• 한국미생물·생명공학회지
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• 제48권4호
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• pp.439-446
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• 2020

Two Bacillus strains, K3 and K208, both demonstrating strong fibrinolytic activities were isolated from Kimchi, a traditional Korean preparation of fermented vegetables. Isolates were subjected to various molecular biology based identification methods including RAPD-PCR and identified as B. subtilis and B. velezensis, respectively. Tryptic soy broth (TSB) was found to best maintain both the growth and the fibrinolytic activity of these strains. Culture supernatants were analyzed by SDS-PAGE and fibrin zymography, and the results indicate that a 40 and 27 kDa band seem to be responsible for the fibrinolytic activities of these two isolates and the 27 kDa band was subsequently identified as the mature form of AprE, the major fibrinolytic enzyme. Thus the aprE genes were cloned and the translated amino acid sequences demonstrated 99.3% identity with each other, and 86.5% identity with BsfA, a fibrinolytic enzyme from B. subtilis ZA400 also isolated from Kimchi, and AprE2, a fibrinolytic enzyme from B. subtilis CH3-5 isolated from Cheonggukjang, a traditional Korean fermented soy. Given this B. subtilis K3 and B. velezensis K208 may be promising starter cultures in the production of fermented foods.

• 한국식품영양학회지
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• 제33권6호
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• pp.737-746
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• 2020

In this study, we developed vinegar depending on the quantity consumed and type of peeled and unpeeled roots of Platycodon grandiflorum (PG) using Acetobacter pasteurianus A11-2, analyzed vinegar samples using colorimeter and HPLC for 15 days to assess the characteristics on quality, and evaluated their antioxidant activity using 1,1-diphenyl-2-picry1 hydrazy1 (DPPH) and 2.2'-azinobis-(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical scavenging activities. The major result in PG vinegar was the high acidity of 6.39~6.74% and alcohol was totally converted on the 15th day of fermentation. When we fermented vinegar from peeled roots of 8% PG with a starter culture, we observed high contents of acetic acid, platycodin D, and total polyphenol and high antioxidant activity. Moreover, the vinegar fermented using 8% peeled roots of PG had the high intensity on umami and sour taste and low salty, bitter, and astringent tastes. Consequently, we could develop the PG vinegar with quality and functional characteristics from 8% peeled roots and A. pasteurianus A11-2.

• 한국축산식품학회지
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• 제42권1호
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• pp.46-60
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• 2022

In this study, angiotensin-I-converting enzyme inhibitory (ACEI) activity was evaluated in fermented goat milk fermented by lactic acid bacteria (LAB) from fermented foods and breast milk. Furthermore, the potential for ACEI peptides was identified in fermented goat milk with the highest ACEI activity. The proteolytic specificity of LAB was also evaluated. The 2% isolate was inoculated into reconstituted goat milk (11%, w/v), then incubated at 37℃ until pH 4.6 was reached. The supernatant produced by centrifugation was analyzed for ACEI activity and total peptide. Viable cell counts of LAB and titratable acidity were also evaluated after fermentation. Peptide identification was carried out using nano liquid chromatography mass spectrometry (LC-MS/MS), and potential as an ACEI peptide was carried out based on a literature review. The result revealed that ACEI activity was produced in all samples (20.44%-60.33%). Fermented goat milk of Lc. lactis ssp. lactis BD17 produced the highest ACEI activity (60.33%; IC₅₀ 0.297±0.10 mg/mL) after 48 h incubation, viable cell counts >8 Log CFU/mL, and peptide content of 4.037±0.27/mL. A total of 261 peptides were released, predominantly derived from casein (93%). The proteolytic specificity of Lc. lactis ssp. lactis BD17 through cleavage on the amino acid tyrosine, leucine, glutamic acid, and proline. A total of 21 peptides were identified as ACEI peptides. This study showed that one of the isolates from fermented food, namely Lc. lactis ssp. lactis BD17, has the potential as a starter culture for the production of fermented goat milk which has functional properties as a source of antihypertensive peptides.

