• Microbiology and Biotechnology Letters
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• v.44 no.1
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• pp.40-47
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• 2016

This study was conducted to evaluate the possible utility of 3 Aspergillus oryzae strains (designated as SCF-6, SCF-37, and JJSH-1), isolated from Korean traditional fermented materials, as starter cultures in the soybean paste industry. Doenjang (fermented soybean paste) was made with the A. oryzae strains described above, and its quality attributes were analyzed during a 60-day aging period. No significant differences in pH, moisture, or salt content were detected among the doenjang varieties made with the 3 Aspergillus strains. The concentration of amino-nitrogen, an indicator of doenjang aging, increased in each sample during the aging period. After the 60-day aging period, the contents of amino-nitrogen and free amino acid in doenjang made with SCF-6 showed the highest concentrations among the tested doenjang products: 971.6 and 8,064.9 mg%, respectively. Measurements of the color of doenjang showed that lightness and yellowness decreased during the aging period, but redness increased. After the 60-day aging period, the ${\gamma}$-aminobutyric-n-acid (GABA) concentrations in doenjang made with SCF-6 and SCF-37 were 61.3 and 53.7 mg%, respectively. In doenjang samples, aflatoxin was not detected and the concentrations of biogenic amines (histamine and tyramine) were 2.55-5.60 mg/kg and 3.70-5.87 mg/kg, respectively. These results indicated that A. oryzae SCF-6 isolated from traditional fermented foods could be useful as a starter culture in the soybean paste industry.

• Preventive Nutrition and Food Science
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• v.10 no.1
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• pp.29-33
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• 2005

To facilitate establishing regulations for irradiated foods, Korean traditional soybean-based fermented powdered doenjang (PD), kanjang (PK), kochujang (PKC) and chungkukjang (PC) were irradiated at 1, 3, 5 and 7 kGy, and subjected to irradiation detection analyses as part of establishing a database for detecting irradiated foods. Photostimulated luminescence (PSL) and electron spin resonance (ESR) were applied as the detection methods. Using PSL analysis, the irradiated PD, PK and PKC could be easily distinguished from the non-irradiated ones, while irradiation of the PC at 5 kGy or higher was detectable. The ESR spectra of the irradiated PD, PK and PKC exhibited symmetrical multiplet lines, which might be induced from the crystalline sugar, whereas, the PC showed a single signal at the paramagnetic centers. The signal intensity increased with incremental increases of irradiation doses distinguishing the irradiated samples from the control. In addition, the peak height also revealed that irradiation induced an increment in the intensity of single and/or multiplet lines of the ESR signals, resulting in clear confirmation of irradiation. Thus, the data from this study could be used as references for detecting irradiated soybean-based fermented powdered sauces.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.9
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• pp.1194-1199
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• 2006

Effects of Korean traditional soybean fermented foods on weight reduction and lipid lowering activities were studied using Spraque-Dawley (SD) rats fed a high fat diet. The rats were raised for four weeks after adaptation period on either a normal diet (ND, based on the AIN-93 diet), high fat diet (HFD, supplemented with 12% lard oil in the ND), or diets containing 10% of freeze dried Doenjang, Chungkukjang, Kochujang, or Samjang to HFD. The final weight, food efficiency ratio (FER) and the weight of adipose tissue were decreased significantly by the consumption of Doenjang and Samjang, compared to HFD (p<0.05). The contents of cholesterol and triglyceride increased by HFD were reduced by the fermented foods in liver and perirenal fat tissues of the rats, especially Doenjang and Samjang diets showed high lipid lowering activity. And TG and cholesterol contents in the plasma serum were simillar trend to liver and perirenal fat tissue. These results suggested that Korean traditional soybean fermented foods, especially Doenjang showed the highest weight reduction and lipid lowering activities of the rats fed high fat diet.

