• The Journal of Korean Academy of Prosthodontics
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• v.44 no.1
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• pp.124-134
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• 2006

Statement of problem: Streptococcus produces energy and forms extracellular polysaccharides by metabolizing sucrose. Insoluble glucan, a kind of extracellular polysaccharide, is the important material of dental plaque. Fructose affects the metabolism of sucrose. Purpose: The purpose of this study was to evaluate the effect of fructose on the metabolism of sucrose in Streptococcus mutans. Materials and methods: To determine the effect of fructose on the formation of artificial plaque by Streptococcus mutans Ingbritt, S. mutans and fructose were placed in beakers containing M17 broth and sucrose. The wires were hung on frameworks inserted into cork stoppers, and then immersed in each of the beakers. After the incubation with gentle shaking, each wire was weighed. To analyze the effect of fructose on the sucrose metabolism by S. mutans or glucosyltransferase, S. mutans and fructose were placed in M17 broth containing sucrose. After the incubation. the remaining sucrose and polymers were analysed by thin layer chromatography. Results: The following results were obtained; 1. When Streptococcus mutans was cultured in the media containing 3% sucrose for 8 hours, the mean weight of formed artificial plaque on the wires was $124.3{\pm}3.0mg$, whereas being reduced to $20.7{\pm}10.2mg$ in the media added with 3% sucrose and 4% fructose(p<0.05) 2. When the control containing glucose was added with sucrose, the optical density of Streptococcus mutans solution cultured for 24 hours was not increased compared with the control, while being increased by adding with fructose. 3. When Streptococcus mutans was incubated in the media added with sucrose and fructose for 8 hours, the number of viable cells was increased compared with the media added with sucrose. 4. The amount of remained sucrose was increased in Streptococcus mutans culture supernatant of media added with sucrose and fructose than with sucrose only. but the amount of produced insoluble glucan was decreased. 5. The amounts of remained sucrose and produced soluble glucan were increased in the culture of glucosyltransferase-contained media added with sucrose and fructose than with sucrose only, but the amount of produced insoluble glucan was decreased . Conclusion: These results indicated that the sucrose metabolism and the production of insoluble glucan were inhibited in Streptococcus mutans by adding fructose in the media containing sucrose.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.3
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• pp.411-416
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• 2002

Yogurt base was prepared from whole milk and skim milk added with 0.2∼1.0% (w/v) of Saururus chinensis(Lour.) Bail water extract (SCe) and fermented with lactic acid bacterias (the mixed strain of Streptococcas themophilus and Lactobacillus bulgaricus) at 37$\^{C}$ for 24 hr. Quality characteristics of the yogurt were evaluated in terms of acid production, number of viable cells, viscosity and sensory property during lactic acid fermentation. The composition of organic acids was also measured by HPLC. Addition of SCe stimulated the growth of lactic acid bacteria and remarkably enhanced the acid production. The viscosity and lactic acid content of yogurt were also increased by addition of SCe. The sensory score of yogurt added with 0.4% of SCe was significantly higher than other groups in taste and overall acceptability The storage abilities of yogurts added with SCe were relatively good at 5$\^{C}$ for 15 days.

• Journal of Korean society of Dental Hygiene
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• v.5 no.2
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• pp.131-145
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• 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 add bacteria were isolated from normal inhabitants of children's oral cavity, which inhibited the production of volatile sulfur compounds by anaerobic bacteria. The authors identified the isolates by 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 $5.2{\pm}2.0$ mg and $10.6{\pm}6.6$ mg 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 Fusoacterium nucleatum after vortexing for 30 minutes, whereas in the supernatant of combined Fusoacterium nucleatum and each isolate, they were reduced to 0.628 and 00497, which the percentages of coaggregation between them were 2904% and 57.8%, respectively. 5. The optical density of Fusoacterium 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 Fusoacterium nucleatum and each isolate. 6. The similarity values of 16S rDNA sequence between each of isolates and Lactobacillus salivarius subsp. salicinius were 99.60% and 99.73%, respectively, meaning that isolates were Lactobacillus salivarius subsp. salicinius. These results indicated that two strains isolated from children's saliva, which inhibited the formation of plaque and the production of volatile sulfur compounds, were identified as Lactobacillus salivarius subsp. salicinius.

