• Journal of the East Asian Society of Dietary Life
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• v.26 no.6
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• pp.491-497
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• 2016

The objective of this research was to determine the fermentation and quality properties of soy yogurt incorporating insoluble components fermented with Streptococcus thermophilus (S. thermophilus) and Lactobacillus bulgaricus (L. bulgaricus) for 24h. Boiled soybeans were ground and reconstituted into equivalent total solids (18%). After soymilk was homogenized with sugar, it was pasteurized in a water bath at $90^{\circ}C$ for 30 min. Two kinds of lactic acid bacteria were inoculated into two types of soymilk after cooling down $40{\sim}45^{\circ}C$ and fermentation at $37^{\circ}C$ for 24h. Titrable acidity, pH, viscosity, sugar content, and number of viable cells were determined in triplicate. Soy yogurt fermented with L. bulgaricus did not reach pH 4.5, where as S. thermophilus was considered good for achieving pH 4.08 and titratable acidity of 2.27% for 24 h. Soy yogurt fermented with S. thermophilus had a higher viscosity and lower sugar contents than that fermented with L. bulgaricusas incubation time increased. Total viable count was $1.80{\times}10^{10}CFU/mL$ on S. thermophilus and $2.16{\times}10^8CFU/mL$ on L. bulgaricus after 24 h at $37^{\circ}C$. However, there was no significant difference in sensory intensities and preference between the two samples. As a result, S. thermophilus was identified as a better culture than L. bulgaricus for the manufacture of soy yogurt incorporating insoluble components.

• Korean Journal of Food Science and Technology
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• v.39 no.6
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• pp.676-680
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• 2007

This research was conducted to investigate the changes in quality characteristics of cheonggukjang made with 24-hr germinated soybeans during fermentation. Our study confirmed that the pH of the 24-hr germinated soybeans was 6.7, and the value increased as fermentation progressed. The amount of viscous substances in the cheonggukjang produced with the 24-hr germinated soybeans constantly increased to 5.89% at 36 hr of fermentation, and then remained unchanged. Free sugars (raffinose, sucrose, glucose, and fructose) rapidly decreased with the fermentation process. The levels of free amino acids in the 24-hr germinated agakong and the 48-hr fermented cheonggukjang were 391.0 and 10,994.8 mg%, respectively. Glutamic acid content was highest, followed by aspartic acid, lysine, leucine, and proline. The ratio of glutamic acid to total free amino acids at 48-hr of fermentation was 18.0%. Finally, it was confirmed that the sensory evaluation score of the 24-36 hr fermented cheonggukjang, made with the 24-hr germinated soybeans, was superior to that of the 24 and 48-hr fermented cheonggukjang.

• The Korean Journal of Food And Nutrition
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• v.28 no.3
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• pp.499-506
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• 2015

The aim of this study was to investigate the changes in the taste components of cheonggukjang made with germinated soybeans, which is produced by the addition of a smoking process. The total organic acid content of smoked cheonggukjang made with germinated soybeans (SCGS) was four times higher than that of non-smoked cheonggukjang made with non-germinated soybeans (NCNS). The total organic acid content of SCGS was lower than that of non-smoked cheonggukjang made with germinated soybeans (NCGS). The total free sugar content of NCGS and SCGS was approximately three times higher than that of NCNS. The total free amino acid content of NCGS was significantly decreased compared with that of NCNS, whereas the total free amino acid content of SCGS was 1.2 times higher than that of NCGS. The essential amino acid content of SCGS was significantly increased compared with that of NCGS. The ratio of glutamic acid to the total free amino acid in NCNS and SCGS was 19.6%. Similarly, the ratio of glutamic acid to the total free amino acid in NCGS was 19.1%. There were no significant differences in the total fatty acid content of NCNS, NCGS, and SCGS. The sensory evaluation of appearance, aroma, taste, and overall quality of SCGS was significantly increased compared with that of NCNS and NCGS. These results suggest that smoked cheonggukjang made with germinated soybeans could be utilized for the development of a novel fermented food.

• Korean journal of food and cookery science
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• v.14 no.5
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• pp.509-512
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• 1998

Changes in the contents of stachyose and raffinose were determined during soybean fermentation. ${\alpha}$-Galactosidase activities were also monitored in soybean and its fermented products. The stachyose contents were 31.8239 mg/g of soybean, 4.2217 mg/g of Meju, and 2.1184 mg/g of Doenjang. The raffinose contents were 2.6914 mg/g of soybean, 1.7413 mg/g of Meju, and negligible of Doenjang. ${\alpha}$-Galactosidase activities was distinct in soybean and Meju. They were 14.5954 units/mg protein of soybean, 13.1489 units/mg protein of Meju, and 1.9157 units/mg protein of Doenjang. The results suggested that the decrease of stachyose and raffinose contents in fermented soy products were due to the ${\alpha}$-galactosidase activity.

• 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.

• Journal of Microbiology and Biotechnology
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• v.31 no.3
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• pp.447-455
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• 2021

Strains of four Bacillus spp. were respectively inoculated into sterilized soybeans and the free amino acid profiles of the resulting cultures were analyzed to discern their metabolic traits. After 30 days of culture, B. licheniformis showed the highest production of serine, threonine, and glutamic acid; B. subtilis exhibited the highest production of alanine, asparagine, glycine, leucine, proline, tryptophan, and lysine. B. velezensis increased the γ-aminobutyric acid (GABA) concentration to >200% of that in the control samples. B. sonorensis produced a somewhat similar amino acid profile with B. licheniformis. Comparative genomic analysis of the four Bacillus strains and the genetic profiles of the produced free amino acids revealed that genes involved in glutamate and arginine metabolism were not common to the four strains. The genes gadA/B (encoding a glutamate decarboxylase), rocE (amino acid permease), and puuD (γ-glutamyl-γ-aminobutyrate hydrolase) determined GABA production, and their presence was species-specific. Taken together, B. licheniformis and B. velezensis were respectively shown to have high potential to increase concentrations of glutamic acid and GABA, while B. subtilis has the ability to increase essential amino acid concentrations in fermented soybean foods.

