• Korean Journal of Microbiology
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• v.51 no.2
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• pp.169-176
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• 2015

The malolactic fermentation (MLF), which is widely used in winemaking, is the conversion of malic acid to lactic acid conducted by the malolactic enzyme (Mle) of lactic acid bacteria. In order to select the strains with MLF among 54 lactic acid bacteria isolated from the traditionally fermented foods, we designed a primer set that specifically targets the conserved regions of the mle gene and then selected four strains that harbor the mle gene of Lactobacillus plantarum. All strains were identified as L. plantarum by analyzing the 16S rRNA sequences, biochemical properties, and the PCR products of the recA gene. From comparison of the mle gene sequences consisting of 1,644 bp, the nucleotide and amino acid sequence of strain JBE60 correspond to 96.7% and 99.5% with those of other three strains, respectively. The strain JBE60 showed the highest resistant against 10% (v/v) ethanol among the strains. The strains lowered the concentration of malic acid to average 43%. Considering the ethanol resistance and conversion of malic acid, the strain JBE60 is considered as a potential starter for the malolactic fermentation.

• Journal of the East Asian Society of Dietary Life
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• v.25 no.1
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• pp.183-192
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• 2015

This study aimed to produce fermented extracts with sugar made from lotus root (LR) and Platycodon grandiflorum (PG), using lactic acid fermentation, and confirmed their physiological and anti-oxidative activities as basic data for manufacturing functional drinks through sensory tests. For the final sugar concentrations, PG showed $48.1^{\circ}brix$ and LR showed $52.0^{\circ}brix$. Sugar concentrations during lactic acid fermentation following dilution of sugar to $12^{\circ}brix$, ranged from $11.5{\sim}12.1^{\circ}brix$ for PG and $11.9{\sim}12.4^{\circ}C$ for LR. During lactic acid fermentation, lactic acid bacteria numbers tended to decrease in both fermented LR and PG extracts with sugar as the fermentation period increased. For DPPH radical scavenging ability, LR was three times higher in control without lactic acid fermentation while PG showed significant increases in L. acidophilus (77%), L. brevis (90%), and L. delbrueckii (177%) during lactic acid fermentation. For total polyphenol content, LR showed a higher concentration than PG, and except for fermented L. delbrueckii extract showing similarity with the control, contents of fermented extracts decreased. In the case of PG, CUPRAC, increased significantly in L. brevis, whereas FRAP, increased significantly in L. delbrueckii with lactic acid fermentation. For reducing power, except for fermentation with L. brevis, all PG showed lower reducing power activities. In the sensory test of fermented LR and PG extracts with sugar, both fermented extracts showed better results with L. brevis or L. delbrueckii than control or those with L. acidophilus in every item. Based on these results, it is highly possible to develop fermented extract drinks with sugar using LR or PG. In particular, lactic acid bacteria such as L. delbrueckii and L. brevis showed generally higher activities with potential as a functional drink.

• Journal of Applied Biological Chemistry
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• v.57 no.1
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• pp.23-28
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• 2014

Mul-kimchi was prepared with addition of 0.025, 0.05, and 0.1% (w/v) chlorella powder and fermented at $10^{\circ}C$ for 6 days. Quality characteristics of the Mul-kimchi were evaluated in terms of acid production (pH and titratable acidity) and lactic acid bacterial counts during fermentation. The addition of chlorella powder stimulated the growth of lactic acid bacteria and significantly enhanced the acid production. After 3 days fermentation, titratable acidity of chlorella Mul-kimchi was 0.12-0.14% and was higher than that (0.11%) of Mul-kimchi made without chlorella. The acid production and the number of viable lactic acid bacterial cell increased with increasing the concentration of added chlorella powder. The sensory score of Mul-kimchi added with 0.05% chlorella powder showed the highest values in taste and overall acceptability among the tested Mul-kimchi preparations. When chlorella Mul-kimchi preparations incubated for 3 days were kept at $4^{\circ}C$ for 19 days, their quality characteristics were well maintained through storage period. According to sensory score and storage ability, the optimum concentration of chlorella powder was around 0.05%.

