Fermented Soybean Paste Research Articles

Improvement of mannitol-yolk-polymyxin B agar by supplementing with trimethoprim for quantitative detection of Bacillus cereus in foods.

Mannitol-yolk-polymyxin B agar (MYPA) was modified by supplementation with trimethoprim. The ability of the supplemented medium to select for and recover Bacillus cereus from pure cultures and food samples with high background microflora was compared with MYPA. For evaluation of the modified MYPA (mMYPA) in food samples with high background microflora, B. cereus was experimentally spiked into red pepper powder, fermented soybean paste, vegetable salad, and radish sprouts, and then it was recovered on MYPA and mMYPA for comparison. In all food samples, there was no difference in recoverability (P > 0.05) between mMYPA (red pepper powder, 3.34 ± 0.24 log CFU/g; fermented soybean paste, 3.52 ± 0.47 log CFU/g; vegetable salad, 3.51 ± 0.23 log CFU/g; radish sprouts, 3.32 ± 0.40 log CFU/g) and MYPA (red pepper powder, 3.18 ± 0.20 log CFU/g; fermented soybean paste, 3.33 ± 0.43 log CFU/g; vegetable salad, 3.36 ± 0.19 log CFU/g; radish sprouts, 3.33 ± 0.31 log CFU/g). However, mMYPA exhibited better selectivity than MYPA, because additional trimethoprim made the differentiation of suspected colonies easier by inhibiting competing flora. The addition of trimethoprim to conventional media could be a useful option to improve selectivity in foods with high background microflora.

조선조의 공문서 및 왕실자료에 나타난 장류

This paper investigated the system that is relevant to Jang(fermented soybean paste or solution), the relief of hungerstricken people by Jang, 33 kinds of Jang, and its consumption in the documents, such as the annals of the Chosun Dynasty, Ihlseong-document, Seungjeongwon daily, Uigwe(record of national ceremony), official documents on the basis of Kyujanggak institute for the Korean studies and data base of Korean classics. There are lots of Jang named after the place of particular soybean's production from the ancient times. Jang, soybean, salt and Meju(source of Jang), during the Dynasty, were collected as taxation or tribute. In the 5th year of Hyeonjong(1664), the storage amount of soybean in Hojo(ministry of finance) was 16,200 ㎘, and its consumption was 7,694 ㎘ a year. In the 32nd year of Yongjo(1756), the 1,800 ㎘ of soybean was distributed to the people at the time of disaster, and in his 36th year(1756), the 15,426 ㎘ of soybean was reduced from the soybean taxation nationwide. The offices managing Jang are Naejashi, Saseonseo, Sadoshi, Yebinshi and Bongsangshi. Chongyoongcheong(Gyeonggi military headquarters) stored the 175.14 ㎘ of Jang, and the 198 ㎘ of Jang in Yebinshi. There are such posts managing Jang as Jangsaek, Jangdoo, and Saseonsikjang. In the year of Jeongjong(1777～ 1800), the royal family distributed the 3.6 ㎘ of Meju to Gasoon-court, Hygyeong-court, queen's mother-court, queen's court, royal palace. The 13.41 ㎘ of Gamjang(fermented soybean solution) was distributed to the Gasoon-court, 17.23 ㎘ to

Isolation of halophilic lactic acid bacteria from traditional Chinese fermented soybean paste and assessment of the isolates for industrial potential

Lactic acid bacteria (LAB) from traditional Chinese fermented soybean paste were isolated and identified. A total of 61 LAB were selectively obtained from 32 homemade Chinese soybean pastes. The isolated LAB were divided into two groups by their salt tolerance, 28 halophilic LAB and 33 non-halophilic LAB. Phenotypic analysis showed that these LAB belonged to four genera and 13 species. Tetragenococcus halophilus was the predominant species in the identified strains. Four species of LAB were firstly isolated from fermented soybean food product, Lactobacillus panis, Lactobacillus pentosus, Lactobacillus vaccinostercus and Lactobacillus collinoides. T. halophilus T5 showed vigorous growth and fast acidification in high salt concentration. The volatile compounds of mixed microorganism soybean paste with T. halophilus T5, Zygosaccharomyces and Torulopsis candida, during the different fermentation stage were higher in number than those of normal soybean paste at same processing procedure.

