• 생명과학회지
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• 제29권8호
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• pp.846-853
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• 2019

천궁은 동양 전통 의학에서 사용되고 있는 식물로 항진통, 부인과 질환, 항산화활성, 뇌질환에 사용되고 있다. 본 연구는 한국 전통발효식품인 김치에서 분리된 Lactobacillus plantarum BHN-LAB 129를 이용해 발효한 천궁 추출물의 항산화 효과를 조사하였다. 발효하지 않은 천궁 추출물에 비해 L. plantarum BHN-LAB 129 발효 천궁 추출물에서 총 폴리페놀 함량은 약 161.2%, 총 플라보노이드 함량은 약 281.0% 증가된 것을 확인하였다. 또한, SOD 유사활성능, ABTS radical 소거활성능, DPPH radical 소거 활성능, 환원력은 각각 약 139.9%, 199.6%, 301.0% 및 137.1% 증가된 것을 확인하였다. 이 결과를 통해 L. plantarum BHN-LAB 129을 이용한 생물전환을 통한 천궁 발효 추출물의 항산화능 증대에 효과적인 것을 확인하였다. 또한, 생물전환기술은 생리활성을 증대시키기 위한 매우 유용한 기술임을 확인하였으며, 생물전환기법을 통한 기능성 식품소재 및 화장품 소재 개발 및 응용이 가능할 것으로 기대된다.

• 한국미생물·생명공학회지
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• 제46권1호
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• pp.1-8
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• 2018

Gul (oyster) jeotgals (GJs) were prepared using different types of salt (23%, w/v): purified salt, solar salt aged for 3 years, and bamboo salt crystalized 3 times. One set of GJs was fermented with Bacillus subtilis JS2 ($10^6CFU/g$), while the other GJ set was fermented without starter. During fermentation for 24 weeks at $15^{\circ}C$, the starter GJs showed 10-fold higher bacilli counts than the no-starter GJs, where the maximum bacilli count was $8{\times}10^3CFU/g$. All 28 bacilli strains isolated from the 6-week GJs were identified as B. subtilis by using a RAPD-PCR, indicating that some of the B. subtilis JS2 cells remained viable. Lactic acid bacteria (LAB) and yeasts were present at low levels, $10^1-10^2CFU/g$. LAB with protease activities isolated from 10-week samples were identified as Enterococcus species. The isolates obtained at 16 weeks were all Staphylococcus species. The GJs with bamboo salt showed higher pH and lower titratable acidity (TA) values than the other GJs due to the strong alkalinity of bamboo salt. The amino-type nitrogen in the GJs increased slowly during the fermentation. At 24 weeks, the GJs with purified salt showed the highest amino-type nitrogen (412-430 mg%), followed by the GJs with solar salt (397-406 mg%) and GJs with bamboo salt (264-276 mg%). Meanwhile, the GJs with bamboo salt showed the highest ammonia-type N (63.67 mg%), followed by the GJs with purified salt (49 mg%) and solar salt (48 mg%).

• Journal of Dairy Science and Biotechnology
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• 제23권2호
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• pp.149-153
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• 2005

Lactic acid bacteria had been widely utilized in fermented foods such as fermented dairy products, traditional sauces, kimchi, fermented sausages, medicines or probiotic feed additives for a long time. LAB are also widely distributed in the mammalian gastrointestinal tracts, oral cavity, vagina, and various foods or soils. The most familiar examples of using LAB would be the fermented milk products, and those had become one of the favorite foods in Korea f3r more than 34 years of history. The main benefits of the fermented milk products were originally the improvement of the balance of intestinal flora to control diarrhea and congestion disorders, and gradually, they were chosen by the consumer preference of the taste. The very beginning of the fermented milk products in Korea was the Yakult type products in 1971, and it was the commencement of the solid foundation of the dairy industry and the understanding beneficial effect of probiotic yogurt. After middle of 80's, stirred type fermented milk products had been firstly produced, and it was the time that the domestic dairy industry took root in Korea. From 90's, functional fermented milk products were produced, and drink type yogurt sales a mount increased drastically, and these products began to be chosen not only with the values of nutrition but also with physiological functions. The health claims are classified into intestinal health, gastric health and hepatic health. The prospects for the Korean market are as follows; The majority of leading products would be the premium functional yogurt products as it was last year. It is because the sales of lower cost products shows slow-down, and industries tend to increase the commercial advertisements of premium functional yogurt products through mass media. These tendencies would make the market situation become more competitive.