• Journal of Animal Science and Technology
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• v.49 no.4
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• pp.515-522
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• 2007

To develop the manufacturing method of ice cream with microbiologically safe and proper sensory quality using irradiation for sensitive consumer, 3 different flavors, which were resistant to their flavors against irradiation, were selected and used for ice cream manufacturing to reduce the irradiation-induced off-flavor problem. The general composition was not different among treatments. Total aerobic bacteria were detected as 2.38, 1.23, 1.38, and 1.15 log CFU/g level in ice cream with control(no flavor added), spearmint, mint, and citrus flavor, respectively. No viable cells were observed by irradiation at 1 kGy except for the control. Sensory evaluation indicated that the irradiated ice cream with spearmint flavor at 1 kGy and citrus flavor at 3 kGy had higher overall acceptability. Therefore, a low dose irradiation (less than 3 kGy) with mint or citrus flavors may enhance the safety of ice cream with proper sensory quality for sensitive consumer.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.4
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• pp.477-484
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• 2008

For the effective use of the conger eel by-products, such as head and frame, Tang, which is the Korean-type soup, from conger eel by-products (TCEB) was developed and its food component characterization was compared with that of commercial Chueotang, loach Tang. According to the results of viable cells and coliform group of TCEB heated at $115^{\circ}C$ for various times, the reasonable $F_0$ value was 8 min. The proximate composition of TCEB was 90.7% for the moisture, 4.8% for the protein, 2.6% for the lipid, and 1.5% for the ash. The extractive-nitrogen content of TCEB was 243.1 mg/100 g, which was higher than that of commercial Chueotang, 208.0 mg/100 g. The total amino acid content of TCEB was 4,310 mg/100 g and its major amino acids were glutamic acid (637.3 mg/100 g, 14.8%), glycine (409.1 mg/100 g, 9.5%) and alanine (404.4 mg/100 g, 9.3%). TCEB was not felt in the sensual fish odor and its sensual taste was good. The health functional properties for health of TCEB were 1.29 as a PF (protection factor) for antioxidative activity and 39.4% for angiotensin Ⅰ converting enzyme (ACE) inhibiting activity.

• Korean Journal of Food Science and Technology
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• v.48 no.5
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• pp.445-453
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• 2016

Eighty-four strains of lactic acid bacteria were isolated from Korean fermented foods for the production of fermented apple juice. Among these strains, the JBE245 strain that showed rapid growth and food functionality was selected and identified as Lactobacillus plantarum. This strain reached the stationary phase after 24 h fermentation at $30^{\circ}C$ with $1.5{\times}10^8$ colony forming unit (CFU)/mL of viable cells, and maintained its viability levels even after 14 days of storage. During fermentation, the ${\alpha}-glucosidase$ inhibitory activity (40.4%), total polyphenol content (583.6 mg gallic acid equivalent (GAE)/mL), and 2,2-diphenyl-l-picryl-hydrazyl hydrate (DPPH) radical scavenging activity (52%) were increased. As judged by a sensory test, the overall preference for the fermented juice (4.22) was comparable to that for the unfermented juice (4.72), indicating that fermentation does not significantly affect the sensory characteristics of apple juice. Consequently, the fermented beverage containing L. plantarum JBE245 and apple juice is a promising functional health food.

• Korean journal of food and cookery science
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• v.21 no.2 s.86
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• pp.149-154
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• 2005

The objective of this research was to estimate the shelf-life of 4 kinds of Korean soup (Yukkaejang, Sagol-woogeojitang, Kalbitang, and Seolleongtang), under an accelerated experiment, based on the changes in the selected physico-chemical, microbiological and sensory characteristics. The 4 kinds of Korean soup (Yukkaejang, Sagol-woogeojitang, Kalbitang and Seolleongtang) were 1.sated at $121^{\circ}C$ for 30 min. and the shelf life was evaluatedthrough accelerated experiment, based on tile changes in the physico-chemical, microbiological and sensory characteristics. No viable cells were detected in any of the treatments and no significant differences were shown in pH, TBA and Hunter's color values for 3 weeks at $37^{\circ}C$. The periods found to be acceptable by sensory evaluation were 1 days for Yukkaejang and Kalbitang, 14 days for Sagol-woogeojitang, and 21 days for Seolleongtang. For an assumed $Q_10$ value of 2.5, shelf-life was predicted as 109 days for Yukkaejang and Kalbitang, 219 days for Sagol-woogeojitang, an d 328 days for Seolleongtang at $5^{\circ}C$, suggesting that these 4 kinds of Korean soup are suitable for commercial distribution.

