• Korean Journal of Food Science and Technology
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• v.34 no.2
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• pp.174-179
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• 2002

A simple and sensitive analysis method based on reverse phase (RP) HPCL with flourescence detector was developed for simultaneous determination of bisphenol A (BPA), bisphenol F (BPF), bisphenol A diglycidyl ether (BADGE), bisphenol F diglycidyl ether (BFDGE), and their degradation products, $BADGE{\cdot}H_2O$, $BADGE{\cdot}2H_2O$, $BFDGE{\cdot}H_2O$, $BFDGE{\cdot}2H_2O$, $BADGE{\cdot}HCl{\cdot}H_2O$, $BADGE{\cdot}HCl$, $BADGE{\cdot}2HCl$, $BFDGE{\cdot}HCl{\cdot}H_2O$, $BFDGE{\cdot}HCl$ and $BFDGE{\cdot}2HCl$, which were hydrolyzed and chlorinated forms of BADGE and BFDGE, in canned foods and food simulants. These compounds were identified by GC/MSD with $MSTFA-NH_4I-DTE$ derivatization. Recovery study was performed at each 100 ng/mL levels of BPA, BPF, BADGE and BFDGE added to canned foods and food simulants. This method was resulted in recovery of $90{\sim}114%$ with relative standard deviation of $4.1{\sim}7.0%$, detection limits of $6{\sim}11$ ng/mL and quantitation limits of $12{\sim}18\;ng/mL$. Calibration curves were linear with correlatin coefficients of 0.997 for BPF, 0.996 for BPA, 0.9987 for BFDGE, and 0.9989 for BADGE.

• Korean Journal of Food Science and Technology
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• v.32 no.3
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• pp.659-667
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• 2000

Quality attributes of fresh-cut green onion(Allium fistulosum L.) as affected by rinsing and packaging were investigated in terms of flesh weight, color, viable cell counts, sensory properties during storage at $10^{\circ}C$. Fresh green onions were trimmed, cut, and rinsed with cold water(approximately $5^{\circ}C$) as well as chlorine solution(100 mg/L) and then packaged in low density polyethylene film pouches of $63\;{\mu}m$ thickness. Rinsing treatments with cold water or chlorine solution did not significantly influence changes in microbial populations but sensory characteristics, resulting in cut green onions of better visual quality as compared to the control without rinsing. Fresh-cut green onions were also rinsed with cold water and packaged in sealed bags of low density polyethylene films with different thickness(22, 36, $63\;{\mu}m$), and stored at $10^{\circ}C$ for 18 days. Thickness of polyethylene film was a significant factor for microorganisms populations and sensory attributes. Mesophilic aerobic bacterial count after 13 days for the control, packed in punched film bags, was $3.07{\times}10^6}$ CFU/g, while those for samples in hermetically sealed bags ranged only $1.74{\sim}2.02{\times}10^5}$ CFU/g. Gas composition within the sealed packages changed from normal air to about $1.3{\sim}5.4%\;O_2$ and $4.0{\sim}8.0%\;CO_2$ after 13 days of storage. Particularly, the visual sensory quality of cut green onion samples was retained better in polyethylene film bags of $63\;{\mu}m$ thickness(gas transmission rate: 600 $O_2\;mL/day{\cdot}m^2{\cdot}atm;\;2,500\;CO_2\;mL/day{\cdot}m^2{\cdot}atm$) than in the others.

• Korean Journal of Food Science and Technology
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• v.35 no.5
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• pp.818-824
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• 2003

Capillary electrophoresis (CE) and near-infrared spectroscopy (NIRS) were performed to discriminate astragalus roots (Astragalus membranaceus) according to geographical origin (domestic or foreign). Two-hundred-and-four astragalus roots were extracted with 30% methanol in 0.1 M phosphate buffer (pH 2.5) and separated in a uncoated fused-silica $(50\;{\mu}m{\times}27\;cm)$ capillary. Conditions for optimal analysis included: temperature $-45^{\circ}C$, voltage -14 kV, and pressure injection time -8 sec. The optimal separation buffer was 0.1 M phosphate buffer (pH 2.5) containing 40 mM hexane sulfonic acid with 20% 2-methoxy ethanol. Raw NIR spectra were obtained using NIRS, and modified partial least square regression was used to develop the prediction model. The correlation coefficient and standard error of prediction were 0.915 and 14.3%, respectively. Under the optimal conditions established for CE and NIRS, the geographical origins of the astragalus roots were correctly identified in 80 and 97%, respectively. Astragalus roots that were not discriminated by NIRS were correctly discriminated by CE. Hence, CE and NIRS are potential methods for discriminating the geographical origins of astragalus roots that complement one another.

