• Journal of Microbiology and Biotechnology
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• 제24권6호
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• pp.795-802
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• 2014

The aim of this study was to determine the effects of temperature and supplementation with skim milk powder (SMP) on the microbial and proteolytic properties during the storage of cottage cheese. Cottage cheese was manufactured using skim milk with 2% SMP and without SMP as the control, and then stored at $5^{\circ}C$ or $12^{\circ}C$ during 28 days. The chemical composition of the cottage cheese and the survival of the cheese microbiota containing starter lactic acid bacteria (SLAB) and non-starter culture lactic acid bacteria (NSLAB) were evaluated. In addition, changes in the concentration of lactose and lactic acid were analyzed, and proteolysis was evaluated through the measurement of acid soluble nitrogen (ASN) and non-protein nitrogen (NPN), as well as electrophoresis profile analysis. The counts of SLAB and NSLAB increased through the addition of SMP and with a higher storage temperature ($12^{\circ}C$), which coincided with the results of the lactose decrease and lactic acid production. Collaborating with these microbial changes, of the end of storage for 28 days, the level of ASN in samples at $12^{\circ}C$ was higher than those at $5^{\circ}C$. The NPN content was also progressively increased in all samples stored at $12^{\circ}C$. Taken together, the rate of SLAB and NSLAB proliferation during storage at $12^{\circ}C$ was higher than at $5^{\circ}C$, and consequently it led to increased proteolysis in the cottage cheese during storage. However, it was relatively less affected by SMP fortification. These findings indicated that the storage temperature is the important factor for the quality of commercial cottage cheese.

• 한국미생물·생명공학회지
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• 제48권4호
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• pp.533-538
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• 2020

To investigate the effect of the predominant microorganisms in kimchi on quality, Leuconostoc mesenteroides ATCC 8293 was used as starter culture during kimchi fermentation. A higher number of lactic acid bacteria and lower initial pH were observed in starter kimchi than in non-starter kimchi in the early stage of fermentation. The concentrations of the main metabolite, lactic acid, were 69.88 mM and 83.85 mM for the non-starter and starter fermented kimchi, respectively. The free sugar concentrations of starter kimchi decreased earlier than those of non-starter kimchi, and the levels of free sugars in both kimchi samples decreased during fermentation. At the end of fermentation, non-starter kimchi had a softer texture than starter kimchi, suggesting that L. mesenteroides is useful in extending shelf life. Sensory evaluation showed that starter kimchi had higher sourness and lower bitterness and astringency values, resulting in high sensory quality. These results suggest that the L. mesenteroides ATCC 8293 strain could be a potential starter culture in kimchi.

• 육가공
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• 통권35호겨울호
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• pp.46-55
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• 2008

본 연구의 목적은 시판 중인 스타터를 이용한 발효육제품과 스타터를 이용하지 않고 자연발효시킨 육제품의 발효 및 숙성 중 미생물학적, 이화학적인 특성에 미치는 영향을 연구하고, 원료육에서의 전자선 조사(2 kGy) 효과를 검증하고자 한다. 2 kGy로 전자선 조사한 스타터 첨가구는 발효 및 숙성 중 pH가 급격히 감소하였으며(p<0.05), 최종 pH 는 4.25를 나타내었다. 총균수와 젖산균수는 스타터 첨가에 의해 좌우되는데 발효가 진행됨에 따라 총균수와 젖산균수가 유사한 경향을 나타내었다. TBARS 값은 발효 및 숙성기간이 증가함에 따라 모든 처리구에서 증가하였다. 본 연구결과를 통해 발효육 생산 전 2 kGy로 전자선 조사처리한 경우 총균수를 감소시키고 젖산균수는 증식하는 것을 확인하였다. 조사처리 후 육에 스타터를 첨가하게 되면 발효육 생산에 매우 유용하게 이용될 수 있을 것으로 사료된다.

• 한국축산식품학회지
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• 제27권3호
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• pp.308-313
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• 2007

본 연구의 목적은 시판 중인 스타터를 이용한 발효육제품과 스타터를 이용하지 않고 자연발효시킨 육제품의 발효 및 숙성 중 미생물학적, 이화학적인 특성에 미치는 영향을 연구하고, 원료육에서의 전자선 조사(2 kGy) 효과를 검증하고자 한다. 2 kGy로 전자선 조사한 스타터 첨가구는 발효 및 숙성 중 pH가 급격히 감소하였으며(p<0.05), 최종 pH 는 4.25를 나타내었다. 총균수와 젖산균수는 스타터 첨가에 의해 좌우되는데 발효가 진행됨에 따라 총균수와 젖산균수가 유사한 경향을 나타내었다. TBARS 값은 발효 및 숙성기간이 증가함에 따라 모든 처리구에서 증가하였다. 본 연구결과를 통해 발효육 생산 전 2 kGy로 전자선 조사처리한 경우 총균수를 감소시키고 젖산균수는 증식하는 것을 확인하였다. 조사처리 후 육에 스타터를 첨가하게 되면 발효육 생산에 매우 유용하게 이용될 수 있을 것으로 사료된다.

