• Journal of the Korean Society of Food Science and Nutrition
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• v.22 no.2
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• pp.215-221
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• 1993

This study aims to construct the conditions of thermal hydrolysis (40, 45, 5$0^{\circ}C$) of koji for the purpose of rapid soy sauce fermentation. Koji hydrolysate was stable for fermentation, when koji hydrolyzed at 4$0^{\circ}C$ with 12% NaCl or at 45$^{\circ}C$ with 8% NaCl. The highest extracted total nitrogen was 1.75%, when the salt level was 9% and at 45$^{\circ}C$. The amount of reducing sugar was 7.2% and that of formol nitrogen was 0.9% when NaCl concentration was 12% and at 45$^{\circ}C$. The viscosity of koji hydrolyzate was in good condition with 15% NaCl and at 45$^{\circ}C$ until after 12days. On the other hands, free amino acid extracted from koji hydrolyzates showed the highest levels of 3268mg% at 45$^{\circ}C$. Free amino acids consisted of glutamic acid, leucine, arginine, aspartic acid, lysine, valine and phenylalanine which dominated 50% of total amino acids.

• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.2
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• pp.268-274
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• 1998

The traditional kanjang has been prepared by mixing meju and 18% saline solution, and fermenting for 60 days. The traditional kanjang is very salty and inferior in flavor and taste comparing with commercial fermented soy sauce. To improve the quality of traditional kanjang, Zygosaccharomyces rouxii H-62, a flavor-related mutant, was inoculated during fermentation. It was found that the addition of Z rouxii helped to improve the organoleptic quaity of traditional kanjang. The optimal condition for preparing traditional kanjang was to use 5L of 15.5% saline solution per meju. Meju must be cut into 12 pieces to get a proper total nitrogen and pure extract content. The optimal fermentatin temperature was 3$0^{\circ}C$. The prepared kanjang contained over 0.8% total nitrogen and 6.0% pure extract after 60 days of fermentation.

• Mycobiology
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• v.43 no.3
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• pp.218-224
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• 2015

Aspergillus is an important fungal genus used for the fermentation of Asian foods; this genus is referred to as koji mold in Japan and China. A. oryzae, A. sojae, and A. tamari are used in the production of miso and shoyu in Japan, but a comprehensive taxonomic study of Aspergillus isolated from Meju, a fermented soybean starting material for traditional soy sauce and soybean paste in Korea, has not been conducted. In this study, various Aspergillus species were isolated during a study of the mycobiota of Meju, and the aspergilli were identified based on phenotypic characteristics and sequencing of the ${\beta}$-tubulin gene. Most strains of Aspergillus were found to belong to the following sections: Aspergillus (n = 220), Flavi (n = 213), and Nigri (n = 54). The most commonly identified species were A. oryzae (n = 183), A. pseudoglaucus (Eurotium repens) (n = 81), A. chevalieri (E. chevalieri) (n = 62), A. montevidensis (E. amstelodami) (n = 34), A. niger (n = 21), A. tamari (n = 15), A. ruber (E. rubrum) (n = 15), A. proliferans (n = 14), and A. luchuensis (n = 14); 25 species were identified from 533 Aspergillus strains. Aspergillus strains were mainly found during the high temperature fermentation period in the later steps of Meju fermentation.

• Food Science and Preservation
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• v.19 no.6
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• pp.873-881
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• 2012

This study was to examine the quality characteristics of Cedrela shoots according to soy sauce conditions. First, the results were on solid samples (pickled Cedrela sinensis shoot) as follows: The pH and acidity of Cedrela shoots tended to decrease slightly in the licorice added section. The sugar content and salinity of Cedrela shoots tended to decrease gradually during the storage period. The color values of Cedrela shoots tended to change from green to dark green due to soy sauce as their storage periods. The texture of Cedrela shoots had differences according to their unique characteristics, but the change was small in the licorice added section. The overall preference appeared most high in P1-1. Next, the results were on Liquid samples (soy sauce) as follows: The pH and acidity of soy sauce tended to decrease gradually during the storage period. The sugar content and salinity did not change a lot. Microorganisms were not detected during the storage period in the established conditions. Therefore, the conditions for quality changes about pickling soy sauce during the storage period have been established and it can be anticipated to commercialize various pickle food using Cedrela shoots.

