• Food Science and Preservation
• /
• v.13 no.3
• /
• pp.329-336
• /
• 2006

The characteristics of mash qualities of takju prepared by addition of chestnut peel powder(5%, 10%, 20% and 30% per steamed rice) were investigated during fermentation. That is, in all fermentation periods, changes of pit total acid, organic acids, solids, amino nitrogen, total sugar and reducing sugar, microorganisms, alcohol and color were determined and analyzed. There was significant differences in characteristics of mash qualities by addition of chestnut peel powder. In general, contents of total acid, organic acids, amino nitrogen, total sugar, reducing sugar and ethanol of takju added with chestnut peel powder were lower than those of steamed rice only, whereas solid contents was higher. But ethanol content of takju added with 5% of chestnut peel powder after 8 days of fermentation was 9.6% which was similar to that of takju prepared by addition of steamed lice only. Also, microbial populations such as total viable cells, yeast and lactic acid bacteria of the treatments were increased to about $10^8CFU/mL$ after 2 days of fermentation and then decreased gradually. In the beginning stage of fermentation color differences value of the treatments were $1.99{\sim}10.27$, and the differentials reduced gradually during fermentation.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.46 no.1
• /
• pp.100-107
• /
• 2017

This study was conducted to evaluate the quality characteristics of got mul-kimchi during storage by type of kimchi container using a plastic ark shell. The pH level, acidity, hardness, color, sensory evaluation, and microbiological activity were performed. Kimchi containers were prepared with 0%, 2%, and 3% plastic ark shell. The pH level of 2% container samples showed no significant difference compared with that of the control, whereas pH levels of 3% container samples were significantly (P<0.05) higher than those of the control and 2% sample. Acidity was not different among treatments up to 4 weeks, whereas acidity of 3% container samples was significantly (P<0.05) lower than those of the control and 2% samples after 8 weeks. Hardness significantly decreased (P<0.05) upon 0, 2, and 3% treatments with increasing storage time, but there was no significant difference among the treatments. Hunter color L values increased in the order of 0, 3, and 2% with increasing storage time. In sensory evaluation of crunchiness, 3% container samples had significantly (P<0.05) higher crunchiness than the control. Total viable cells in the 3% container with got mul-kimchi were significantly (P<0.05) lower than those of other samples at 12 and 16 weeks of fermentation. Numbers of lactic acid bacteria in the 2% and 3% container samples were significantly (P<0.05) lower than those of the control samples after 16 weeks of fermentation. These results show that the plastic ark shell kimchi container extended storage compared with the control.

• Radiation Oncology Journal
• /
• v.15 no.3
• /
• pp.175-186
• /
• 1997

Purpose : To evaluate the qualitative immunologic changes by ionizing radiation. we studied the altered capacities of the macrophages and lymphocytes to produce cytokines in conjunction with resistance to Listeria monocytegenes (LM) infection in mice Materials and Methods : BALB/c mice and Listeria monocytogenes were used. The mice were infected intraperitoneally with $10^5LM$ at 1 day after irradiation (300cGy) and sacrificed at 1, 3, 5 days after infection, and then the numbers of viable LM per spleen in the irradiated and control group were counted. Tumor necrosis factor-alpha ($TNF-\alpha$), interferon-gamma ($IFN-\gamma$). interleukin-2 (IL-2), and nitric oxide (NO) were assessed after irradiation. Results : Under gamma-ray irradiation with a dose range of 100-850cGy, the number of total splenocytes decreased markedly in a dose-dependent manner, while peritoneal macrophages did so slightly Cultured peritoneal macrophages produced more $TNF-\alpha$ in the presence of lipopolysaccharide (LPS) during the 24 hours after in vitro irradiation, but their capacity of $TNF-\alpha$ Production showed a decreased tendency at 5 days after in vivo total body irradiation. With 100cGy and 300cGy irradiation, cultured peritoneal macrophages produced more NO in the presence of LPS during the 24 hours after in vitro irradiation than without irradiation. Activated splenocytes from irradiated mice (300cGy) exhibited a decreased capacity to Produce IL-2 and $IFN-\gamma$ with Concavalin-A stimulation at 3 days after irradiation. When BALB/c mice were irradiated to the total body with a dose of 300cGy, they showed enhanced resistance during early innate phase, but a significant inhibition of resistance to LM was found in the late innate and acquired T-cell dependent phases. Conclusion : These results su99es1 that increased early innate and decreased late innate and acquired immunity to LM infection by ionizing radiation (300cGy) may be related to the biphasic altered capacity of the macrophages to produce $TNF-\alpha$ and the decreased capacities of the lymphocytes to produce IL-2 and $IFN-\gamma$ in addition to a marked decrease in the total number of cells.