• 한국축산식품학회지
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• 제33권6호
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• pp.744-751
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• 2013

The objective of this study was to assess the physicochemical and sensory changes of a kefir manufactured by a two-step fermentation (MTY, $1^{st}$ step: $37^{\circ}C$ for 9 h; $2^{nd}$ step: $24^{\circ}C$ for 15 h) and compare it with kefirs produced by two conventional methods (GTY, fermentation at $37^{\circ}C$ for 24 h; KEY, $22^{\circ}C$ for 24 h). Rapid changes in pH and titratable acidity (TA) were observed in samples from all three manufacturing methods during fermentation process and storage period. Lactic acid bacteria (LAB) counts of MTY increased gradually up to 12 h of fermentation, reaching 9.28 Log CFU/mL, with maximum value observed in this experiment of 9.48 Log CFU/mL. The LAB counts of all samples decreased significantly during storage. The highest viscosity was observed for MTY (1750-1771 cPs), compared with the lowest viscosity observed for KEY (1250-1277 cPs). The viscosity of all samples increased slightly during storage (1250-1805 cPs, p<0.05), as well as carbon dioxide content (0.01-1.36%, p<0.05), except for GTY. The most significant increase in alcohol concentration during storage period was seen in MTY from 0.01% to 1.36% (p<0.05). MTY scored significantly higher in most items of the sensory analysis, indicating that the product manufactured by the two-step fermentation method is more acceptable compared with conventionally produced kefirs.

• Journal of Microbiology and Biotechnology
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• 제28권7호
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• pp.1052-1060
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• 2018

Numerous studies suggest that the effects of lactic acid bacteria (LAB) on oxidative stress in vivo are correlated with their antioxidative activities in vitro; however, the relationship is still unclear and contradictory. The antioxidative activities of 27 Lactobacillus plantarum strains isolated from fermented foods were determined in terms of 2,2-diphenyl-1-picrylhydrazyl, hydroxyl radical, and superoxide radical scavenging abilities, reducing activity, resistance to hydrogen peroxide, and ferrous chelating ability in vitro. Two fuzzy synthetic evaluation models, one with an analytic hierarchy process and one using entropy weight, were then used to evaluate the overall antioxidative abilities of these L. plantarum strains. Although there was some difference between the two models, the highest scoring strain (CCFM10), the middle scoring strain (CCFM242), and the lowest scoring strain (RS15-3) were obtained with both models. Examination of the antioxidative abilities of these three strains in $\text\tiny{D}$-galactose-induced oxidative stress mice demonstrated that their overall antioxidative abilities in vitro could reveal the abilities to alleviate oxidative stress in vivo. The current study suggests that assessment of overall antioxidative abilities with fuzzy synthetic models can guide the evaluation of probiotic antioxidants. It might be a more quick and effective method to evaluate the overall antioxidative abilities of LAB.

• Asian-Australasian Journal of Animal Sciences
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• 제31권8호
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• pp.1252-1258
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• 2018

Objective: This study was carried out to determine the effects of cumin essential oil on the silage fermentation, aerobic stability and in vitro digestibility of alfalfa silages. Methods: Alfalfa was harvested at early bloom (5th cutting) stage in October and wilted for about 3 hours. The research was carried out at three groups which were the control group where no additive control was done (CON), cumin essential oil (CMN3) with 300 mg/kg and CMN5 with 500 mg/kg cumin essential oil addition. Alfalfa was ensiled in plastic bags. The packages were stored at $8^{\circ}C{\pm}2^{\circ}C$ under laboratory conditions. All groups were sampled for physical, chemical and microbiological analysis 120th day after ensiling. At the end of the ensiling period, all silages were subjected to an aerobic stability test for 7 days. In addition, enzimatic solubility of organic matter (ESOM), metabolizable energy (ME), and relative feed value (RFV) of these silages were determined. Results: pH level decreased in the cumin groups compared to CON (p<0.05), thus inhibiting proteolytic enzymes from breaking down proteins into ammonia. In addition, it increased ESOM amount, and concordantly provided an increase of ME contents. Similarly, dry matter intake and RFV ratio increased. After opening the silage, it kept its aerobic stability for three days. Conclusion: Cumin essential oil improved fermentation, and affected chemical and microbiological characteristics of silages. Especially the addition of 300 mg/kg cumin provided cell wall fractionation through stimulating the activities of enzymes responsible. It also increased the number and activity of lactic acid bacteria (LAB) through providing a development of LAB.

• 한국축산식품학회지
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• 제34권3호
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• pp.346-354
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• 2014

Fermented foods with probiotics having functional properties may provide beneficial effects on health. These effects are varied, depending on the type of lactic acid bacteria (LAB). Different probiotic LAB might have different functional properties. Thus, this study was performed to evaluate the quality of fermented sausages manufactured with functional starter cultures (Lactobacillus plantarum 115 and 167, and Pediococcus damnosus L12) and different fat levels, and to determine the optimum condition for the manufacture of these products. Medium-fat (~15%) fermented sausages reduced the drying time and cholesterol contents, as compared to regular-fat counterparts. In proximate analysis, the contents of moisture and protein of regular-fat products were lower than medium-fat with reduced fat content. The regular-fat products also had a lighter color and less redness, due to reduced fat content. Approximately 35 volatile compounds were identified in functional fermented sausages, and hexanal, trans-caryophyllene, and tetradecanal were the major volatile compounds. Selected mixed starter culture showed the potential possibility of replacing the commercial starter culture (LK30 plus) in flavor profiles. However, medium-fat fermented sausage containing selected mixed starter culture tended to be less acceptable than their high-fat counterparts, due to excess dry ring developed in the surface. These results indicate that the use of combinations of L. plantarum 115 and 167, and P. damnosus L12 as a starter culture, will prove useful for manufacturing the fermented sausage.