• Journal of Radiation Industry
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• v.6 no.2
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• pp.177-180
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• 2012

The acid and bile tolerance changes of 5 different lactic acid bacteria (LAB; Lactobacillus paracasei, Lactobacillus casei, Lactobacillus acidophilus, Lactobacillus plantarum, and Lactobacillus debruekii) with gamma irradiation were evaluated. The abilities of LAB to survive in the acidic conditions at the stomach and the bile acidic conditions at the beginning of the small intestine are the key functions for applying LAB to probiotics. In the results, all of LAB survived more than 50% after incubation in PBS (pH 2.5) for 2 hr, which indicated more than half of LAB are possible to pass through the stomach. However, gamma irradiation decreased the acid tolerances of LAB. The bile tolerances of all bacteria except Lactobacillus acidophilus were observed to survive at a 3% oxgall concentration in MRS, and 1 kGy of gamma irradiation to LAB did not affect any bile tolerances changes. But gamma irradiated Lactobacillus casei and Lactobacillus casei (3 kGy) showed decreasing survival rate with oxgall added MAS agar. In conclusion, gamma irradiation should be applied to yogurt or fermented foods with care because LAB could be changes their properties on acid and bile tolerances.

• Korean Journal of Environmental Biology
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• v.17 no.4
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• pp.415-420
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• 1999

A biochemical oxygen demand (BOD) sensor loaded with Candida sp. was designed and constructed for the quick measurement of the concentrations of biologically assimilable organic substances dissolved in water. The sensitivity of the sensor was higher for glucose, acetic acid, aspartic acid and glutamic acid than that for lactose, sucrose and lactic acid. The sensitivities of BOD sensors loaded with $Zn^{2+}$ tolerant and intact strains were almost identical while the sensitivity of sensor loaded with Cd$^{2+}$ tolerant strain was considerably lower. The sensitivities of the sensors loaded with intact or $Zn^{2+}$ tolerant strains did not change with the concentration of $Cd^{2+}$ in the aqueous solution while the sensitivity of the sensor loaded with $Cd^{2+}$ tolerant strain decreased slightly. The sensitivities of the sensors loaded with intact strain, $Zn^{2+}$ or $Cd^{2+}$ tolerant strains were not affected by the concentration of $Zn^{2+}$ in the aqueous solution.n.

• Journal of Microbiology and Biotechnology
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• v.13 no.2
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• pp.207-216
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• 2003

A number of different sources, such as composts, leachates, and pig feces samples, were collected from different pig farms in Korea, and several microorganisms were screened for their ability to deodorize the malodorous gases. Consequently, a novel malodorous gases-deodorizing bacterial strain, KJ-108. was isolated, because it was highly abundant in nitrate-supplemented minimal medium ($MM-NO_3^-$) under anaerobic culture conditions. Airtight crimp-sealed serum bottles containing $MM-NO_3^-$ , medium were inoculated with KJ-108. Nitrate concentration was decreased rapidly after 20 h of incubation, and incubation was carried out until nitrite production reached almost zero. Taxonomic identification, including 16S rDNA base sequencing and phylogenetic analysis, indicated that the isolate had $100\%$ homology in its 165 rDNA base sequence with Lactobacillus pentosus. Among the volatile fatty acids, acetic acid contained in large amounts in fresh piggery slurry was decreased by about $40\%$ after 50 h incubation with strain KJ-108. n-Butyric acid, n-valeric acid, and isovaleric acid were gradually decreased, and isobutyric acid and capronic acid were dramatically eliminated at theinitial period with the treatment. Moreover, NH, removal efficiency reached a maximum of $98.5\%$ after 50 h of incubation, but the concentration of $H_2S$ was not changed.

• Journal of Mushroom
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• v.11 no.4
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• pp.181-186
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• 2013

${\gamma}$-Aminobutyric acid(GABA) is a four carbon non-protein amino acid that has several well-known physiological functions, such as a postsynaptic inhibitory neurotransmitter in the brain and induction of hypotensive and tranquilizer effects. A lactic acid bacterium was isolated from button mushroom bed, which is showing high GABA productivity by TLC or HPLC analysis. The strain was identified as Lactobacillus hilgardii by analysis of 16S rDNA gene sequence. When the maximum production of GABA by L. hilgardii was investigated with various concentration of monosodium glutamate, the yield of GABA reached to be 53.65 mM at 1% mono sodium glutamate (MSG) in flask cultivation. A Glutamate decarboxylase (GAD) enzyme, which was known to convert MSG to GABA, was purified from a cell-free extract of L. hilgardii and the molecular weights of purified GAD was estimated to 60,000 by SDS-PAGE. The optimum pH and temperature of GAD were at pH4.6 and at $37^{\circ}C$, respectively. The GAD activity was increased by the addition of sulfate ions such as ammonium sulfate, sodium sulfate and magnesium sulfate, indicating that the increase of hydrophobic interaction causes the increase of GAD activity.

