• 생명과학회지
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• 제9권1호
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• pp.111-120
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• 1999

우리 고유의 전통 발효 음식인 김치로부터 bacteriocin 생성능이 우수한 Lactococcus sp. J-105균주를 분리하였다. Lactococcus sp. J-105의 생육 및 bacteriocin 생성에 대한 최적 조건을 검토한 결과 bacteriocin 생성은 대수 증식기 말기에서 정지기 초기에 가장 많이 생성되었다. Lactococcus sp. J-105의 생육 및 bacteriocin 생성 최적 탄소원 및 질소원은 각각 maltose와 polypeptone이었다. 균의 생육 및 bacteriocin 생성 최적 온도는 $25^{\circ}C$였으며 생육 최적 pH는 pH 8 부근이었다. bacteriocin 생성 또한 pH 8에서 최고를 나타내었다. 한편 NaCl은 오히려 균체 증식과 bac-tericoin 생성을 저해하였다. Lactococcus sp. J-105가 생산하는 bacteriocin의 pH 및 열에 대한 안정성을 검토한 결과 pH 2~4, $121^{\circ}C$ 15분에서 각각 안정하였다. 또한 J-105의 항균 spectrum을 검토한 결과 Lactobacillus sp. Leuconostoc s 그리고 Bacillus subtilis 등의 Gram 양성균에 대해서 항균활성 나타내었으며 Gram 음성균인 Acetobacter acid에 대해서도 항균 활성을 나타내었으나 E. coli에 대해서는 항균 활성을 나타내지 않았다. 본 bacteriocin은 trypsin, protease와 같은 peptide 분해효소에 대해서는 안정한 반면, pepsin에 의해서는 활성이 상실되는 특이한 성질을 나타내었다

• 한국식품과학회지
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• 제10권1호
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• pp.36-45
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• 1978

맥백혈구(脈白血球) Lysosomal 효소를 pH(7.0, 4.0), 온도($37^{\circ}C$, $4^{\circ}C$) 및 처리기간($37^{\circ}C$에서 12 24시간, $4^{\circ}C$에서 36 168시간)을 달리하여 처리(處理)한 우(牛)의 요근조직(腰筋組織)의 변화(變化)에 대(對)하여 endomysial connective tissue, sarcolemma 및 transverse ridge등 근(筋)섬유 표면조직(表面組織)의 변화(變化)를 SEM으로 관찰한 바, 처리온도(溫度)에 관계(關係)없이 pH 7.0에서는 endomysial connective tissue, sarcolenna 및 transverse ridge의 분해(分解)를 나타내어 이 효소의 높은 역가(力價)를 보였으나, pH4.0에서는 이들 표면조직(表面組織)에 변화(變化)가 없었으며 특(特)히 transverse ridge는 $37^{\circ}C$에서 24시간, 그리고 $4^{\circ}C$에서 7일간 처리(處理)하여도 변화(變化)를 나타내지 않아 안정(安定)됨을 보였다.

• 한국식품과학회지
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• 제9권1호
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• pp.31-35
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• 1977

Rhizopus japonicus S-62가 생산(生産)하는 acid protease에 관(關)한 연구(硏究)로서, 효소(酵素)의 생산조건(生産條件) 및 조효소(粗酵素)의 특성(特性)을 검토(檢討)하여 다음과 같은 결과(結果)를 얻었다. 1. 밀기울에 배양(培養)하는 경우 최적배양(最適培養) 시간(時間)은 48시간(時間) 첨수량(添水量)은 $100{\sim}120%$이었다. 2. 각종(各種) 배지중(培地中) 밀기울 배지(培地)가 가장 우수(優秀)하였다. 3. 밀기울에 sucrose, fructose, $NH_4Cl$, $NaH_2PO_4$의 첨가(添加)는 protease생산(生産)을 크게 증가(增加)시켰다. 4.본효소(本酵素)의 작용최적(作用最適)pH는 $2.4{\sim}2.6$, Opt. temp.는 약(約) $40^{\circ}C$, 안정(安定) pH 범위(範圍)는 $2.5{\sim}5.0$이고, $40^{\circ}C$이하(以下)에서는 안정(安定)하나 그 이상(以上)의 온도(溫度)에서는 급격(急激)하게 불활성화(不活性化)되었다.

