• Journal of the Korean Society of Food Culture
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• v.25 no.1
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• pp.76-81
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• 2010

This study was conducted to evaluate the influence of Lactobacillus bulgaricus and/or Sterptococcus thermophilus on the fermentation of yoghurt containing 5% (w/v) buckwheat sprouts. The results revealed that after 12 hours of fermentation the appropriate pH, titratable acidity and number of viable cells were attained. At that time, the rutin content of the buckwheat sprout-added yoghurt prepared by the mixed culture method was not changed, but the quercetin content increased greatly. Conversely, the rutin content of yoghurt that only contained Streptococcus thermophilus was decreased while the quercetin content was increased. The total phenol contents as well as the DPPH radical scavenging activities of both the mixed culture and Streptococcus thermophilus yoghurt did not differ significantly. Taken together, the results revealed that the use of a mixed culture of Lactobacillus bulgaricus and Streptococcus thermophilus during the preparation of buchwheat sprout-added yoghurt was desirable due to the decrease in pH and increase in titratable acidity and viable cells that occurred after 12 hr of fermentation. Moreover, phytochemicals in buckwheat sprouts such as rutin, quercetin and phenol compounds were comparatively increased during fermentation and influenced the antioxidant activity in buckwheat sprout-added yoghurt.

• Journal of the Korean Society of Food Science and Nutrition
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• v.21 no.1
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• pp.60-63
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• 1992

Individual starter culture were inoculated into liquid medium and incubated at $40^{\circ}C$ for 16 hours. Whole cell were obtained and evaluated for ${\beta}-galactosidase$ activity using orthonitrophenyl-${\beta}-D-galactopyranoside$ (ONPG) as substrate. S. thermophilus had more ${\beta}-galactosidase$ activity than other Lactobacilli did. To study the effect of storage temprature on enzyme activity of yoghurt, some samples of cultured yoghurt were stored under refrigeration $(4^{\circ}C)$, and the others under room temperature $(23^{\circ}C)$. At $4^{\circ}C$, yoghurt had ${\beta}-galactosidase$ activity and many viable bacteria in 1 month. After 20 days, yoghurt had maximum ${\beta}-galactosidase$ activity. At $23^{\circ}C$, yoghurt had ${\beta}-galactosidase$ activity by 5 days. As this experiment shown ${\beta}-galactosidase$ activity was ascribed to viable bacteria, especially S. thermophillus. Commercial yoghurt had lower ${\beta}-galactosidase$ activity. There were considerable variations with regard to the lactose hydrolyzing capabilities of commercial yoghurt samples.

• Food Science of Animal Resources
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• v.34 no.1
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• pp.88-98
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• 2014

Total spleen lymphocytes, lymphocyte proliferation, tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$), and interleukin-10 (IL-10) in spleen lymphocyte culture were studied in malnourished Wistar rats fed with goat milk yoghurt. Malnourished rats were created by using standard feed restriction as much as 50% of normal rats for 21 d. Goat milk yoghurt containing three types of microorganism e.g., Lactobacillus acidophilus, Sterptococcus thermophilus and Bifidobacterium longum derived from Lacto-B culture in powder form. After 21 d, the rats continued to receive restricted feeding and supplemented with goat milk yoghurt for 7 d. Total splenocytes were counted by hemocytometer. Splenocytes proliferation was expressed as stimulation index, whereas the TNF-${\alpha}$ and IL-10 of spleen lymphocyte culture were measured by ELISA technique. The total number of splenocytes and stimulation index of splenocytes in moderate malnourished and normal rats supplemented with goat milk yoghurt was not significantly different. The level of TNF-${\alpha}$ in the rat supplemented with goat milk yoghurt was lower (p<0.05) than the control group, whereas the level of IL-10 in the rat supplemented with goat milk yoghurt was higher (p<0.05) than the control group. In conclusion, goat milk yoghurt supplementation in malnourished rats could decrease TNF-${\alpha}$ as a representation of the pro-inflammatory cytokine, while it increases IL-10 as a representation of the anti-inflammatory cytokine.