Degradation characteristics of proteins in cheonggukjang (fermented unsalted soybean paste) prepared with various soybean cultivars

In order to select the most ideal soybean cultivars for producing cheonggukjang, the protein degradation characteristics of cheonggukjangs prepared with 30 different soybean cultivars were compared. Cheonggukjang prepared with ‘Nampung’ (18.00±0.28%) and ‘Sohwang’ (17.91±0.63%) soybeans showed the highest contents of viscous substances. Acidic-protease activity was highest (590.24±2.92 μg/mL) in cheonggukjang prepared with small ‘Pungsannalmul’ soybeans. Neutral-protease activity was highest (528.13±3.11 and 527.36±0.44 μg/mL, respectively) in cheonggukjang prepared with ‘Singi’ and ‘Nampung’ soybeans. Cheonggukjang prepared with ‘Wonkwang’ and ‘Sohwang’ soybeans had amino-type nitrogen contents of 780.50±2.92 and 729.95±1.07 mg%, respectively. Glutamic acid, which is a major component of viscous substances, was also detected. Although total free amino acid levels in cheonggukjang prepared with ‘Daewon’ and ‘Wonkwang’ soybeans measured 2,551.21 and 2,340.02 mg%, respectively, cheonggukjang prepared with black soybeans exhibited low levels of total free amino acids. Therefore, based on protein degradation characteristics, large ‘Daewon’ soybeans and small ‘Wonkwang’ soybeans were the most suitable for producing cheonggukjang.

Microbial community analysis of Korean soybean pastes by next-generation sequencing

Soybean pastes, doenjang, have long been consumed as a fortified protein source in Korea. The quality of doenjang is determined by fermentation and Bacillus subtilis is suspected to be the main microorganism responsible. In the current culture-independent analysis, 17,675 bacterial sequences were derived from nine local and two commercial brands of doenjang samples by a barcoded pyrosequencing method targeting the hyper-variable regions V1/V2 of the 16S rRNA gene. In contrast to what has previously been found using plating or conventional molecular biology based methods, doenjang contains a diversity of bacterial species (total 208 species) and each doenjang reflects a region-specific bacterial community. While the Bacillus species was thought to be dominant in soybean pastes, we found that they were in high abundance (58.3–91.6%) only in samples from the central region of Korea, whereas lactic acid bacteria (LAB) (39.8–77.7%) were the dominant bacterial members of other doenjang samples. Compared to local brands of doenjang, commercial brands contain simple microbial communities dominated by Tetragenococcus and Staphylococcus that resemble the microbial communities of Japanese miso; this suggests that artificial inoculation was used for the quality control and standardization of doenjang. In this study, a massive sequencing approach was applied for the first time to analyze the microbial communities of different doenjang samples. Thus, we have determined that massive sequencing is a valid approach for assessing the overall microbial community of Korean fermented soybean pastes.

A method for the determination of acrylamide in a broad variety of processed foods by GC–MS using xanthydrol derivatization

A novel GC–MS method was developed for the determination of acrylamide, which is applicable to a variety of processed foods, including potato snacks, corn snacks, biscuits, instant noodles, coffee, soy sauces and miso (fermented soy bean paste). The method involves the derivatization of acrylamide with xanthydrol instead of a bromine compound. Isotopically labelled acrylamide (d 3-acrylamide) was used as the internal standard. The aqueous extract from samples was purified using Sep-Pak™ C18 and Sep-Pak™ AC-2 columns. For amino acid-rich samples, such as miso or soy sauce, an Extrelut™ column was used for purification or extraction. After reaction with xanthydrol, the resultant N-xanthyl acrylamide was determined by GC–MS. The method was validated for various food matrices and showed good linearity, precision and trueness. The limit of detection and limit of quantification ranged 0.5–5 and 5–20 µg kg−1, respectively. The developed method was applied as an exploratory survey of acrylamide in Japanese foods and the method was shown to be applicable for all samples tested.

