• Journal of Dairy Science and Biotechnology
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• v.41 no.2
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• pp.76-85
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• 2023

This study investigated the effect of the addition of pomegranate concentrate to yogurt on the growth of pathogenic and lactic acid bacteria. The concentration of the MRS broth was adjusted to one-half and used for an experiment. Pomegranate concentrate was added at concentrations of 4%, 2%, 1%, and 0.5%, which significantly promoted the growth of Lacto-coccus cremoris, Weissella cibaria, Weissella paramesenteroides, Lactobacillus plantarum, Lactobacillus acidophilus, Streptococcus thermophillus, Lactobacillus bulgaricus, and Lactobacillus lactis. The growth of lactic acid bacteria increased with higher concentrations of pomegranate. However, the addition of pomegranate concentrate inhibited the growth of Escherichia coli KCCM11587, E. coli KCCM11591, E. coli KCCM11596, and E. coliKCCM11600. Yogurt with added pomegranate concentrate demonstrated optimal conditions compared to that of the control without the addition. Particularly, the viable cell count of lactic acid bacteria was significantly higher in the yogurt with pomegranate concentrate. Furthermore, the viability of the lactic acid bacteria in the yogurt with pomegranate concentrate was higher than that of the control without the addition of concentrate during storage.

• 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.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.23 no.5
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• pp.464-471
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• 2020

Purpose: Some probiotic strains reduce the duration of acute diarrhea. Because of strain and product specificity, each product needs to be supported by clinical data. This study aimed to test the efficacy of the synbiotic food supplement Probiotical (Streptococcus thermophilus, Lactobacillus rhamnosus, Lactobacillus acidophilus, Bifidobacterium lactis, Bifidobacterium infantis, fructo-oligosaccharides) in children with acute gastroenteritis of likely infectious origin. The primary endpoint was the number of children with normal stool consistency during the treatment duration. Methods: A total of 46 children (aged 3.6 months to 12 years) with acute gastroenteritis that started less than 48 hours prior to their visit at a hospital-based emergency department were included in this prospective, randomized, placebo-controlled trial. All children were treated with oral rehydration solution and placebo (n=20) or the test product (n=26). Results: Significantly more children had a normal stool consistency on days 1 and 2 in the probiotic group: 5 children (20%) on day 1 in the probiotic group compared with none in the placebo group (p=0.046). On day 2, 11 children in the probiotic group (46%) and 3 (16%) in the placebo group (p=0.024) had a normal stool consistency. The mean duration of diarrhea was shorter in the probiotic group compared with that in the placebo group (3.04±1.36 vs. 4.20±1.34 days) (p=0.018). Conclusion: The test product was shown to normalize stool consistency significantly more rapidly than the placebo. These data confirm the findings from a previous study in a larger group of children performed in a primary healthcare setting.

• Microbiology and Biotechnology Letters
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• v.29 no.1
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• pp.1-11
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• 2001

Lactic acid bacteria (LAB) are widely used for various food fermentation. With the recent advances in modern biotechnology, a variety of bio-products with the high economic values have been produced using microorganisms. For molecular cloning and expression studies on the gene of interest, E. coli has been widely used mainly because vector systems are fully developed. Most plasmid vectors currently used for E, coli carry antibiotic-resistant markers. As it is generally believed that the antibiotic resistance markers are potentially transferred to other bacteria, application of the plasmid vectors carrying antibiotic resistance genes as selection markers should be avoided, especially for human consump-tion. By contrast, as LAB have some desirable traits such that the they are GRAS(generally recognized as safe), able to secrete gene products out of cell, and their low protease activities, they are regarded as an ideal organism for the genetic manipulation, including cloning and expression of homologous and heterologous genes. However, the vec-tor systems established for LAB are stil insufficient to over-produce gene products, stably, limiting the use of these organisms for industrial applications. For a past decade, the two popular plasmid vectors, pAM$\beta$1 of Streptococcus faecalis and pGK12 theB. subtilis-E. coli shuttle vector derived from pWV01 of Lactococcus lactis ssp. cremoris wg 2, were most widely used to construct efficient chimeric vectors to be stably maintained in many industrial strains of LAB. Currently, non-antibiotic markers such as nisin resistance($Nis^{r}$ ) are explored for selecting recombi-nant clone. In addition, a gene encoding S-layer protein, slp/A, on bacterial cell wall was successfully recombined with the proper LAB vectors LAB vectors for excretion of the heterologous gene product from LAB Many food-grade host vec-tor systems were successfully developed, which allowed stable integration of multiple plasmid copies in the vec-mosome of LAB. More recently, an integration vector system based on the site-specific integration apparatus of temperate lactococcal bacteriophage, containing the integrase gene(int) and phage attachment site(attP), was pub-lished. In conclusion, when various vector system, which are maintain stably and expressed strongly in LAB, are developed, lost of such food products as enzymes, pharmaceuticals, bioactive food ingredients for human consump-tion would be produced at a full scale in LAB.