• The Korean Journal of Food And Nutrition
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• v.17 no.1
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• pp.8-17
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• 2004

The effect of chlorella extract on the growth and acid production of yoghurt starter was investigated in order to prepare the yoghurt added with chlorella extract. The various levels of chlorella extract powder were added to skim milk medium and the medium was fermented by single or mixed culture of 4 types of lactic acid bacteria such as Streptococcus thermophilus, Lactobacillus acidophilus, Lactobacillus casei, and Lactobacillus bulgaricus. The changes in acid production(pH, titratable acidity) and number of viable cells of the medium during fermentation in skim milk added with chlorella extract powder have determined. When chlorella extract powder was added to skim milk medium at the levels of 0.5%, 1.0%, 2.0%, and 3.0%, the addition of 0.5% chlorella extract powder with the single culture of Str. thermophilus, Lac. casei, and Lac. bulgaricus showed the highest number of viable cell counts after 9 hours incubation. And also all single cultures of the yoghurt starter produced the higher amounts of acid with the addition of 0.5% chlorella extract powder. When chlorella extract powder was added to the medium at the levels of 0.25%, 0.5%, 1.0%, and 2.0%, the addition of lower lever(0.25∼0.5%) of chlorella extract powder with the mixed culture of the lactic acid bacteria showed more the acidity of pH and the number of viable cell counts. Among the treatments tested, the addition of 0.25% chlorella extract powder with the mixed culture of Str. thermophilus and Lac. casei produced the highest number of viable cell counts after 12 hours incubation. Therefore it was suggested to manufacture the yoghurt with the addition of 0.25% chlorella extract powder and the inoculation of mixed culture of Str. thermophilus and Lac. casei for on the stimulation of growth of the yoghurt starter.

• The Korean Journal of Food And Nutrition
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• v.6 no.3
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• pp.208-210
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• 1993

In order to know the influences of heat treatment of yoghurt on pH, $\beta$-galactosidase and viable cells, yoghurt sample was made by general method with Lactobacillus bulgaricus and Streptococcus thermophilus, and the changes in pH, $\beta$-galactosidase-activity and viable cell-count were determined during heating at 55$^{\circ}C$ and 7$0^{\circ}C$. The pH of yoghurt was not changed when the yoghurt was heated at 7$0^{\circ}C$, but at 55$^{\circ}C$ it decreased slightly. The stability of $\beta$-galactosidase was not affected markedly by heat treatment at 55$^{\circ}C$, but was rapidly inactivated at 7$0^{\circ}C$. The heat treatment of yoghurt at 55$^{\circ}C$ had the halb of viable cell in 1 hour, but the heat treatment at 7$0^{\circ}C$ had considerable effect on viable cell in 5 minutes.

• Microbiology and Biotechnology Letters
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• v.18 no.1
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• pp.71-75
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• 1990

Yoghurt was prepared with Bifidobacterium longum TK-100 and Lactobacillus acidophilus TK-2070. The prepared yoghurt showed the increase of the titratable acidity under cold storage condition. This was derived from the active L. acidophilus TK-2070 on the logarithmic phase rather than from the B. longumn TK-2070. B. longum TK-100 grew well in the facultative anaerobic condition as well as in the strict anaerobic condition. Reinforced clostridial agar medium with 0.1% aniline blue was tried for the differential viable cell counts in the mixed culture and in the yoghurt. B. longurn TK-2070 had the light gray, blue-dotted colonies of about 2 mm diameter. L. acidophilus TK-2070 had the light gray colonies of about 1 mm diameter.