• 한국미생물·생명공학회지
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• 제50권3호
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• pp.319-327
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• 2022

γ-Aminobutyric acid (GABA) is a multi-functional compound with broad applications for food industry. GABA producing bacteria were isolated from cabbage kimchi. Among them, B737 was the best GABA producer when culture supernatants were analyzed by TLC. B737 was identified as Levilactobacillus brevis by 16S rRNA gene sequencing. Its glutamate decarboxylase (GAD) gene was cloned by PCR and the nucleotide sequence determined. B737 GAD consisting of 485 amino acids is the largest in size among GADs reported from LAB so far. gadB from L. brevis B737 was overexpressed in Escherichia. coli BL21(DE3) using pET26b(+).pET26b(+). The recombinant GAD was purified and its size was 55 kDa by SDS-PAGE. Maximum GAD activity was observed at pH 5 and 40℃ and the activity was dependent on pyridoxal 5'-phosphate. K_m and V_max of recombinant GAD were 6.2 ± 0.06 mM and 0.34 ± 0.002 mM/min, respectively. L. brevis B737 can be used as a starter for fermented foods with high GABA contents.

• 한국축산식품학회지
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• 제43권2호
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• pp.232-244
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• 2023

We investigated the effects of different phosphate replacements on the quality of ground pork products cured with sodium nitrite or radish powder to determine their potential for achieving clean-label pork products. The experimental design was a 2×5 factorial design. For this purpose, the ground meat mixture was assigned into two groups, depending on nitrite source. Each group was mixed with 0.01% sodium nitrite or 0.4% radish powder together with 0.04% starter culture, and then processed depending on phosphate replacement [with or without 0.5% sodium tripolyphosphate; STPP (+), STPP (-), 0.5% oyster shell calcium (OSC), 0.5% citrus fiber (CF), or 0.5% dried plum powder (DPP)]. All samples were cooked, cooled, and stored until analysis within two days. The nitrite source had no effect on all dependent variables of ground pork products. However, in phosphate replacement treatments, the STPP (+) and OSC treatments had a higher cooking yield than the STPP (-), CF, or DPP treatments. OSC treatment was more effective for lowering total fluid separation compared to STPP (-), CF, or DPP treatments, but had a higher percentage than STPP (+). The STPP (+) treatment did not differ from the OSC or CF treatments for CIE L^* and CIE a^*. Moreover, no differences were observed in nitrosyl hemochrome content, lipid oxidation, hardness, gumminess, and chewiness between the OSC and STPP (+) treatments. In conclusion, among the phosphate replacements, OSC addition was the most suitable to provide clean-label pork products cured with radish powder as a synthetic nitrite replacer.

• 한국미생물·생명공학회지
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• 제51권2호
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• pp.157-166
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• 2023

Three lactic acid bacteria (LAB) producing exopolysaccharides (EPSs) were isolated from Pa (green onion)-kimchi, and identified as Weissella confusa (SKP 173), Weissella cibaria (SKP 182), and Leuconostoc citreum (SKP 281), respectively by 16S rRNA gene sequencing. The yields of EPS were 21.27, 18.53, and 15.4 g/l for EPS from SKP 173, 182, and 281, respectively when grown in MRS broth containing sucrose (5%, w/v). Total sugar contents were 64.39, 62.84, and 65.16% (w/w) for EPS from SKP 173, 182, and 281, respectively while the protein contents were 0.33, 0.31, and 0.25% (w/w), respectively. EPSs from W. confusa SKP 173 and W. cibaria SKP 182 contained glucose only but EPS from L. citreum SKP 281 contained glucose and glucitol. Viscosities of the 2% (w/w) freeze-dried EPS solution were 9.60, 8.00, and 8.20 centipoise (cP) for EPS from SKP 173, 182, and 281, respectively. Viscosities of culture grown in MRS broth with 5% sucrose (no glucose) were 92.98, 57.19, and 18.8 cP, respectively. The average molecular weights of EPSs were larger than 2 × 10⁷ Da. Fourier transform infrared spectroscopy (FT-IR) analyses of EPSs showed typical carbohydrate peaks, suggesting that the EPSs consisted of pyranose saccharides with α-(1,6) and α-(1,3) glycosidic linkages. L. citreim SKP 281 was used as the starter for yogurt fermentation, and EPS production was confirmed.