• Korean Journal of Environmental Biology
• /
• v.18 no.4
• /
• pp.403-409
• /
• 2000

Surface and bottom water samples were collected from 10 stations located in the coastal area of Tongyong in April, August and October 2000. Distribution of heterotrophic bacteria, coliform bacteria and fungi in the sea water samples was investigated by measuring the corresponding viable cell number according to the plate counting method. Heterotrophic bacteria in the surface water counted 3.1$\times$10$^2$- 4.0$\times$10$^3$cfu ml$\^$-1/, 2.7$\times$10$^3$- 1.2$\times$10$\^$5/cfu ml$\^$-1/ and 1.3$\times$10$^2$- 7.2$\times$10$^2$cfu ml$\^$-1/ in April, August and October, respectively. The cell number of coliform bacteria in the surface water amounted to 0-1.5$\times$10$^1$cfu ml$\^$-1/, 3.5$\times$10$^1$- 5.2$\times$10$^3$cfu ml$\^$-1/ and 0-1.8$\times$10$^2$cfu ml$\^$-1/ in April, August and October, respectively. As for fungi, the cell number in the surface water was 0-3.0$\times$10$^1$propagules ml$\^$-1/, 3.0$\times$10$^1$- 8.0$\times$10$^1$ propagules ml$\^$-1/ and 0-2.2$\times$10$^1$ propagules ml$\^$-1/ in April, August and October respectively. The surface water samples from the station 3 in August were added with feed stuffs for fish as much as 0.01 gl$\^$-1/, 0.1 gl$\^$-1/ and 1 gl$\^$-1/ and cultured at 5$\^{C}$, 15$\^{C}$, 25$\^{C}$ and 35$\^{C}$. Microbial cells were not isolated at all when the culturing temperature was 5$\^{C}$. However, the microbial cell number increased significantly in all the surface water samples containing 1 gl$\^$-1/ of the feed stuffs when cultured at 15$\^{C}$, 25$\^{C}$ and 35$\^{C}$

• Korean journal of food and cookery science
• /
• v.18 no.1
• /
• pp.43-50
• /
• 2002

This study was carried out to evaluate the quality attributes of frozen soy yogurts prepared by freezine soy yogurts, which are made of different types of Bifidobacteria (B. bifidum, B.breve, B. infantis) and oligosaccharides (fructooligosaccharides, galactooligosaccharides, isomaltooligosaccharides) containing $\alpha$-chymotrypsin treated soy protein isolate were evaluated in terms of overrun, melt-down quality, changes in the total number of Bifidobacteria after freezing, and sensory evaluation. The quality attributes of soy yogurts were also evaluated in terms of changes in the number of viable cells of Bifidobacteria in soy yogurts after incubation at 37$\^{C}$, pH 3.0 for 90 min, water holding capacity, and viscosity. The overrun of frozen soy yogurts fermented by B. bifidum showed the hiehest value but those fermented by B. infantis showed the lowest, while the melt-down quality of soy yogurts were vice versa. The total numbers of Bifidobacteria after freezing for 30 min in ice cream maker showed more than 10$\^$9/ CFU/ml. In sensory evaluation, all $\alpha$-chymotrypsin treated frozen soy yogsurt showed little beany flavor. In sour, sweet, and bitter tastes and mouth feel, the frozen soy yogurts fermented by B. bifidum evaluated better but those fermented by B. infantis evaluated worse. Also in the overall quality, the frozen soy yogurts fermented by B. bifidum were evaluated desirable but those fermented by B. infantis were evaluated undesirable. The water holding capacity and viscosity of soy yogurts fermented by B. bifidum showed the highest values but those fermented by B. infantis showed the lowest values. The total numbers of Bifidobacteria of all soy yogurts decreased from 10$\^$9/ CFU/ml to 10$\^$8/ CFU/ml after incubation at 37$\^{C}$, pH 3.0 for 90 min.

