• Korean Journal of Food Science and Technology
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• v.32 no.3
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• pp.640-645
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• 2000

The effect of gamma-irradiation on the quality changes of the grain shape improved Meju was studied. Meju was prepared, irradiated at 0, 5, 10 and 20 kGy, and then stored at $25^{\circ}C$ for six months. The results showed that the fungi and acid producing bacteria were completely eliminated by gamma-irradiation with dose of 10 kGy or higher and the Bacillus was decreased by 5 log cycles with dose of 10 kGy. The $D_{10}$ values of the fungi, Bacillus and acid producing bacteria were 0.79, 2.28 and 1.17 kGy, respectively. Also, the microorganisms that survived irradiation was decreased significantly with the duration of storage period. The $NH_3-nitrogen$, negative factors of quality of Meju, and browning were repressed and the protease activity and pH were not affected by gamma-irradiation. Therefore, it was considered that the Meju treated with gamma-irradiation maintained better quality than that of the control with storage.

• Food Science and Preservation
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• v.9 no.2
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• pp.205-211
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• 2002

In order to selection of the suitable soybean varieties, the quality characteristics of meju and doenjang on 4 domestic soybean cultivars(Daeweon, Sodam, Jinpeum and Hwangkeum) were evaluated. Crude protein and lipid content was 26.7∼30.5% and 16.89∼19.31%. The content of total free sugar among 4 soybean cultivars were 4.99∼5.26% and composed mainly stachyose(2.59∼3.51%), raffinose and sucrose. The content of total free sugar of meju were the highest in Jinpeum among 2.10∼2.66% and composed mainly glucose. The lightness of meju lump in Hwangkeum was larger decrease than the others, the redness were higher in Daeweon and Hwangkeum, the yellowness was the highest in Sodam. The lightness of meju powder was the highest in Sodam, the redness was the lowest in Sodam, the yellowness was the highest in Hwangkeum. The chemical composition of doenjang were that : was the highest in Jinpeum among the 7.90∼9.71% crude lipid, in Daeweon among 9.67∼13.50% crude protein, in Sodam among 2739∼3825 mg% Formol nitrogen and in Daeweon among 6.88∼8.36% crude saponin, respectively. The content of total free sugar of doenjang were the highest in Hwangkeum among 1.88∼2.22% and composed mainly fructose and glucose. The lightness and yellowness of doenjang was the highest in Sodam, the redness was the highest in Hwangkeum. Doenjang by Hwangkeum had good score for taste, texture and overall quality in sensory evaluation.

• Korean Journal of Food Science and Technology
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• v.13 no.4
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• pp.319-327
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• 1981

In order to reproduce and improve the Korean traditional Kochujang(fermented hot pepper-soybean paste), traditional and improved Kochujang Koji were prepared according to the standard method investigated in Chunrabookdo area and combined the raw materials of Kochujang by the traditional habit. Amino nitrogen contents were higher in improved Kochujang than in traditional one, those were in the range from 83 to 106 mg% immediately after brewing and 191 to 313 mg% at the end stage of brewing. Water soluble and ammonia nitrogen contents were most high in the improved Kochujang which was mixed with sodium chloride and brewed soysauce as seasoning. The content of reducing sugar of traditional Kochujang was higher than that of improved one during the brewing. Ethyl alcohol contents of all Kochujang samples were 0.04% at the early stage of brewing and that reached above 2.5% after $40{\sim}50$ days brewing.

• Korean Journal of Agricultural Science
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• v.22 no.2
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• pp.188-196
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• 1995