Visceral fat and body weight are reduced in overweight adults by the supplementation ofDoenjang, a fermented soybean paste

Various forms of fermented soybean products are well documented for their health benefits. The efficacy of anti-obesogenic effect of Doenjang, one of the most commonly used seasonings in Korean cuisine, has been reported only in animal models; thus, an evaluation of Doenjang needs to be conducted in human studies. We aimed to test the hypothesis that Doenjang supplementation reduces body weight and changes body composition in overweight adults. A total of 51 overweight adults participated in this study. A group of males with BMI ≥ 23 kg/m2 and waist to hip ratio (WHR) ≥ 0.90, and a group of females with BMI ≥ 23 kg/m2 and WHR ≥ 0.85 were randomly assigned to either a Doenjang supplement (9.9 g dry/day) group or a placebo group for a 12-week randomized, double-blind and placebo-controlled study. Anthropometric parameters, abdominal fat distribution by computerized tomography (CT) and blood components were measured before and after the intervention period. After the 12-week study, the Doenjang supplementation group had significant reductions in body weight (kg), body fat mass (kg) and body fat (%) compared to the placebo group, the supplementation of Doenjang resulted in a significant reduction in visceral fat (cm2), although no changes were observed in total and subcutaneous fat are as (cm2), serum lipid profiles and dietary intakes. The present study demonstrated that daily supplementation of 9.9 g dry/day of Doenjang for 12 weeks reduces body weight and visceral fat in overweight adults.

메밀 속성장 유래 효소활성 우수 저영양성 균주 분리 및 특성

메밀 속성장 유래 세포외효소(protease, amylase, cellulase, lipase, xylanase) 분비능이 우수한 균주를 분리하여 혈전 용해능, 항균 활성 및 내염성을 분석하였다. 선발된 균주 중 HJ0-3을 비롯한 13개 균주는 표준 균주 B. subtilis KACC 10114보다 우수한 protease 활성을 보였다. Amylase 분비능의 경우, HJ18-4을 포함한 10개 균주는 표준 균주 B. subtilis KACC 10114보다 우수한 효소 활성을 보였다. HJ11-19 등 5균주는 표준 균주 B. subtilis KACC 10114보다 cellulase 분비능이 우수함을 확인할 수 있었다. 선별된 23개 균주 중에서 HJ5-21(21.12%), HJ18-4(86.11%), HJ18-9(31.16%), HJ18-13(63.80%)가 높은 혈전 용해능을 보였다. 선별된 23개 균주 중, 5개 균주(HJ18-4, HJ18-9, HJ18-13, HJ25-6, HJ25-11)는 3개 이상의 병원성 균에 대해 항균 활성을 나타내었고, 특히 HJ18-4는 모든 병원성 균에 대하여 항균활성을 나타내었으나 표준 균주 B. subtilis KACC 10114는 항균 활성이 나타나지 않았다. 메밀 속성장 유래 분리 균주 중 세포외효소 활성 및 혈전 용해능, 항균 활성이 우수한 균주 HJ18-4(AB601598)는 API kit 분석결과 B. subtilis(89.6%), 16S rDNA 염기서열 분석으로는 B. subtilis(99%)로 동정되었다. HJ18-4는 표준 균주 B. subtilis KACC 10114와 마찬가지로 NaCl의 농도가 높아질수록 생육이 억제되나 5%와 10%의 NaCl 농도에서 표준 균주 B. subtilis KACC 10114 보다 HJ18-4가 우수한 생육 특성을 나타내었다. 이는 HJ18-4가 염 농도 5-10%에서 우수한 생육특성을 가짐으로써 저염 및 고염 장류 제조에 있어서 starter로 사용이 가능함을 보여주었다. Bealmijang is a short-term fermented regional product that is prepared with soybean and extra ingredients. In this study, starter strain candidates were screened from Bealmijang for fermented soybean paste products. Twenty one bacterial strains producing extracellular enzymes (amylase, cellulase, protease, xylanase and lipase) were isolated from Bealmijang, buckwheat sokseongjang. The isolates were assessed for fibrinolytic and antibacterial activities, and salt tolerance. Strain HJ18-4, identified as Bacillus subtilis (AB601598) by biochemical properties (89.6%) and 16S rDNA sequencing (100%), showed the highest enzymatic, fibrinolytic, and antibacterial activities among the isolates. Although the growth of HJ18-4 was inhibited by the increase of NaCl concentration, the growth still exceeded that of B. subtilis KACC 10114 at 5% and 10% NaCl. These results suggest that B. subtilis HJ18-4 is suitable as a starter for soybean paste manufacture.