• Applied Biological Chemistry
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• v.13 no.3
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• pp.187-191
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• 1970

This experiment was carried out to isolate osmophilic yeasts for higher concentration of NaCl than 20 per cent may affect greatly the fermentation of soy sauce. 6 strains of yeasts were selected from the soy sauce mashes at the fermentating periods and identified observing their morphological characteristics. Their salt-resistance and effects upon the flavor of soy sauce were examined. The results obtained were as follows: (1) The strain $T_3,T_5,$ and $T_{11},\;T_8,\;T_9,\;and\; T_{10},$ selected were identified Saccharomyces cerevisiae group II, Debaryomyces nicotianae, Saccharomyces chevalieri, Saccharomyces rouxii and Saccharomyces rosei, respectively. (2) They were more salt-resistant on the liquid media than on the solid media in the case of cultures on the media containing more than 26 per cent of NaCl. (3) They were grown on the media containing 5-23 per cent of NaCl better than containing none of NaCl. (4) The strain $T_3,\;T_8,\;T_9,\;and\; T_{10}$ were grown on the media containing up to 28 per cent of NaCl, and $T_5\;and\;T_{11}$ up to 32 per cent of NaCl is the case of liquid cultures. (5) Among them, the strain $T_9$ showed the best alcohol fermentation ability and the best fermentative flavor, and $T_5\;and\;T_{11}$ formed moldy smell and pellicle.

• Food Science and Preservation
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• v.20 no.6
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• pp.818-826
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• 2013

To evaluate the practical use of okara koji in soy sauce fermented with soybean koji, the okara koji was fortified with different contents (0, 50, and 100%) in soybean koji and then fermented for 90 days. The saltiness of the soy sauce was about 17.15~17.22%. The higher okara koji content showed lower net soluble solid contents of 8.73, 6.12, and 2.50%, as well as lower acidity levels of 1.09, 0.98, and 0.47%. The buffering capacity of the soy sauce decreased to 1.26-3.41 by adding higher okara koji. The protease activity was higher in the soy sauce with 50% orara koji and decreased with longer fermentation. Also, the tyrosine content peaked to 275.2 mg% after 90 days. ${\alpha}$-amylase showed higher activity in the soy sauces fortified with okara koji, which resulted in the highest total sugar and reducing sugar contents after 60 days. The total sugar and the reducing sugar in the soy source decreased after longer fermentation. The total free amino acid contents of the soy sources fortified with okara koji (0, 50, and 100%) were 41.68 mg/mL, 33.10 mg/mL, and 9.27 mg/mL, respectively. In particular, the glutamic acid contents of the three types of soy sauces were highest, and most amino acids, except for glutamine, increased during the fermentation for 90 days. The sensory evaluation, except of the saltiness and color, showed similar values in the soy sauces, except in the okara koji 100%. Thus, okara koji could be a valuable ingredient of traditional soy sauces. However, the 50% okara koji did not differ significantly from the others.

• Applied Biological Chemistry
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• v.30 no.2
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• pp.147-152
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• 1987

Soy sauce which was prepared with a mixture of defatted soybeans ant wheat flour koji added into acid-hydrolyzed soy sauce was evaluated for the chemical changes in levulinic acid, ethanol and amino acids composition during fermentation, Results showed that the highest reducing sugar content of $12.13{\sim}15.76%$ was found after $20{\sim}40\;days$ fermentation. The contents of total nitrogen, amino nitrogen, and ethanol increased with increase in fermentation time. A high levulinic acid content was fount at the initial fermentation period which was gradually decreased with further fermentation. The content of lactic acid also increased during fermentation. Amino acids such as Glu, Leu, Ala, Phe, Asp, Thr, Ser, Gly, Met, Tyr, Lys, His, Arg and Pro were detected in all tested groups. Higher values were found particularly for Glu, Leu, Ala and Phe and lower values for His, Tyr and Met. The most of amino acids increased in their contents after 120 days of fermentation.