• Journal of Microbiology and Biotechnology
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• 제34권3호
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• pp.622-633
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• 2024

For quality standardization, the application of functional lactic acid bacteria (LAB) as starter cultures for food fermentation is a well-known method in the fermented food industry. This study assessed the effect of adding a non-thermally microbial inactivated starter culture to kimchi, a traditional Korean food, in standardizing its quality. In this study, pretreatment based on sterilization processes, namely, slightly acidic electrolyzed water (SAEW) disinfection and ultraviolet C light-emitting diode (UVC-LED) of raw and subsidiary kimchi materials were used to reduce the initial microorganisms in them, thereby increasing the efficiency and value of the kimchi LAB starter during fermentation. Pretreatment sterilization effectively suppressed microorganisms that threatened the sanitary value and quality of kimchi. In addition, pretreatment based on sterilization effectively reduced the number of initial microbial colonies in kimchi, creating an environment in which kimchi LAB starters could settle or dominate, compared to non-sterilized kimchi. These differences in the initial microbial composition following the sterilization process and the addition of kimchi LAB starters led to differences in the metabolites that positively affect the taste and flavor of kimchi. The combined processing technology used in our study, that is, pre-sterilization and LAB addition, may be a powerful approach for kimchi quality standardization.

• 한국축산식품학회지
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• 제39권5호
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• pp.804-819
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• 2019

Ezine cheese is a non-starter and long-ripened cheese produced in the Mount of Ida region of Canakkale, Turkey, with a protected designation of origin status. Non-starter lactic acid bacteria (NSLAB) have a substantial effect on the quality and final sensorial characteristics of long-ripened cheeses. The dominance of NSLAB can be attributed to their high tolerance to the hostile environment in cheese during ripening relative to many other microbial groups and to its ability to inhibit undesired microorganisms. These qualities promote the microbiological stability of long-ripened cheeses. In this study, 144 samples were collected from three dairies during the ripening period of Ezine cheese. Physicochemical composition and NSLAB identification analyses were performed using both conventional and molecular methods. According to the results of a 16S rRNA gene sequence analysis, 13 different species belonging to seven genera were identified. Enterococcus faecium (38.42%) and E. faecalis (18.94%) were dominant species during the cheese manufacturing process, surviving 12 months of ripening together with Lactobacillus paracasei (13.68%) and Lb. plantarum (11.05%). The results indicate that NSLAB contributes to the microbiological stability of Ezine cheese over 12 months of ripening. The isolation of NSLAB with antimicrobial activity, potential bacteriocin producers, yielded defined collections of natural NSLAB isolates from Ezine cheese that can be used to generate specific starter cultures for the production of Ezine cheese (PDO).

• Journal of Microbiology and Biotechnology
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• 제30권9호
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• pp.1404-1411
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• 2020

Lactic acid bacteria (LAB) play an important role in dairy fermentations, notably as cheese starter cultures. During the cheese production and ripening period, various enzymes from milk, rennet, starter cultures, and non-starter LABs are involved in flavor formation pathways, including glycolysis, proteolysis, and lipolysis. Among these three pathways, starter LABs are particularly related to amino acid degradation, presumably as the origins of major flavor compounds. Therefore, we used several enzymes as major criteria for the selection of starter bacteria with flavor-forming ability. Lactococcus lactis subsp. lactis LDTM6802 and Lactococcus lactis subsp. cremoris LDTM6803, isolated from Korean raw milk and cucumber kimchi, were confirmed by using multiplex PCR and characterized as starter bacteria. The combinations of starter bacteria were validated in a miniature Gouda-type cheese model. The flavor compounds of the tested miniature cheeses were analyzed and profiled by using an electronic nose. Compared to commercial industrial cheese starters, selected starter bacteria showed lower pH, and more variety in their flavor profile. These results demonstrated that LDTM6802 and LDTM6803 as starter bacteria have potent starter properties with a characteristic flavor-forming ability in cheese.

• Journal of Microbiology and Biotechnology
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• 제30권7호
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• pp.1060-1066
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• 2020

This study was focused on developing and obtaining a kimchi starter for use in commercial kimchi production. Kimchi varieties made with selected starters are of high quality, have high levels of mannitol, and extended shelf life. The starters were screened for properties such as mannitol production, low gas/acid production, and acid resistance. Finally, kimchi fermentation testing was performed using selected LAB starters. Kimchi samples were prepared with lactic acid bacteria (LAB) starters, including Leuconostoc mesenteroides PBio03 and Leuconostoc mesenteroides PBio104. The LAB starters are isolated from kimchi and can grow under pH 3.0 and low temperature conditions of 5℃. Four kimchi samples were fermented and stored for 28 days at 5℃. The kimchi samples made with starters (PBio03 and PBio104) had better quality (production of mannitol and maintenance of heterofermentative LAB dominance) than the non-starter kimchi samples. In the starter kimchi, Leu. mesenteroides was the dominant LAB, comprising 80% and 70% of total LAB counts at 7 and 21 days, respectively. Mannitol content of the kimchi with Leu. mesenteroides PBio03 was 1,423 ± 19.1 mg/100 g at 28 days, which was higher than that of the non-starter kimchi sample (1,027 ± 12.2 mg/100 g). These results show the possibility of producing kimchi with improved qualities using Leu. mesenteroides PBio03 and PBio104 as starters.