대두와 청국장 추출물의 항산화능과 혈전용해능

대두를 이용하여 천연보존료나 건강 기능성식품을 개발하기 위하여 백태와 태광으로 청국장을 제조하여 물과 70% 에탄올로 추출한 후, 폴리페놀 함량, 항산화능 및 혈전용해능을 측정하였다. 백태와 백태 청국장에 대한 물추출물의 폴리페놀 함량은 각각 189.25 mg/100g, 814.58 mg/100g 이었으며 태광과 태광 청국장에 대한 물추출물의 폴리페놀 함량은 각각 210.23 mg/100g, 834.23 mg/100g으로 대두 청국장 물추출물의 폴리페놀 함량은 각각의 대두에 비하여 4~4.3배 증가하였다. 대두로 제조한 청국장 물추출물의 전자공여능과 SOD 유사활성은 원료의 콩에 비하여 높은 활성을 나타내었다. 대두와 대두 청국장의 물과 에탄올추출물은 모두 혈전용해능을 나타내었으며 백태 청국장의 물추출물이 가장 우수한 혈전용해능을 나타내었다. 이러한 결과를 종합해 볼 때, 대두에 비하여 대두로 제조한 청국장 추출물의 폴리페놀 함량이 유의적으로 높았으며 청국장의 제조와 함께 항산화능과 혈전용해능도 증가하는 것으로 분석되었으므로 청국장은 건강식품의 개발이나 천연항산화제로서의 이용가능성이 높을 것으로 판단된다. To develop natural preservatives or functional health foods from soybeans (Baektae and Taekwang), the antioxidant and fibrinoytic activities of the water and 70% (v/v) ethanol extract of soybeans and fermented soybean paste (Chungkukjang) were examined. The polyphenol contents of water extracts from Baektae and Baektae Chungkukjang were 189.25 mg/100 g and 814.58 mg/100 g, respectively, whereas those from Taekwang and Taekwang Chungkukjang were 210.23 mg/100 g and 834.23 mg/100 g. The polyphenol contents of the water extracts from Chungkukjang was 4.0~4.3-fold higher than those from soybean. The electron-donating abilities (EDAs) and superoxide dismutase-(SOD)-like activities of the water and ethanol extracts from Chungkukjang were higher than those of the extracts from soybean. Both extracts were found to have had fibrinolytic activity, and the highest activity was present in the water extracts of Baektae Chungkukjang. The polyphenol contents and antioxidative and fibrinolytic activities of the extracts from Chungkukjang were higher than those of the other soybean extracts. These results indicate that Chungkukjang can be used as a material for health foods or natural antioxidants.

