• Korean Journal of Food Science and Technology
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• v.9 no.1
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• pp.73-80
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• 1977

In order to detect the occurrence of aflatoxins in some suspecious Korean foodstuffs, 54 samples of Meju (a naturally inoculated soybean substrate for soy sauce and paste fermentation), 125 samples of Doenjang (a Korean-style fermented soybean paste), both produced at household level, and 31 samples of peanut were collected from 8 major cities of South Korea and subjected to assay by the official method of AOAC. The results were as follows: 1) Frequencies for the occurrence of aflatoxins in Meju, Doenjang and peanut were 7.4%(4/54), 8.8%(11/125) and none (0/31), respectively, in which Meju and Doenjang samples from Daegu and Busan showed the high ratio of the presence. 2) A Doenjang sample from Busan was found to contain the highest content of aflatoxins, of which $B_1,\;B_2,\;G_1\;and\;G_2$ were 66 ppb, 13 ppb, non-detectable and 5 ppb, respectively, while other samples detected were for $G_2$ only. 3) The identity of aflatoxin $B_1$ isolated from the Doenjang sample from Busan was confirmed by thin-layer chromatographic behavior, derivative formation and chicken embryo bioassay.

• Culinary science and hospitality research
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• v.15 no.2
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• pp.298-308
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• 2009

In order to establish the quality standard of Jeju traditional Doenjang(soybean paste), general components, free sugar, organic acid, fatty acids, amino acids, and isoflavones contents were analyzed. Moisture, crude ash, crude protein, crude lipid, acid value, pH, and salinity were 37.33~47.43%, 12.75~15.97%, 11.06~14.28%, 0.08~0.53%, 17.83~27.55 mg/g, 4.82~5.12, and 10.66~13.91% respectively. The content of amino type nitrogen was 301.06~573.89 mg%. The compositions of free sugar were glucose (0.81~10.22 mg/g), maltose(0.64~5.28 mg/g), sucrose(0.78~3.86 mg/g), and fructose(0.72~1.11 mg/g). The major organic acid was lactic acid (89.30~180.39 mg/g). Total free amino acids were from 13.89 to 15.51%, which makes no difference between the test samples. Among amino acids, glutamic acid was abundant (2.12~2.55%). The contents of isoflavones were 274.87~431.96 mg/kg, less than those of commercial soybean paste. In fatty acid composition of soybean paste, the most abundant fatty acid was found to be linoleic acid as 61.54~66.79% in Jeju traditional Doenjang. This results might be caused by the differences of brewed periods, microflora, processing methods and used soybean cultivars.

• Korean Journal of Food Science and Technology
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• v.47 no.5
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• pp.599-607
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• 2015

Fermented-Rhus verniciflua (FRV) extract is increasingly used in fermented soy products, fermented vinegars, and certain alcoholic beverages. In this study, we investigated the effects of FRV extract on the physicochemical properties of doenjang (soybean paste). Addition of FRV extract to doenjang resulted in a 28.2-45.4% increase in the amino acid content and a 1.3- to 1.5-fold increase in the concentrations of glutamic acid, which imparts a savory flavor to doenjang. The concentration of biogenic amine (BA) of the sample containing the extract was 5.3-52.6% lower than that of the control. The major components of BA included tyramine (55.1-74.6%), followed by putrescine, spermidine, tryptamine, and cadaverine, in decreasing concentrations. The organic acid concentration of the sample containing the extract was 1.2-1.3-fold higher than that of the control. The total free sugar concentration was 163.4 mg/100 g in the control and 206.6-276.8 mg/100 g in the supplemented sample, showing a 1.3- to 1.9-fold increase as the addition of the extract.

• Korean journal of food and cookery science
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• v.30 no.4
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• pp.435-443
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• 2014

In this study, we investigated the quality characteristics of Korean soybean paste, Doenjang, fermented for 6 weeks at room temperature with the addition of 0, 10, 20 and 30% garlic. Samples were analyzed in one-week intervals. The lightness decreased in all samples as the fermentation period and garlic concentration increased. Yellow index decreased in weeks 5~6 compared with weeks 0-1, for which the values were lower for the garlic-added Doenjang than the control. The pH increased, greatly reducung the acidity in week 1 compared with week 0. Significant differences in the pH and acidity were not observed among the sample groups. Amino type nitrogen contents increased continuously up to weeks 5, displaying no significant differences among the sample groups at weeks 5 and 6. In addition, reduction in the sugar content increased depending on the fermentation period. It increased in all sample groups by about 2.5 times after 6 weeks compared with the initial levels. Isoflavone content was also reduced generally depending on the fermentation period. In the early fermentation periods, the aglycone contents were the higher than the glycosides, while the glycoside contents increased over the fermentation period. The presence of Bacillus was not significantly different among the garlic added groups, but yeast was lower in the Doenjang with high garlic content.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.4
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• pp.519-523
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• 2005

Soybean paste (Doenjang) was prepared by adding Lotus root powder (LRP) at $5\~15\%$ (w/w) to improve quality of the Doenjang and to give some functional properties. Moisture content was ranged about $50.05\~54.04\%$ and amino nitrogen content was $635\~648\;mg\%$ following the LRP contents. Crude protein amounts were $11.55\~12.56\%$ that was no difference between test samples. Carbohydrates contents increased $1.5\~2$ times in the test samples than the control depending on the LRP contents. However, contents of crude lipid $(6.99\~8.55\%)$ and ash $(13.99\~15.17\%)$ were decreased as increased the amounts of LRP. The pH of the product was decreased until 45 days during aging period and then slightly increased without significantly differences among test samples. The values of acidity were $1.85\~2.18\%$ at the early stage of aging but slightly increased with further aging. The total phenolic content in the Doenjang adding $15\%$ LRP was $461.8\;mg\%$ which is higher than $368.6\;mg\%$ in the control. Doenjang prepared with LRP showed an anti-browning effect of the product itself.

