• Korean journal of food and cookery science
• /
• v.21 no.1 s.85
• /
• pp.33-39
• /
• 2005

The present study was carried out to develop sausage using Leuconostoc citreum which was isolated from Kimchi. Leuconostoc citreum was added to sausage at three concentrations of 1, 3 and $5\%$, and was stored at $10^{\circ}C$ for 40 days. The pH of the sausage containing Leuconostoc citreum was similar to the control group. The TBA value of the group containing Leuconostoc citreum was lower than the control group. However, the TBA value of the control group steadily increased after 10 days of storage, and there were only minor changes in the groups containing Leuconsostoc citreum. In addition, the TBA value of the sausages employed for the present study was either 0.46MA mg/kg or less than that over the entire period of storage. The residual nitrite value was 47.1 ppm at the beginning of the storage in the control group and was 32.5, 32.2 and 30.9 ppm in the groups containing Leuconostoc citreum. The sausages with TBA values higher than 70 ppm are not permitted in Korea. With regards totexture characteristics, it was observed the hardness was lower in the groups containing Leuconostoc ctireum than in the control group while springiness was almost the same in both the groups, but the group containing $1\%$ Leuconostoc citreum showed the best springiness. Both gumminess and brittleness were lower in the groups containing Leuconostoc citreumthan than in the control group. It was inferred that with an increase in the concentration of Leuconostoc citreum there was a decrease in the value of gumminess and brittleness. The results of the sensory evaluation were generally better in the groups containing Leuconostoc citreum than the control group. The sausage containing $3\%$ Leuconostoc citreum obtained the most excellent scores.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.36 no.5
• /
• pp.534-539
• /
• 2007

The present study was carried out to investigate the potential acute toxicity of Leuconostoc citreum GJ7 (Leu. citreum GJ7), a lactic acid bacterium isolated from Kimchi, in ICR male and female mice. The test article was administered to the mice orally or intraperitoneally. Mortality rates, clinical findings, and body weight changes were monitored for the 2 weeks following administration. The results showed that in 50% of the cases, lethal doses ($LD_{50}$) of Leu. citreum GJ7 were determined as >5, 000 mg/kg (p.o.) and >2500 mg/kg (i.p.) in both sexes. There were no significant changes in general conditions, body weights clinical signs and any gross lesions between vehicle control and Leu. citreum GJ7-treated groups. Hence, it is suggested that Leu. citreum GJ7 does not induce any significant acute toxicity in ICR mice.

• Microbiology and Biotechnology Letters
• /
• v.34 no.3
• /
• pp.196-203
• /
• 2006

Three slime-forming lactic acid bacteria were isolated from Kimchi and shown to produce viscous exopolysaccharides (EPS) in sucrose media. The isolated strains, GJ2, C3 and C11, were identified as Leuconostoc kimchii, Leuconostoc citreum and Leuconostoc mesenteroides, respectively, by examining their metabolic characteristics and determining their 16S rDNA sequences. Leu. kimchii GJ2, Leu. citreum C3 and Leu. mesenteroides C11 exhibited high viability (maintained initial viable cell count of $10^8$ CFU/ml) in 0.05 M sodium phosphate buffer (pH 3.0) for 2 h, in artificial gastric juice for 2 h and in 0.3% oxgall for 24 h. When tested, Leu. kimchii GJ2, in particular, displayed antimicrobial activity against pathogenic microorganisms. Leu. kimchii GJ2, Leu. citreum C3 and Leu. mesenteroides C11 produced 21.49 g/l, 16.46 g/l and 22.98 g/l EPS, respectively, in sucrose (5%) medium. The amount of purified EPS extracted from Leu. kimchii GJ2, Leu. citreum C3 and Leu. mesenteroides C11 was 14.61 g/l, 7.73 g/l and 4.77 g/l, respectively. Although the EPS produced by Leu. kimchii GJ2, Leu. citreum C3 and Leu. mesenteroides C11 differed in viscosity, TLC and HPLC analysis revealed that each contained only one type of monosaccharide, glucose. The average molecular mass of EPS produced by Leu. kimchii GJ2 was 306,606 Da.

• Journal of Microbiology and Biotechnology
• /
• v.17 no.12
• /
• pp.2081-2084
• /
• 2007

A 2.5 kb aga gene encoding ${\alpha}$-galactosidase (${\alpha}$-Gal) from Leuconostoc mesenteroides SY1 was cloned into pSJE, an E. coli-Leuconostoc shuttle vector. The recombinant plasmid, pSJEaga, was introduced into Leuconostoc citreum KCTC3526 (ATCC49370) by electroporation. Transcription level of aga was the highest in cells grown on raffinose (1%, w/v) followed by cells grown on galactose, melibiose, fructose, glucose, and sucrose. Western blot using antibodies against ${\alpha}$-Gal showed similar results to slot-blot results and enzyme activity measurements. All the results indicated that the aga was successfully expressed in L. citreum and its transcription was under the carbon catabolite repression (CCR).