• Journal of Microbiology and Biotechnology
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• 제28권8호
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• pp.1293-1298
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• 2018

Phosphomannomutase (ManB) converts mannose-6-phosphate (M-6-P) to mannose-1-phosphate (M-1-P), which is a key metabolic precursor for the production of GDP-D-mannose used for production of glycoconjugates and post-translational modification of proteins. The aim of this study was to express the manB gene from Escherichia coli in Lactococcus lactis subsp. cremoris NZ9000 and to characterize the encoded enzyme. The manB gene from E. coli K12, of 1,371 bp and encoding 457 amino acids (52 kDa), was cloned and overexpressed in L. lactis NZ9000 using the nisin-controlled expression system. The enzyme was purified by Ni-NTA column chromatography and exhibited a specific activity of 5.34 units/mg, significantly higher than that of other previously reported ManB enzymes. The pH and temperature optima were 8.0 and $50^{\circ}C$, respectively. Interestingly, the ManB used in this study had two substrate specificity for both mannose-1-phosphate and glucose-1-phosphate, and the specific activity for glucose-1-phosphate was 3.76 units/mg showing 70% relative activity to that of mannose-1-phosphate. This is the first study on heterologous expression and characterization of ManB in lactic acid bacteria. The ManB expression system constructed in this study canbe used to synthesize rare sugars or glycoconjugates.

• Journal of Microbiology and Biotechnology
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• 제17권5호
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• pp.822-829
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• 2007

A gene coding for phosphoketolase, a key enzyme of carbohydrate catabolism in heterofermentative lactic acid bacteria(LAB), was cloned from a Lactobacillus paraplantarum C7 and expressed in Escherichia coli. The gene is 2,502 bp long and codes for a 788-amino-acids polypeptide with a molecular mass of 88.7 kDa. A Shine-Dalgarno sequence(aaggag) and an inverted-repeat terminator sequence are located upstream and downstream of the phosphoketolase gene, respectively. The gene exhibits an identity of >52% with phosphoketolases of other LAB. The phosphoketolase of Lb. paraplantarum C7(LBPK) contains several highly conserved phosphoketolase signature regions and typical thiamine pyrophosphate(TPP) binding sites, as reported for other TPP-dependent enzymes. The phosphoketolase gene was fused to a glutathione S-transferase(GST::LBPK) gene for purification. The GST::LBPK fusion protein was detected in the soluble fraction of a recombinant Escherichia coli BL21. The GST::LBPK fusion protein was purified with a yield of 4.32mg/400ml by GSTrap HP affinity column chromatography and analyzed by N-terminal sequencing. LBPK was obtained by factor Xa treatment of fusion protein and the final yield was 3.78mg/400ml. LBPK was examined for its N-terminal sequence and phosphoketolase activity. The $K_M\;and\;V_{max}$ values for fructose-6-phosphate were $5.08{\pm}0.057mM(mean{\pm}SD)$ and $499.21{\pm}4.33{\mu}mol/min/mg$, respectively, and the optimum temperature and pH for the production of acetyl phosphate were $45^{\circ}C$ and 7.0, respectively.

• 한국축산식품학회지
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• 제33권1호
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• pp.24-30
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• 2013

This study was conducted to compare the physicochemical and sensory properties of yogurt added with nanopowdered ginseng (NPG) and powdered ginseng (PG) of different concentrations (0.1, 0.3, 0.5, and 0.7%) (w/v) during the storage at $7^{\circ}C$ for 20 d. The pH and viscosity values of yogurt added NPG or PG decreased during the storage. The pH values of the yogurt samples were ranged from 4.0 to 4.6 as a reflective of the fresh state. Viscosity values of yogurt with NPG at lower concentrations 0.1 and 0.3% (w/v) showed higher values during increased storage time. DPPH radical scavenging activity was significantly higher in the NPG-added yogurt than in the PG during the storage period (p<0.05). The lactic acid bacteria (LAB) counts ranged from $3.0{\times}10^9$ to $1.3{\times}10^9$ and $2.2{\times}10^9$ to $1.1{\times}10^9CFU/mL$ in 0.3% NPG and PG-added yogurts, respectively. Increased storage period showed decrease in LAB counts irrespective of the type of ginseng powder and storage period. In sensory test, 0.1 and 0.3% NPG-added yogurt showed similar results to control in yellowness, viscosity, and bitterness. Based on the data obtained from the present study, it was concluded that the concentrations 0.1 and 0.3% (w/v) of NPG could be used to produce NPG-added yogurt without significant adverse effects on physicochemical and sensory properties, and enhance functional value of yogurt.