• Korean Journal of Food Science and Technology
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• v.35 no.2
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• pp.291-296
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• 2003

Effects of Bacillus subtilis and Rhizopus oryzae on chitooligosaccharides (COS) content of doenjang (soybean paste) and kanjang (soy sauce) were investigated using kojis made with the two strains. Competitive direct enzyme-linked immunosorbent assay (cdELISA) system using anti-COS mixture (COSM) antibody was applied for COS detection ranging from 0.001 to $1{\mu}g/mL$, and the recoveries of COSM spiked to doenjang and kanjang were 102 and 115%, respectively. Doenjang and kanjang products made with a mixture of B. subtilis and R. oryzae kojis showed COS contents of 171 and $29{\mu}g/mL$, respectively, during two-month aging period, much higher than those of Japanese and Korean commercial ones.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.6
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• pp.936-940
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• 2004

Doenjang (Korean soy paste) is one of the popular soybean based fermented foods in Korea. This study investigated the growth and DNA synthesis inhibitory effect of doenjang methanol extracts on AGS human gastric adenocarcinoma cells, Hep 3B human hepatocellular carcinoma cells and HT-29 human colon cancer cells. In order to determine an anticancer effect of doenjang methanol extracts, other soybean fermented foods and original materials were compared. The treatment of doenjang methanol extracts (200 $\mu\textrm{g}$/mL) to the AGS, Hep 3B and HT-29 cancer cells inhibited the growth of cancer cells by 80%, 77% and 86%, respectively. Compared to other soybean fermented foods and original materials, doenjang methanol extracts showed the highest growth inhibitory effect on different cancer cells. In addition, doenjang methanol extracts (200 $\mu\textrm{g}$/mL) significantly inhibited DNA synthesis of AGS and Hep 3B cancer cells by 76% and 59%, respectively. These results suggested that this anticancer effect of doenjang may be due to specific active compounds, which will be newly produced during soybean fermented process and not contained in soybean.

• Korean Journal of Food Science and Technology
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• v.31 no.3
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• pp.848-854
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• 1999

Inhibitory compounds of angiotensin converting enzyme (ACE) were separated from Doenjang (traditional Korean fermented soybean paste). Water extracts from Doenjang which showed ACE inhibitory activity were separated with gel permeation chromatography (GPC), in which two fractions with high ACE inhibitory activities were obtained. The first fraction from GPC was further isolated by semi-preparative reverse phase preparative-HPLC (high performance liquid chromatography) and 2-dimensional electrophoresis/thin layer chromatography (TLC). The purified spot had molecular weight of 759 daltons and ninhydrin-positive non-peptide. The second fraction from GPC was also further isolated by semi-preparative reverse phase HPLC and $NH_2-column$ HPLC. One fraction with high ACE inhibitory activity was purified and characterized. Molecular weight of this fraction by LC-MS was 272.34 daltons. The active fraction was identified as Arg-Pro with ACE $IC_{50}$ of $92\;{\mu}M$.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.6
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• pp.1043-1048
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• 2004

This study was carried out to investigate the effect of soy protein dispersibility on the bread making properties when Doenjang powders (DP) were added to the bread formula at the levels of 2.5 or 5.0%, comparing with full fat (FSF) or defatted (DSF) soy flours which contain same protein contents as those of DP. Protein dispersibility indices (PDI) for DP, FSF, DSF and strong wheat flour were 57.1, 7.3, 10.8 and 32.8%, respectively. Addition of DP decreased significantly the resistance to extensibility of wet gluten and increased its extensibility. However, FSF and DSF showed different changes in gluten rheology due to their PDI. In correlation coefficient values, PDI affected positively both gluten extensibility (r=0.98, p<0.01) and ovenspring (r=0.88, p<0.05) resulting in loaf volume and texture improvement of bread with addition of DP.

• Korean journal of food and cookery science
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• v.20 no.4
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• pp.365-370
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• 2004

The study was carried out to evaluate the radical scavenging activity, and antimutagenic and anticancer effects in Korean soybean paste(doenjang) added with various mushrooms. Ganoderma lucidum doenjang(Gl-TD) showed significant inhibitory activity against the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, with an IC$\sub$50/ value of 245$\mu\textrm{g}$/$m\ell$. In contrast, the other doenjang varieties appeared to have weaker antioxidant activity. Four kinds of doenjang didn't have any antimutagenic activity against N-methyl-N'-nitro-N-nitrosoguanidine(MNNG) by adding of 5mg/plate, but exhibited a strong inhibitory effect(55∼70%) against aflatoxin B$_1$(AFB$_1$). Especially Phellinus linteus doenjang(Pl-TD) inhibited more than 70% of the mutagenicity induced by AFB$_1$ in Salmonella typhimurium TA100. On the other hand, the mushroom doenjang varieties showed relatively weak activity toward MNNG in SOS chromotest, their inhibitory rate ranging from 23% to 33%. Methanol extracts of Gl-TD and Pl-TD inhibited by 91∼92% the growth of AGS gastric cancer cells in a concentration of 100$\mu\textrm{g}$/$m\ell$.