Grapefruit extract rich in functional substances adjusting pH 5.0 and adding sucrose (final concentration, 2%) was fermented by Leuconostoc mesenteroides CJNU 0147 strain, consequently prepared a fermented grapefruit extract containing dextran. As a result of analyzing the growth inhibitory effect on gut harmful bacterium Clostridium difficile strain using the prepared fermented grapefruit extract, the viable cell count was significantly reduced (p<0.05 vs. control for 0.5 brix as a final concentration; p<0.001 vs. control for 1.0 brix). On the other hand, the proliferative ability of the extract for Bifidobacterium breve strain, which is one of the species of the genus Bifidobacterium well known as human gut beneficial bacteria, was confirmed (p<0.001 vs. control for both 0.5 and 1.0 brix). These results indicate fermented grapefruit extract with Leu. mesenteroides CJNU 0147 strain inhibits the growth of gut harmful bacterium C. difficile and promotes the proliferation of beneficial bacterium B. breve and is expected to be used as a functional food material for gut health.

Leuconostoc spp. are generally utilized as kimchi starters, because these strains are expected to have beneficial effects on kimchi fermentation, including improvement of sensory characteristics. Here, we developed a detection method for verifying the presence of the kimchi starter Leuconostoc mesenteroides WiKim33, which is used for control of kimchi fermentation. A primer set for multiplex polymerase chain reaction was designed based on the nucleotide sequence of the plasmids in strain WiKim33, and their specificity was validated against 45 different strains of Leuconostoc spp. and 30 other strains. Furthermore, the starter strain consistently tested positive, regardless of the presence of other bacterial species in starter kimchi during the fermentation period. Our findings showed that application of a strain-specific primer set for strain WiKim33 presented a rapid, sensitive, and specific method for detection of this kimchi starter strain during natural kimchi fermentation.

본 연구에서는 김치로부터 L. mesenteroides CJNU0041 을 분리하여 16S rRNA 염기서열 분석을 통해, 동정하였 으며, β-glucosidase 활성이 우수한 것으로 나타났다. L. mesenteroides CJNU0041를 이용한 브로콜리 발효 동안 생 균수와 pH 및 β-glucosidase 활성에 대해 분석한 결과, 발효 시간은 48 hours이 적당한 것으로 판단되었다. 또한, 발효 후 생물 전환이 일어남을 HPLC 분석을 통해 확인 하였다. 그리고, L. mesenteroides CJNU0041의 브로콜리 발효물에서 C. difficile에 대한 생육 억제 효과를 확인 할 수 있었다. 따라서, 본 연구를 통해 분리된 신규 L. mesenteroides CJNU0041을 C. difficile의 생육 제어를 위한 유산균 제재화가 가능할 것으로 판단되며, 브로콜리 발효물도 다양한 식품에 적용이 가능할 것으로 사료된다.

Many traditional fermented foods contain diverse bacteria and many lactic acid bacteria (LAB) play important roles for the fermentation of foods such as many dairy foods and kimchi. Especially, Leuconostoc mesenteroides is one of major bacteria in those fermented foods and the development of this species would be expected to be critical for strain improvement as well as the industrialization. Up to now, a lot of plasmids were isolated from Leuconostocs species including Leu. mesenteroides and a number of vector systems has been developed. Many plasmid vector systems using Leuconostocs spp. employ RCR (rolling circle replication) producing single-stranded DNA intermediates or sometimes takes theta replication. These plasmids include the sequences for Pre protein, recombination specific sites such as RSA (recombination site A) and RSB (recombination site B), and single strain origins for RCR replication. This information might be helpful to elucidate the improvement of Leuconostocs spp. and moreover the development of diverse products using Leuconostocs spp.

