• Food Science of Animal Resources
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• v.36 no.1
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• pp.90-99
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• 2016

This study evaluated the effects of two Korean traditional plant extracts (Diospyros kaki THUNB. leaf; DK, and Nelumbo nucifera leaf; NN) on the fermentation, functional and sensory properties of herbal yogurts. Compared to control fermentation, all plant extracts increased acidification rate and reduced the time to complete fermentation (pH 4.5). Supplementation of plant extracts and storage time were found to influence the characteristics of the yogurts, contributing to increased viability of starter culture and phenolic compounds. In particular, the increase in the counts of Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus was highest (2.95 and 1.14 Log CFU/mL respectively) in DK yogurt. Furthermore, supplementation of the plant extracts significantly influenced to increase the antioxidant activity and water holding capacity and to produce volatile compounds. The higher antioxidant activity and water holding capacity were observed in NN yogurt than DK yogurt. Moreover, all of the sensory characteristics were altered by the addition of plant extracts. Addition of plant extracts increased the scores related to flavor, taste, and texture from plain yogurt without a plant extract, as a result of volatile compounds analysis. Thus, the overall preference was increased by plant extracts. Consequently, supplementation of DK and NN extracts in yogurt enhanced the antioxidant activity and physical property, moreover increased the acceptability of yogurt. These findings demonstrate the possibility of using plant extracts as a functional ingredient in the manufacture of herbal yogurt.

• Journal of Microbiology and Biotechnology
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• v.9 no.4
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• pp.498-503
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• 1999

Protease produced from Bacillus sp. FSE-68 was isolated from Meju, a Korean fermented soybean starter, and was purified by a two-consecutive aqueous two-phase system. The change of partition coefficient (K) in the polyethylene glycol (PEG)/potassium phosphate buffer (PPB) aqueous two-phase system was measured at different pHs (6.0- 9.2), PPB concentrations (8-12%), and temperatures (4 and $20^{\circ}C$). As the PPB concentration in the aqueous two-phase system increased, the protease concentration in the top phase (PEG-rich phase) increased, thereby enhancing the partition coefficient. The minimum partition coefficient of the protease was achieved at pH 7.0, whereas that of the total protein was at pH 6.0. The biggest difference in partition coefficients of total protein and protease occurred at pH 6.0. It was interesting to note that the partition coefficient of protease decreased as the temperature increased. The optimum condition of the primary aqueous two-phase extraction of Bacillus sp. FSE-68 was pH 6.0, 14% (w/w) PPB, and 16% (w/w) PEG at $4^{\circ}C$, and the crude enzyme concentration in this system was 50% (w/w). The protease, which was concentrated in the top phase, was further mixed with 15% (w/w) PPB (pH 7.0) in the ratio of 1:1 at $20^{\circ}C$ to elute the bottom phase (PPB-rich phase). Using these steps, the purification fold achieved was 9.2 with a 44.7% yield.

• KSBB Journal
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• v.6 no.4
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• pp.413-424
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• 1991

The optimal condition for manufacturing the yoghurt by using B. bifidum and L. acidophilus was studied. Optimal growth condition of B. bifidum and fermentation effects of B. bifidum, L. acidophilus and Str. thermophilus in mixed culture were investigated separately. Fermentation conditions of B. bifidum were optimized in 12% reconstitued skim milk. The addition of BIOS 2000 to 12% skimmilk was effective on the growth and acid production of B. bifidum. There was asymbiosis among B. bifidum, L. acidophilus and Str. thermophilus in mixed culture which resulted in higher viable cell numbers and acid production. The optimum production of yoghurt was achieved by incubation at $37^{\circ}C$ for 8 hours with 5% mixed starter culture (B. bifidum+L.acidophilus+Str. thermophilus). In this case the effective ratio of B. bifidum: L. acidophilus: Str. thermophilus was 2:1:1 on both acid production and viable cell counts.