• Journal of Nutrition and Health
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• v.5 no.1
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• pp.33-42
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• 1972

This study was designed to investigate the nutritional value of fermented soybean bran as animal feed. Natural soybean bran has low protein quality and high cellulase contents. The soybean bran was supplemented by urea and ammoniumsulfate as N-source for incubation of Aspergillus niger. After incubation of soybean bran with Aspergillus niger, the nutritional quality of protein and riboflavin contents were increased in general and more in aging process than in fermentation. In order to elucidate the biological efficiency of prepared soybean bran, 120 male weanling rats were divided into 22 groups, five rats each, and were fed by standard casein diet mixed with soybean bran in the proportion of 1/10, 1/15, 1/20 respectively. The animals were kept under the experimental diet for nine weeks. In the result of this study, food efficiency ratio showed higher in the groups of urea and ammonium-sulfate-add group than row soybean bran group but the former group is lower than the later in the body weight gains. Protein efficiency ratio was also same trend. It was noteworthy that the nitrogen retention rate in total body on the basis of urinary nitrogen excretion and dietary intake nitrogen and in big organ such as liver and spleen were higher in fermented group than raw soybean bran fed group. It was worth while to treat the soybean bran in first place fermentation and further aging process to elevate the biological efficiency and effect of nutritional values specifically of protein and of riboflavin.

• Toxicological Research
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• v.31 no.3
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• pp.289-297
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• 2015

Ethyl carbamate (EC) classified as a probable human carcinogen (Group 2A) is naturally formed in alcoholic beverages and fermented foods during fermentation process and/or during storage. The objective of this study was to analyze EC in 34 food items including 14 alcoholic beverages and 20 fermented foods sold in Korea. Each food was collected from 18 supermarkets in 9 metropolitan cities in Korea, and then made into composite. According to food composition and alcohol content, samples were divided into four matrices such as apple juice, milk, Soju (liquor containing about 20% alcohol), and rice porridge. The maximum EC value of $151.06{\mu}g/kg$ was found in Maesilju (liquor made from Maesil and Soju). Whisky and Bokbunjaju (Korean black raspberry wine) contained $9.90{\mu}g/kg$ and $6.30{\mu}g/kg$, respectively. EC was not detected in other alcoholic beverages. Of 20 fermented foods, Japanese-style soy sauce had highest level of $15.59{\mu}g/kg$ and traditional one contained $4.18{\mu}g/kg$. Soybean paste had $1.18{\mu}g/kg$, however, EC was not found in other fermented foods.

• Journal of Microbiology and Biotechnology
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• v.27 no.2
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• pp.251-261
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• 2017

Initially, we screened 18 Aspergillus sojae-like strains from Aspergillus spp. isolated from meju (Korean traditional fermented soybean brick) according to their morphological characteristics. Because members of Aspergillus section Flavi are often incorrectly identified because of their phylogenetic similarity, we re-identified these strains at the morphological and molecular genetic levels. Fourteen strains were finally identified as A. sojae. The isolates produced protease and ${\alpha}-amylase$ with ranges of 2.66-10.64 and 21.53-106.73 unit/g-initial dry substrate (U/g-IDS), respectively, which were equivalent to those of the koji (starter mold) strains employed to produce Japanese soy sauce. Among the isolates and Japanese koji strains, strains SMF 127 and SMF 131 had the highest leucine aminopeptidase (LAP) activities at 6.00 and 6.06 U/g-IDS, respectively. LAP plays an important role in flavor development because of the production of low-molecular-weight peptides that affect the taste and decrease bitterness. SMF 127 and SMF 131 appeared to be non-aflatoxigenic because of a termination point mutation in aflR and the lack of the polyketide synthase gene found in other A. sojae strains. In addition, SMF 127 and SMF 131 were not cyclopiazonic acid (CPA) producers because of the deletion of maoA, dmaT, and pks/nrps, which are involved in CPA biosynthesis. Therefore, A. sojae strains such as SMF 127 and SMF 131, which have high protease and LAP activities and are free of safety issues, can be considered good starters for soybean fermentations, such as in the production of the Korean fermented soybean products meju, doenjang, and ganjang.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.3
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• pp.376-382
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• 1997

