• Journal of Life Science
• /
• v.26 no.12
• /
• pp.1438-1445
• /
• 2016

Yeast can be post-contaminated by the equipment, producer, or air, and this can degrade yogurt quality. This study aimed to demonstrate the yeast inhibiting effect in fermented milk by adding Lactobacillus paracasei and Lactobacillus rhamnosus along with current fermenting lactic acid bacteria such as Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus. A certain amount of yeast was added to fermented milk samples that were soon after stored at variable temperatures, and the number of yeast cells was counted periodically. The swelling phenomenon caused by the gas produced by the yeast in fermented products was also observed. In the two experiments, compared to the control, the L. paracasei- and L. rhamnosus-added-groups showed much slower rate of yeast appearance and lower frequency of swelling phenomena. This suggests that using a mixture of L. paracasei and L. rhamnosus in fermented milk inhibits the growth of yeast. Furthermore, if the products are stored at $10^{\circ}C$, post-acidification is rarely seen in the experimental group compared to the control group. This means that the organoleptic flavor can be kept consistent from the production day till the expiration day, resulting in improved organoleptic quality for customers. In other words, the use of L. paracasei and L. rhamnosus in fermented milk will result in the following positive effects: improvement in storage stability by delaying yeast appearance, increase in quality consistency by inhibiting post-acidification, and improved organoleptic quality by enhancing texture and flavor.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.41 no.3
• /
• pp.253-261
• /
• 2015

In this study, cosmeceutical activities of the co-cultures of both lactic acid bacteria isolated from the hands of women, Lactobacillus rhamnosus (L. rhamnosus) and Lactobacillus paracasei (L. paracasei) were first reported: For whitening and anti-wrinkle activities, the co-culture showed the highest tyrosinase inhibition of 20.68%, compared L. paracasei and L. rhamnosus. The co-culture also showed the highest inhibition of melanin synthesis as 63.7%. In observing the anti-wrinkle activities of the co-culture, it generated only 3726.3 pg/mL of matrixmetalloproteinase-1 (MMP-1) production when 13613.5 pg/mL and 13012.0 pg/mL of MMP-1 production were estimated from L. rhamnosus and L. paracasei. Besides these, the extract from the co-culture yielded higher collagen production as 380.7 ng/mL, compared to 323.4 ng/mL and 304.1 ng/mL from L. paracasei and L. rhamnosus. These results indicate that the co-culture of both lactic acid could improve its cosmetic activities. This hypothesis was also confirmed that the co-culture of both bacteria showed strong antioxidant activities of DPPH free radical scavenging while the extract of L. rhamnosus and L. paracasei.

• Microbiology and Biotechnology Letters
• /
• v.40 no.3
• /
• pp.186-189
• /
• 2012

A gene coding for mannanase (manA) from Bacillus subtilis was introduced into a shuttle vector pGK12 between Escherichia coli, B. subtilis and Lactobacillus paracasei. As a result of transferring the resultant plasmid, designated pGK12M3, into three different strains, the manA gene was found to be expressed in L. paracasei as well as in B. subtilis and E. coli. In a 4 L fermentor culture, the production of mannanase by recombinant L. paracasei (pGK12M3) reached a maximum level of 5.4 units/ml in an MRS medium with a fixed pH 6.5. Based on the zymogram of mannanase, it is assumed that mannanase produced by recombinant L. paracasei is not maintained stably with proteolytic degradation. The optimal temperature and thermostability of mannanase produced by recombinant L. paracasei were also found to be different from those of enzymes produced by B. subtilis.

• Korean Journal of Microbiology
• /
• v.46 no.4
• /
• pp.375-382
• /
• 2010

In present study, five strains of Lactobacillus acidophilus GK20, Lactobacillus brevis GK55, Lactobacillus paracasei GK74, Lactobacillus plantarum GK81, and Leuconostoc mesenteroides GK104 isolated from the mustard leaf kimchi were investigated for resistance to reactive oxygen species (ROS) and antioxidant activity. L. acidophilus GK20, L. brevis GK55, L. paracasei GK74, and L. plantarum GK81 were resistant to hydrogen peroxide (0.5 mM), showing a survival rate of 50% or more. In particular, L. acidophilus GK20 and L. paracasei GK74 were the most superoxide anions-resistant and L. paracasei GK74 and L. plantarum GK81 were most likely survive hydroxyl radicals. Meanwhile, the intracellular cell-free extract (ICFE) from L. plantarum GK81 exhibited significantly higher DPPH radical scavenging values ($96.4{\pm}2.8%$) than the intact cells (IC). The ICFE of L. plantarum GK81 showed the highest superoxide radical scavenging ability and chelating activity for $Fe^{2+}$ ions among the 5 lactic acid bacteria (LAB) tested, and IC and ICFE from L. plantarum GK81 demonstrated excellent reducing activity, which was higher than those of BHA and vitamin C as a positive control.

