배박에서 펙틴의 추출을 위한 Exo-polygalacturonase의 반응조건 검토

육현균(Hyun-Gyun Yuk),최진호(Jin-Ho Choi),조용진(Yong-Jin Cho),하정욱(Jung-Uk Ha),황용일(Yong-Il Hwang),이승철(Seung-Cheol Lee) 한국식품과학회 1999 한국식품과학회지 Vol.31 No.4

Gas Chromatography를 이용한 멸치젓의 DHA 분석

육현균,하정욱,이승철 慶南大學校 附設 工業技術硏究所 1998 硏究論文集 Vol.16 No.-

멸치젓은 한국의 고유 수산발효식품으로 널리 이용되고 있는 기호식품이다. 멸치젓의 기능성을 살펴보기 위한 기초연구로 기능성 소재인 docosahexaenoic acid (DHA) 함량을 gas chromatorgraphy를 이용하여 분석 하였다. 먼저 산분해법에 의해 고형분의 경우 평균 4,520 ppm 검출되었으며, 액젓의 경우 농축을 하지 않고 산분해법으로 처리한 것과 농축을 한 후 산분해법으로 처리하여 측정한결과 전자는 평균 108 ppm, 후자는 82 ppm으로 검출되었다. 또한 시간이 경과함에 따라 멸치 액젓이 DHA 함량이 감소되어 정확한 검출을 위해서는 항산화제의 첨가가 필요하다. The anchovy-jeot (salt-fermented anchovy) has being widely used as a traditional fish fermented food in Korea. For examining the functional characteristic of the anchovy-jeot, docosahexaenoic acid (DHA) was analyzed by gas chromatography. DHA contents of anchovy solid and anchovy sauce by acidolysis method was 4,520 ppm and 108 ppm, respectively, while that of anchovy sauce by acidolysis method after concentration was 82 ppm. That means that the condition of previous treatment for anchovy sauce would affect the determination of DHA. Furthermore, addition of antioxidant would be needed because DHA of anchovy-jeot was decreased with days by oxidation.

Stabilization of Retinol through Incorporation into Liposomes

이승철,육현균,이동훈,이경은,황용일,Richard D. Ludescher 생화학분자생물학회 2002 Journal of biochemistry and molecular biology Vol.35 No.4

Chemical and photochemical processes during storage and preparation rapidly degrade retinol, the most active form of vitamin A. therefore, the efficacy of incorporation into liposomes in order to modulate the kinetics of retinol degradation was investigated. Retinol was readily incorporated into multilamellar liposomes that were prepared form soybean phosphatidylcholine; the extent of the incorporation was 98.14±0.93% at pH 9.0 at a ratio of 0.01 : 1 (wt:wt) retinol : phospholipid. It was only marginally lower at higher retinol concentrations. The pH of the hydration buffer had a small effect. The incorporation efficiency ranged from 99.25±0.47% at pH 3 to 97.45±1.13% at pH 11. The time course of the retinol degradation in the aqueous solution in liposomes was compared to that of free retinol and free retinol with α-tocopherol under a variety of conditions of pH(3, 7, and 11), temperature(4, 25, 37, and 50℃), and light exposure(dark, visible, and UV). The retinol that was incorporated into the liposomes degraded significantly slower than the free retinol or retinol with α-tocopherol at pH 7 and 11. At pH 3, where the free retinol degrades rapidly, the degradation kinetics were similar in liposomes and the presence of α-tocopherol. At pH 7.0 and 4℃ in the light, for example, free aqueous retinol was completely degraded within 2 days, while only 20% of the retinol in the liposomes were degraded after 8 days. In general, the protective effect of the liposome incorporation was greater at low temperatures, at neutral and high pH, and in the dark. The results suggest that protection is greater in the solid, gel phase than in the fluid liquid crystalline phase lipids. These results indicate that the incorporation into liposomes can extend the shelf-life of retinol under a variety of conditions of temperature, pH, and ambient light conditions.

