• Applied Biological Chemistry
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• v.39 no.6
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• pp.460-465
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• 1996

The production of bacterial protease and its characteristics were investigated with Bacillus subtilis globigii CCKS-118 which was isolated from Korean traditional soy sauce. The optimum culture condition of the strain for the production of alkaline protease was as follow : 2% soluble starch, 0.2% yeast extract, 0.1% $(NH_4)_2SO_4$, 0.2% $MgSO_4$, pH 7.5, $35^{\circ}C$ and 20h rs. The optimum pH and temperature for the enzyme action of alkaline protease producing Bacillus subtilis globigii CCKS-118 were pH 9.0 and $50^{\circ}C$, respectively. The enzyme was relatively stable at $pH\;6.0{\sim}9.0$ and at temperature below $40^{\circ}C$. The activity of the enzyme was inhibited by $Hg^{2+}$ whereas $Cu^{2+}$ gave rather activating effects on the enzyme activity. The enzyme was inhibited by phenylmethane-sulfonyl fluoride indicating serine pretense metal ion group are required for the enzyme activity. Km value was $1.242{\times}10^{-4}M$, $V_{max}$ value was $25.99\;{\mu}g/min$. This enzyme hydrolyzed casein more rapidly than the hemoglobin.

• Applied Biological Chemistry
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• v.42 no.4
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• pp.283-287
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• 1999

This study was carried out to select the most suitable soybean cultivars for the quality kanjang preparation. Six cultivars of soybean, Taekwangkong, Kumjungkong #1, Sinpaldalkong #2, Hwangkeumkong, Danbaegkong and Danyeobkong, were used as the raw materials for kanjang preparations. Grain type meju was prepared by the inoculation of Bacillus subtilis var. globigii seed culture on the cooked soybean of respective cultivar and cultivation at $30^{\circ}C$ for 10 days. Two month matured respective kanjang mash, which was prepared by mixing meju and 20% salt brine in the ratio of 1 : 3, was separated and the liquid portions were used as kanjang samples for this work. The highest crude protein content of 47.5% was obtained from Danbaegkong cultivar among six soybean cultivars tested. High sugar soybean cultivars were found to be Kumjungkong l and Danbaegkong and the content 15.87% and 13.33% respectively. The highest total nitrogen(TN) content of 1.18% was shown from Danbaegkong kanjang. Although the major free organic acid in kanjang was found to be succinic acid, no significant differences in free organic acid and sugars content were observed among cultivars. The highest free total amino acids(TA) and glutamic acid(GA) content in kanjang was observed to be 3365 mg% and 734.44 mg% respectively from Danbaegkong kanjang. Danbaegkong cultivar soybean which was shown to contain the highest crude protein was found to be the most suitable one for the preparation of quality kanjang with high TN, GA content and GA/TA ratio.

• Applied Biological Chemistry
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• v.41 no.6
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• pp.405-409
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• 1998

This work was carried out to investigate the behavior of sugars contained in raw soybean during cooking and meju preparation processes, and the effects of sugar addition to the raw kanjang digestion liquor made from G8 and SB meju on the lactic acid and alcoholic fermentation of kanjang. Sharp reduction in sugars content in soybean during cooking and meju preparation process was observed. Rapid lactic acid and alcoholic fermentation in the G8 and SB kanjang with 5% added glucose was observed but not in the corresponding kanjang without sugar addition after inoculation of Pediococcus halophilus, Zygosaccharomyces rouxii and Candida versatilis starter culture to the low-salted raw kanjang digestion liquor made respectively from G8 and SB meju. 0.46% and 0.88% of lactic acid and 1% and 2% of alcohol content in the G8 and SB kanjang respectively was observed 160 hours after the inoculation of the lactic acid bacteria starter culture.

• Applied Biological Chemistry
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• v.40 no.5
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• pp.365-368
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• 1997

This study was carried out to investigate the optimum mashing and maturing conditions for Korean traditional Kanjang(soy sauce) production and to reduce the fermentation period. The effects of maturing time of soy sauce mash, maturing temperature, salt concentration and the ratio of Meju to salt brine on the quality of Kaniang(total nitrogen, pH and color) were examined. Soy sauce pigments and about 90% of N constituents contained in soybean Meju(Koji) in soy sauce mash were degraded and solubilized into liquid portion (soy sauce) of the mash within five days of maturing at $30^{\circ}C$ with the mashing ratio(weight/volume) of 1 : 4 of soybean(as raw soybean) to 20% salt brine. No remarkable effects of soy sauce maturing temperature in the range of $5^{\circ}C{\sim}30^{\circ}$ on the digestion and solubilization of N components and pigment extraction during five days of soy sauce mash maturing were observed. Optimum mashing salt brine concentration for the digestion and solubilization of N components and pigment extraction during soy sauce maturing at $30^{\circ}C$ were observed to be in the range of $15{\sim}20%$. The suitable mashing ratio of Meju to salt brine (wt./vol.) to match N content of the standards of identity of Korean traditional Kanjang(soy sauce) was found to be below 1 : 5.