Evaluation of Antioxidant Activities of Peptides Isolated from Korean Fermented Soybean Paste, Chungkukjang

The objectives of present study were to characterize the peptides which were isolated from Korean fermented soybean paste, chungkukjang, and to determine their antioxidant activities. Four fractions were collected from the methanol extract of chungkukjang by using a recycling preparative HPLC. Among fractions, Fr-2 was identified to be highly potent free radical scavenging activity in the assay of 1,1-diphenyl-2-picryl-hydrazyl (DPPH) and nitroblue tetrazolium(NBT)-reduction inhibition. Base on antioxidant effects, fraction Fr-2 was employed for the refraction with a prep-column and separated into five fractions of which two fractions were identified to have higher antioxidant activity. To confirm the amino acid constituents of antioxidant fractions Fr-2-2 and Fr-2-3 were analyzed, and eight kinds of amino acids such as aspartic acid, threonine, serine, glutamic acid, glycine, lysine, histidine, and arginine were identified as the constituent amino acids. Antioxidant activities of the separated peptides were further assessed cell viability with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl terazolium bromide (MTT), and fluorescence-activated cell sorting (FACS) analysis of H4IIE cells treated with hydrogen peroxide (H2O2). Chungkukjang peptides have shown their ability to protect H4IIE rat hepatoma cells against H2O2- induced oxidative stress by concentration and time-dependent manner. Therefore, These results indicated that fermented soybean paste chungkukjang will be promoted the antioxidant and radical scavenging activities, and beneficial for health. The antioxidant peptide fractions Fr-2-2 and Fr-2-3 were denominated as P-NICS-1 and P-NICS-2, respectively. However, further studies were required to clarify their amino acid sequences and molecular properties, and physiological significances.

Effects of Ortho‐dihydroxyisoflavone Derivatives from Korean Fermented Soybean Paste on Melanogenesis in B16 Melanoma Cells and Human Skin Equivalents

In this study we investigated the inhibitory effects and possible mechanisms of action of 8'-hydroxydaidzein and 3'-hydroxydaidzein, two ortho-dihydroxyisoflavone derivatives from Korean fermented soybean paste, on melanogenesis in B16 murine melanoma cells. The two hydroxydaidzeins reduced melanin synthesis comparably to treatment with kojic acid, a proven whitening agent, in B16 melanoma cells. Furthermore, when in vitro human skin equivalents were treated with the hydroxydaidzeins, the levels of melanogenesis were significantly reduced relative to a kojic acid control. The RT-PCR results demonstrated that depigmentation was due to transcriptional repression of several melanogenesis genes, including microphthalmia-associated transcription factor (MITF), by the hydroxydaidzeins. The immunoblotting results confirmed that diminution of MITF expression subsequently decreased expression of tyrosinase, and tyrosinase-related proteins 1 and 2. Cumulatively, these results suggest that hydroxydaidzeins would be potent attenuators of melanin synthesis as well as effective inhibitors of hyperpigmentation in human skin.

Regional variability in fermented soybean paste sold in supermarkets and its values as a teaching material in geographic education

Regional variability in fermented soybean paste sold in supermarkets and its values as a teaching material in geographic education

Interspecies Interaction of Signal Peptide PapR Secreted by Bacillus cereus and Its Effect on Production of Antimicrobial Peptide

This study was carried out to investigate the interspecies interaction of PapR peptide secreted by Bacillus cereus on production of BSAP-254, an antimicrobial peptide produced by Bacillus subtilis SC-8 isolated from the Korean fermented soybean paste and exhibited narrow antagonistic activity against the B. cereus group, but not against other foodborne pathogens. PapR is a signal peptide that activates PlcR, which is a pleiotropic regulator controlling the expression of various virulence factors in B. cereus. When B. subtilis SC-8 was co-cultured with B. cereus, it completely inhibited the growth of B. cereus within 12 h, and the rate of BSAP-254 production was increased 34.2% at 12 h. Furthermore, 5 μM of synthetic PapR peptide added to the culture of B. subtilis SC-8 increased the rate of BSAP-254 production up to 59.7%. The growth of B. subtilis SC-8, however, was not significantly different with or without the addition of PapR. When B. cereus papR mutant was co-cultured with B. subtilis SC-8, the growth of the mutant was not inhibited and the rate of BSAP-254 production was decreased by 45%.

