• Food Engineering Progress
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• v.21 no.2
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• pp.126-131
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• 2017

Millimeter waves are electromagnetic waves with frequencies of 30-300 GHz (wavelength 1-10 mm), and millimeter wave stimulation affects microorganism growth. The present study stimulated Bacillus subtilis with 60 and 70 GHz millimeter waves during cheonggukjang fermentation and characterized the effects on cheonggukjang quality. Cheonggukjang treated with millimeter wave irradiation showed no significant difference in total bacterial count but generated only 5.52-5.92% viscous substance. Irradiation with 60 GHz millimeter waves yielded bright and intense color values relative to 70 GHz millimeter waves. Examination of the amylase activity and reducing sugar content of finished cheonggukjang revealed that irradiation at 70 GHz inhibited amylase activity in cheonggukjang. Furthermore, irradiation at 70 GHz increased protease activity, whereas irradiation at 60 GHz inhibited the activity. Moreover, the amino acid content changed with millimeter wave irradiation.

• Food Science and Preservation
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• v.23 no.4
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• pp.488-494
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• 2016

Cheonggukjang was prepared by addition of peanut (Arachis hypogaea L.) powder in order to improve its quality and functional properties. The physicochemical and sensory properties of Cheonggukjang added peanut powder were investigated, after adding the peanut powder with the amount of 5, 15 and 25% (w/w). The proximate composition of peanut powder was as follows: moisture, 1.80%; crude protein, 24.9%; crude lipid, 48.3%; crude ash, 2.90%; and carbohydrates, 22.1%. Crude protein and lipid content of Cheonggukjang increased with increaes in the amounts of peanut powder, while the moisture content decreased. Calcium and amino acid contents showed disparity depending on the increasing addition of peanut powder. Cheonggukjang containing 15% (w/v) peanut powder was found to be highest calcium contents. The major amino acids of Cheonggukjang were glutamic acid, aspartic acid, lysine, leucine, arginine and proline. Depending on increasing amounts of peanut powder, the L and b values (measured using Hunter's color values) were decreased, while the a value was increased. In addition, pH was decreased as the amount of peanut powder was increased. Sensory scores of Cheonggukjang containing 15% (w/v) peanut powder were best when considering both quality characteristics and sensory evaluation. This study suggested that peanut powder could enhance the quality and functionality of Cheonggukjang further.

• Food Science and Preservation
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• v.18 no.2
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• pp.149-155
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• 2011

Cheonggukjang tablet was prepared by addition of medicinal herb extracts (from Lentinus edodes, Codonopsis lanceolata, or Houttuynia cordata Thunb.) to improve its quality and functional properties. Lightness and yellowness (measured using Hunter's color values) were generally increased with increasing amount of medicinal herb extracts, whereas pH decreased. In proximate composition, the levels of crude protein, lipid and fiber levels of Cheonggukjang tablet decreased with increasing amount of added medicinal herb extracts, whereas moisture and crude ash were increased. The major amino acid of Cheonggukjang tablet were glutamic acid, aspartic acid, leucine and the principal fatty acids of Cheonggukjang tablet were linolenic acid, linoleic acid and palmitic acid, respectively. Hardness levels of Cheonggukjang tablet decreased with increasing amounts of added medicinal herb extracts. The Cheonggukjang tablet added with medicinal herb extracts increased both crude saponin and quercetin contents. Sensory score of Cheonggukjang tablet containing 20% (w/v) medicinal herb extracts were optimal in terms of both quality characteristics and sensory evaluation.