• Applied Biological Chemistry
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• v.22 no.3
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• pp.160-165
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• 1979

This study was carried out to investigate effects of iron content on the quality of soy sauce, bean paste and red pepper paste, and to elucidate the origin of iron and change of the contents during production processes. For the first step, the iron contents in commercial soy sauce and changes of the contents during brewing process were determined. The results obtained were as follows. 1, Iron contents of raw materials were 108 ppm in soy bean, 133ppm in defatted soy bean, 79 ppm in wheat, 5 ppm in sodium chloride, 58 ppm in seed koji, 300-2000 ppm in spore of Aspergillus oryzae, 240 ppm in wheat gluten, 20 ppm in sodium carbonate (above figures were of dry weight basis), 6 ppm in hydrochloric acid, 18 ppm in caramel and 0.3ppm in brewing water respectively. 2, Iron contents in koji were 200-240 ppm (as dry weight basis) and increased, more or less, in progress of koji-making period. 3. Iron contents in the mashes during fermentation were 40 rpm after 1 month, 43-47 ppm after 3 months and 49-62ppm after 6 months. 4. In chemical soy sauce, the iron content was 159 ppm after hydrolysis of wheat gluten with hydrochloric acid, and 184 ppm after neutralization. 5. Higher iron contents were detected both in fermented and chemical soy sauce when the concentration of total nitrogen increased, but the levels were higher in chemical soy sauce than in fermented one at the same concentration of total nitrogen. 6. In the case of fermented soy sauce, the iron content in the filtrate was decreased by press-filtration, but no significant change was found between before and after heat-sterilization. 7. Iron contents in commercial soy sauce were varied with the producers, however, the average value was 62.7 ppm as calculated as 1.0 percent of total nitrogen. And the average level of iron in home-made soy sauce produced by conventional method was 37.68 ppm.

• Journal of the Korean Society of Food Culture
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• v.31 no.4
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• pp.348-356
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• 2016

The purpose of this study was to investigate the chemical contents (sugar, nitrogen, and amino acids) and sensory characteristics of traditional soy sauce according to three different methods. The samples were taken from four different periods (0, 20, 40, and 60 days after fermentation). Total sugar contents increased in all groups according to ripening period, and Gyupjang (G) showed the highest sugar content among the groups. Total nitrogen and amino acid contents of all groups increased after 60 days of ripening, and Gyupjang (G) and Gyupjang mixed with salt water (SG) had higher total nitrogen content compared to Chungjang (S) at the same period. The results from the sensory evaluation show that preferable sensory characteristics, such as color preferences, sweetness, umami taste, and overall preference, were significantly higher in Gyupjang (G) and Gyupjang mixed with salt water (SG) than in Chungjang (S). Preferable sensory characteristics had significantly high positive correlation with most amino acids, total nitrogen, and sugar contents, except for glutamine. Based on the significant difference in preferable sensory characteristics between Gyupjang mixed with salt water (SG) and Chungjang (S), Gyupjang mixed with salt water (SG) can be used to improve sensory characteristics. This research implies that adding salt water during the manufacturing Gyupjang process is advisable to yield high quality soy sauce.

• KSBB Journal
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• v.18 no.6
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• pp.455-460
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• 2003

This study was designed to find out the rapid fermentation of soy sauce from koji hydrolyzates using air bubble column reactor packed with coimmobilized mixed culture system. Continuous ripid production was performed by coimmobilized Z. rouxiii BH-90 and C. versatilis BH-91. Coimmobilized cells of Zygosaccharomyces rouxii BH-90 and Candida versatilis BH-91 mixture cells in the column reactor produced 2.8％ ethyl alcohol and 18mg/L 4-ethylguaiacol over 96 hours under the optimal conditions. Coimmobilized cells produced 2.30∼2.4% ethyl alcohol during 30 days, and decreased gradually from 40 days to 70 days. Also coimmobilized cells produced 4-ethylguaiacol at the constant rate of 16∼18mg/L and decreased gradually after 40 days. Final product of soy sauce contained 2.4% ethyl alcohol and 18mg/L 4-ethylguaiacol. However, amino acid compositions of soy sauce were consisted of predominantly glutamic acid, leucin, arginine, aspartic acid, Iysine and valine, which were more than 50% of total amino acid.