Doenjang, a Fermented Soybean Paste, Decreased Visceral Fat Accumulation and Adipocyte Size in Rats Fed with High Fat Diet More Effectively Than Nonfermented Soybeans

Soybean is known to have an anti-obesity effect. We compared the anti-obesity effect of doenjang, a fermented soybean paste, with that of nonfermented soybeans in rats. Steamed soybeans and doenjang (steamed soybeans fermented and aged for 10 months) were sampled and freeze-dried. Male Sprague-Dawley rats were fed basal (BA) (5% fat), high fat (HF) (30% fat), HF+steamed soybeans (SOY), or HF+doenjang (DJ) diet ad libitum for 8 weeks. HF significantly increased body weight gain, liver weight, hepatic triglyceride (TG) and cholesterol levels, and epididymal fat pad weight compared with BA. Compared with HF, body weight gain and hepatic TG and cholesterol levels were significantly lower in SOY and DJ groups, but they were not significantly different from each other. DJ significantly reduced visceral fat weight and epididymal adipocyte size compared with HF, whereas SOY resulted in a mild reduction without significance. This was possibly because DJ showed lowered fatty acid synthase (FAS) activity and elevated carnitine palmitoyltransferase (CPT)-1 activity in liver tissue more than SOY. SOY and DJ did not affect serum total and high-density lipoprotein-cholesterol levels compared with HF; however, DJ significantly lowered the atherogenic index and serum leptin level. In conclusion, doenjang, a fermented soybean product, was more effective than soybeans for preventing diet-induced visceral fat accumulation, possibly because of its greater effects on CPT-1 activity stimulation and FAS activity suppression. These effects may be due in part to the higher content of aglycone isoflavones in doenjang.

The production of surfactin during the fermentation of cheonggukjang by potential probiotic Bacillus subtilis CSY191 and the resultant growth suppression of MCF-7 human breast cancer cells

Bacillus subtilis CSY191, the potential probiotics and surfactin-like compound producer, was isolated from doenjang (Korean traditional fermented soybean paste).The survival rate of this strain appeared to be the 58.3% under artificial gastric conditions after 3h at pH 3.0. Surfactin was purified from the strain CSY191. Three potential surfactin isoforms were detected, with protonated masses of m/z 1030.7, 1044.7, and 1058.71. These different structures were detected in combination with Na+, K+ and Ca2+ ions by MALDI-TOF mass spectrometry. Upon 500MHz 1H NMR analysis, the surfactin isoforms had identical amino acids (GLLVDLL) and hydroxy fatty acids (of 13–15 carbons in length). The MTT assay showed that surfactin inhibited growth of MCF-7 human breast cancer cells in a dose-dependent manner, with an IC50 of approximately 10μg/ml at 24h. Additionally, the surfactin contents, during cheonggukjang fermentation with strain CSY191, increased from 0.3 to 48.2mg/kg over 48h of fermentation, while the level of anticancer activity increased from 2.6- to 5.1-fold.

