• Food Science and Preservation
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• v.8 no.1
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• pp.92-101
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• 2001

In order to develop the Production and application of cholesterol oxidase, a cholesterol degradation bacteria which produces a remarkable amount of extracellular cholesterol oxidase has been isolated from Korea traditional salt fermented flat fish. The isolated strain was identified as a strain of Bacil1us sp. based on its morphological, physiological characteristics and cellular fatty acid compositions. Experiments were carried out to optimize the condition of cholesterol oxidase production using Bacillus sp. SFF34. Bacillus sp. SFF34 was shown to give the maximum yield of cholesterol oxidase in the medium containing 2.0% glucose, 0.5% yeast extract, 0.02% MgSO$_4$$.$7H$_2$O, 0.025% K$_2$HPO$_4$, 0.15% NH$_4$NO$_3$ and 0.2% cholesterol. The optimum culture conditions, temperature, initial pH and agitation speed were 30$^{\circ}C$, 7.0 and 150rpm respectively. The enzyme production reached a maximum level at 24 hrs of cultivation(2.42 U/ml).

• KSBB Journal
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• v.8 no.2
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• pp.164-171
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• 1993

The production of extracellular polysaccharide by Methylomonas mucosa (NRRL B-5696) was investigated. The microorganism uses methanol as the carbon source for their growth and produces exopolysaccharides. The productivity of exopolysaccharides was investigated under various culture modes: batch, fed-batch and continuous culture. In flask culture the growth of cell mass and the production of polysaccharide were inhibited at above 1% (v/v) methanol. At 1%(v/v) methanol maximum specific growth rate was obtained. As C/N ratio (g methanol/g ammonium sulfate) increased, polysaccharide production increased and cells mass decreased. Magnesium ion was also found to be essential for the polysaccharide production. In batch culture the production of polysaccharides was more affected by the specific growth rate than the cell concentration. In fed-batch culture the concentration of polysaccharide was 4 times higher than that of batch culture, but the yield was lower. The productivity of fed-batch with continuous feeding was higher than that of batch or fed-batch with intermittent feeding. This is due to no methanol limitation or inhibition that used to occur in fed-batch culture with intermittent feeding. In continuous culture pure oxygen was supplied to avoid the oxygen limitation. As the dilution rate in- creased up to 0.21 h-1, the yield and productivity increased. The solution viscosity of the produced polysaccharide obtained from above increased exponentially with the concentration of polysaccharide.

• Microbiology and Biotechnology Letters
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• v.12 no.4
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• pp.285-291
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• 1984

In making liquid yoghurt, the influences of proteolytic ability of lactic acid bacteria on acid production and on protein stability were investigated. L. bulgaricus CH-2, L. helviticus IAM 1042 and L. jugurti 3048 showed a comparatively high proteolytic activity in milk, while L. casei YIT 9018 did not show any marked proteolysis. Starter organisms having high proteolytic ability showed more rapid growth and acid production than those having low ability in milk. The most active proteolysis occurred during logarithmic growth phase of yogurt organisms, and most of the proteolysis took place in the first 24-48 hrs of incubation. Highly proteolysed yogurts made by L. bulgaricus CH-2, L. jugurti 3048, L. helviticus IAM 1042, L. acidophilus L-54 and L. casei 3012 had low protein solubility at pH 3.5 and had much protein precipitates during storage of product, but those having little protein hydrolysates made by L. casei YIT 9018 or artificial acidification showed no precipitation during keeping.

• Korean Journal of Food Science and Technology
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• v.40 no.6
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• pp.643-648
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• 2008

The principal objective of this study was to evaluate the effects of the addition of sourdough to bread dough, specifically with regard to the physicochemical characteristics of bread dough, organoleptic evaluation, and bread storage. Marked increases in lactic acid bacterial counts $10^{9-10}CFU/g$ in dough samples with 30, 50, and 100% of added sourdough to the respective bread dough were observed after the first fermentation period of the dough, but decreases were observed in yeast cells. The highest overall acceptance scores were recorded for the 100% sourdough-added bread, and almost no differences in taste and texture were detected between the regular bread (control bread) and sourdough-added bread on the sensory evaluations, with slightly lower evaluation scores (for sour taste) in the sourdough-added bread. The sourdoughadded bread also showed retarded mold growth in the bread on our storage tests. Six days had elapsed prior to the appearance of mold growth in the sourdough-added bread, whereas three days elapsed in the regular bread. The more sourdough was added to the dough, the less was the total count in bread. Increases of 13.1, 20.9, and 36.2% in the retardation of starch retrogradation of the bread were observed as the result of additional increases in sourdough quantity to bread at 30, 50, and 100%, respectively.

