• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.1
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• pp.75-80
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• 2002

The growth inhibition by nisin-Producing lactococci against Bacillus subtilis and its application to doenjang fermentation were investigated. Lactococcus lactis subsp. lactis IFO 12007, L. lactis subsp. lactis ATCC 7962 and L. lactis subsp. lactis ATCC 11454 were used as nisin-producing lactococci. All of three strain rapidly proliferated to more than 10$^{9}$ CFU/g in steamed soybeans. Only L. lactis subsp. lactis IFO 12007 was in steamed soybean without any pH decrease. In spite of the mild decrease in pH, the growth of B. subtilis was completely inhibited; no living cells were detected in a soybean sample inoculated with 10$^{6}$ CFU/g and incubated for 24 to 72h. The L. lactis subsp. lactis IFO 12007 was applied to doenjang fermentation as a starter culture. It produced high nisin activity in steamed soybean, resulting in the complete growth inhibition of B. subtilis, which had been inoculated at the beginning of the meju fermentation, throughout the process of doenjang production. Over-acidification, which is undesirable for doenjang quality, was successfully prevented simply by adding salt which killed the salt-intolerant L. lactis subsp. lactis IFO 12007. Furthermore, the nisin activity in doenjang disappeared with aging.

• Food Science and Preservation
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• v.22 no.6
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• pp.920-925
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• 2015

The microbial composition in Nuruk, a Korean cereal fermentation starter, is a critical factor for the quality and organoleptic properties of traditional alcoholic beverages. This study was aimed at monitoring the compositional change and enzyme activity of culturable lactic acid bacteria (LAB) in two types of Nuruk fermented at different temperatures. All culturable LAB were isolated at various time points (0, 3, 6, 10, 20, and 30 days) and identified by 16S rRNA sequencing. In traditional Nuruk type A (TN-A), which was fermented at $36^{\circ}C$, the population of total culturable LAB during the fermentation period was between $10^4$ and $10^5$ log CFU/mL. On the other hand, the LAB population in traditional Nuruk type B (TN-B) fermented at $45^{\circ}C$ (primary fermentation for 10 days) and $35^{\circ}C$ (secondary fermentation for 20 days) was $10^2$ log CFU/mL; however, these bacteria could not be detected after 6 days. Major LAB strains were identified in both Nuruk types: (1) from the MRS-culture of TN-A, Pediococcus pentosaceus at 3-30 days; (2) from MRS-culture of TN-B, P. pentosaceus at 3 days and Enterococcus hirae at 6 days. The protease activities of the dominant LAB isolated from the TN-A and TN-B cultures were within the ranges of 0.64~1.03 mg/mL and 0.74~0.81 mg/mL (tyrosine content), respectively, whereas the ${\alpha}$-amylase activities were 0.75~0.98 mg/mL and 0.78~0.79 mg/mL (amylose content), respectively.

• Korean Journal of Microbiology
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• v.51 no.4
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• pp.407-418
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• 2015

This study is focused on establishing the optimal conditions to enhance the production of antilisterial substances by Lactobacillus paracasei BK57 isolated from Baikkimchi. In addition, the growth and in situ lactic acid and bacteriocin production of this strain were investigated during the manufacture of fresh cheese. And then the efficacy of using Lactobacillus starter as a protective culture to improve the safety of fresh cheese against Listeria monocytogenes KCTC 3569 was estimated. Maximum growth rate and activity of antibacterial substances were obtained in Lactobacilli MRS broth at $37^{\circ}C$ with controlled pH 6.0 after 30 h of incubation under aerobic condition. However, the growth rate and antimicrobial activity of bacteriocin produced in whole milk supplemented with yeast extract (2.0%) as a substrate were lower than those obtained in MRS broth. Live cells and cell-free culture supernatant of BK57 strain were effective in the suppression of L. monocytogenes in milk, whereas the inhibitory of the bacteriocin obtained from BK57 strain was higher in BHI broth than in milk. During storage at $4^{\circ}C$ and $15^{\circ}C$ for 6 days, no significant difference was found in the cell viability and antimicrobial activity of BK 57 strain in fresh cheese. In samples held at two temperatures, there was at least a 15% reduction in the numbers of the pathogen in fresh cheese artificially contaminated with approximately $10^5CFU/ml$ of L. monocytogenes within 6 days. Our results demonstrated the usefulness of L. paracasei BK57 having antilisterial activity as a biopreservative in the cheese making process.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.8
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• pp.1030-1036
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• 2008