• Korean Journal of Food Science and Technology
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• v.35 no.1
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• pp.125-131
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• 2003

Physiological activities of hot water extracts of 10 commercial instant curry powders and 6 spices, were investigated. All spice extracts except ginger showed significant antioxidant activities on the autoxidation of linoleic curry acid (p＜0.01). Antioxidant activities of clove and fennel were significantly higher than ${\alpha}-tocopherol$, instant curry powders, and other spices, Red pepper $(52.8{\pm}2.13%)$, clove, and coriander showed significant inhibitory activities against angiotensin-I-converting enzyme (p＜0.001). Cytotoxic effects of instant curry powder and spices against human cancer cell lines were examined through MTT assay. Black pepper $(29.31{\pm}2.21%\;cytotoxic\;rate)$ and cardamon $(19.41{\pm}3.92%)$ were effective against MCF-7 (p＜0.01), Clove $(42.92{\pm}5.57%)$ against HeLa (p＜0.01). Ginger $(34.21{\pm}1.11%)$, cardamon, and black pepper against A172 (p＜0.001), garlic $(82.88{\pm}0.53%)$ against SN12C (p＜0.001), garlic $(71.63{\pm}0.38%)$, red pepper, ginger, fenugreek, SPC, cumin, and MPC against SNU-638 (p＜0.001), and cassia $(82.84{\pm}16.92%)$ against A549 (p＜0.001).

• Korean Journal of Food Science and Technology
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• v.35 no.1
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• pp.15-22
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• 2003

Nutritional compositions of three Tochukaso species (Paecilomyces tenuipes hosted by Larva and pupa, Cordyceps militaris, C. sinensis) were compared. Fruiting body and host fractions were separately analyzed. Fruiting body fraction of P. tenuipes (36.6%) hosted by larva was higher than that hosted by pupa (10.2%), an indication that the quality of the former is superior to the latter. Carbohydrate content of C. sinensis (39.6%) was $2.5{\sim}7$ times higher than those of others, probably due to the presence of polysaccharides. Protein and crude lipid contents of C. sinensis and C. militaris were 25.8 and 10.3%, and 75.1 and 3.9%, respectively. C. sinensis showed the lowest Ca content and $30{\sim}75$ times higher Fe content among the samples tested. Vitamin A content of C. militaris was 308.9 IU/100g, two fold higher than those of the other species. Saturated fatty acid content was the highest in P. tenuipes (pupa, 27.7%), whereas unsaturated fatty acid was the highest in P. tenuipes (larva, 83.3%). Aspartic acid, glutamic acid, and glycine were abundant in all species. Cordycepin content of C. militaris was $20{\sim}50$ times higher than those of the other species.

• Korean Journal of Food Science and Technology
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• v.16 no.1
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• pp.71-77
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• 1984

A study on the stability of chlorophyll a in Undaria pinnatifida during blanching, salting and storage was carried out. Raw Undaria pinnatifida was blanched for 25 seconds in the temperature range of 70 to $100^{\circ}C$. To stabilize the chlorophyll a some chemicals such as 1% solutions of $Ca(CH_3CO_2)_2,{\;}Ca(OH)_2,{\;}MgCO_3,{\;}0.5%{\;}Ca(CH_3CO_2)_2$ with $0.5%{\;}MgCO_3$, and reed ash solution were used during/after blanching. The blanched product was salted with table salt after centrifuging for 2 minutes at 1500 rpm, and then again centrifuged after 48 hours for dewatering. The product which was mixed with 8% of table salt was sealed in a polyethylene film bag and stored at 10, 20, 30 and $40^{\circ}C$. The most effective blanching temperature for maximal residual amount of chlorophyll a was $85^{\circ}C$. The quantities of total organic and volatile acids were not significantly changed by the blanching temperature. Blanching in 1% chemical solutions showed bitter results than soaking in 1% chemical solutions for 20 minutes after blanching without chemicals. Reed ash and 0.5% $Ca(CH_3CO_2)_2$ with 0.5% $MgCO_3$ solutions were more effective than the 1% solutions of other chemicals, but the effect was not significant, compared with the group not treated with chemicals. The most reasonable ratio of added salt to dewater the product for 48 hours was 30% in w/w. The amount of total organic and volatile acids revealed no correlation with the amount of added salt. Color and odor of salted product was not severely changed during the storage of 77 days at $10^{\circ}C$. But the changes were accelerated with increasing storage temperatures. The degradation of chlorophyll a in salted product during storage could be interpreted as a first order reaction, and the rate constants at 10, 20, 30 and $40^{\circ}C$ were 0.1289, 0.1028, 0.0770 and 0.0550, respectively. $Q_{10}$ and the activation energy were 1.33 and 5.01 Kcal/g mole.