• Food Science and Preservation
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• v.30 no.6
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• pp.905-917
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• 2023

The optimal fermentation conditions for producing fermented black soybeans rich in sulfur-containing amino acids were investigated. Response surface methodology monitored fermentation conditions. A central composite design examined the effect of independent variables: enzyme concentration (X₁) and fermentation time (X₂) on yield and methionine content. Both factors significantly influenced these dependent variables. Enzyme concentration more profoundly affected amino nitrogen content than fermentation time. β-Glucan content and cystine level were primarily affected by fermentation time. We elicited each variable's regression formula and identified optimal fermentation conditions for functional compounds. The predicted optimum conditions were an enzyme concentration of 0.28-0.32% and a fermentation time of 58.0-62.0 min. Under these optimal conditions, each black soybean variety's sulfur amino acid content ranged from 818.62 to 922.62 mg/100 g, demonstrating significant variety differences.

• Food Science and Preservation
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• v.23 no.6
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• pp.811-818
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• 2016

The purpose of this study was to investigate changes in the amino acid content and physicochemical properties of Cheonggukjang prepared by using various soybean cultivars (Daewon, Deapung, Seadanbeak, and Taekwang) and a functional microorganism (Bacillus subtilis HJ18-9). These soybeans were conventional Cheonggukjang (control) and Cheonggukjang fermented with Bacillus subtilis HJ18-9 (treated). The moisture contents of steamed, control, and treated soybean were 62.45~67.12%, 63.28~67.14%, and 64.50~66.87%; amino-type nitrogen contents were 6.53~24.25 mg%, 27.63~122.09 mg%, and 37.29~133.48 mg%; and ammonia-type nitrogen contents were 26.92~47.95 mg%, 45.45~156.36 mg%, and 28.02~121.13 mg%, respectively. The umami taste associated with several amino acids (aspartic acid and glutamic acid) in Cheonggukjang was lower than that for steamed soybeans, while the bitter taste from amino acids (methionine, valine, isoleucine, leucine, and phenylalanine) was higher than that for steamed soybeans. The result of sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis showed that the molecular weight of steamed soybeans was less than 100 kDa, while control and treated groups showed low molecular weights below 34 kDa, confirming their protein hydrolysis to small molecular weight. These results are information for developing functional fermented soybean paste and diversification using soybean cultivars.

• Korean Journal of Microbiology
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• v.49 no.4
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• pp.391-397
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• 2013

Changes in ${\beta}$-glycosidase activity, total phenolic and isoflavone contents, and antioxidant activities during the fermentation of Korean black soybeans (Seoritae and Seomoktae) fermented food cheonggukjang by the potential probiotic Bacillus subtilis CSY191 were investigated. The levels of total phenolic and isoflavone-malonylglycoside and -aglycone contents increased, while 2,2-azinobis (3-ethyl-benzothiazoline-6-sulfonic acid) diammonium salt (ABTS) radical scavenging activity and ferric reducing/antioxidant power (FRAP) increased, but the isoflavone-glycoside contents decreased after cheonggukjang fermentation. The content of antioxidant compounds, including isoflavone-aglycones and -malonylglycosides, was increased by fermenting-processing, whereas the content of isoflavone-glycosides was decreased in the fermented soybeans. In particular, the Seoritae soybean fermented at 3 $7^{\circ}C$ for 48 h displayed the highest antioxidant activities, compared to those of the Seomoktae soybean and the fermented. The highest levels of daidzein, glycitein, and genistein were present at concentrations of 253.0 ${\mu}g/g$, 72.5 ${\mu}g/g$, and 114.1 ${\mu}g/g$ after 48 h of Seoritae soybean fermentation. From those results, we suggest that the high antioxidant activity of cheonggukjang of black soybeans might be related to the markedly higher levels of total phenolic and isoflavone-aglycone and -malonylglycoside contents achieved during fermentation.

• Applied Chemistry for Engineering
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• v.16 no.3
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• pp.348-353
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• 2005

The extracts from natural and fermented products such as Artemisia plants, Rhodiola Salientness, fermented soybeans and soybean paste were used to investigate the whitening effect. 10 g of Artemisia plant were added to 300 mL of ethanol and extracted by sonification at room temperature for 3 h. The extract was further partitioned by the equal volume percent in the order of the n-hexane, chloroform and ethyl acetate. 5 g of Rhodiola salientness was also added to 150 mL of methanol and extracted at the room temperature for 12 h. The effluents from a chromatographic column ($3.9{\times}250mm$, $C_{18}$, $15{\mu}m$) were collected and concentrated in two parts. The extraction of fermented soybeans and soybean paste were done by 60% ethanol. In this work, tyrosinase inhibitory activity and melanin inhibitory effect were measured to confirm the whitening effect. The water layer of Artemisia princeps Pampan showed the good inhibitory of antioxidant, while the hexane layer of Artemisia iwayomogi Kitamura and the chloroform layer of Artemisia princeps Pampan had the excellent melanin inhibitory effect. The Rhodiola salientness had the superior whitening effect to the arbutin in in-vivo melanin production ratio assay. However, the fermented soybeans and soybean paste did not show any whitening effect.