• Food Quality and Culture
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• v.1 no.1
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• pp.22-26
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• 2007

This study was performed to determine the feasibility of developing a healthy yogurt using tofu whey concentrates separated by nanofiltration (NF). The curd yogurt was prepared from whole milk with added skim milk powder, in which the NF powder was substituted at 0, 6.25, 12.5, or 25% for the skim milk powder. The quality characteristics were evaluated for pH, titratable acidity, viscosity, color, and viable cell counts. There were no significant differences in pH or titratable acidity between the control (yogurt with added skim milk powder only) and the yogurts with added NF powder, after 24 hr of fermentation at $37^{\circ}C$. The apparent viscosities of the yogurts with added NF powder were higher ($3,197{\sim}3,574\;cps$) than that of the control yogurt (3,196 cps). Lightness decreased, while yellowness increased, as the amount of NF powder increased. Sensory evaluations showed that the NF powder could be substituted for the skim milk powder at 6.25% without lowering the yogurt quality.

• Korean Journal of Microbiology
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• v.37 no.2
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• pp.151-157
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• 2001

This study was conducted to select lactic acid bacteria which possess potential inhibitory effect on Helicobacter pylori, and to make feasibility test of fermented milk products using them. In order to select lactic acid bacteria specifically inhibiting the growth of H. pylori, antibacterial activity using paper disk method, adherence ability to Caco-2 cell inhibitory effect on urease activity of H. pylori, and milk fermentation feasibility were measured. Among 45 strains of lactic acid bacteria tested, 28 strains showed clear zone and Lactobacillus gasseri MK-03 showed the largest clear zone. Caco-2 cell adherence by lactic acid bacteria and inhibitory effect of them on H. pylori adherence were also evaluated. Of 28 strains tested, 18 strains appeared to be effective on adherence to Caco-2 cell, and especially Bifidobacterium longum MK-26 was found to be superior to others. When Bif. longum MK-26 and H. pylori were reacted with Caco-2 cell 2hrs before, adherence percentage of H. pylori decreased from 0.105% to 0.004%. To investigate inhibitory effect of lactic acid bacteria-derived supernatant on urease activity of H. pylori, pH-adjusted fermented supernatant(pH-4.4) was assessed by co-cultivation method. There of Lb. acidophilus MK-07-derived supernatant showed the most inhibitory effect on urease activity of H. pylori. Considering milk fermentation ability of selected 3 strains, they were comparably feasible to fermented milk products. Consequently, Lb. gasseri MK-03, Lb. acidophilus MK-07, and Bif. longum MK-26 were selected to specifically inhibit the growth of H. pylori, by antibacterial activity, inhibition of urease activity, and inhibition of Caco-2 cell adherence, respectively.