• Food Science of Animal Resources
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• v.36 no.3
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• pp.427-434
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• 2016

Benzoic acid is occasionally used as a raw material supplement in food products and is sometimes generated during the fermentation process. In this study, the production of naturally occurring yogurt preservatives was investigated for various starter cultures and incubation temperatures, and considered food regulations. Streptococcus thermophilus, Lactobacillus acidophilus, Lactobacillus delbrueckii subsp. bulgaricus, Lactobacillus rhamnosus, Lactobacillus casei, Lactobacillus paracasei, Lactobacillus reuteri, Lactobacillus plantarum, Bifidobacterium longum, Bifidobacterium lactis, Bifidobacterium bifidum, Bifidobacterium infantis, and Bifidobacterium breve were used as yogurt starter cultures in commercial starters. Among these strains, L. rhamnosus and L. paracasei showed the highest production of benzoic acid. Therefore, the use of L. rhamnosus, L. paracasei, S. thermophilus, and different incubation temperatures were examined to optimize benzoic acid production. Response surface methodology (RSM) based on a central composite design was performed for various incubation temperatures (35-44℃) and starter culture inoculum ratios (0-0.04%) in a commercial range of dairy fermentation processes. The optimum conditions were 0.04% L. rhamnosus, 0.01% L. paracasei, 0.02% S. thermophilus, and 38.12℃, and the predicted and estimated concentrations of benzoic acid were 13.31 and 13.94 mg/kg, respectively. These conditions maximized naturally occurring benzoic acid production during the yogurt fermentation process, and the observed production levels satisfied regulatory guidelines for benzoic acid in dairy products.

• Korean Journal of Food Science and Technology
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• v.11 no.3
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• pp.200-205
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• 1979

Effects of monosodium phosphate, disodium phosphate, trisodium phosphate, ${\alpha}-polygel$, sodium ultrametaphosphate and sodium tripolyphosphate on the growth of bacteria, pH and acidity in single culture of Lactobacillus bulgaricus and mixed-culture of Lactobacillus bulgaricus and Streptococcus thermophilus were investigated. Phosphates exerted definite effect in enhancing the growth of the bacteria and acidity of the fermented milk. For the single-culture of Lactobacillus bulgaricus monosodium phosphate and sodium tripolyphosphate were most effective in terms of bacterial growth and acidity, whereas for the mixed-culture of Lactobacillus bulgaricus and Streptococcus thermophilus monosodium phosphate and disodium phosphate showed the best results. In the presence of the phosphates, particularly of trisodium phosphate, the decrease of viable count of bacteria in fermented milk during storage was reduced significantly. The stability of the fermented milk prepared with the mixed-culture of Lactobacillus bulgaricus and Streptococcus thermophilus was improved by the addition of phosphates, particularly of monosodium phosphate.

• Food Science of Animal Resources
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• v.26 no.4
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• pp.532-539
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• 2006

This study was conducted to evaluate the inhibitory effects of exopolysaccharide(EPS) produced by Streptococcus thermophilus BODY1 on rotavirus(RV). EPS was isolated from a commercial lactic acid bacteria, Str. thermophilus BODY1. The results obtained were as follows : At 0.1% of EPS, inhibitory effects of EPS on the MA-104 cell using MTT assay were, $Wa\;51.58{\pm}8.08%,\;KU \;63.09{\pm}7.58%,\;S2\;51.23{\pm}5.43%,\;YO\; 51.45{\pm}5.67%,\;K-21\;52.84{\pm}5.49%,\;NCDV\;57.50{\pm}10.85%,\;UK\;51.64{\pm}4.74%,\;KK3\;54.53{\pm}8.44%,\;JBR\;58.67{\pm}7.51%,\;S97\;50.63{\pm}5.17%,\;OSU\;55.48{\pm}5.75%,\;and\;RRV\;54.36{\pm}8.72%$, respectively. At 0.1/128%, the effects were $Wa\;5.5{\pm}6.45%,\;KU\;10.33{\pm}8.39%,\;S2\;0.98{\pm}8.39%,\;YO\;4.25{\pm}2.86%,\;K-21\;4.25{\pm}6.60%,\;NCDV\;4.01{\pm}4.12%,\;UK\;6.55{\pm}7.09%,\;KK3\;5.19{\pm}4.86%,\;JBR\;11.11{\pm}8.11%,\;S97\;6.75{\pm}6.95%,\;OSU\;10.14{\pm}8.54%,\;and\;RRV\;3.66{\pm}8.57%$, respectively. These results indicate that EPS have inhibitory effects on various serotype and sources of RV from different animals.