• Korean Journal of Veterinary Service
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• v.22 no.4
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• pp.411-418
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• 1999

In this studies, the ability of chlorine and lactic acid to reduce bacterial population of the pathogenic microorganisms were examined on artificially inoculated chicken skin. About 10$^{5}$ cells of staphylococcus aureus, salmonella enteritidis, listeria monocytogenes and escherichia coli O157:H7 were inoculated in chicken skin. The contaminated samples were washed for 1 min with sodium hypochlorite solutions that contained 2, 5, 10, 20 and 50mg/$\ell$ available chlorine and counted number of the agents. Viable population were no significantly difference (p$\geq$0.05) between concentration of chlorine and strains of the pathogens. In the samples inoculated with pathogens were washed in 20mg/$\ell$ chlorine and then stored at $^5{\circ}C$ for up to 10 days, the initial counts of psychrotrophs and aerobic plate counts were 4.02 to 4.36 log cfu/$\textrm{cm}^2$ and increased slightly in course of time. But 10 days after, the pathogens were a little reduced from 3.66~4.91 log cfu/$\textrm{cm}^2$ to 2.54~4.66 log cfu/$\textrm{cm}^2$. In the case of washed skin with solution of 20mg/$\ell$ chlorine and 0.5% lactic acid then store at $^5{\circ}C$ for up to 10 days, population of psychrotrophs and aerobic plate counts on chicken skin were markedly reduced immediately after treatment, but the numbers of contaminants were slightly increased after 6 and 8 days. Specifically, numbers of St aureus, S enteritidis, L monocytogenes and E coli O157:H7 were reduced to 0.5, 0.4, 0.3 and 1.15 log cfu/$\textrm{cm}^2$ after 10 days of storage, respectively, on aerobic plate counts.

• The Korean Journal of Physiology
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• v.23 no.1
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• pp.109-117
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• 1989

The changes in adenosine triphosphate (ATP), creatine phosphate (CP) and lactic acid (LA) contents of guinea pig hearts were studied during the cardioplegia and recovery phase. 1) ATP and CP contents in cardiac ventricular tissue were decreased during the cardioplegia, regardless of $Ca^{2+}$ concentration in the cardioplegic solutions, and CP contents were recovered with the reperfusion of normal Tyrode solution faster than those of ATP. And there were no significant differences in the recovery of CP contents with different concentration of $Ca^{2+}$ in the cardioplegic solutions tested, while the recovery of ATP contents was faster with 15 mM $K^{+}$, 0.1 mM $Ca^{2+}$ cardioplegic solutions. 2) LA contents were increased during the cardioplegia and decreased with the reperfusion of normal Tyrode solution. 3) The more recovery time (up to 3 hrs), the more CP contents were recovered with the reperfusion of normal Tyrode solution faster than those of ATP. And LA contents were decreased as the duration of recovery time. These results suggest that $Ca^{2+}$ and $K^{+}$ concentration in the cardioplegic solution is one of the major factors influencing the recovery of cardiac tissue from the cardioplegia.

• Journal of the Korean Society of Food Culture
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• v.12 no.1
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• pp.53-61
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• 1997

This study was carried out in order to investigate general characteristics, sugars and organic acids contents of Korean traditional soy sauce, and to find out possibility of high quality soy sauce production in a short period through high concentration soy sauce making. In this study, we prepared three different types of soy sauce, low concentration soy sauce (Chungjang), high concentration soy sauce and Kyupjang, high quality traditional Korean soy sauce. pH of soy sauce were $4.46{\sim}4.90$ and did not show difference among three samples. Titratable acidity, buffering power and total free acid content were the highest value in Kyupjang. Kyupjang showed the highest contents of salt and pure extract. As the ripening period increased, the salt content increased in Chungjang samples, but decreased in Kyupjang. Reducing sugar contents of Kyupjang, high concentration soy sauce and low concentration soy sauce were 1.13%, 0.76% and 0.53%, respectively. Free sugar in soy sauce were analyzed maltose, glucose, galactose and fructose. Total free sugar content was highest in high concentration soy sauce, however, contents of glucose and fructose were higher in Kyupjang than in Chungjang samples. Galactose was the main free sugar in Chungjang, but glucose was in Kyupjang. Among identified volatile organic acid, acetic acid was present in the highest concentration, and volatile organic acid content was highest in the high concentration soy sauce at 150 days. 20 nonvolatile organic acids were detected in Korean traditional soy sauce. Succinic acid, lactic acid and 2,5-pyridine dicarboxylic acid were the main nonvolatile organic acid in soy sauce.