전통된장의 면역증강 효과

된장의 면역증강 효과에 미치는 영향을 위장관도에서 관찰하여 다음과 같은 결과를 얻었다. CD4₊/CD8₊ T 림프구의 면역조직화학적 염색반응에서 된장식이를 첨가한 모든 실험군에서 CD4₊ T 세포는 공장의 점막 고유층과 음와 아래의 고유층에서 강한 면역 반응을 나타내었고, 결장에서는 점막 하층과 외막층의 혈관 주위에서 강한 면역반응을 나타내었다. 반면, CD8₊ T 세포는 Group Ⅲ에서 결장의 점막상피, 점막 고유층, 점막하층 및 외막층에서 강한 면역반응을 나타내었고, uNOS에 대한 면역 반응에서는 된장 식이를 첨가한 모든 실험군에서 결장 점막하층과 근육층신경얼기에서 강한 면역반응을 나타내었다. Protein kinase C-α에 대한 면역반응은 Group Ⅱ와 Group Ⅲ에서 점막상피와 근육층에서 강한 면역반응을 나타내었고, stem cell factor에 대한 면역 반응은 된장식이를 첨가한 모든 실험군의 점막상피와 GroupⅠ의 근육층에서 강한 면역반응을 나타내었다. 이상의 실험 결과로 대조군에 비하여 농도별로 된장식이를 첨가한 실험군에서 CD4₊/CD+8에 대하여 강한 면역반응을 보인 것으로 보아 위장관에서 면역능을 증가시킬 것으로 사료되며, uNOS의 증가에 따른 NO의 방출이 위장관의 운동과 혈관운동을 촉진하여 위비움과 결장의 운동을 촉진할 것으로 사료되었다. 또한 농도별로 된장 식이를 첨가한 실험군에서 protein kinase C-α와 stem cell factor에 대한 면역반응이 위장관의 점막상피에서 강하게 나타난 것으로 보아 점막 상피세포의 증식과 분화를 촉진시켜 여러 가지 물질의 흡수와 전달에 관여할 것으로 사료되었다.

Characterization of the Bacteriocin J4 Produced by Bacillus amyloliquefaciens J4 Isolated from Korean Traditional Fermented Soybean Paste

In order to isolate the antibacterial bacteriocin-producing bacteria against Listeria monocytogenes, one of noxious and prevalent food-poisoning bacterium, 117 strains of indigenous ferment bacteria were isolated from Korean traditional fermented soybean paste (Doenjang) in Korea. Among the isolated strains, 4 isolates inhibited the growth of L. Monocytogenes. Strain J4, showing the strongest inhibition activity against L. Monocytogenes, was identified as a Bacillus amyloliquefaciens by 16S rDNA sequencing. The strain had a broad spectrum of antibacterial activity against various food-borne pathogens such as Micrococcus luteus, Vibrio parahaemolyticus, and Staphylococcus aureus besides L. monocytogenes. The bacteriocin J4 was purified by 60% ammonium sulfate precipitation, carboxymethyl (CM)-Sephadex column chromatography, and Sephadex G-100 gel filtration. The purified bacteriocin J4 was estimated to be 39 kDa molecular weight by tricine sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Bacterocin J4 had antimicrobial activity in a wide pH range (2.0-12.0) and was heat-stable at 80oC for 20 min, but the activity of bacterocin was inactivated by heating at 100oC for 15 min. The antimicrobial activity of the bacteriocin J4 was completely abolished by treatment with proteolytic enzymes such as protease (type I and IX), papain, trypsin, proteinase K, and pepsin, but not when treated with α-amylase, α-glucosidase, and β-glucosidase. The encoding gene of the bacteriocin J4 was included in chromosomal DNA, not plasmid. The bacteriocin J4 had a bacteriolytic mechanism, resulting in cell wall degradation of L. Monocytogenes.

6,7,4′-Trihydroxyisoflavone from Doenjang inhibits lipid accumulation

Doenjang is a unique traditional Korean fermented soybean paste. 6,7,4′-Trihydroxyisoflavone was identified from traditional Korean fermented Doenjang. The four products isolated from 100 g Korean Doenjang using acetonitrile and methanol (70/30, v/v) was identified as daidzein, genistein, glycitein and 6,7,4′-trihydroxyisoflavone. The products were structurally elucidated by GC–MS and 1H NMR analysis. 6,7,4′-Trihydroxyisoflavone was evaluated for antioxidant activity against the free radical 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging and superoxide radical scavenging activity. Among four products isolated, 6,7,4′-trihydroxyisoflavone had remarkable antioxidant activity with IC 50 values of 31.5 μM, 50.0 μM, respectively. Furthermore, 6,7,4′-trihydroxyisoflavone was found to inhibit fat droplet formation triglyceride accumulation in 3T3-L1 adipocytes. Accordingly, 6,7,4′-trihydroxyisoflavone compound is of growing scientific interest due to its attractive biological properties.