• Journal of Dairy Science and Biotechnology
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• 제31권2호
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• pp.133-141
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• 2013

본 연구는 치즈 숙성 중 오염원인 곰팡이균 제거 기술 개발의 일환으로 치즈 숙성실에서 자생하는 곰팡이와 다양한 지역의 김치로부터 유산균을 분리하여 곰팡이에 대한 생육억제활성이 있는 항진균 활성 유산균을 선발하고, 선발된 유산균의 배양특성을 확인하였다. 치즈와 치즈 숙성실에 자생하는 곰팡이 8종과 다양한 지역의 김치로부터 유산균 44종을 분리 동정하였고, 김치에서 분리한 유산균 44종 중 항진균 활성이 있는 유산균 6종을 최종 선발하여 그 특성을 규명하였다. 최종 선발된 유산균 6종 중에서 유산균 ALH (L. sakei subsp.)가 곰팡이균 8종에 대하여 항진균 활성이 가장 크게 나타났다. 최종 선발된 6종의 유산균의 생육은 배양 5시간부터 20시간까지 활발하였고, 배양시간이 경과할수록 배양액의 pH는 낮아졌다. 유산균 생육의 최적온도는 $30{\sim}37^{\circ}C$였으며, 최적 pH는 7이었다. 단백질 분해력은 6종 유산균 모두 유사하였으며, 단백질 응고력은 ALH, ALL, ALS 균주가 ALD, ALJ, ALT 균주에 비해 좋았다. 또한 ALD, ALH, ALJ 균주는 ALL, ALS, ALT 균주보다 산성조건에서 잘 견디는 것을 확인하였다. 유산균 배양액의 유기산 조성을 분석한 결과, lacic acid가 가장 많이 생성되었다. 본 실험에서 김치에서 분리한 유산균은 항진균력이 뛰어나고, 배양특성이 유제품을 제조하기에 적합하다고 사료되므로, 추후 곰팡이의 생육을 억제할 수 있는 치즈 및 유제품 개발에 활용할 수 있을 것으로 기대된다.

• 농업과학연구
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• 제11권1호
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• pp.120-132
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• 1984

어육단백분해물(魚肉蛋白分解物)이 Starter로써 이용(利用)되는 Str. lactis, Str. thermophilus, L. bulgaricus, L. acidophilus, L. helveticus 등의 유산균(乳酸菌)에 미치는 성장(成長) 촉진효과(促進效果)를 규명(糾明)하기 위하여 어육단백질(魚肉蛋白質) 분해시(分解時)의 최적조건(最適條件)을 검토(儉討)하고 분해물(分解物) 첨가시(添加時)의 유산균(乳酸菌)의 산생성도(酸生成度), pH 및 유산생균수(乳酸生菌數)의 변화(變化) 등을 실험(實驗)한 결과(結果)는 다음과 같다. 1. Pancreatin으로 고등어 배육(背肉)을 가수분해(加水分解)시킬때의 최적조건(最適條件)은 $50^{\circ}C$의 분해온도(分解溫度), pH 8, 48시간(時間) 처리(處理)와 어육(魚肉)의 단백질량(蛋白質量)에 대(對)하여 6%의 효소농도(酵素濃度)였다. 2. 조제(調製)된 어육단백분해물(魚肉蛋白分解物)의 조성(組成)은 수분(水分)53.6%, 단백질(蛋白質) 32.4%, 지방(脂肪) 1.0%, 회분(灰分) 3.2%, 탄수화물(炭水化物) 10.7%였다. 3. Str. lactis와 Str. thermophilus는 어육단백분해물(魚肉蛋白分解物)이 0.1%, L. acidophilus와 L. helveticus는 0.2% 이상(以上) 첨가(添加)된 배지(培地)에서 유산산도(乳酸酸度)가 크게 증가(增加)되었으나 L. bulgaricus의 경우에는 뚜렷한 효과(效果)를 보이지 않았다. 4. Str. lactis와 Str. thermophi1us는 어육단백분해물(魚肉蛋白分解物)을 0.1% 이상(以上) 첨가(添加)하였을 때 배지(培地) pH가 뚜렷하게 저하(低下)되었으나 L. bulgarilus, L. helveticus와 L. acidophilus는 어육단백분해물(魚肉蛋白分解物)을 첨가(添加)하여도 pH의 변화(變化)가 별로 없었다. 5. 모든 공시유산균주(供試乳酸菌株)는 어육단백분해물(魚肉蛋白分解物)의 첨가농도(添加濃度)에 비례(比例)하여 생균수(生菌數)가 증가(增加)하였다.