• 한국식품영양학회지
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• 제21권4호
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• pp.510-517
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• 2008

Effects of addition of Chinese chives into frozen noodle on retrogradation of the cooked frozen noodle were examined by enzymatic evaluation during the storage 3 days at $4^{\circ}C$. The retrogradation rate during storage was significantly reduced by addition Chinese chives. Thus we hypothesized that retarogardation and textural changes of frozen noodle might be linked to thermostable amylase in Chinese chives. The amylase isolated from Chinese chives was affected by temperature and pH of buffer used. The enzyme was mainly extracted 20 mM potassium phosphate buffer(pH 7.0). The enzyme was extremly stable at wide temerature and pH. Amylase activity was maximal at $50^{\circ}C$ and pH 7.5. The enzyme was not inactivated by heat treatment at $70^{\circ}C$, $80^{\circ}C$ for 30 min. We suggest the enzyme was stable at high temperature. To investigate the effect of different storage packge on texture properties, color, sensory evaluation, parent-packged and unparent packaged frozen noodle was compared with control. As the storage passed, the frozen noodle packaged with parent showed a rapid decrease in the color. The hardness was gradually decreased during storage. It was found that unparent packged must be nessasry in the Chinese chives frozen noodle. In changes of sensory properties by traind panel, Chinese chives frozen noodle with 2% blanched Chinese chives got the highest score in overall acceptability, therefore we tried acceptance test by consumers with 2% blanched frozen Chinese chives noodle.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2001년도 추계학술발표대회
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• pp.329-332
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• 2001

적색 색소를 생성하는 곰팡이 RF10l 로부터 여러 용매를 이용하여 추출물을 얻어낸 후 각 추출물의 특성을 조사한 결과 chloroform 용액은 510nm 에서 흡수 peak를 나타냈으며, pH 5-9 영역에서 안정함을 보였고, 암상태의 저온과 실온에서 5 일이 경과 한 후90% 이상이 구조적으로 안정함을 보였다. 금속이온들 중 NaCl을 제외하고 KCl. $CaCl_2$, $MgCl_2$ 용액에서 5 일이 경과한 후에도 60% 이상의 안정함을 나타내었고, 균사체 powder 가 0.5% 첨가된 배지에서는 모든 균주의 생장이 억제되었으며 70% methanol 추출물 . $70^{\circ}C$ D.W 추출물에서도 생장억제 효과가 크게 나타났다. 이러한 결과로 볼 때, 더 많은 연구가 진행된다면 곰팡이 RFl0l로부터 산업적 이용 가치가 있는 물질을 생산할 수 있을 깃으로 생각되며 그에 대한 연구는 계속 수행중에 있다.

• 한국식품영양학회지
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• 제14권6호
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• pp.527-531
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• 2001

옻나무는 독성이 있는 금기물질임에도 불구하고 한국에서는 민간요법으로 옻닭 등의 가공식품 형태로 사용하여 왔다. 항산화 물질은 옻나무 껍질에 물을 가하여 추출하여 분리하였다. 물 추출물은 DEAE, CN, ODS 컬럼을 사용하여 HPLC로 정제하였다. 정제된 순수물질 안정성은 pH 3.0~6.0의 산성영역에서는 안정하였으나, pH 6.5 이상에서는 불안정하였으며, 10$0^{\circ}C$에서 5시간 열처리하여도 80%의 활성을 보였다. 항균력 실험에서는 그람양성, 음성 균주에 대하여 항균 활성이 없었다. 항산화력은 DPPH 방법으로 조사한 결과 동일한 농도에서 (20$\mu\textrm{g}$/m1) BHT, BHC 보다 좋았으나, ascorbic acid 보다 낮았다.