• Journal of Life Science
• /
• v.27 no.2
• /
• pp.202-210
• /
• 2017

As an effort to find a potential biopreservative, we isolated bacterial strains producing bacteriocin from fermented foods. A strain was finally selected and characteristics of the bacteriocin were investigated. The selected strain was identified as Bacillus subtilis E9-1 based on the 16S rRNA gene analysis. The culture supernatant of B. subtilis E9-1 showed antimicrobial activity against Gram-positive bacteria. Subtilisin A, ${\alpha}$-chymotrypsin, trypsin and proteinase K inactivated the antimicrobial activity, which means its proteinaceous nature, a bacteriocin. The bacteriocin activity was fully retained at the pH range from 2.0 to 8.0 and stable at up to $100^{\circ}C$ for 60 min. Solvents such as ethanol, isopropanol and methanol had no effect on the antimicrobial activity at the concentration of 100% but acetone and acetonitrile reduced the activity at up to 100% concentration. Cell growth of four indicator strains was dramatically decreased in dose-dependent manner. Listeria monocytogenes was the most sensitive, but Enterococcus faecium was the most resistant. Bacillus cereus and Staphylococcus aureus showed the medium sensitivity. The bacteriocin showed its antimicrobial activity against B. cereus and L. monocytogenes via bactericidal action. The number of viable cells of L. monocytogenes started to reduce after addition of bacteriocin to the minced beef. The bacteriocin was purified through acetone concentration, gel filtration chromatography and RP-HPLC. The whole purification step led to a 6.82 fold increase in the specific activity and 6% yield of bacteriocin activity. The molecular weight of the purified bacteriocin was determined to be 3.3 kDa by MALDI-TOF/TOF mass spectrometry.

• Korean Chemical Engineering Research
• /
• v.43 no.1
• /
• pp.103-109
• /
• 2005

Isolation and primary culture technique of rabbit oral keratinocytes, and the study for effect of environmental factors on the cell growth were carried out in T75-flask. $1.92{\pm}0.59{\times}10^6$ viable cells were isolated by trypsin enzymatic digestion method from $0.25cm^2$ biopsy of rabbit oral mucosa. Primary culture with 10 mL of K-SFM containing 50 mg/L BPE, $5.0{\mu}g/L$ EGF and 0.15 mM $Ca^{2+}$ showed confluence after 8 days and doubling time was 2.54 days. Effect of medium types, medium volume and supplement types on the cell growth was investigated after the cultured keratinocytes had been harvested from primary confluence. Serum addition showed adverse effect and the increase of serum concentration didn't have an effect on the cell growth. The increase of medium volume decreased the cell growth. The increase of calcium concentration increased the cell growth and 2.0 mM was optimum value. In conclusion, when rabbit oral keratinocytes was cultured in T75-flask, the most effective conditions was to use 10 mL of K-SFM containing 50 mg/L BPE, $5.0{\mu}g/L$ EGF and 2.0 mM $Ca^{2+}$, and doubling time was 1.32 days. This study can provide the useful informations to develop a process and design a bioreactor for the culture of keratinocytes in human body like skin and cornea, as well as mucosa.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.32 no.2
• /
• pp.344-356
• /
• 2005

There are normal inhabitants doing medically useful functions in the body. There are many kinds of bacteria performing specific functions in the oral cavity. Two strains of lactic acid bacteria were isolated from inhabitants of caries-free children's oral cavity, which inhibited the formation of artificial plaque by Streptococcus mutans and the production of volatile sulfur compounds by anaerobic bacteria. The isolates were identified by the test using API 50 CHL medium kit and 16S rDNA partial sequencing. 1. Two isolates were Gram-positive bacilli and produced hydrogen peroxide. 2. When Streptococcus mutans was cultured in the media, the mean weight of formed artificial plaque on the orthodontic wires was $124.4{\pm}30.4\;mg$, whereas being reduced to $5.2{\pm}2.0mg$ and $10.6{\pm}6.6mg$ in the media cultured with Streptococcus mutans and each isolate, respectively (p<0.05) 3. The number of viable cells of Streptococcus mutans was $3.4{\times}10^9$ per ml in the cultured solution, whereas those of Streptococcus mutans in the combined culture with each of isolates were $4.6{\times}10^8\;and\;2.4{\times}10^8$ per ml. 4. The optical density was 1.286 in the supernatant of Fusobacterium nucleatum after vortexing for 30minutes, whereas in the supernatant of combined Fusobacterium nucleatum and each isolate, they were reduced to 0.628 and 0.497, which the percentages of coaggregation between them were 29.4% and 57.8%, respectively 5. The optical density of Fusobacterium nucleatum precipitate was 1.794 in the culture media containing cysteine and $FeSO_4$, being reduced to 1.144 and 0.915 in the coaggregated precipitates of Fusobacterium nucleatum and each isolate. The optical density of Porphyromonas gingivalis precipitate was 1.932 in the culture media, being reduced to 1.170 and 1.266 in the coaggregated precipitates of Porphyromonas gingivalis and each isolate. 6. When two isolates were tested with API 50 CHL medium kit, those were identified Lactobaciallius salivarius and Lactobaciallius delbrueckii subsp. lactis. 7. The similarity values of 16S rDNA sequence between each of isolates and Lactobaciallius salivarius subsp. salicinius were 99.60% and 99.73%, respectively, meaning that isolates were Lactobaciallius salivarius subsp. salicinius. These results indicated that two strains isolated from caries-free children's saliva, which inhibited the formation of artificial plaque and the production of volatile sulfur compounds, were identified as Lactobaciallius salivarius subsp. salicinius.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.31 no.2
• /
• pp.202-211
• /
• 2004