• Proceedings of the Korean Society for Food Science of Animal Resources Conference
• /
• 2005.05a
• /
• pp.375-379
• /
• 2005

본 연구는 ${\beta}-galactosidase$와 phytase활성이 높은 균주의 선발을 목적으로 수각 미생물들을 Kefir와 자연환경에서 분리하여 효소활성을 측정하였다. 배양한 유산균과 효모 균체액을 French pressure cell press로 세포를 파쇄하였을 때, 각 미생물의 단백질농도는 효모보다 유산균이 높은 것으로 나타났다. ${\beta}-galcactosidase$의 비활성은 Kluyveromyces maxiranus와 Candida utilis를 제외하고는 대부분 $0.80{\sim}0.89\;umol/min/mg$ 사이였다. 체적활성의 경우는 Lactobacillus paracasei 및 Lactobacillus rahmnosus, Enterococcus faecium이 각각 15.9 및 14.5, 14.5 umol/ml를 기록하여 ${\beta}-galcactosidase$의 추출재료로 우수하였다. phytase의 비활성은 Lactobacillus paracasei 와 Enterococcus faecium이 0.032와 0.038 umol/min/mg로 가장 높았다. 체적활성의 경우는 Lactobacillus paracasei가 35.12 umol/ml로 가장 높았다. 결론적으로 ${\beta}-galactosidase$와 phytase의 생산측면에서 이용한 미생물중에서는 Lactobacillus paracasei가 가장 우수한 것으로 사료되었다.

• Korean Journal of Food Science and Technology
• /
• v.46 no.2
• /
• pp.148-152
• /
• 2014

A mutant strain of Lactobacillus paracasei (ML-7) was derived by ultraviolet irradiation of the parent L. paracasei LS-2 strain, followed by colony selection on pH 3.5 MRS agar plates, on which L. paracasei LS-2 cannot grow. The L. paracasei ML-7 mutant strain produced an increased amount of organic acids compared to the L. paracasei LS-2 parent strain. Broiler chickens were randomly fed with one of three experimental diets: a basal diet as a control, and basal diets supplemented with 0.3% of the L. paracasei LS-2 and L. paracasei ML-7 strains. When concluding the study, the final body weights of the broilers fed with the supplemented basal diets were found to be significantly higher (1.9% for LS-2 and 6.2% for ML-7) than the control broiler group. Broilers fed with basal diet supplemented with the mutant L. paracasei ML-7 strain showed increased body weight and food intake, compared to broilers fed with the basal diet with or without the parent L. paracasei LS-2 strain.

• Korean Journal of Microbiology
• /
• v.55 no.3
• /
• pp.258-267
• /
• 2019

The purpose of this study was to investigate the effect of lactic acid bacteria (LAB) on the growth and biogenic amines (BA) formation of Enterobacter aerogenes CIH05 in skim milk and soymilk. Lactobacillus acidophilus GK20, Lactobacillus paracasei GK74, and Lactobacillus plantarum GK81 isolated from mustard kimchi did not produce BA in the decarboxylation broth. L. paracasei GK74 exhibited the highest cell viability and antimicrobial compounds producing ability in fermented skim milk and soymilk samples, while the lowest producer was L. plantarum GK81. The production yield of lactic acid, hydrogen peroxide, and bacteriocin was dependent on the species of Lactobacillus and the type of culture medium. As LAB the number of viable cells of E. aerogenes CIH05 were higher in skim milk than in soymilk. When mixed culture with L. acidophilus GK20 and L. paracasei GK74 and treated with bacteriocin solution (300 AU/ml) obtained from these strains in milk media, the cell growth and cadaverine and histamine contents of E. aerogenes CIH05 were significantly (P < 0.05) lower than the respective values in control sample.

• Korean Journal of Microbiology
• /
• v.51 no.2
• /
• pp.156-168
• /
• 2015

The objective of this study is to investigate the anti-Helicobacter pylori and anti-cancer activities of the live cells (LC), cell-free culture supernatants (CFCS), and bacteriocin solution (BS) obtained from Lactobacillus acidophilus BK13 and Lactobacillus paracasei BK57 strains. After incubation for 30 h in MRS broth, the concentration of lactic acid produced by L. paracasei BK57 ($155.9{\pm}10.2mM$) was higher than in MRS broth using L. acidophilus BK13 ($126.8{\pm}7.9mM$). Maximum bacteriocin activity (128 AU/ml) of BK13 strain was observed after 30 h of cultivation at $37^{\circ}C$, however its magnitude was significantly lower than that of BK57 strain (256 AU/ml). The LC of L. acidophilus BK13 and L. paracasei BK57 were able to inhibit the growth of H. pylori ATCC 43504 at different incubation times, depending on the initial inoculum of the LAB. These CFCS and BS obtained from BK13 and BK57 strains dramatically inhibited the growth, adhesive ability, and enzymatic activity of H. pylori. Meanwhile, the anti-cancer effect of the lactic acid from L. acidophilus BK13 and L. paracasei BK57 strains on AGS cells had significant differences with the control group. Therefore, these antagonistic substances-producing strains are potentially useful as new potential antimicrobial agents for the management and prevention of H. pylori infections.

• Food Science of Animal Resources
• /
• v.30 no.2
• /
• pp.223-231
• /
• 2010

In order to develop a new starter for fermented milk, Lactobacillus paracasei subsp. paracasei BFI46 (BFI46) obtained from new-born infant feces was investigated for physiological characteristics. Good immunomodulating activity was evident compared with commercial lactic acid bacteria starter cultures. The optimum growth temperature of BFI46 was $40^{\circ}C$ with 12 h required to reach pH 4.3. Testing with 13 different antibiotics revealed greatest sensitivity of BFI46 to penicillin- G and chloramphenicol, and heightened resistance to neomycin, kanamycin and polymyxin. BFI46 displayed higher esterase activities compared to 18 other enzymes, was comparatively tolerant to bile juice and able to survive at pH 2 for 3 h, and displayed high resistance against Escherichia coli and Salmonella Typhimurium with a survival rate of 57.14% and 96.36%, respectively. The results indicate that BFI46 could be an excellent starter culture for fermented milk with high level of immunomodulating activity.

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