• Food Science and Biotechnology
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• 제16권4호
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• pp.572-575
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• 2007

The angiontensin converting enzyme (ACE) inhibitory peptides were separated from beef sarcoplasmic protein extract and their amino acid sequences were identified as GFHI, DFHINQ, FHG, and GLSDGEWQ. The 4 peptides were synthesized in a laboratory and the ACE inhibitory activities of pep tides was measured after 2 months of storage at $4^{\circ}C$ under different pH conditions (6.0, 6.5, 7.0, 7.5, and 8.0) and the exposure of different temperatures (70, 80, 90, and $100^{\circ}C$) for 20 min to evaluate industrial use. No significant difference was detected by pH and temperature abuse for 20 min during storage. When the synthetic peptides were digested by pepsin, trypsin, and chymotrypsin, the ACE inhibitory activity was not changed. These results indicated that the 4 synthetic peptides with ACE inhibitory activity were pH-stable, heat-stable, and resistant to proteinases in gastro-intestinal tracts. Therefore, those 4 peptides can be used as a source for functional food product with various applications.

• 한국식품영양과학회지
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• 제27권6호
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• pp.1105-1109
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• 1998

The superoxide dismutase(SOD) in peeled pericarp of cucumber was most stable at pH 8.0 and relatively stabe between pH 5.0 and 9.0. The enzyme was stable up to 6$0^{\circ}C$ and retained 12% by heat treatment at 10$0^{\circ}C$ for 5 min. At pH 2.0, the peeled pericarp enzyme activity was decreased to 10% by incubation for 3 hrs. However, the enzyme activity was increased above 25% after incubating the enzyme at pH 7.0 for 6 hrs. Retention of SOD activity in cucumber by various heating methods was also measured. The residual SOD activities of peeled pericarp and whole cucumber was estimated to be 25% and 27% after blanching(2 min), respectively. The skin enzyme retained 53% of its activity after steaming (3 min). When the peeled pericarp enzyme was incubated at 4$^{\circ}C$ for 20 days, the enzyme activity remained about 81%. However, when the enzyme incubated at 3$0^{\circ}C$ for 20 days, the peeled pericarp enzyme activity decreased to 17% of its original activity. The enzyme activity of peeled pericarp cucumber was not changed after exhaustive dialysis for 3 days, which indicated that the SOD activity in cucumber seems to have molecular weight above 12,000.

• Journal of Microbiology and Biotechnology
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• 제2권1호
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• pp.14-20
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• 1992

Some microorganisms isolated from soil, including some bacteria and fungi, were found to secrete an extracellular soymilk-clotting enzyme. Among them, an isolated fungus showed the highest soymilk-clotting activity and the strain was assigned to genus Penicillium based on its cultural and morphological characteristics, and designated as Penicillium sp. L-151K. Soymilk-clotting enzymes A and B produced by Penicillium sp. L-151K were purified by ammonium sulfate precipitation and chromatographies on Sephadex G-25, CM-Sephadex, Sephadex G-100 and phenyl-Toyopearl gel. The two purified enzymes A and B were found to be homogeneous by polyacrylamide gel electrophoresis at pH 9.5. The molecular weights of enzyme A and B were 24, 000 and 40, 000, respectively, by gel filtration on Sephadex G-100. Enzymes A and B coagulated soymilk optimally at $60^\circ{C}$ and were stable up to $50^\circ{C}$. Both enzymes were most active at pH 5.8 for soymilk coagulation, and were stable with approximately 80% of original activity from pH 3.0 to 5.0. Each enzyme was an acidic protease with an optimum pH of 3.0 for casein digestion. The soymilk-clotting efficiency of these enzymes was improved with $CaCl_2\;or\;MgCl_2$ when making soymilk-curd.

• Toxicological Research
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• 제7권2호
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• pp.183-189
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• 1991

Since streptozotocin has been known to be chemically stable only under acidic condition(pH 4), the spontaneous degradation and cellular uptake of streprozotocin in neutral incubation medium was determined by chemical assay. Streptozotocin levels in both phosphate buffered saline (pH 7.4) and Krebs-Henseleit buffer (pH 7.4) decreased with a half life of about 2 hours. The presence of erythrocytes or pepatocytes under the same buffers did not affect the streptozotocin degradation rate at all. However, streptozotocin levels in plasma isolated from rats decreased rapidly compared to those in neutral buffers.