• Korean Journal of Food Science and Technology
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• v.45 no.4
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• pp.515-520
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• 2013

Bacterial communities derived from cheonggukjang and raw rice straw collected from a Mireuksan farm and a Heungup cheonggukjang in Gangwon province were investigated using both culture-based method and denaturing gradient gel electrophoresis (DGGE) analysis. Pure cultures, which were isolated from raw rice straw and cheonggukjang and cultured on tryptic soy agar plates (53-76 colonies per plate), were identified by analysis of 16S rRNA sequences. The traditional culture-based method and analysis of PCR-amplified 16S rRNA by DGGE revealed that for samples collected from the Mireuksan farm, Pantoea agglomerans and Bacillus subtilis were the predominant species in the raw rice-straw and cheonggukjang, respectively. For samples collected from the Heungup cheonggukjang, Bacillus amyloliquefaciens was the predominant species in both raw rice straw and cheonggukjang. Other microorganisms, including members of Pantoea, Bacillus, Enterococcus, Enterobacter, Pseudomonas, Rhodococcus, and Acinetobacter, were also present in the raw rice-straw and cheonggukjang, as were bacteria that could not be cultured.

• Preventive Nutrition and Food Science
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• v.14 no.1
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• pp.90-93
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• 2009

Cheonggukjang was prepared from soybean inoculated with B. licheniformis ATCC 10716 cells transformed with pHY3-5 carrying a fibrinolytic enzyme gene. During the 54 hr of fermentation at $37^{\circ}C$, fibrinolytic activities of cheonggukjang were significantly higher than cheonggukjang fermented with B. licheniformis 10716 control cells. The plasmid, pHY3-5 was stably maintained during the 54 hr without antibiotic selection and more than 52% of cells retained the plasmid.

• Food Science and Biotechnology
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• v.15 no.1
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• pp.96-101
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• 2006

Isoflavone distribution and ${\beta}$-glucosidase activity in cheonggukjang, a traditional Korean whole soybean-fermented food prepared with or without addition of Bacillus subtilis, were analyzed every 6 hr for 36 hr. Thermal cooking of raw-soaked soybeans significantly increased ${\beta}$-glucoside isoflavone level by 57.1 % and decreased malonyl-${\beta}$-glucosides by 57.6% (p<0.05). Consistent changes of isoflavone profiles in cheonggukjang without B. subtilis addition (COB) and samples with addition of B. subtilis (CWB) were not observed during 36 hr fermentation. ${\beta}$-Glucosides of isoflavones are major forms in both COB and CWB. ${\beta}$-Glucosidase activity in cheonggukjang decreased significantly compared to that of soaked soybeans due to thermal denaturation, while recovery of enzyme activity in COB was observed. Two new unidentified peaks were detected, and their relative peak areas in CWB were significantly larger than those in COB with increasing fermentation period (p<0.05), which indicates both peaks could be associated with fermentation metabolites.

• The Korean Journal of Food And Nutrition
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• v.32 no.4
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• pp.342-348
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• 2019

The objective of this study was to investigate the changes in flavor components of cheonggugjang prepared with hazelnut. Amino nitrogen content in cheonggukjang was significantly lower in the 30~40% hazelnut group compared to the control group. The volatile basic nitrogen of hazelnut added cheongkukjang showed a similar pattern to that of amino nitrogen. The number of B. subtilis was slightly increased in relation to the amount of hazelnut added, but there was no significant difference. The content of glucose increased proportionally with increasing hazelnut. Total amino acid content decreased with increasing hazelnut. The ratio of glutamic acid to total free amino acids increased with increasing hazelnut. Oleic acid content increased proportionally with increasing hazelnut, while linoleic acid content decreased. In conclusion, the addition of hazelnut may contribute to the quality diversification of cheonggukjang by changing the taste and flavor while maintaining the amino nitrogen content of cheonggukjang.

• Journal of Applied Biological Chemistry
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• v.52 no.3
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• pp.133-141
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• 2009