효소반응과 부분 산가수분해 결과를 해석하여 Leuconostoc mesenteriodes M-12 덱스트란수크라제 억셉터 반응 산물이 새로운 분지올리고당의 구조를 확인하였다. 분지올리고당 B_4의 구조는6^2-O-α-D-kojibiosylmaltose인 것으로 확인되었으며, 분지올리고당 B_5의 구조는 6^3-O-α-D-kojibiosylpanose였다. 억셉터 반응산물을 덱스트라나제로 분해한 결과 새로운 올리고당인 D_4를 확인할 수 있었다. 억셉터 반응의 산물을 억셉터로 이용한 두 번째 억셉터 반응의 생성물을 덱스트라나제 처리하여 D_4를 얻었는데 덱스트라나제와 글루코아밀라제에 의해 분해되지 않았다. 그 구조는 6^2-O-α-D-kojibiosylisomaltose로 확인되었다. 직선상 또는 분지결합을 가진 d.p. 6이하의 억셉터 반응산물의 생성 패턴도 확인하였다.

Sweet pumpkin paste (SPP) was fermented by Leuconostoc mesenteroides SM at 25℃ for 3 days for enhancing its physicochemical properties. SPPs with 5%, 10%, and 15% solid contents (SC) were fortified with 20% sucrose and 0.5% yeast extract. The unfermented SPP with 15% SC indicated L, a, and b color values of 25.02, 4.66, and 13.35, respectively, and a consistency index of 48.6 Pa·sn. During the 3 days of fermentation, both the a and b color values decreased slightly, whereas the consistency index increased to 188.8 Pa·sn, giving the fermented product a pudding-like consistency. This fermented SPP (15% SC) showed the highest acid production and viable cell counts among samples, indicating pH 3.85, 1.30% acidity and 9.2×108 CFU/mL respectively. The added sucrose was completely utilized after 1 day of fermentation. After 3 days, the insoluble and soluble dextran contents were 8.9% and 4.5%, respectively. Furthermore, the contents of mannitol and fructose were 3.11% and 1.76%, respectively. Regarding the sensory evaluation, this fermented sample also indicated the highest color, taste and texture scores, and was the overall preferred sample. In conclusion, the fermented SPP with 15% SC was carotinoid-rich a wholesome pumpkin-based product that is rich in probiotics and lactic bacteria-produced mannitol and dextran, which gave the product an acceptable viscous pudding-like consistency and good organoleptic properties.

Antioxidant activity is important for reducing oxidative stress that causes various metabolic disorders. Metabolic disorders are highly related to loss of productivity in livestock. Therefore, development of effective antioxidant compounds originating from plants is important for organic agriculture. Phenolic compounds in edible plants are regarded as major components relevant to antioxidant activity. The present study investigated the changes in antioxidant activity and phenolic compound profiles of Aronia (Aronia meloncarpa) by fermentation using different strains of Leuconostoc mesenteroides. A total of 5 strains of L. mesenteroides were used as starter cultures and their β-glucosidase activities were measured. A total of 6 experiment runs were prepared, one for control (uninoculated) and the others (inoculated) for treatments. For biological activity, antioxidant and antibacterial activities were measured. For phenolic compound profiling, TLC and HPLC analysis were performed. The strains of KACC12313 and KACC12315 showed greater enzyme activity than others. Treatment with KCCM35046 showed strong and broad antibacterial activity against to Listeria monocytogenes. Treatments with KCCM35046 and KACC12315 showed the highest total polyphenol content. The highest antioxidant activity was found in KACC12315 treatment. No remarkable alteration was found in thin layer chromatography (TLC) analysis. In phenolic compound profiling analysis, KCCM35046 showed notable alteration in compound area ratio compared to others and also showed the highest caffeic acid content. In chlorogenic acid, treatments with KCCM35046 and KACC12315 showed great content than others. Treatment with KACC12315 showed the greatest content of trans-ferulic acid. As a result of relative performance indexing analysis, L. mesenteroides KCCM35046 and KACC12315 were selected as the best strain for the fermentation of Aronia.

동치미에서 분리한 유산균인 Leu. mesenteroides subsp.cremoris DLAB19 균주의 aflatoxin Bl에 대한 항 돌연변이원성 물질 생산을 위한 최적 조건을 조사한 결과, 탄소원으로 glucose를 첨가시 가장 높은 항 돌연변이 효과를 나타내었으며, 질소원으로서는 yeast extract 첨가시 항 돌연변이 효과가 우수하였다. 탄소원으로 glucose의 농도을 2 첨가시aflatoxin Bl에 대한 항 돌연변이 효과가