• Korean Journal of Food Science and Technology
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• v.27 no.2
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• pp.176-180
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• 1995

Direct contact heat exchange (DCHE) method has been employed to investigate the separation of ethanol from dilute aqueous solutions. Bubbles at high temperature were dispersed into a continuous liquid phase, generating temperature gradient in air-liquid interface, which causes heat and mass transfer accordingly. The experiments were performed in the ranges of jet regime air flow. The air-water stripping coefficient increased $5{\sim}10,\;and\;1{\sim}1.5$ times as temperature and air flow rate increased, respectively. The recovery ratio based on the initial ethanol concentration reached into 80% at the air flow rate of 84.88 m/min. The initial ethanol concentration showed little effect on the stripping coefficient and the recovery ratio.

• Journal of Life Science
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• v.16 no.6
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• pp.877-883
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• 2006

An alternative method to remove and recover heavy metals is biosorption based on metal-sequestering properties of natural or biological origin. In this study, the effects of factors such as temperature, pH, initial concentration of lead, and initial amount of biomass on biosorption of lead using Aureobasdium pullulans were investigated. A. pullulans has an excellent selectivity to remove lead than other heavy metals such as cadmium, chromium, nickel in pure and mixed solution. The optimum temperature of biosorption with A. pullulans was $40^{\circ}C$ and the amount of removal increased at high pH. The higher initial lead concentration or the lower cell dry weight, the higher amount of lead was adsorbed. The adsorption isotherm of lead was accorded with Freundlich model. The adsorption capacity and initial adsorption rate of living A. pullulans were about twice higher than that of dead one.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 1994.07a
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• pp.7-8
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• 1994

한국산 표고버섯 균사체를 액체배양하여 천연항암물질로 알려진 단백다당체를 추출한 후 그 물질의 특성에 대하여 검토하였다. 균사체의 최적 재양조건을 TGY배지로 조사한 바 온도 $25^{\circ}C$, 배양초기 pH4.0, 교반속도 300rpm, 균사배지 접종량을 10.0%로 하고 산소 통기량을 1.0volume of ait/volume of medium/mimute으로 하였을때 가장 양호한 조건이였으며, 대량생산 하기 위한 SCM배지에서 최적의 C/N비는 13.1오써 7일간 배양하였을때 18.8g/L의 균사령을 얻었으며, 이때 생산수율은 0.46으로 나타났다. 발효가 끝난 배양액에서 균사, 여액 그리고 배양액의 전체에서 단백다당체를 분리한 결과 각 분획에서 단백다당체가 각각 0.55%, 0.12%, 0.69%가 회수되어 배양액 전체에서 단백다당체를 추출하는 것이 바람직하며, 추출방법으로 열수추출, glass bead추출 및 cellulasa처리를 하여 단백다당체의 수율을 비교한 결과 0.25-0.5mm glass nead로 30분간 균사체를 분쇄한 다음 열수추출을 1시간을 하였을때 990mg/100ml의 단백다당체를 얻을 수 있었다. 고단백다당체를 1차 단백질 가수분해 효소로 분해하고, EDAE cellulose 및 Sepadex G-100 column chromatography로 정제한 후, TLC/FLD, ultracentrifugation한 결과 순수한 물질임을 알 수 있었다. 단백다당체의 항암효과 조사중 in vitro배양에서 $P_{388}$과 $L_{1210}$에 대한 단백다당체의 활성단위 1 unit는 1mg정도였으며, 인체의 장암세포인 HCT-48, HRT-18, HT-29 밀 간암세포인 Hep G2 대한 생육저해 단위는 각각 4.4, 3.6, 6.6, 2.6mg이었다. HCT-48과 Hep G2 세포의 크기 분포도는 대조군에 비하여 시간이 경과함에 따라, 그리고 단백다당체의 농도가 증가함에 따라 peak가 작은 size 쪽으로 이동하였다. 또, 단백다당체를 첨가 배양한 HCT-48과 Hep G2세포의 현미경 관찰에서 본래의 암세포 형태가 변형되고 크기가 감소하며 세포사이의 경계막이 흐트러지면서 세포수가 감소하고 사멸하였다. In vivo실험에서는 대조군보다 단백다당체를 첨가한 군에서 항체 형성능력이 대조군에 비하여 형질세포가 2배로 증가하였다. 단백다당체의 화학적 성분 분석에서 다당함량은 46.1%이면 구성다당류는 glucose, galactose, mannose, xylose로 구성되었고 단백질의 함량은 7.28%이며, 구성아미노산은 15종의 아미노산으로 되었다. 또 무기물은 Na, K, Zn, Ca등의 순으로 이루어 짐을 알 수 있었다.