유기용매의 처리에 따른 Bacillus subtilis IFO 12113 유래 Protopectinase의 회수

이승철,육현균,황용일 ( Seung Cheol Lee,Hyun Gyun Yuk,Yong Il Hwang ) 한국응용생명화학회 1997 Applied Biological Chemistry (Appl Biol Chem) Vol.40 No.2

To recover protopectinase (PPase) secreted from Bacillus subtilis IFO 12113, culture filtrate of the microorganism was treated with acetone, methanol, and ethanol, respectively. In the case of treatment with acetone at a ratio of 1 : 1 (culture filtrate : acetone, v/v), PPase was purified 1.7-fold with 59.2% recovery. The recovery of PPase was increased by increasing the acetone concentration. PPase was purified 4-fold with 100% recovery when the culture filtrate was precipitated with methanol at a ratio of 1 : 2 (culture filtrate : methanol, v/v). However, recovery of PPase was decreased by increasing the methanol concentration. PPase was purified 13.5-fold resulting in 68% recovery by the addition of ethanol with the final ratio 1 : 1(culture filtrate : ethanol, v/v) to the supernatant, which was obtained after precipitation of the culture filtrate with ethanol at a ratio of 1 : 0.5. These results show that methanol treatment is better than other organic solvent treatments for the simple recovery of PPase, whereas fractionated treatment of ethanol can recover PPase with higher purification fold.

Mealworm larvae (Tenebrio molitor L.) exuviae as a novel prebiotic material for BALB/c mouse gut microbiota

권규택,육현균,이수정,Yi Hyung Chung,Han Su Jang,유종상,조경훈,공현석,신대근 한국식품과학회 2020 Food Science and Biotechnology Vol.29 No.4

The objective of this study was to evaluate the effect of yellow mealworm (Tenebrio molitor L.) exuviae (ME) given as a prebiotic in 20% of the diet fed to BALB/c mice. Analysis of the ME revealed that it was mostly composed of crude protein (52.94%), crude fiber (10.70%), and moisture (10.54%). When ME was fed to mice for 8 weeks, the number of intestinal lactic acid bacteria increased, reaching similar numbers (4.50 ± 0.80 CFU/ mL) to those (4.70 ± 0.80 CFU/mL) of the control group not fed ME. Microbiome analysis showed that 8 weeks feeding of ME promoted the growth of Bifidobacteriaceae and Lactobacillaceae compared to the POS group, indicating the positive effects of feeding 20% ME on the intestinal microbiota of mice. These results suggest that ME can be considered as a dietary prebiotics to improve human gut microbial population, but further application study to human is necessary.

압출떡의 유통기한 연장을 위한 LED 조사의 Bacillus cereus 억제 효과 및 LED의 배열에 따른 빛의 조사 패턴 시뮬레이션

정화빈,육현균,윤원병 한국응용생명화학회 2019 Journal of Applied Biological Chemistry (J. Appl. Vol.62 No.2