To obtain useful mould strain in soybean fermentation industry, we collected conventional Meju all over the Korea and tested existance of aflatoxin in Meju collected. Also, we measured distribution of microorganism and enzyme activity of Meju and isolated Aspergillus oryzae O4-5 as a industrially useful mould. The results obtained were summarized as follows: 1. Aflatoxin was not detected by EZ-Screen Test Kit and HPLC analysis in various Meju sample collected all over the Korea from 1994.12 to 1995.2. 2. Colony forming units(CFU) of mould, yeasts, aerobe, and anaerobe were $1.3{\times}10^4-2.8{\times}10^6$, $1{\times}10^2-1.5{\times}0^6$, $2.0{\times}10^7-8.0{\times}10^8$ and $3.0{\times}10^6-7.3{\times}10^8$ per gram of Meju, respectively, indicating that CFU inter Meju samples were varied with big difference. 3. The activities of ${\alpha}$-amylase and gluco-amylase were 5-80 units and 2-34 units per g of Meju, respectively. It was shown that enzyme activity was varied depending on where the Meju was collected. 4. The activities of acidic, neutral and alkaline protease were 5-33 units, 5-302 units and 5-363 units per g of Meju, respectively. Acidic protease of Improved Meju made by D-Company was higher than that of conventional Meju as 66 units per g of Meju. 5. CNU O4-5 strain selected as a noble strain could produce amylase and protease in high level, and identified as a strain that belongs to Aspergillus oryzae. 6. The activities of acidic and neutral protease of Aspergillus oryzae CNU O4-5 strain isolated were about 10% higher than those of Aspergillus oryzae JM which has been used in soybean fermentation industry. Amylase activity of CNU O4-5 strain was similar to Aspergillus oryzae JM.

• Korean Journal of Food Science and Technology
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• v.30 no.4
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• pp.908-915
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• 1998

By using Korean native soybean, traditional meju was prepared in Chuncheon, Kangweondo according to the traditional process. Analysis of physico-chemical, enzymatic and microbiological changes during meju fermentation were carried out in order to obtain a basic information for industrial scale production of meju. The enviroments for natural meju fermentation were $10{\sim}15^{\circ}C$ and $60{\sim}70%{\;}RH$. Moisture content decreased from 59% to 11% (exterior section) and 19% (interior section). the pH of meju rapidly increased up to 8.5 at $33^{rd}{\;}day$ of fermentation and thereafter decreased down to 7.9 at $70^{th}{\;}day$ of fermentation. Souble protein content was 1.47% at initial stage and increased up to $6.31{\sim}7.34%$ at $33^{rd}{\;}day$ of fermentation. Amino nitrogen content was $460{\sim}770{\;}mg%$ at $70^{th}{\;}day$ of fermentation. the color of meju became gradually black and decreased in redness and yellowness. During the process, protease and lipase seemed to play an important role in the digestion of soy protein and fat. Acidic protease activity increased up to $135.9{\sim}152.4{\;}unit/g$ at $33^{rd}{\;}day$ of fermentation and were $181.3{\sim}272.6{\;}unit/g$ at $70^{th}{\;}day$ of fermentation. Lipase activity increased up to 6 unit/g (interior section) and 15 unit/g (exterior section) at $70^{th}{\;}day$ of fermentation. the viable cell count of meju was at the level of $10^8{\;}CFU/g$ during the overall fermentation period. Aerobic halophilic count was $1.51{\times}10^7{\;}CFU/g$ at initial stage and maintained $10^8{\;}CFU/g$ level during the process. Initial anaerobic cell count was $2.0^9{\times}10^4{\;}CFU/g$ and increased up to $10^5{\;}CFU/g$ level at 47 days. Yeast and mold counts were $10^4{\sim}10^5{\;}CFU/g$ for the fermentation period.

• Microbiology and Biotechnology Letters
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• v.26 no.6
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• pp.551-557
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• 1998

Whole soybean cereal was fermented with four Aspergillus strains in pilot meju fermentation system. The pH range of the product was 7.40~7.98, the contents of reducing sugar and amino-nitrogen were 0.04~2.78%, 178~309 mg%, respectively and that of free fatty acid ranged 2.67~5.05%. The components of the amino acid, organic acid, free sugars and fatty acid showed distinctive patterns among four groups of fermented soybean cereals. Amylase activity and carbohydrate degradation rate of A. usami was higher than other strains. But protease and protein degradation rate, lipase and lipid degradation rate were similar in four strains. The odor concentrates of soybean cereals fermented with Aspergillus strains were different from Bacillus strains. Especially, pyrazine components, the main and common flavor chemicals in Bacillus strains, were not determined in this study and Aspergillus specific components were 9-methyl-acridine, dl-limonene and 2,3-butanediol. Soybean paste, made from A. oryzae fermented soybean cereal, showed excellent sensory evaluation.