• Microbiology and Biotechnology Letters
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• v.36 no.3
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• pp.182-188
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• 2008

A hyperthermophilic bacteria (strain HJ6) was isolated from a hot springs located in the Arima-cho, Hyogo, Japan. The cells were long-rod type ($2-4{\mu}m$), about $0.4{\mu}m$ in diameter. The pH and temperature for optimal growth were 6.5 and $80^{\circ}C$, respectively. Phylogenetic analysis based on the 16S rDNA sequence and biochemical studies indicated that HJ6 belonged to the genus Thermus thermophilus (Tt). The gene encoding the Trehalose synthase (TS) was cloned and sequenced. The open reading frame (ORF) of the TtTS gene was composed of 2,898 nucleotides and encoded a protein (975 amino acids) with a predicted molecular weight of 110.56 kDa. The deduced amino acid sequence of TtTS showed 99% and 83% identities to the Thermus caldophilus TS and Meiothermus ruber TS, respectively. TtTS gene was expressed in Escherichia coli cells, and the recombinant protein was purified to homogeneity. The optimal temperature and pH for Trehalose synthase activity were found to be $80^{\circ}C$ and 7.5, respectively. The half-life of heat inactivation was about 40 min at $90^{\circ}C$. The maximum trehalose conversion rate of maltose into trehalose by the enzyme increased as the substrate concentration increased, and reached 55.7% at the maltose concentration of 500 mM, implying that the enzyme conversion was dependent of the substrate concentration.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.3
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• pp.439-443
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• 2001

The effect of fermentation of peanut milk with lactic acid bacteria on n-hexanal content was investigated. Changes in pH, titratable acidity and viable cell populations indicated that Streptococcus salivarius subsp. thermophilus was adapted better than Lactobacillus delbrueckii subsp. bulgaricus during fermentation. Analysis of headspace volatiles revealed that n-hexanal, which is one of the compounds responsible for undesirable green/beany flavor in peanut milk, completely disappeared as a result of fermentation. S. salivarius subsp. thermophilus was more effective than L. delbrueckii subsp,. bulgaricus in reducing the n-hexanal content. No significant difference was found in water sorption between fermented and unfermented peanut milk.

• The Korean Journal of Food And Nutrition
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• v.26 no.1
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• pp.146-149
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• 2013

This study was performed to identify the effect of lactic-fermentation of peanut milk on n-hexanal content. Changes in viable cell populations, pH and titratable acidity indicated that there was a synergistic interaction between Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus salivarius subsp. thermophilus during fermentation. The analysis of headspace volatiles revealed that n-hexanal nearly disappeared due to fermentation. S. salivarius subsp. thermophilus was more effective than L. delbrueckii subsp. bulgaricus in reducing the n-hexanal content.

• The Korean Journal of Food And Nutrition
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• v.7 no.1
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• pp.45-50
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• 1994

This study was carried out to Investigate the effects of Panax ginseng, Ganoderma lucidum extract and crude polysaccharide of G. lucidum on the growth of lactic acid bacteria. p. ginseng extract contained 60.7% carbohydrate and 27.5% protein, whereas G. lucidum contained 35.9% carbohydrate and 46.3% protein. The total sugar and protein content of crude polysaccharide of G. lucidum were 47.2% and 15.2%, respectively. Two amino acids(hg, Trp) were detected in p. ginseng extract and 11 amino acids (hg, Trp, Ua, Lys, Ser, etc.) in C. lucidum extract. By the addition of p. ginseng, 5. lucidum extract and crude polysaccharide, the cia. p. ginseng was more effective on the growth of 1. casei an: G. lucidum was more effective on that of S. thermophilus. The effect of free amino acids on the growth of tactic acid bacteria was also examined. Arginine and lysine stimulated the growth of L. casei, whereas Lysine, serine, arginine, and glutamic acid stimulated the growth of 5. thermophilus.