In Korea, many types of traditional grape wine have existed starting from seven hundred years ago and horse-blossom-like-grape (mayu-podo) was mainly cultivated. Korean traditional wine (KTW) was manufactured by a unique method in which grape juice-added porridge made from glutinous rice was fermented by nuruk as a starter for brewing. Unfortunately, KTW making was discontinued in 20th century; thus, restoration of Korean wine culture is needed. KTWs were prepared by four traditional methods, and their qualities were compared to commercial wine made by sugaring grape juice. Ethyl alcohol contents, total acidity, pH and amino acid of the four KTWs were $9.2{\sim}11.2%$, $0.93{\sim}1.20\;mg$/100 mL, $3.02{\sim}3.48$ and $0.80{\sim}0.88\;mg$/100 mL respectively. The KTWs showed higher values in total acidity and amino acid than those of commercial grape wine. KTWs were rich in maltose, acetic acid and lactic acid. L, a and b value in Hunter's color value ranged $3.59{\sim}3.69$, $20.63{\sim}38.06$, and $1.20{\sim}1.56$, respectively. Sensory quality properties in color, flavor, taste and overall of KTWs were not different from commercial dry wine. Contents of total phenolic compounds and free radical scavenging activity using DPPH of KTWs were $599.6{\sim}652.2\;mg$/100 mL and $50.59{\sim}56.75%$, respectively.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.10
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• pp.1398-1405
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• 2016

The effects of Sparassis crispa extracts fermented with isolated strain from S. crispa on antioxidant and immunological activities were determined. S. crispa extracts fermented with Meyerozyma guilliermondii FM showed significantly higher total phenol contents and DPPH radical scavenging activities compared to those fermented with lactic acid bacteria. In methotrexate-induced immunosuppressed rats, reduced levels of tumor necrosis factor (TNF)-${\alpha}$, interleukin (IL)-2, and immunoglobulin E (IgE) and increased levels of IL-10 were detected in S. crispa extract injected groups regardless of fermentation. We confirmed that rats treated with S. crispa fermented with M. guilliermondii FM showed higher blood leukocyte contents compared to other treatments. These results suggest that M. guilliermondii FM has high potential as a starter culture for fermentation of S. crispa extracts with increased antioxidant and immunological activities.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.11
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• pp.1308-1315
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• 2017

This study was conducted to develop Momordica charantia L. juice fermented by four Lactobacillus species such as Lactobacillus paracasei (LPA), Lactobacillus plantarum (LPL), Lactobacillus rhamnosus (LRH), and Lactobacillus reuteri (LRE) as well as to investigate their inhibitory effects against digestive enzymes and antioxidant activities. Fermentation was performed at $37^{\circ}C$ without nutrient supplementation for 72 h. The pH and total lactic acid contents were within the ranges of 3.75~3.96 and 5.21~10.04% in fermented juices, respectively. The type of starter culture and fermentation time induced changes in flavonoid contents more than total phenolic contents. All juices fermented for 48 h strongly inhibited ${\alpha}$-glucosidase activity with the percentage of inhibition ranging of 91.24~95.05%. Antioxidant activities of all juices mostly increased after 48 h of fermentation. Our results suggest that fermented juice possesses inhibitory activity against digestive enzymes and antioxidant activity, and they can be used as health functional beverages.

• 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.

• Journal of Dairy Science and Biotechnology
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• v.32 no.2
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• pp.77-92
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• 2014

Fermented foods have often been implicated as causative agents in poisoning due to toxic levels of biogenic amines. Cheese, a milk-based fermented food, is the product most likely to contain potentially harmful levels of biogenic amines, such as tyramine, histamine, putrescine, and so on. Recently, the risk awareness of a dietary uptake of high loads of biogenic amines has increased. Hence, we here review the published literature on several factors known to affect the biosynthesis of biogenic amines and their accumulation in milk-based foods. Furthermore, with regard to risk analysis, we discuss the control of factors related to the synthesis and accumulation of biogenic amines as a means to reduce their incidence in milk-based products, and thus to increase food safety.