• Korean Journal of Food Science and Technology
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• v.35 no.4
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• pp.666-670
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• 2003

Strains producing the protease, which is essential for growth of lactic acid bacteria and fermented kimchi, were screened and identified. Among five types of selected pulmuone kimchis (Jeonlado kimchi, ripened kimchi, yeolmu kimchi, kakdugi, and baechu kimchi), nine strains of bacteria were screened and identified by whole cell protein pattern and API test. The nine strains consisted of one of Lactobacillus sp., one of Leuconostoc sp., six of Bacillus sp., and one of Brevibacillus sp. The protease activities of these strains were compared with known strains (Bac. subtilis KCCM 12248 and Bac. licheniformis KCCM 11851) producing protease. Among tested strains, K-2 (Brevibacillus sp.) showed the highest value (0.11 unit/mg) in protease activity.

• Food Science and Preservation
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• v.6 no.4
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• pp.456-462
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• 1999

The radish juice inoculated with mixed culture of Leuconostoc mesenteroides and Lactobacillus brevis was fermented and stored. Radish juice was heat-treated for 30 min at 65$^{\circ}C$ and 15 min at 80$^{\circ}C$, and stored for 8 weeks at 25$^{\circ}C$, 15$^{\circ}C$, and 5$^{\circ}C$, respectively. When the radish juice was heat-treated, any bacteria were not detected and any quality changes were not occured. On the other hand non-heated radish Juice, pH was decreased and acidity was increased during storage. The turbidity of the heat-treated radish juice was higher than that of the non-heated juice when it stored at 5'E. From the sensory evaluation, the pasteurization condition of 15 min at 80$^{\circ}C$ was not appropriate because the fresh smell of Dongchimi was decreased and the cooked smell was increased. The radish juice stored at 5$^{\circ}C$ without heat-treatment was evaluated to have the best quality. The storage period of the non-heated radish juice was shown to be extended over 8 weeks at 5$^{\circ}C$.

• Journal of Microbiology and Biotechnology
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• v.29 no.3
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• pp.347-356
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• 2019

Bacillus sp. BS2 showing strong fibrinolytic activity was isolated from sea squirt (munggae) jeotgal, a traditional Korean fermented seafood. BS2 was identified as B. velezensis by molecular biological methods. B. velezensis BS2 grows well at 15% NaCl and at $10^{\circ}C$. When B. velezensis BS2 was cultivated in TSB broth for 96 h at $37^{\circ}C$, the culture showed the highest fibrinolytic activity ($131.15mU/{\mu}l$) at 96 h. Three bands of 27, 35 and 60 kDa were observed from culture supernatant by SDS-PAGE, and fibrin zymography showed that the major fibrinolytic protein was the 27 kDa band. The gene (aprEBS2) encoding the major fibrinolytic protein was cloned, and overexpressed in heterologous hosts, B. subtilis WB600 and E. coli BL21 (DE3). B. subtilis transformant showed 1.5-fold higher fibrinolytic activity than B. velezensis BS2. Overproduced AprEBS2 in E. coli was purified by affinity chromatography. The optimum pH and temperature were pH 8.0 and $37^{\circ}C$, respectively. $K_m$ and $V_{max}$ were 0.15 mM and $39.68{\mu}M/l/min$, respectively, when N-succinyl-Ala-Ala-Pro-Phe-pNA was used as the substrate. AprEBS2 has strong ${\alpha}$-fibrinogenase and moderate ${\beta}$-fibrinogenase activity. Considering its high fibrinolytic activity, significant salt tolerance, and ability to grow at $10^{\circ}C$, B. velezensis BS2 can be used as a starter for jeotgal.