• Journal of Dairy Science and Biotechnology
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• v.37 no.1
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• pp.57-68
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• 2019

The effects of yogurt supplementation with enzyme-bioconverted ginseng (EBG), ascorbic acid, and yeast extract on the bacterial counts of Streptococcus thermophilus, Lactobacillus acidophilus LA-5, and Bifidobacterium BB-12 were investigated to develop healthy yogurts with high probiotic counts during storage. In addition, the colors and viscosities of the yogurts were determined. EBG, ascorbic acid, and yeast extract did not affect S. thermophilus counts. EBG and ascorbic acid enhanced the viabilities of L. acidophilus LA-5 and Bifidobacterium BB-12 during storage. Yeast extract improved growth of L. acidophilus LA-5 and Bifidobacterium BB-12 during fermentation. EBG turned the yogurt into brown color. We conclude that supplementation of yogurt with EBG, ascorbic acid, and yeast extract may enhance its health-promoting functions by increasing the viability of probiotics, which can thus promote consumption of the yogurt.

• Current Research on Agriculture and Life Sciences
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• v.3
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• pp.151-157
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• 1985

This study was carried (Jut to find out changes of ${\gamma}$-globulin and cholesterol of rat blood fed on yoghurt and Koumiss. Yoghrt and koumiss were manufactured with fortifed milk and Lactobacillus bulgaricus, streptococcus thermophilus and Saccharomyces fragilis were used. The twenty rats were devised into 4 groups with 5 replications by completely randomized design. The experimental groups are the control, milk, yoghrt and koumiss feeding groups. The results are summerized as follows ; The changes of pH after 8hrs incubation with Lactobacillus bulgricus, Streptococcus thermophilus and the mixed strains were 3.7, 4.6 and 3.5 at $42^{\circ}C$, respectively. Average alcohol percentage of Koumiss was 1.2 (%). The average viscosity of yoghurt and Koumiss with milk showed 1500 cp and 390 cp. respectively at 11 % of milk total solid. ${\gamma}$-globulin contents in blood of rat fed on yoghurt and Koumiss were higher than those of control and milk. Cholesterol of rat blood in yoghurt and Koumiss group were lower than those of control and milk group.

• Applied Biological Chemistry
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• v.46 no.4
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• pp.367-375
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• 2003

The puree of Rubus coreanus was fermented using lactic acid bacteria and its biological activities were examined. Lactobacillus acidophilus KCCM 32820, L. casei KCCM 12452, Lactococcus lactis subsp. lactis KCCM 40104, and Streptococcus thermophilus KCCM 40430 were used as a single or mixed starter for the lactic acid fermentation, and their cultures at the late logarithmic growth phase were inoculated to final concentration of 2% (v/v). L. casei fermented the puree of Rubus coreanus best when used as a single starter, and the culture of L. casei and L. lactis with the inoculation ratio of one to one showed the highest fermentation activity when used as a mixed starter. However, the fermented broth of the puree of Rubus coreanus using L. acidophilus and S. thermophilus showed the best results in the sensory evaluation. The optimal lactic acid fermentation conditions were as follows; the concentration of oligosaccharide added was 1% (w/v), pH of puree and fermentation temperature were 4.0 and $37^{\circ}C$, respectively, and fermentation time was $72{\sim}96$ hours. Glucose and fructose were major free sugars, and the content of lactic acid was 698.2 mg/100 g in the fermented broth. The fermented broth of the puree of Rubus coreanus showed the electron donating ability and nitrite scavenging ability with the value of 69% and 38.3% at pH 1.2, respectively. SOD-like activity and inhibitory activity on xanthine oxidase were also found in the fermented broth with the value of 60.3% and 41.8%, respectively. When the antimicrobial activities of the fermented broth were examined, it showed the highest growth inhibitory activity against Escherichia coli O-157:H7, and also contained antimicrobial activities against Salmonella typhimurium, Bacillus cereus, and Staphylococcus aureus.