• Food Science of Animal Resources
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• v.39 no.1
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• pp.73-83
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• 2019

The aim of this study was to investigate the effect of glucose oxidase (GOX) immobilized on magnetic chitosan nanoparticles (MCNP) on the viability of probiotic bacteria and the physico-chemical properties of drinking yogurt. Different concentrations (0, 250, and 500 mg/kg) of free and immobilized GOX were used in probiotic drinking yogurt samples. The samples were stored at $4^{\circ}C$ for 21 d. During storage, reduction of the number of probiotic bacteria in the samples with enzyme was lower than the control sample (without enzyme). The sample containing 500 mg/kg immobilized enzyme had the highest number of Bifidobacterium lactis and Lactobacillus acidophilus. The samples containing immobilized enzyme had lower acidity than other samples. Moreover, moderate proteolytic activity and enough contents of flavor compounds were observed in these samples. It can be concluded that use of immobilized GOX is economically more feasible because of improving the viability of probiotic bacteria and the physico-chemical characteristics of drinking yogurt.

• Food Science of Animal Resources
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• v.41 no.2
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• pp.261-273
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• 2021

Leuconostoc mesenteroides H40 (H40) was isolated from kimchi, and its probiotic properties and neuroprotective effect was evaluated in oxidatively stressed SH-SY5Y cells. H40 was stable in artificial gastric conditions and can be attached in HT-29 cells. In addition, H40 did not produce β-glucuronidase and showed resistant to several antibiotics. The conditioned medium (CM) was made using HT-29 cells refined with heat-killed probiotics (Probiotics-CM) and heated yogurts (Y-CM) to investigate the neuroprotective effect. Treatment with H40-CM not only increased cell viability but also significantly improved brain derived neurotropic factor (BDNF) expression and reduced the Bax/Bcl-2 ratio in oxidatively stress-induced SH-SY5Y cells. Besides, probiotic Y-CM significantly increased BDNF mRNA expression and decreased Bax/Bcl-2 ratio. The physicochemical properties of probiotic yogurt with H40 was not significantly different from the control yogurt. The viable cell counts of lactic acid bacteria in control and probiotic yogurt with H40 was 8.66 Log CFU/mL and 8.96 Log CFU/mL, respectively. Therefore, these results indicate that H40 can be used as prophylactic functional dairy food having neuroprotective effects.

• Food Science of Animal Resources
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• v.33 no.3
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• pp.363-368
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• 2013

The main attributes of yogurt that affect consumer satisfaction are taste, consistency, and a firm texture. This study evaluates the influence of xanthan gum, barley beta-glucan, and guar gum in concentrations of 0.05%, 0.1%, 0.2%, and 0.3% on probiotic yogurt. The set-type yogurt samples were prepared by using raw cow's milk. The statistical analysis showed that none of these gum additions had any marked effect on pH, titratable acidity, total solids content, and probiotic bacteria counts of yogurt samples. Evaluations for syneresis and water-holding capacity (WHC) in the yogurt samples were affected by the type and concentration of the stabilizer. Yogurts treated with 0.1% xanthan gum and 0.3% beta-glucan recorded the highest WHC and the least syneresis. The largest amount of gel firmness was recorded in yogurt samples treated with 0.2% xanthan gum and 0.3% beta-glucan. Yogurt samples treated with 0.1% xanthan gum and 0.3% beta-glucan were considered acceptable by trained panelists and gained the highest scores in sensory evaluations. The correlation coefficient between the amount of syneresis, WHC and stiffness of texture was significant compared to scores for sensory evaluation (p<0.01). Results for effects of guar gum on the tested parameters were contrary to the results expected from a gum. According to this study, the use of xanthan gum and beta-glucan are highly recommended for low-fat yogurt production.

• Food Science of Animal Resources
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• v.38 no.6
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• pp.1160-1167
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• 2018

The objective of this study was to evaluate the composition, pH, titratable activity, microbial properties, and antioxidant effect of yogurt using ginseng extract powder (GEP), Lactobacillus plantarum NK181, and Streptococcus thermophilus as the starter culture. Different concentration of GEP (0%, 0.5%, 1%, 1.5%, and 2% (w/v)) were used in the yogurt. During yogurt fermentation, pH was decreased; however, titratable acidity and viable cell counts were increased. The addition of GEP to yogurt led to a decrease in moisture content and an increase in the fat, ash, and total solids content. The antioxidant effect using 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging, ${\beta}$-carotene bleaching, and ferric reducing antioxidant power (FRAP) assay gradually increased with added GEP. Overall, yogurt fermented with 1% GEP was acceptable in terms of cell viability and antioxidant effect. These results might provide information regarding development of ginseng dairy products with enhanced antioxidant activities and probiotic properties.

• Journal of Dairy Science and Biotechnology
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• v.41 no.1
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• pp.9-25
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• 2023

Yogurt fermentation is known to be beneficial because it provides a low pH and harsh environment for foodborne pathogens and improves organoleptic properties. Additionally, organic acids produced through fermentation have a good effect on the viscosity and gelling properties of yogurt. Several potential health benefits of probiotic and generally recognized as safe strains have been suggested. Yogurt is the preferred vehicle for delivering probiotics to health-conscious consumers. Therefore, manufacturers of probiotic beverages must comply with the relevant regulations. The development of probiotic yogurt begins with the selection of strains with safety and functional properties of probiotics. The selected probiotic strain should be technically suitable for viability and improve organoleptic quality while maintaining the number of bacteria above the standard value during processing and storage conditions. In addition, the efficacy of probiotic strains contained in yogurt should be investigated, confirmed, and approved according to well-designed clinical trials. Although various methods are used to detect probiotic strains, the recently widely used next generation sequencing method can be actively utilized. In the future, more research should be conducted with the latest methods to identify probiotic functions and accurately detect probiotic strains.