• Korean journal of food and cookery science
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• v.20 no.1
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• pp.42-48
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• 2004

The effect of xylitol on the Dongchimi fermentation was investigated by measuring the sensory, physicochemical and microbiological properties during fermentation of up to 30 days. Dongchimi with 0, 1, 2, 3 and 4％ w/v xylitol was fermented at 10$^{\circ}C$. The addition of 1％ xylitol gave the highest scores in terms of the overall acceptability, texture, ripeness, sweet taste and smell. During the fermentation, the total acidity increased, while the pH gradually decreased. The reducing sugars showed the highest content with the addition of 1％ xylitol. The vitamin C was increased in the early stage of fermentation, but reduced gradually after 5 days. The vitamin C content of the Dongchimi with 2％ xylitol addition was shown to be the highest. The total viable cells and lactic acid bacteria increased between 2 and 5 days of fermentation, but were gradually reduced thereafter. The numbers of lactic acid bacteria with 1％ xylitol addition were more numerous than with the other percentage additions. The current study showed that the application of 1％ xylitol to the fermentation of Dongchimi enhanced the sensory values of the fermented product.

• Korean journal of food and cookery science
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• v.19 no.5
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• pp.609-615
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• 2003

In the Kimchi manufacturing industry, the process of brining baechu produces a vast amount of high salinity waste water. To study if this brine can be recycled, the quality characteristics of Kimchi salted by waste brine(F), which was used five times successively, was compared with those salted using water after recycling filtration through sand (F1) and activated carbon (F2) columns. No significant difference in the salinity and soluble solid contents, during fermentation at 10 was observed among the samples, but the salinity and soluble solid contents of the F-sample were slightly higher than in the control. The F1 and control Kimchi showed similar pHs and titratable acidities, while the F-Kimchi had a lower pH and a higher acidity during fermentation. The numbers of total viable cells were highest in the F, and lowest in the F2-Kimchi, while the counts of lactic acid bacteria were lowest in the F-Kimchi. The sensory tests for appearance, odor, taste and overall acceptance showed that the F-Kimchi was the least desirable, the F2-Kimchi had lower sour odor and taste, and a higher toughness, than the others. The F1- and control Kimchi had similar sensory grades for appearance, odor, and tastes, and there were no significant difference in the overall acceptance, showing the possibility of recycling wastewaters as brine for the production of baechu Kimchi.

• Food Science of Animal Resources
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• v.30 no.3
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• pp.479-486
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• 2010

Tolerance against heat, sanitizers, and antibiotics of 112 Cronobacter isolates classified by desiccation was determined to permit effective biocontrol in powdered foods. The isolates were classified into three groups: dry-tolerant (n=37), dry-sensitive (n=7), and dry-intermediate (n=68). The strains that were highly tolerant to drying also showed high heat tolerance that they seemed to have high tolerance to heat after dry stress in powdered foods like infant formula. Sodium hypochlorite and benzalkonium chloride concentrations necessary to achieve a 5-log reduction in viable counts (CFU/mL) were 15-25 ppm and 5-15 ppm, respectively. However, there was little difference of the efficacy of these sanitizers between dry-sensitive and -tolerant strains for planktonic cells suspended in 3% albumin. The minimal inhibition concentration (MIC) of $\beta$-lactam ampicillin was 64-128 ppm for 90% of the strains. The isolates were consistently sensitive to kanamycin and naldixic acid (MIC=4 ppm). Dry-tolerant strains displayed more antibiotic resistance than dry-sensitive strains. The results indicate that dry-tolerant Cronobacter isolates often possess heat and antibiotic resistance, indicated the need for potent sterilization treatments of powdered foods.