Antioxidative characteristics of doenjang(fermented soybeans paste) phenolics on the lipid oxidation systems were studied by the determination of the oxidative related activity including lipoxygenase (LOX) inhibition, metal chelating and free radical scavengning of doenjang phenolics. Manlikong variety containing the highest amounts of phenolic compounds among the soybean variety, was used for doenjang processing. Doenjang was prepared by the series of processes including soaking for overnight, cooking for 1hr at 12Lb, first fermentation (3 days at 30$\pm$2$^{\circ}C$) for the preparation of meju(soybean koji) after inoculation of Asp. oryzae, and further fermentation(60 days at 30$\pm$2$^{\circ}C$) for the ripening after addition of salt 13% to meju. In order to investigate the antioxidative activity of phenolics in doenjang, the doenjang phenolics was extracted with methanol form freeze dried defatted doenjang. Antioxidative effects of methanol extract on linoleic acid oxidation system were observed by the significantly decreased levels of peroxide and conjugated diene formation. In addition, methanol extract resulted in the inhibition of LOX activity. and also, metal(FeCl$_3$) chelation and free radical scavengning activities were increased with increasing concentration of methanol extract.

• Korean Journal of Food Science and Technology
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• v.32 no.1
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• pp.25-30
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• 2000

Phytoestrogen has been used as a suppliment of estrogen in order to treat osteoporosis. The representative phytoestrogens, isoflavones, are daidzein, genistein and formononetin which were present highly in our traditional soybean foods. The quantitative analysis of the isoflavone was done with a high performance liquid chromatography(HPLC) using a UV/VIS detector for the contents of the isoflavones in Astragali Radix, soybean sprouts, bean-curd(Tofu), soybean, soybean oil, pea, kidney pea, black bean(Yak-kong), soybean sauce(Ganjang). soybean paste(Doenjang), and fermented soybean(Maejoo). The content of free daidzein in soybean sprouts was $43.49{\pm}3.41\;mg/kg$$ which was much higher than that in soybean, $14.52{\pm}0.58\;mg/kg$, although total daidzein of fermented soybean was lower than that in soybean (Table 2. P<0.01). The amounts of free genistein in soybean sprouts, fermented soybean. and soybean paste were $27.63{\pm}1.66\;mg/kg,\;291.52{\pm}6.81\;mg/kg,\;and\;18.75{\pm}1.33\;mg/kg$, respectively. The level of free formononetin in soybean paste was the highest among the soybean products (P<0.01). The content of formononetin in Aatragali Radix, $9629.73{\pm}0.57\;{\mu}g/kg$, was about 160 times higher than that in soybean. Thus Korean traditional soybean products, black bean(Yak-Kong) and Astragali Radix can be a good choice of phytoestrogens.

• Food Science and Preservation
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• v.31 no.3
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• pp.374-384
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• 2024

Soybean paste is a staple food used to make doenjang (DE), cheonggukjang (CGJ), and miso (MI). In this study, solid-phase microextraction followed by gas chromatography-mass spectrometry was used to identify volatile components in DE, CGJ, and MI, and principal component analysis (PCA) was performed to determine their correlation between soybean pastes. Esters and hydrocarbons accounted for more than 55% of the total volatile components. PCA showed that esters were highly correlated with DE; pyrazines were correlated with CGJ; and alcohols were highly correlated with MI. Because DE, CGJ, and MI are made of the same material, their overall volatile content tended to be similar. However, the main volatile components and fragrances were different. These findings will be used as basic research data to promote quality improvement of soybean-based fermented foods in Korea and Japan.

• Journal of the East Asian Society of Dietary Life
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• v.7 no.1
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• pp.41-46
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• 1997

Diet is generally accepted as one of the important factors in human cancer development. Ethyl carbamate has been associated with cancer for several decades and mainly found in the fermented beverages and foodstuff. The relationship between ethyl carbamate and the human health cannot be ignored especially in the areas where fermented foods consists of regular food consumption. To investigate the ethyl carbamate exposure level in Korean population, commercial fermented food samples were collected form local markets I Seoul area and home-made varieties were collected throughout the country. Following partial purification the concentration of ethyl carbamete was determined by GC/ MS. The concentration of ethyl carbamate ranged to 70 ppb in soysauce, to 10 ppb in soybean paste, and to 5 ppb in vinegars. Korean traditional alcoholic beverages showed small amount of ethyl carbamate. The estimated daily exposure of Korean population was 0~1900ng/day. It would be prudent to put efforts to minimize the formation of ethyl carbamate since the risk from the higher range exposure cannot be ignored.