Xylitol is a 5-carbons carbohydrate, which can be replaced with sucrose for preventing dental caries. To study the effect of xylitol on the fermentation of lactose in bacteria, the important oral bacteria such as Streptococcus(S.) mutans, S. oralis and S. salivarius were studied. The optical density using spectophotometer and the cell concentration were assessed to evaluate the combined effect of lactose and xylitol against the bacteria. Thin layer chromatography and lactose-PTS activity test were performed to evaluate the effect of xylitol on the fermentation of lactose in S. mutans and by ${\beta}-galactosidase$ with the following results. 1. The optical density of Streptococcus mutans culture was not increased for 8 hours-incubation in the media added with lactose and xylitol, but was increased at 24 hours-incubation. The number of viable cells at 8 hours-incubation was smaller in the media containing lactose and xylitol in comparison with lactose only. 2. The optical densities of Streptococcus oralis culture and Streptococcus salivarius culture were not increased for 8 hours-incubation in the media added with lactose and xylitol but were increased at 24 hours-incubation. 3. When Streptococcus mutars was incubated for 8 hours in the media added with lactose and xylitol, the amount of remained lactose was larger compared with the media added with lactose only But all lactose was fermented in both media after 24 hours-incubation. 4. When Streptococcus mutans was incubated in the media added with lactose and xylitol, the activity of lactose-PTS was higher compared with the media added with lactose only. 5. When ${\beta}-galactosidase$ was incubated in the media added with lactose and xylitol, the amount of remained lactose was larger compared with the media added with lactose only. These results indicated that xylitol inhibited the fermentation of lactose by Streptococcus.

• Food Science and Preservation
• /
• v.19 no.5
• /
• pp.633-638
• /
• 2012

The aim of this study was to investigate the growth of aerobic bacteria in fresh-cut salad during short-term temperature abuse ($4{\sim}30^{\circ}C$temperature for 1, 2, and 3 h) for 72 h and to develop predictive models for the growth of total viable cells (TVC) based on Predictive food microbiology (PFM). The tool that was used, Pathogen Modeling program (PMP 7.0), predicts the growth of Aeromonas hydrophila (broth Culture, aerobic) at pH 5.6, NaCl 2.5%, and sodium nitrite 150 ppm for 72 h. Linear models through linear regression analysis; DMFit program were created based on the results obtained at 5, 10, 20, and $30^{\circ}C$ for 72 h ($r^2$ >0.9). Secondary models for the growth rate and lag time, as a function of storage temperature, were developed using the polynomial model. The initial contamination level of fresh-cut salad was 5.6 log CFU/mL of TVC during 72 h storage, and the growth rate of TVC was shown to be 0.020~1.083 CFU/mL/h ($r^2$ >0.9). Also, the growth tendency of TVC was similar to that of PMP (grow rate: 0.017~0.235 CFU/mL/h; $r^2=0.994{\sim}1.000$). The predicted shelf life with PMP was 24.1~626.5 h, and the estimated shelf life of the fresh-cut salads with short-term temperature abuse was 15.6~31.1 h. The predicted shelf life was more than two times the observed one. This result indicates a 'fail safe' model. It can be taken to a ludicrous extreme by adopting a model that always predicts that a pathogenic microorganism will grow even under conditions so strict as to be actually impossible.