Comparison of Fermented Soybean Paste (Doenjang) Prepared by Different Methods Based on Profiling of Volatile Compounds

In this study, 2 different extraction methods, namely solvent-assisted flavor evaporation (SAFE) and solid-phase microextraction (SPME), were employed to investigate the comprehensive volatile profile of Doenjang (one of Korean fermented soybean pastes) efficiently. Quantitatively, major volatiles of Doenjang isolated by SAFE were 3-methylbutanoic acid, butanoic acid, 3-hydroxy-2-methyl-4H-pyran-4-one (maltol), ethyl 2-methylbutanoate, 2-methylpropanoic acid, tetramethylpyrazine, and 4-ethyl-2-methoxyphenol, while ethanol, ethenylbenzene, ethyl benzoate, ethyl linoleate, ethyl acetate, ethyl butanoate, tetramethylpyrazine, and ethyl 2-methylpropanoate extracted by SPME. In addition, volatile profiling that applied principal component analysis to gas chromatography-mass spectrometry datasets allowed Doenjang samples that had been prepared using different traditional and commercial methods to be discriminated, and the volatile compounds that contributed to their discrimination were assigned. The major volatiles that were related to differentiation of traditional and commercial Doenjang samples were 2-pentylfuran, 4-ethylphenol, dihydro-5-methyl-2(3H)-furanone, butanoic acid, pyrazines (for example, 2-ethyl-5-methylpyrazine and 2,3-dimethylpyrazine), esters (for example, ethyl 4-methylpentanoate and diethyl succinate), maltol, dimethyl disulfide, 2- and 3-methylbutanal, hexanal, 4-vinylphenol, and ethanol.

냄새저감형 율무청국장 제조에 관한 연구

This study was performed to develop an odor-reduced Korean traditional Cheonggukjang (fermented soybean paste) by adding Job's tears to Cheonggukjang made with soybean (control) only. The study included the determinationof best addition percentage of Job's tears versus soybean, sensory evaluation, and aroma patterns and its components as well as proximate composition analyses of Cheonggukjang. Job's tears Cheonggukjang (CAJT) was prepared by inoculating Bacillus subtilis and fermented at 40℃ for 48 hours. Ratios of soybean : Job's tears for Job's tears Cheonggukjang were 1:1, 2:1, 3:1, and 4:1, respectively. In comparison of proximal composition, Job's tears Cheonggukjang was high in moisture and carbohydrates, but low in calorie, fat, protein, ash and amino nitrogen. The pH of CAJT was lower than those of control and conventional Cheonggukjang (CC) sold in the market, and the acidity was the lowest in CC. The color of Job's tears Cheonggukjang appeared the whiter and more yellowish, but less reddish in proportion to contents of Job's tears. The contents of viscous substances were higher in CAJT compared with those of control and CC. The contents of glutamic acid, the major components of viscous substances were lower in CAJT than in control and CC, and the contents of fructosehigher in CAJT. The scores of sensory evaluation were the highest in Job's tears Cheonggukjang mixed with soybean : Job's tears＝4:1. The aroma pattern of CC analyzed was conspicuously dissimilar to the control and CAJT and also discriminated by electronic nose examination. The pyrazines, volatile compounds peculiar to Cheonggukjang, were found to be lower in CAJT by SPME-GC/MS assay. Additionally, the acetic acid, butanoic acid, and naphthalene causing off-flavor were identified in CC, but not in Job's tears Cheonggukjang. The strength of odor through sensory evaluation was by far the lowest in CAJT among the groups. From the findings, it had shown that Job's tears Cheonggukjang would be produced successfully when the ratio of 4:1 (soybean : Job's tears) is employed. Also, it was proved that appropriate ratio of Job's tears addition makes Cheonggukjang odor-reduced and well accepted by people.