• 한국생물공학회:학술대회논문집
• /
• 2005.04a
• /
• pp.68-72
• /
• 2005

Leuconostoc citreum is one of the representative strains of Leuconostoc spp. that show fast growth rates in fermented vegetables. Sequential experimental designs including the Plackett-Burman design, fractional factorial design, steepest ascent analysis, central composite design and response surface methodology were introduced tooptimize and improve the medium for Leuconostoc citreum. Fifteen medium ingredients were examined and glucose (20 g/l), yeast extract (12.5 g/l), sodium acetate trihydrate (6.12 g/l), potassium phosphate (42.55 g/l) and dibasic ammonium citrate (4.12 g/l)were chosen as the best components to give a critical and positive effect for cell-growth. The biomass was increased to 2.79 g/l (169%), compared to the 1.65 g/l in MRS medium.

• Journal of the East Asian Society of Dietary Life
• /
• v.12 no.1
• /
• pp.47-54
• /
• 2002

This study examined the chemical and sensory characteristics of Altari Dongchimi with inoculation of Leuconostoc citreum IH22. Dongchimi was stored at room temperature for the first day and at 4$^{\circ}C$ from 2nd to 28th day. The pH was somewhat lower in Altari Dongchimi when first inoculated with Leuconostoc citreum IH22 than non -treated Dongchimi. As fermentation proceeded, titratable acidity of Altari Dongchimi significantly increased. The patterns of microflcral changes in both the inoculated and the control were similar during fermentation: the total number of bacteria increased at the beginning, but rapidly decreased right after the optimum ripening point. The hardness and fracturability of both Dongchimi's decreased gradually during fermentation. The evaluation of the sensory qualities showed that the sour taste and fresh taste resulted in similar scores in both Dongchimi's but overall acceptability of the control was higher than that of inoculated one with Leuconostoc citreum IH22.

• Biotechnology and Bioprocess Engineering:BBE
• /
• v.9 no.4
• /
• pp.278-284
• /
• 2004

Leuconostoc citreum is one of the representative strains of Leuconostoc spp. that show fast growth rates in fermented vegetables. Sequential experimental designs including the Plackett-Burman design, fractional factorial design, steepest ascent analysis, central composite design and response surface methodology were introduced to optimize and improve the medium for L. citreum. Fifteen medium ingredients were examined and glucose ($20 g/\ell$), yeast extract ($12.5g/\ell$), sodium acetate trihydrate ($6.12g/\ell$), potassium phosphate ($42.55g/\ell$), and dibasic ammonium citrate ($4.12g/\ell$), were chosen as the best components to give a critical and positive effect for cell-growth. The biomass was increased to ($2.79g/\ell$), (169%), compared to the $1.65g/\ell$ in MRS medium.

• Journal of Microbiology and Biotechnology
• /
• v.27 no.10
• /
• pp.1778-1782
• /
• 2017

To identify and discriminate the bacterial species at the subspecific level, rep-PCR is a reliable genomic fingerprinting tool. Fourteen strains of bacteria were isolated from different food sources, identified as Leuconostoc citreum using 16S rRNA gene sequencing, and amplified using rep-primers (REP, ERIC, and $(GTG)_5$). Fingerprinting patterns generated bands in the range of 300-6,000 bp with REP, 150-6,000 bp with ERIC, and 200-1,700 bp with $(GTG)_5$ primers. In UPGMA dendrogram analysis, 14 strains were clustered into three clades (I, II, and III) with all the primers, thus differentiating them at the molecular level. The present study revealed the differentiation of L. citreum strains using rep-PCR.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.42 no.4
• /
• pp.600-607
• /
• 2013

This study was performed to investigate the repeated-dose toxicity of Leuconostoc citreum GR1 (Leuc. citreum GR1), a lactic acid bacterium isolated from kimchi, in male and female rats. Sprague-Dawley male and female rats were divided into four group (ten animals in each group) and Leuc. citreum GR1 was administered daily by gavage to rats at dosage levels of 0, 500, 1,000, or 2,000 mg/kg/day for four weeks. There were no bacterial-related deaths or abnormal clinical signs in either gender of rats during the observation period. Furthermore, no differences were found between the control and treatment groups in terms of body weight, food intake, and water consumption. Hematological parameters, serum biochemical analysis, and histopathological examination also showed insignificant dose-dependent alterations. There were also no alterations in organ weights upon administration of Leuc. citreum GR1 alone. These results suggest the oral application of Leuc. citreum GR1, up to a dosage level of 2,000 mg/kg, causes no adverse effects in both male and female rats.

• Food Science and Preservation
• /
• v.20 no.1
• /
• pp.121-126
• /
• 2013

The present study was carried out to investigate the in vivo single-dose acute toxicity of Leuconostoc citreum GR1 (Leuc. citreum GR1), a lactic acid bacteria isolated from kimchi, in ICR male and female mice. The test article was orally administered once to both sexes of mice. The mortalities, clinical findings, autopsy findings, and body weight changes were monitored daily for two weeks. The male and female mice were gavaged with Leuc. kimchi GR1 of four doses (625, 1,250. 2,500 and 5,000 mg/kg). The oral $LD_{50}$ of Leuc. citreum GR1 was considered higher than 5,000 mg/kg. No significant changes in the general conditions, body weights, clinical signs and presence of gross lesions were observed in both sexes of mice to whom Leuc. citreum GR1 was administered orally. The results indicated that the 5,000 mg/kg dose of Leuc. citreum GR1 showed no adverse effect.