• Applied Biological Chemistry
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• v.37 no.4
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• pp.266-271
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• 1994

In order to investigate the effects of the mixing ratio of rice on Doenjang, Meju Doenjang and Koji Doenjang were prepared respectively with oaring mix ratio of raw materials. The following results were obtained, after fermentation of up to 3 months. Significant differences between the kinds of Doenjang were not found in moisture and salt contents. Protein solubility $(water\;soluble\;nitrogen/total\;nitrogen{\times}100)$ was $32{\sim}50%$ and $14{\sim}24%$ in Koji Doenjang and Meju Doenjang, respectively. Protein digestibility $(formol\;nitrogen/total\;nitrogen{\times}100)$ was similar to the tendency of protein solubility. Reducing sugar content was $5{\sim}6%$ in Meju Doenjang, while $19{\sim}21%$ in Koji Doenjang. As the mixing ratio of rice increased, reducing sugar content also increased. Sensory evaluation showed that Koji Doenjang was desirable than Meju Doenjang and the mixing ratio of 20% rice was recommened for Koji Doenjang.

• Journal of the Korean Society of Food Science and Nutrition
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• v.21 no.5
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• pp.557-565
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• 1992

Volatile components of domestic Meju and Doenjang were extracted by simultaneous steam distillation extraction, and analyzed by GC-MS. Sixty-four kinds of compounds were identified from neutral fraction. The contents of pentanal, hexanal and 1-octen-3-ol were high in cooked soybean while those of 3-methylbutanal and 1-butanol were high in Meju. In the case of Doenjang, so many compounds including acetic acid, ethylester were identified which was not appeared in Meju. The main compounds in Meju were 3-methyl-1-butanol, 2-furancarboxyaldehyde, 1-octen-3-ol, benzeneacetaldehyde, methyloctadecadienoate and methyloctadecenoate. Of the eleven compounds identified from basic fraction, the contents of 2,6-dime-thylpyrazine, trimethylpyrazine and tetramethylpyrazine were high in Meju and Doenjang. Nine kinds of compounds were identified from phenolic fraction and appeared that 4-vinylphenol and p-ethylguaiacol were major compounds in Meju and Doenjang. Fifteen kinds of volatile compounds were contained in acidic fraction. Only four acidic compounds were identified in cooked soybean and Meju, but in Doenjang ten compounds were identified which did not appeared in other samples. Among them pentadecanoic acid was major compound.

• Korean Journal of Food Science and Technology
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• v.29 no.5
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• pp.1006-1015
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• 1997

Whole soybean meju was fermented with four Bacillus strains for 45 hr in its model system. The pH range of the product was $7.98{\sim}8.68$, the contents of amino nitrogen and ammoniacal nitrogen were $286{\sim}439\;mg%,\;0.11{\sim}0.23%$, respectively and that of reducing sugar ranged $0.65{\sim}2.24%$. During fermentation, the enzyme activities increased up to $30{\sim}40\;hr$ of fermentation and slightly decreased after 45 hr. Stachyose was special sugar components for B. licheniformis and raffinose was for B. natto. The components of the organic acid showed distinctive patterns among four products and the patterns of amino acids and fatty acids were almost similar to those of other reports. The main and common odor concentrates of meju were pyrazine components, 3-methyl-1-butanol, acetic acid and ethanol. Chunggukjang, mixed with B. natto and B. licheniformis showed more acceptabilities than other combinations. Soybean paste, mixed with B. megaterium and B. subtilis, soysauce, mixed with B. megaterium and A. oryzae showed excellent acceptability, respectively.

• Food Science and Preservation
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• v.24 no.1
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• pp.145-152
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• 2017

In this study, near infrared (NIR) spectroscopy known as a non-destructive analysis technique was applied to investigate peptide cleavage and consequent release of amino acids in soybean lumps as affected by its moisture content and incubation time during fermentation at 25 for 3 weeks. The NIR spectra of the soybean lump semi-dried and soaked in saline water showed that absorption intensity around 1,400 nm originating from hydrogen bonds of water decreased and absorption band shifted to 1,430 nm as moisture content decreased during incubation at 25 for 3 weeks. In addition, absorption around 2,050 nm which was assigned to amino groups increased as incubation time increased. NIR spectra data from 1,000 to 2,250 nm showed higher accuracy in the discriminant analysis between outside and inside parts of fermented soybean lumps than visible spectra result. NIR spectroscopy for the amino acid and moisture contents in traditional fermented soybean lumps showed relatively good accuracy with the multiple correlation coefficient ($R^2$) of 0.91 and 0.81, respectively, and root mean square error of cross validation (RMSECv) of 0.23 and 0.83%, respectively, in partial least square regression (PLSR). These results indicate that NIR spectral observations could be applicable to control the fermentation process for preparation of soybean products.