• Food Science of Animal Resources
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• v.37 no.6
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• pp.906-916
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• 2017

To investigate the effects of a single bacterium and a mixture of bacteria as probiotics in loperamide-treated animal models, loperamide (3 mg/kg) was administered to SD rats to induce constipation. The individual lactic acid bacterial doses, Enterococcus faecium (EF), Lactobacillus acidophilus (LA), Streptococcus thermophilus (ST), Bifidobacterium bifidum (BB), Bifidobacterium lactis (BL), Pediococcus pentosaceus (PP), and a mixture of the bacteria were orally administered to loperamide-induced constipated rats at a concentration of $10^8CFU/kg$ for 14 days. The weights and water contents of their stools were found to be significantly higher in PP, CKDB (mixture of 5 strains except PP), and CKDBP (CKDB+PP) groups than in the normal (constipation not induced) and the control (constipation-induced) groups (p<0.05). The intestinal transit ratio was significantly higher in all probiotic-treated groups than in the control group, and was the highest in the CKDBP group (p<0.05). The mucosal length and mucus secretion were significantly improved in all probiotic-treated-groups, as compared to that in the control group, and the CKDBP group was found to be the most effective according to immunohistochemistry (IHC) staining and total short chain fatty acid content analysis (p<0.05). Lastly, PP, CKDB, and CKDBP showed relatively higher Lactobacillus sp. ratios of 61.94%, 60.31% and 51.94%, respectively, compared to the other groups, based on metagenomic analysis.

• Food Science of Animal Resources
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• v.33 no.3
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• pp.335-340
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• 2013

This study screened for radio-resistant strains lactic acid bacteria (LAB) by evaluating their capability to survive exposure to ionizing radiation. Ten strains of LAB - Lactobacillus bulgaricus, Lactobacillus paracasei, Lactobacillus casei, Lactobacillus acidophilus, Lactobacillus plantarum, Lactobacillus delbruekii, Lactococcus lactis, Streptococcus thermophilus, Bifidobacterium breve, and Pediocuccos pentosaceus - were selected and subcultuted twice. The LAB was then further cultured for 3 d at $37^{\circ}C$ to reach 7-10 Log colony-forming units (CFU)/mL prior to irradiation and immediately exposed to gamma rays or electron beams with absorbed doses of 0, 1, 2, 3, 4, 5, 6, 8, and 10 kGy. Gamma irradiation gradually decreased the number of the tested viable LAB, and the effect was irradiation dose dependent. A similar effect was found in electron beam-irradiated LAB. Radiation sensitivity of LAB was calculated as $D_{10}$ values, which ranged from 0.26 kGy to 0.9 kGy and 0.5 kGy to 1.44 kGy with exposure to gamma and electron beam irradiation, respectively, in all tested LAB. L. acidophilus was the most resistant to gamma and electron beam irradiation, with $D_{10}$ values of 0.9 kGy and 1.44 kGy, respectively. These results suggest that L. acidophilus might be suitable for the preparation of probiotics as direct-fed microbes for astronauts in extreme space environments.

• Food Science and Biotechnology
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• v.16 no.1
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• pp.83-89
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• 2007

In our study, lactic acid bacteria (LAB)-fermented whey solutions were applied in the soybean soaking process to minimize bacterial contamination and to enrich the biologically functional components of isoflavone and $\gamma$-aminobutyric acid (GABA). Among the 11 LAB tested, Bifidobacteria infantis and a mixed culture (Lactobacillus acidophilus, Bifidobacteria lactis, and Streptococcus thermophilus; ABT-3) displaying the greatest $\beta$-glucosidase activity were selected to produce improved biologically functional soybean preparations. In the soybean soaking processing (without water spraying), the LAB-cultured 10% whey solution was used to soak and to ferment the soybeans and the fermented soybeans were finally dried by heat-blowing at $55^{\circ}C$. The processing conditions used in this study demonstrated that the final soybean product had a reduced contamination by aerobic and coliform bacteria, compared to raw soybeans, likely due to the decrease in pH during LAB fermentation. The aglycone content of the isoflavone increased up to 44.6 mg per 100 g of dried soybean by the processing method, or approximately 8-9 times as much as their initial content. The GABA contents in the processed samples increased as the processing time of soaking-fermentation proceeded as well. The soybean sample that fermented by ABT-3 culture for 24 hr showed the greatest increase in GABA content (23.95 to 97.79 mg/100 g), probably as a result of the activity of glutamate decarboxylases (GAD) released from the soybean or produced by LAB during the soaking process.