• Korean Journal of Food Science and Technology
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• v.12 no.4
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• pp.254-262
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• 1980

A series of experiment were carried out to separate the factor accelerating the lysis of cell wall of $Saccharomyces\;sak{\acute{e}}$ from the preparation of crude zymolyase obtained from Arthrobacter luteus. An attempt was also made to purify the enzyme which is essential for the study on the separation of the factor. The results are summarized as follows: 1. Crude zymolyase was fractionated 5 peaks $(A{\sim}E)$ containing three peaks $(A{\sim}C)$ passed through the column by the chromatography on Biogel CM-30. 2. Among the five peaks, peak E (protease fraction) was found to contain the factor accelerating the lytic activity of the zymolyase. 3. L-c fraction purified in almost free form from the nonlytic ${\beta}-1$, 3-glucanase, protease and inert protein by the affinity adsorption chromatography with Sephadex G-75 gel was obtained from zymolyase fraction (peak D). When it was subjected to polyacrylamide gel disc electrophoresis, only one clear protein band was observed at pH 4. 5, but still detected two or more band at pH 8. 3.

• Korean Journal of Food Science and Technology
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• v.12 no.4
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• pp.292-298
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• 1980

In order to improve the storage stability of powdered soybean curd, moisture sorption characteristics of the curd stored at specific relative humidity and temperature were investigated. The results obtained are summarized as follows; 1. When the fresh soybean curd (2cm thickness) was dried in a hot air drier at $55^{\circ}C$, it took 18 hrs to reduce its moisture content from 85% to 8.8%, and drying rate was very high during the first 5 hrs. 2. Equilibrum moisture content (E.M.C.) of powdered soybean curd by freeze drying was higher than that of sample by got air drying, but the particle size did not influence E. M. C. 3. The monolayer value of freeze dried powder of high E. M. C was higher than that of the hot air dried(8.30 vs 7.35). 4. The free energy for moisture absorption of freeze dried powder at 11% RH were 1285.1 cal/mole, 1323.5 cal/mole at $15^{\circ}C$ and $30^{\circ}C$, respectively, and the free energy of freeze dried product was lower that of hot air dried product. 5. The moisture sorption rate constant was not affected by particle size, and it showed that the moisture sorption rate decreased as temperature was increased. The rate constant of powder produced by freeze drying were 0.00804 at $15^{\circ}C$ and 0.00696 at $30^{\circ}C$.

• Korean Journal of Food Science and Technology
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• v.3 no.3
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• pp.178-184
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• 1971

Samples of refined soybean oil were irradiated with lights from a 20-watt incandescent tungsten lamp, a 20-watt fluorescent daylight type lamp, a 20-watt low-pressure mercury vapor germicidal lamp, and direct sunlight for an experimental period of 147 days. Some samples were stored in a dark room throughout the period as a control. The peroxide values of all samples were measured every week. The induction period of the samples was arbitrarily taken as the time required for the samples to reach a peroxide value of 15. The induction period of the control was estimated at 198 days. Those of the samples irradiated with the incandescent light, the fluorescent light, the ultraviolet light, and the sunlight were estimated at 196, 119, 52 and 6 days, respectively. The sunlight showed by far the strongest prooxidant activity whereas the incandescent light showed the weakest but distinct prooxidant activity. The small temperature differences observed among the various samples throughout the experimental period did not seem to affect the oxidation rates of the irradiated samples in any significant way.

• Korean Journal of Food Science and Technology
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• v.20 no.4
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• pp.576-584
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• 1988

Neutral detergent fiber(NDF) were extracted from the Nampung, Milyang #23, Whasung and Jinhung varieties of rice by neutral detergent fiber method. To determine the properties of NDF three factors were measured : water-binding capacity(WBC), Fe-binding capacity and sodium taurocholate binding with NDF. The average WBC of NDF was $5.60{\pm}0.87gH_2O/g$ NDF, and the average Fe-binding capacity ranged from 24.63% at pH 5.0 to 19.6% at pH 6.0 and 48.98% at pH 7.0. Binding of sodium taurocholate with NDF was determined in vitro using C-14 labeled sodium taurocholate at 100M sodium taurocholate concentrations. NDF binding of Jinhung was 27.87 while Nampung, Milyang #23 and Whasung measured 32% each. When sodium taurocholate concentrations were raised from $40{\mu}M\;to\;240{\mu}M$ the tendency of binding increased as the concentrations increased, but not linearly.