• Microbiology and Biotechnology Letters
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• v.24 no.3
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• pp.304-310
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• 1996

For a probiotic yoghurt it is desirable to utilize lactic acid bacteria with a high survival rate and beneficial function to human beings. We have examined a variety of lactic acid bacteria to assess the acid and bile tolerance and antibiotic resistance. In addition, an in vitro culture experiment was performed to evaluate their ability to reduce cholesterol levels in the growth medium. Thirteen strains were selected from in vitro cholesterol assays and fed to Sprague-Dawley rats with a high-cholesterol diet. Among the 13 strains tested, 8 strains were shown to reduce serum cholesterol levels significantly after 24 days of administration in vivo. Rats were fed lyophilized yoghurt powder fermented with a combination of 3 selected strains: Bifidobacterium infantis AM-220, Lactobacillus AM-245, and Styeptococcus MA-1. The levels of total cholesterol and low density lipoprotein were significantly lower (p$\leq$0.05) in rats fed the yoghurt powder compared with control group. These studies suggest that yoghurt fermented with appropriately selected lactic acid bacteria may have a anticholesterolemic effect.

• Journal of Dairy Science and Biotechnology
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• v.27 no.1
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• pp.53-57
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• 2009

Lactic acid bacteria (LAB) Play an important role in the human diet and are used in the production of edible fermented products such as kimchi and yoghurt. LAB are regarded as safe food additives used to enhance the nutritive value of foods. Plant-origin lactic acid bacteria (PLAB) cultured in vegetal media are now widely used in food industries. PLAB have been found to activate intestinal immunity, modulate the balance of the intestinal bacterial from, and enhance intestinal function. They are known for their strong resistance to acid; this enables them to persist for a longer duration in the human intestine. PLAB can also survive in the intestinal environment under conditions of poor nutrition. They have stronger vitality as compared to LAB of animal origin. Due to the unique characteristics of PLAB, they are being widely used in Japan for processing foods such as yoghurt and beverages. Recently, PLAB has also been used as the culture for processing yoghurt in Korea. We expect further research on the functional effects of PLAB.

• Food Engineering Progress
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• v.14 no.1
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• pp.14-20
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• 2010

The objective of the current study was to determine the cryoprotective effects of trehaolse on lactic acid bacteria in the frozen yoghurt during long-term frozen storage conditions. The frozen yoghurts were prepared using starter culture containing Lactobacillus bulgaricus and Streptococcus thermophilus, as well as trehalose and sorbitol as a cryoprotectant. The viable cell numbers of lactic acid bacteria in frozen yoghurt did not significantly decreased during six weeks frozen storage conditions. The MRS broth, which contains either trehalose or sorbitol, cultured with L. bulgaricus and/or S. thermophilus, and then the cultured medium was kept in the frozen condition for six weeks. The results indicated that lactic acid bacteria viability significantly increased with trehalose addition (2 and 5%) in the media compared to those of control and sorbitol supplement groups. The lactic acid bacteria viability in the yoghurts was examined on the effects of repeated freeze and thaw events. The freeze-thaw resistance of lactic acid bacteria significantly increased with trehalose supplement in the yoghurt. The major volatile aroma compounds (acetaldehyde, acetone, ethanol, diacetyl, and acetoin) in yoghurt were separated and indentified by headspace GC-FID analysis. Distinct flavor components and their ratios are known as important quality factors for yoghurt notes. Trehalose addition to the yoghurt was not influenced these factors during lactic acid fermentation. The results in this study demonstrated that trehalose potentially can be applicable as an effective cryoprotectant for lactic acid bacteria in the frozen yoghurt products.

• Journal of Microbiology and Biotechnology
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• v.7 no.1
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• pp.1-7
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• 1997

The efficient manufacture of fermented dairy products on an industrial scale requires a supply of reliable starter cultures with properties suited to desired product specifications. These cultures must be backed by relevant research and development activities. This article describes the issues involved in establishing a centre to provide starter culture R & D for a group of independent cheese manufacturing companies, and discusses a strategic approach to the management of starter cultures.