• Asian-Australasian Journal of Animal Sciences
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• 제20권6호
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• pp.954-961
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• 2007

The experiments were conducted to determine effects of a mixture of conjugated linoleic acid (CLA) isomers on T cell subpopulations and responsiveness to mitogen of splenocytes in male broiler chicks. In experiment 1, birds (8-d old) were fed basal, CLA-(CLA) and safflower oil-supplemented (SA) diets which were formulated by supplementary 10 g CLA or safflower oil/kg to the basal diet for 14 d. Broiler starter diet, which mainly consisted of corn and soybean meal, was served as the basal diet. Proliferative response and interleukin (IL)-2-like activity stimulated by concanavalin (Con) A at a concentration of $10{\mu}g/ml$ of splenocytes in chicks fed the CLA diet were greater than in chicks fed the SA diet, but not at $20{\mu}g$ Con A/ml. Percentage of CD3-positive T cells in splenocytes did not differ between chicks fed the SA diet and CLA. Ratio of CD4-positive T cells to CD8- positive T cells was significantly affected by dietary fat source. In experiment 2, broiler chicks (1-d old) were fed the same diets as in experiment 1 for 14 d. Results of splenocyte proliferation to Con A were similar to those in experiment 1, but phytohemaggulutinin (PHA)- or pokeweed mitogen (PWM)- induced splenocyte proliferation did not differ between the CLA and SA fed groups. Supplementation with SA or CLA to the basal diet tended to have a depressive effect on the proliferation, with the greater effect being that of SA. In experiment 3, effect of an addition of CLA to splenocyte culture medium on splenocyte proliferation was determined. An addition of CLA to the culture medium resulted in reduction of the splenocyte proliferation to Con A, but an addition of linoleic acid. When PWM and PHA were used as mitogen, the inhibitory effect of CLA and linoleic acid on the proliferation did not differ. The results suggested that the effect of dietary CLA on splenocyte proliferation was similar to that of SA, although the effect of dietary CLA on sub-populations was slightly different from that of dietary SA. Further studies are needed to clarify whether use of CLA would be beneficial for maintaining or enhancing T cell immunity in chicks.

• 미생물학회지
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• 제51권4호
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• pp.407-418
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• 2015

본 연구는 백김치로부터 분리된 Lactobacillus paracasei BK57의 항균물질 생산을 위한 최적의 배양 조건을 검색하고, BK57 유산균으로 프레쉬 치즈를 제조한 후 균주의 활성과 유산 및 박테리오신 생산량을 측정하여 Listeria monocytogenes KCTC 3569에 대한 항균 활성을 조사하였다. 최대의 균 증식과 항균 물질 생산량은 pH 6.0으로 조정한 MRS broth에서 $37^{\circ}C$, 24시간 동안 호기적인 조건으로 배양했을 때 나타났다. 하지만, 효모추출물(2.0%)을 첨가한 전유 내에서 생성된 항균물질의 양과 유산균의 증식률은 MRS broth에서 보다는 다소 낮았다. 우유 내에서 L. monocytogenes의 저해율은 BK57 균주의 생균과 배양 상등액에 의해 높게 나타났으나, 유산균이 생산한 박테리오신에 의한 저해율은 우유 보다는 BHI broth 내에서 더 높게 나타났다. BK57 균주로 발효시킨 프레쉬 치즈를 $4^{\circ}C$와 $15^{\circ}C$에서 6일간 저장하는 동안 유산균수, 유산 생성량 및 박테리오신 활성은 유의한 변화가 없었다. 제조 직 후 프레쉬 치즈에 인위적으로 접종한 L. monocytogenes ($10^5CFU/ml$)의 균수는 각각의 온도대에서 6일 이내에 최소 15% 이상 감소되는 효과가 나타났으므로 BK57 균주를 발효유제품 제조에 이용할 경우 리스테리아균을 제어할 수 있는 생물학적 보존제로서의 가치를 확인하였다.