• Korean Journal of Agricultural Science
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• v.35 no.1
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• pp.1-9
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• 2008

There were four types of Doenjang fermentation as following conditions for investigation ; 1) low temperature fermentation at $13^{\circ}C$ for 180 days, 2) low temperature at $13^{\circ}C$ for 7 days to room temperature at $30^{\circ}C$ for 10 days, to low temperature at $13^{\circ}C$ for 163 days, and for 173 days, 3) low temperature at $13^{\circ}C$ 7 days to room temperature at $30^{\circ}C$, 4) room temperature at $30^{\circ}C$ for 180 days. There were no changes of moisture, NaCl and total nitrogen content during fermentation period of four types conditions, but pH and amino type nitrogen decreased in room temperature at $30^{\circ}C$ for 180 days. It required 3 times more fermentation period until same quantity of the amino type nitrogen. The low temperature fermentation sample was lower than room temperature fermentation sample in pH and amino type nitrogen. The yeast decreased in low temperature fermentation sample taken 15 to 30 days longer than room temperature sample. The yeast is increased up to 30 days, and decreased little by little. After 60 days, it remained a few without effectiveness on the Doenjang quality. The low temperature fermentation sample showed brighter than room temperature fermentation sample. Different fermentation condition affected Doenjnag quality, especially, low temperature fermentation sample showed bright color in Doenjnag. So low temperature fermentation must be expected as good method for getting high quality Doenjnag.

• Korean Journal of Food Science and Technology
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• v.28 no.3
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• pp.538-544
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• 1996

A highly viscous biopolymer from alkali-tolerant Bacillus sp. was purified and its rheological properties were studied. 1% (w/v) solution of purified biopolymer showed pseudoplastic fluid behavior with the yield stress similar to those of xanthan and guar gum, and its consistency index was exponentially dependent on concentration and temperature. The concentration dependency of consistency index exhibited two rectilinear plots with different slopes at 1% concentration and pseudoplastic property increased with the increase of biopolymer concentration. The biopolymer solution exhibited a low temperature dependency and the activation energy of flow was 1.16 kacl/g mol. The apparent viscosity was very dependent on the change of pH and the addition of salt. However, no organic solvent effects were observed effects of viscosity synergism with the addition of viscosifier were not observed.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.5
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• pp.600-605
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• 2006

B. subtilis JM3 pretense from naturally fermented anchovy sauce was purified in $40{\sim}60%$ ammonium sulfate fraction. In order to accelerate the fermentation of anchovy sauce,2% and 4% of crude B. subtilis JM3 protease were added to 6 month-fermented anchovy sauces, respectively and then the various quality characteristics such as pH, lactic acid, amino-nitrogen, VBN, browning and hydrolysis degree, VBN, and sensory evaluation were analyzed at different storage times. pH was constant during storage time in all samples, whereas lactic acid contents of anchovy sauces hydrolyzed by 2% and 4% proteases were higher than that of control. The amino-nitrogen and volatile basic nitrogen contents of anchovy sauce with 2% and 4% proteases were twice higher than those of control. Anchovy sauces with 2% and 4% pretense increased the hydrolysis rate by 27% and 32%, respectively. Browning degree of anchovy sauce with 4% was higher than those of 2% and control. Anchovy sauce with 2% and 4% proteases was good in sensory evaluation of color, aroma, and taste attributes.