• Food Science of Animal Resources
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• v.39 no.1
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• pp.162-176
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• 2019

This study was performed to evaluate the antioxidant activity of yogurt fermented at low temperature and the anti-inflammatory effect it has on induced colitis with 2.5% dextran sodium sulfate (DSS) in Balb/c mice. Yogurt premix were fermented with a commercial starter culture containing Lactobacillus acidophilus, Bifidobacterium lactis, Streptococcus thermophilus, and Lactobacillus delbrueckii subsp. bulgaricus at different temperatures: $22^{\circ}C$ (low fermentation temperature) for 27 h and $37^{\circ}C$ (general fermentation temperature) for 12 h. To measure antioxidant activity of yogurt samples, DPPH, $ABTS^+$ and ferric reducing antioxidant potential (FRAP) assays were conducted. For animal experiments, inflammation was induced with 2.5% DSS in Balb/c mice. Yogurt fermented at low temperature showed higher antioxidant activity than that of the yogurt fermented at general temperature. In the inflammatory study, IL-6 (interleukin 6) was decreased and IL-4 and IL-10 increased significantly in DSS group with yogurt fermented at general temperature (DYG) and that with yogurt fermented at low temperature (DYL) compared to that in DSS-induced colitic mice (DC), especially DYL had higher concentration of cytokines IL-4, and IL-10 than DYG. MPO (myeloperoxidase) tended to decrease more in treatments with yogurt than DC. Additionally, yogurt fermented at low temperature had anti-inflammatory activity, although there was no significant difference with general temperature-fermented yogurt (p>0.05).

• Journal of Dairy Science and Biotechnology
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• v.14 no.2
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• pp.157-164
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• 1996

This study aimed increase the quality during ripening of Cheddar cheese made with proteinase-negative mutant of Streptococcus lactis KCTC 1913 selected by curing. The degradation of protein during cheese ripening were investigated by electrophoresis and chromatography. The results were summarized as follow ; 1. The number of lactic acid bacteria decreased with the ripening stage, and that of the control cheese decreased faster than that of the cheese made with mutant. 2. Polyacrylamide gel electrophoretic analysis of cheese caseins revealed no difference between the cheese made with mutant and the control cheese, but differences along with the ripening stage were evident. 3. On Sephadex G-25 column chromatography, the extracts of bitter components from the green cheese and 3 month ripended cheese were fractionated into 3 fractions. With the progress of ripening, bitter peptides were degraded to rather small peptides or free amino acids. 4. Sensory evaluation of the 3 month ripended Cheddar cheese found no significant differences in color but the cheese made with mutant evidenced higher palatability in flavor and better texture than the control cheese. 5. The yields of the cheddar cheese made with mutant was 0.14% higher than that of the control cheese.

• Korean Journal of Food Science and Technology
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• v.17 no.5
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• pp.389-398
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• 1985

To shorten the processing of cheese slurry, four different slurries, ie, Control, Cheddar 1 and 2, and Italian-type that were made of Na-caseinates, cream, trace elements, lactic culture, and enzymes were fermented at $30^{\circ}C$ for 7days with daily stirring. PH, titratable acidity, soluble nitrogen, viable cell count, active SH groups, total volatile fatty acid, free fatty acid, electrophoretic patterns of degraded caseins, and viscosity were analyzed to investigate physicochemical properties of fermented slurries. Acid production was accelerated in the cheese slurries with protease than that without the enzyme and PH of the former was decreased after three days of fermentation to 4.90. The Change of titratable acidity agreed to PH patterns. Soluble nitrogen of the Control slurry was increased slowly for four days and then rapidly to 40% of total nitrogen while those containing protease to 70%. The protease of lactic cultures used (Streptococcus lactis and Streptococcus cremoris) broke down as-casein more rapidly than $\beta$-casein and most proteins were degraded to peptides and amino acids after three days of fermentation. Total volatile fatty acids were increased by added lipase and free fatty acids composition analyzed by GLC in cheddar slurry with 0.00001% lipase was similar to that of commercial cheddar cheese, while that in Italian-type slurry was a half of that in commercial Italian cheese. Active SH groups were increased in the cheese slurries with glutathione from fourth day of fermentation. The viscosity of slurries decreased very rapidly by addition of protease.