The optimum design of LED device for irradiation of 460 nm blue light on extruded rice cake using simulation and the effect of the blue light on the inactivation of Bacillus cereus (B. cereus) group on the rice cake were investigated. The irradiated light intensity patterns on the surface area of the sample were simulated with three different LED arrays (centered, cross, and evenly spaced) and at various distances (22, 32, 42 mm) between the LED modules and the sample. In addition, the uniformity was calculated as Petri factor. The evenly spaced array resulted the most uniform light intensity pattern in the simulation, and the Petri factor of 32 and 42 mm of the distances showed higher than 0.9, which represents the ideal uniformity of LED device. The bacterial population of the rice cake decreased to less than the initial bacterial population during exposure to LED blue light, whereas the bacterial population of the control sample increased. The bacterial count of the rice cake after blue light irradiation for 24 h was 1.21 log CFU/g lower than the control sample. Petri factor increased with increase of the distance between the light source and sample, however, the reduction rate of B. cereus group decreased. Therefore, the design of LED device, that represented the Petri factor higher than 0.9 and inactivated the population of B. cereus group, with evenly spaced and 32 mm of distance between the light source and sample was suitable for extending shelf-life of rice cake. 본 연구에서는 460 nm 파장의 청색 가시광선을 압출 떡의 표면에 조사하기 위하여 장치의 최적 디자인을 시뮬레이션을 통하여 확인하고 청색광이 압출 떡의 표면에서 식품 위해균인 B. cereus group에 미치는 영향을 확인하였다. LED 장치에서 광원모듈의 세 가지 배열(centered, cross, evenly spaced) 및 광원과 샘플 표면 사이의 거리(22, 32, 42 mm)에 따른 조사 면적에서 빛의 세기 패턴을 시뮬레이션을 통하여 계산하고, Petri factor를 통하여 균일도를 확인하였다. LED 배열의 균일도는evenly spaced 배열에서 가장 균일한 패턴을 보였으며, 광원과의 거리가 32 및 42 mm일 경우 Petri factor가 0.9 이상으로높은 균일도를 나타내었다. 떡볶이 떡에 LED 청색광을 조사한경우 24 h 후 균 수가 초기 균 수에 비하여 감소하였으며, LED 를 조사하지 않은 대조군에서는 초기 균 수가 증가하여 1.21 log CFU/g의 차이를 보였다. LED 조사 시 광원과 샘플의 거리가 증가할수록 Petri factor는 증가하나 감균 효과가 낮아지는결과를 나타내었다. 따라서 Petri factor가 0.9 이상임을 만족하는 evenly spaced 배열의 32 mm 거리가 떡의 유통기한 연장을위한 LED 장치의 디자인에 적합함을 확인하였다.

Bacillus subtilis IFO 12113 유래 Protopectinase 를 이용산 사과박의 펙틴 추출

이승철,조용진,육현균,황용일,최정선 한국농화학회 1999 Applied Biological Chemistry (Appl Biol Chem) Vol.42 No.1

Protopectinase는 불용성의 프로토펙틴을 수용화시켜 펙틴을 생산하는 효소로서, 사과박으로부터 펙틴추출을 위한 최적 pH, 반응시간, 반응온도를 조사하였다. 효소 작용 최적조건은 pH 7.8, 60℃에서 48시간의 반응시간이었으며, 펙틴 추출률은 34.3%이었다. 최적조건에서 protopectinase에 의해 추출된 펙틴의 순도는 52.9%이었으며, methoxyl 함량은 2.75%로서 저 methoxyl 함량의 펙틴이었다. 효소 반응 온도와 시간은 펙틴의 추출률과 methoxyl 함량에 크게 영향을 미치지 않았지만 반응 pH는 사과박의 펙틴 추출률과 methoxyl함량에 크게 영향을 미쳤다. 최적조건에서 추출된 펙틴의 고유점도와 분자량은 각각 0.178 ml/g과 4,900이었다. (1998년 12월 2일 접수, 1999년 1월 10일 수리)

Characterization of Lactobacillus plantarum strains isolated from black raspberry and their effect on BALB/c mice gut microbiota

최혜란,정이형,육현균,이현기,장한수,김요섬,신대근 한국식품과학회 2018 Food Science and Biotechnology Vol.27 No.6

The objective of this study was to evaluate probiotic effects of two Lactobacillus plantarum strains (GBL16 and 17) isolated from black raspberry. Results revealed that the number of GBL16 was gradually decreased as bile salt concentration was increased from 0.3 to 1%. However, GBL17 did not show any difference when GBL17 was applied to 1% bile salt, and it indicates that GBL17 is more tolerant to bile salt than GBL16. GBL17 exhibited higher heat resistance and adhesion ability to Caco-2 cells than GBL16. Regarding gut microbiome, no significant change in the number of total bacteria in intestines of mice after treatment with GBLs was determined. However, the combination of GBL16 and GBL17 significantly increased the number of total bacteria in intestines of mice after they were orally administered. Therefore, the results suggest that both GBL16 and 17 strains could be one of major probiotics that can improve human gut health.

