below 1,000 and there is a possibility of utilization as a material of functional foods for chemoprevention.

• Korean Journal of Food Science and Technology
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• v.32 no.5
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• pp.1158-1167
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• 2000

To produce ${\beta}-cyclodextrin({\beta}-CD)$, a cyclodextrin glucanotransferase(CGTase) producing Aspergillus sp. CC-2-1 was isolated from soil. The enzyme was purified and its enzymological characteristics were investigated. It was found that production of CGTase reached to the maximum when the wheat bran medium containing 0.1% albumin, 2% $(NH_4)_2S_2O_8$, 2% soluble starch and 0.2% $KH_2PO_4$ was cultured for 5 days at $37^{\circ}C$. The purity of CGTase was increased by 13.14 folds after DEAE-cellulose ion exchange chromatography and Sephadex G-100, G-150 gel filtration and the specific activity was 172.14 unit/mg. Purified enzyme was confirmed as a single band by the polyacrylamide gel electrophoresis. The molecular weight of CGTase was estimated to be 27,800 by Sephadex G-100 gel filtration and SDS-polyacrylamide gel electrophoresis. The optimum pH and temperature for the CGTase activity were 9.0 and $80^{\circ}C$, respectively. The enzyme was stable in pH $8.0{\sim}11.0$ at $60{\sim}80^{\circ}C$. The activity of purified enzyme was activated by $K^+,\;Cu^{2+}$ and $Zn^{2+}$. The activity of the CGTase was inhibited by the treatment with 2,4-dinitrophenol and iodine. The result suggests that the purified enzyme has phenolic hydroxyl group of tyrosine, histidine imidazole group and terminal amino group at active site. The reaction of this enzyme followed typical Michaelis-Menten kinetics with the $K_m$ value of 18.182 g/L with the $V_{max}$ of 188.68 ${\mu}mole/min$. The activation energy for the CGTase was calculated by Arrhenius equation was 1.548 kcal/mol.

• Journal of Nutrition and Health
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• v.45 no.5
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• pp.429-436
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• 2012

This study was performed to examine the characteristics of protein of red crab (Chionoecetes japonicus) shell powder hydrolyzed by commercial proteases. Red crab shell was digested by commercial proteases, such as Protamex (P), Neutrase (N), Flavourzyme (F), Alcalase (A), Protease M (PM) and Protease A (PA). Protein yield analyzed by Biuret assay, absorbance at 280 nm and brix revealed that PA was the enzyme having the highest proteolytic activity. SDS PAGE showed that molecular weight of proteins produced by protease treatments was various and below 150 kDa. Combinational treatment of proteases (PA + P, PA + PM, PA + F, PA + A) was tried whether these increase protein hydrolysis from red crab shell powder compared to a PA single treatment. Soluble protein content was similar, but amino acid concentration by combinational treatments was higher than PA single treatment [PA + P 247.4 mg/g > PA + F (206.4 mg/g) > PA + A (133.4 mg/g) > PA + PM (59.1 mg/g) > PA (54.9 mg/g)]. Amino acid composition by combinational treatments was slightly different. Most abundant essential amino acids were phenylalanine, glycine, alanine, and leucine, whereas tyrosine and cystine were not detected.

• Current Research on Agriculture and Life Sciences
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• v.2
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• pp.15-22
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• 1984

This study was conducted to identify the enzyme treatment time, enzyme concentration and plant growth condition for isolation of potato mesopyll, it was also performed to determine the adquate sucrose molarity on purification of protoplasts and to investigate the incubation time, PEG concentration and DMSO effect for potato-petunia protoplast fusion. The results were summarized as follows: The optimal time of incubation in enzyme solution was 3 - 4 hours and high humidity and low light intensity made plants more effective to protoplast releasing enzymes. Our experimental results showed that the pectolyase Y-23 was an ideal agent for isolation from mesophyll cultured in vitro compared with macerozyme. The enzyme solution with 0.5 % macerozyme and 2 % cellulase was very effective and the purity of healthy protoplast was better in 0.4 and 0.5 M sucrose than in others. It was revealed that the rate of potato-petunia fusion according to the incubation time with PEG was effective at 30 min incubation and percentage of protoplast aggregation was increased by high molecular weight and concentration of PEG. Percentage of potato-petunia protoplast heteroplasmic aggregation was increased by 4 to 16 % in PEG 6000 compared with PEG 4000 and PEG 1500. Addition of 5 to 10 % DMSO to the PEG solution increased to the heteroplasmic aggregation of potato-petunia from 2 to 4 %.