• 한국미생물·생명공학회지
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• 제47권3호
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• pp.343-349
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• 2019

Gul jeotgals (GJs) were prepared using solar salt aged for 3 years. One sample was fermented using starters, such as Bacillus subtilis JS2 and Tetragenococcus halophilus BS2-36 (each $10^6CFU/g$), and another sample was fermented without starters for 49 days at $10^{\circ}C$. Initial counts of bacilli and lactic acid bacteria (LAB) in non-starter GJ were found to be $3.20{\times}10^2$ and $7.67{\times}10^1CFU/g$ on day 0, and increased to $1.37{\times}10^3$ and $1.64{\times}10^6CFU/g$ on day 49. Those of starter GJ were found to be $2.10{\times}10^5$ and $3.30{\times}10^7CFU/g$ on day 49, indicating the growth of starters. The pH values of GJ were $5.93{\pm}0.01$ (non-starter) and $5.92{\pm}0.01$ (starter) on day 0 and decreased to $5.78{\pm}0.01$ (non-starter) and $5.75{\pm}0.01$ (starter) on day 49. Amino-type nitrogen (ANN) production increased continuously during fermentation, and $407.19{\pm}15.85$ (non-starter) and $398.04{\pm}13.73$ (starter) mg% on day 49. Clone libraries of 16S rRNA genes were constructed from total DNA extracted from non-starter GJ on days 7, 21, and 42. Nucleotide sequences of Escherichia coli transformants harboring recombinant pGEM-T easy plasmid containing 16S rRNA gene inserts from different bacterial species were analyzed using BLAST. Uncultured bacterium was the most dominant group and Gram - bacteria such as Acidovorax sp., Afipia sp., and Variovorax sp. were the second dominant group. Bacillus amyloliquefaciens (day 7), Bacillus velezensis (day 21 and 42), and Bacillus subtilis (day 42) were observed, but no lactic acid bacteria were detected. Acidovorax and Variovorax species might play some role in GJ fermentation. Further studies on these bacteria are necessary.

• 미생물학회지
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• 제35권4호
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• pp.307-314
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• 1999

본 연구는 동치미에서 유산균을 분리하여 동치미의 가능성이 강화된 무 주스를 제조하기 위한 starter로써의 가능성을 검토하기 위하여 유산균의 발효특성을 조사하였다. 동치미에서 분리 동정된 40 균주는 당 발효능과 양상에 따라 5개의 group으로 분류되었다. Species별 분포를 살펴본 결과는 Leuconostoc mesenteroides, Lactobacillus brevis, Lactobacillus sake, Lactobacillus plantarum, Lactobacillus fermentum의 5개 균종이었으며, 유산균의 분포는 Leuconostoc mesenteroides가 52.5%로 최 우점종으로 나타났다. 분리된 5개의 group에서 가장 생육능이 왕성한 1개 균주씩 Leuconostoc mesenteroides J-9, Lactobacillus brevis J-12, Lactobacillus plantarum J-39, Lactobacillus fermentum J-7 등 5균주를 선정하여 한외 여과한 무즙에 각각 0.3($10^6$ cfu/㎖)%씩 접종하여 25${\circ}C$에서 9일간 숙성하면서 pH 및 총 산도, 비휘발성유기산함량의 변화 등을 조사하였다. 각 접종 균주 중 Lactobacilus plantarum의 생육능이 가장 빠르게 나타났으며 Lactobacillus sake가 가장 느리게 성장하였다. 발효 개시 전의 한외 여과한 무즙의 pH 및 총 산도는 6.30~6.36, 0.09~1.0%이었으나 9일째 pH 3.2~4.3, 0.85~1.2%로 나타났다. 각 접종 균주의 pH, 산도의 변화를 비교해보면 미생물의 생육능과 상관성이 높아 유산균수의 증가속도가 빠를수록 pH는 빠르게 감소하고, 산도는 빠르게 증가하였다. 비휘발성 유기산의 변화를 보면 모든 접종구에서 시트르산, 말산, 말론산, 숙신산은 감소하는 경향으로 나타났으며 락트산은 발효가 진행됨에 따라 증가하였다. 관능적으로 맛에 좋은 영향을 주는 유기산으로 알려진 숙신산과 락트산의 함량을 보면 L. mesenteroides J-9가 가장 높게 나타났다. 락트산 단독의 경우는 L. plantarum J-39m, L. brevis J-12 접종구의 순으로 높게 나타났다. 이 ${\cdot}$ 화학적 검사와 향미에 대한 관능검사결과 L. mesenteroides J-9, L. brevis J-12, L. fermentum J-7이 무쥬스의 젖산발효를 위한 starter로써 적합한 것으로 나타났다.