• International journal of advanced smart convergence
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• v.10 no.1
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• pp.197-208
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• 2021

The deer antler has been used as a major drug in oriental medicine for a long time. Recently, the demand for easy-to-take health functional foods is increasing due to economic development and changes in diet. As part of research on the development of functional materials for antlers, lactic acid fermentation of antler extract was performed. It was intended to develop a functional material with enhanced total polyphenol and flavonoid content and enhanced antioxidant activity. Lactic acid bacteria fermentation was performed by adding 4 types of lactic acid bacteria starter products, B. longum, Lb. Plantarum, Lb. acidophilus and mixture of 8 types of lactic acid bacteria to the antler water extract substrate, respectively. During the fermentation of lactic acid bacteria, the number of proliferation, total polyphenol and total flavonoid content, DPPH radical scavenging and antioxidant activity were quantified and evaluated. As a result of adding these four types of lactic acid bacteria to the antler water extract substrate, the number of lactic acid bacteria measured was 2.04~5.00×107. Meanwhile, a protease (Baciullus amyloliquefaciens culture: Maxazyme NNP DS) was added to the antler extract to decompose the peptide bonds of the contained proteins. Then, these four types of lactic acid bacteria were added and the number of lactic acid bacteria increased to 2.84×107 ~ 2.21×108 as the result of culture. The total polyphenol contents were 4.82~6.26 ㎍/mL in the lactic acid bacteria fermentation extracts, and after the reaction of protease enzyme and lactic fermentation, increased to 14.27~20.58 ㎍/mL. The total flavonoid contents were 1.52~2.21 ㎍/ml in the lactic acid bacteria fermentation extracts, and after the protease reaction and fermentation, increased to 5.59 ~ 8.11 mg/mL. DPPH radical scavenging activities of lactic acid bacteria fermentation extracts was 17.03~22.75%, but after the protease reaction and fermentation, remarkably increased to 32.82~42.90%.

• Journal of Microbiology and Biotechnology
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• v.32 no.8
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• pp.1011-1016
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• 2022

Bacillus subtilis is a useful bacterium in the food industry with applications as a starter strain for fermented food and as a probiotic. However, it is difficult to discriminate B. subtilis from other Bacillus species because of high phenotypic and genetic similarity. In this study, we employed five previously constructed multilocus sequence typing (MLST) methods for the discrimination of B. subtilis from other Bacillus species and all five MLST assays clearly distinguished B. subtilis. Additionally, the 17 housekeeping genes used in the five MLST assays also clearly distinguished B. subtilis. The pyruvate carboxylase (pyrA) and shikimate dehydrogenase (aroE) genes were selected for the discrimination of B. subtilis because of their high number of polymorphic sites and the fact that they displayed the lowest homology among the 17 housekeeping genes. Specific primer sets for the pyrA and aroE genes were designed and PCR products were specifically amplified from B. subtilis, demonstrating the high specificity of the two housekeeping genes for B. subtilis. This species-specific PCR method provides a quick, simple, powerful, and reliable alternative to conventional methods in the detection and identification of B. subtilis.

• Microbiology and Biotechnology Letters
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• v.50 no.3
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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.

• Journal of the Korean Society of Food Culture
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• v.21 no.2
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• pp.179-186
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• 2006

To investigate the production of yogurt added with desalted bamboo shoots, the component analysis was conducted. Desalted bamboo shoots contained 82.59 % of moisture, 4.56 % of protein, 0.52 % of lipid, 0.50 % of ash and 11.72 % of total dietary fiber. The main mineral elements were Ca, P, S, Na, Mg and K. Yogurt base fermented with 0.005 % ABT-5 starter inoculum at $40\;^{\circ}C$ for 13 hr. For the preparation of bamboo shoots yogurt, various sugaring bamboo shoots were added to the yogurt base. Results of sensory evaluation of the yogurt containing bamboo shoots indicated that color, odor, taste, flesh size, flesh amount, mouth feel, and overall acceptability of the 15 %(w/v) bamboo shoots dicing $(5{\times}5{\times}5\;mm)$ showed higher preference than others. When bamboo shoot yogurt was kept at $4\;^{\circ}C$ for 15 days, pH, titratable acidity, viable counts of lactic acid bacteria and Bifidobacterium bifidum of yogurt were not changed.