• 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.

• Food Science and Biotechnology
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• v.17 no.5
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• pp.1025-1031
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• 2008

S-Adenosyl-L-methionine (SAM) exerts several beneficial effects on depression, chronic diseases, and cognitive impairments. Bifidobactrium bifidum BGN4 reportedly produces higher amounts of SAM than any other lactic acid bacterium used in yogurt. The aim of this study was to develop a SAM-reinforced probiotic yogurt using Bifidobacterium. The sensory aspects of the yogurt via response surface methodology (RSM) and the texture and SAM content of the yogurt were assessed. Based on the sensory assessments for sweetness, sourness, and thickness evaluated by 48 panelists, the optimized conditions for preparation of SAM-reinforced yogurt were 4.0-4.4%(w/w) sugar, 3.2-3.5%(w/w) skim milk, and a pH of 4.7-4.8. The SAM content of the developed yogurt was 0.05 nmol/mL. In conclusion, SAM-reinforced probiotic yogurt may provide a vehicle for the potential exploitation of the benefits of increased dietary SAM.

• Food Science and Preservation
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• v.24 no.5
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• pp.559-564
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• 2017

Yogurt contains many microorganisms that are beneficial to human health, and is a probiotic that supplies many nutrients such as calcium and protein. It is difficult to safety preserve for a long time because it possesses a high content of water. To address this problem, powdered "instant" yogurt has been developed, but it has flaws low flowability and solubility. Therefore, yogurt was granulated using a fluidized bed granulator to increase flowability and solubility. The fluidized bed granulator was designed by using response surface methodology (RSM), whose variables were feeding rate (FR), atomization air pressure (AP) and product temperature (PT). After being granulated, the yogurt was analyzed for yield and lactic acid bacteria count. The maximum yield of yogurt granules was 79.42%, at FR of 0.54 mL/min, AP of 2.64 kPa, and PT of $58.18^{\circ}C$, and the colony count for lactic acid bacteria was more than $6log^{10}\;CFU/g$. Therefore, spherical granulation of yogurt using a fluidized bed granulator could be used for making convenient probiotic products with improved flowability and solubility.

• Korean Journal of Microbiology
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• v.53 no.2
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• pp.103-117
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• 2017

The aim of this study was to evaluate the effect of green tea extract on probiotic potential, physico-chemical and functional properties of yogurt fermented with Lactobacillus acidophilus D11 or Lactobacillus fermentum D37 strains isolated from Doenjang. Probiotic activities such as the resistance to artificial digestive juices and the ability to adhere to epithelial cells were slightly higher in yogurt supplemented with green tea extract than in plain yogurt, which may be attributed to the increase in the number of lactic acid bacteria (LAB) by green tea extract supplementation. Furthermore, the microbiological and physico-chemical properties such as the number of LAB, organic acid production and viscosity were significantly (P<0.05) increased in yogurt added green tea extract compared to plain yogurt fermented with L. acidophilus D11. However, the green tea extract did not significantly (P>0.05) affect these properties of yogurt fermented with L. fermentum D37 strain. Meanwhile, the antibacterial activities against Escherichia coli O157 ATCC 43889, Salmonella enteritidis ATCC 13076, and Salmonella typhimurium KCTC 2514 and antioxidant activities including total phenol content, radical scavenging ability, and ferric-reducing antioxidant power were significantly higher in plain yogurt fermented with L. fermentum D37 than with L. acidophilus D11. The antibacterial and antioxidant activities of the yogurt were significantly (P<0.05) increased in proportion to the concentration of green tea extract added to plain yogurt. Consequently, green tea yogurt fermented with L. acidophilus D11 or L. fermentum D37 was considered to be a useful functional food that can inhibit the growth of pathogenic bacteria and scavenge the free radicals from the body cells.

• Journal of Microbiology and Biotechnology
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• v.30 no.6
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• pp.903-911
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• 2020

Addition of probiotics to yogurt with desired health benefits is gaining increasing attention. To further understand the effect of probiotic Lactobacillus plantarum on the quality and function of fermented milk, probiotic fermented milk (PFM) made with probiotic L. plantarum K25 and yogurt starter (L. delbrueckii ssp. bulgaricus and Streptococcus thermophilus) was compared with the control fermented milk (FM) made with only the yogurt starter. The probiotic strain was shown to survive well with a viable count of 7.1 ± 0.1 log CFU/g in the PFM sample after 21 days of storage at 4℃. The strain was shown to promote formation of volatiles such as acetoin and 2,3-butanediol with milk fragrance, and it did not cause post-acidification during refrigerated storage. Metabolomics analysis by GC-MS datasets coupled with multivariate statistical analysis showed that addition of L. plantarum K25 increased formation of over 20 metabolites detected in fermented milk, among which γ-aminobutyric acid was the most prominent. Together with several other metabolites with relatively high levels in fermented milk such as glyceric acid, malic acid, succinic acid, glycine, alanine, ribose, and 1,3-dihydroxyacetone, they might play important roles in the probiotic function of L. plantarum K25. Further assay of the bioactivity of the PFM sample showed significant (p < 0.05) increase of ACE inhibitory activity from 22.3% at day 1 to 49.3% at day 21 of the refrigerated storage. Therefore, probiotic L. plantarum K25 could be explored for potential application in functional dairy products.