김치에서 분리한 Lactococcus lactis 균주의 항리스테리아 활성 및 부분 정제된 박테리오신의 특성

손나연,김태운,육현균 한국식품위생안전성학회 2022 한국식품위생안전성학회지 Vol.37 No.2

Listeria monocytogenes (L. monocytogenes) is one of gram-positive foodborne pathogens with a very high fatality rate. Unlike most foodborne pathogens, L. monocytogenes is capable of growing at low temperatures, such as in refrigerated foods. Thus, various physical and chemical prevention methods are used in the manufacturing, processing and distribution of food. However, there are limitations to the methods such as possible changes to the food quality and the consumer awareness of synthetic preservatives. Thus, the aim of this study was to evaluate the anti-listeria activity of lactic acid bacteria (LAB) isolated from kimchi and characterize the bacteriocin produced by Lactococcus lactis which is one of isolated strains from kimchi. The analysis on the anti-listeria activity of a total of 36 species (Lactobacillus, Weissella, Lactobacillus, and Lactococcus) isolated from kimchi by the agar overlay method revealed that L. lactis NJ 1-10 and NJ 1-16 had the highest anti-listeria activity. For quantitatively analysis on the anti-listeria activity, NJ 1-10 and NJ 1-16 were co-cultured with L. monocytogenes in Brain Heat Infusion (BHI) broth, respectively. As a result, L. monocytogenes was reduced by 3.0 log CFU/mL in 20 h, lowering the number of bacteria to below the detection limit. Both LAB strains showed anti-listeria activity against 24 serotypes of L. monocytogenes, although the sizes of clear zone was slightly different. No clear zone was observed when the supernatants of both LAB cultures were treated with proteinase- K, indicating that their anti-listerial activities might be due to the production of bacteriocins. Heat stability of the partially purified bacteriocins of NJ 1-10 and NJ 1-16 was relatively stable at 60oC and 80oC. Yet, their anti-listeria activities were completely lost by 60 min of treatment at 100oC and 15 min of treatment at 121oC. The analysis on the pH stability showed that their anti-listeria activities were the most stable at pH 4.01, and decreased with the increasing pH value, yet, was not completely lost. Partially purified bacteriocins showed relatively stable anti-listeria activities in acetone, ethanol, and methanol, but their activities were reduced after chloroform treatment, yet was not completely lost. Conclusively, this study revealed that the bacteriocins produced by NJ 1-10 and NJ 1-16 effectively reduced L. monocytogenes, and that they were relatively stable against heat, pH, and organic solvents, therefore implying their potential as a natural antibacterial substance for controlling L. monocytogenes in food.

초산 세척과 키토산 첨가에 의한 간장게장의 미생물학적 품질 향상

이석규,이보람,육현균 한국식품위생안전성학회 2019 한국식품위생안전성학회지 Vol.34 No.3

Ganjang-gejang (soy sauce-marinated crab) is a ready-to-eat (RTE) seafood and is also one of the most popular traditional dishes in Korea. It is generally prepared by washing raw blue crabs and then preserving them in soy sauce. Since this process does not involve cooking or any treatment with heat, it is difficult to control the micro-biological quality of the final product. Thus, the objectives of this study were to compare the efficacies of various sanitizers in eliminating microorganisms on raw blue crab during the washing step and to evaluate the effectiveness of chitosan on the inhibition of microbial growth in the ganjang-gejang during storage. The raw blue crabs were sub-merged in chlorinated water (50 mg/L), peracetic acid (40 mg/L), acetic acid (5%) and lactic acid (5%) for 10 min at 25oC, respectively. The blue crabs treated with 5% acetic acid were marinated with soy sauce containing 0.5 and 1% of soluble chitosan, followed by storing them at 4 and 12oC for up to 30 days. Results show that 5% acetic acid reduced the microbial populations on the blue crabs by 1.5 log CFU/g, which was significantly higher than those of other treatments. Based on these results, 5% acetic acid was selected for the washing step. The microbial populations of all ganjang-gejang samples significantly increased to about 8.0 CFU/g at 12oC for 7 days. At 4oC, the microbial populations of the products containing 1% chitosan increased by about 2.9 CFU/g for 20 days, which were signifi-cantly lower than those (4.2-4.5 log CFU/g) of the products without and with 0.5% chitosan. Thus, these results sug-gest that 5% acetic acid washing of raw blue crabs and the addition of 1% chitosan in ganjang-gejang could improve the microbiological quality of the final products under refrigerated condition.