This study was carried out in order to investigate the changes in chemical components of four kinds of Cheonggukjang during fermentation. Three different kinds of Cheonggukjang were prepared with germinated soybeans using rice straw, Bacillus natto, Bacillus natto plus Aspergillus oryzae, and non-germinated soybeans using rice straw. The nitrogen contents increased significantly during fermentation in all kinds of Cheonggukjang. Especially germinated soybean Cheonggukjang prepared with A. oryzae plus B. natto showed approximately 1.3 to 3.0 fold higher values than the other Cheonggukjangs. Total free amino acid contents of all Cheonggukjangs increased with an increase in fermentation time until 60 h. Lysine content was highest in Cheonggukjang prepared with ungerminated soybean at 72 h of fermentation. Among free amino acids of germinated soybean Cheonggukjang prepared with rice straw, glutamic acid was highest (3.64 mg/g) after 72 h of fermentation. In Cheonggukjang prepared with mixed culture, glutamic acid content was 4.37 mg/g. Total carbohydrate contents of Cheonggukjang decreased rapidly with an increase in fermentation time except the ungerminated soybean Cheonggukjang, and the total carbohydrate contents varied from 9.81 to 14.04% after 72 h of fermentation. On the other hand, total carbohydrate contents of ungerminated soybean Cheonggukjang prepared with rice straw gradually decreased during fermentation. In conclusion, it is expected to increase the contents of functional constituents and to improve quality characteristics of Cheonggukjang when it is prepared with germinated soybeans using B. natto plus A. oryaze.

• Food Science and Preservation
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• v.17 no.5
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• pp.688-697
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• 2010

We investigated the cholesterol-lowering and body-weight loss effects of Cheonggukjang fermented using Bacillus subtilis DJI in rats fed a high-fat/high-cholesterol diet for 4 weeks. Weight-matched male Sprague-Dawley rats were assigned to one of four groups: a normal diet group (N), a high-fat/high-cholesterol diet group (HFC), a high-fat/high-cholesterol diet with DJI Cheonggukjang group (HFC-SCK), and a high-fat/high-cholesterol with commercial Cheonggukjang group (HFC-CCK). All of body weight and liver and adipose tissue weights increased in animals fed a high-fat/high-cholesterol diet, but decreased significantly in rats fed Cheonggukjang powder, compared with the HFC group. Food intake was lower in the HFC group than in the N group, and that of the HFC-CCK group was the lowest among the four groups. Serum total cholesterol levels were significantly lower in the Cheonggukjang-powder fed groups than the other groups. Serum phospholipid and HDL-cholesterol concentrations were significantly decreased in HFC animals and were markedly increased upon feeding of a Cheonggukjang-containing-diet. Levels of serum LDL-cholesterol, the atherogenic index, and cardiac risk factor assessment indications tended to be decreased in Cheonggukjang powder-fed groups, compared with the HFC group. The total cholesterol level in liver tissue was increased by feeding of a high-fat/high-cholesterol diet, and was significantly reduced when Cheonggukjang powder was present in the diet. The levels of total lipids and triglycerides in adipose tissues were lower in the HFC-SCK group than in the HFC group, whereas no significant differences were evidence when the HFC and the HFC-CCK groups were compared. Fecal weight, moisture level, and total lipid content increased in animals fed Cheonggukjang powder. The activities of HR-LPL and TE-LPL in adipose tissues were increased in the HFC group compared with the Cheonggukjang powder-fed groups. These results indicate that dietary Cheonggukjang may improve lipid metabolism and prevent obesity and hyperlipidemia.

• Food Science and Biotechnology
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• v.17 no.2
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• pp.287-294
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• 2008

Protective effects of cheonggukjang fermented with 20% red ginseng (RC) were observed in streptozotocin (STZ)-induced diabetic rats by measuring levels of blood glucose, serum lipid profiles, and hepatic reactive oxygen species generating and scavenging enzymc activities. RC diet was prepared by mixing with AIN-76 diet at the final concentration 2%, and it was fed to STZ-induced diabetic rats for 3 weeks. The RC dict was significantly improved body weight, feed efficiency ratio, levels of serum glucose, and serum and hepatic lipids in diabetes. The significantly elevated O type activity of xanthine oxidase in diabetes was also greatly decreased by the RC diet. The treatment of RC showed the improved hepatic glutathione s-transferase activities in the diabetic animals. The present study indicates that cheonggukjang fermented with red ginseng could ameliorate STZ-induccd diabetic symptoms such as aggravated blood glucose levels, serum lipid profiles, and even the conditions of oxidative stress.