• Korean journal of food and cookery science
• /
• v.25 no.1
• /
• pp.90-97
• /
• 2009

Changes in the quality characteristics of doenjang prepared with a meju containing components of Acanthopanax senticosus, Angelica gigas and Corni fructus during storage were evaluated. Three types of doenjang produced using each of these components showed lower Hunter's L and a values than the values of the control during the initial stage of storage: however, these values were similar to those of the control after 60 days of storage. Doenjang containing A. gigas showed a similar degree of browning to that of the control during the early stage of storage, while the degree of browning observed in the other samples was much higher than that og the control during this period. Despite these initial differences, the browning in all samples became similar after extended storage. The level of acidity increased gradually for up to 60 days, after which it decreased slightly. The pH of all treatments decreased with storage time. The amino-N contents of all types of doenjang increased gradually, reaching peak values after 60 days. Doenjang with A. senticosus and A. gigas had a strong characteristic flavor that reduced the native flavor of doenjang. Doenjang with C. fructus showed a similar overall palatability to that of the control.

• Journal of Food Hygiene and Safety
• /
• v.35 no.5
• /
• pp.438-446
• /
• 2020

Meju and nuruk (respectively soybean and malt) are traditional Korean fermentation starters that are vulnerable to contamination by harmful microorganisms such as aflatoxigenic fungi and their associated aflatoxins (AFs). In this study, Aspergillus spp. were isolated and identified from a total of 57 meju and 18 nuruk samples collected from Korean markets. Their potential aflatoxigenicity was investigated by examining the presence of three aflatoxin biosynthetic genes (aflO, aflP, and aflR) using multiplex polymerase chain reaction (mPCR) assays. Thereafter, aflatoxin production of isolates and the natural occurrence of AFs in meju and nuruk samples were analyzed by high-performance liquid chromatography (HPLC). A total of 177 Aspergillus isolates were identified and 130 isolates were obtained from meju samples. Of these, 25 isolates (19.2%) contained all three aflatoxin biosynthetic genes, and five (20%) of these isolates produced aflatoxins. Forty-seven of the Aspergillus isolates were obtained from nuruk samples, five of which (10.6%) expressed all three AF biosynthetic genes; however, none of these strains produced AFs. HPLC analysis showed that 88% (51/58) of the meju samples and 39% (7/18) of nuruk samples were not contaminated with AFs (below limit of detection). Among the isolates isolated from meju and nuruk, there were aflatoxigenic strains containing all three aflatoxin biosynthetic genes or producing aflatoxin in medium, but the frequency of aflatoxin contamination was low in the meju and nuruk samples.

• Applied Biological Chemistry
• /
• v.42 no.4
• /
• pp.277-282
• /
• 1999

This study was carried out to clarify the microorganisms which participated in the fermentation of kanjang. The changes in the viable cell counts of total aerobic bacteria, lactic acid bacteria and yeasts for raw soybean, soybean during cooking, meju during cultivation, and kanjang mash during maturing were investigated along with the changes in components during those periods. Lactic acid bacteria that were found to be $6{\times}10^2\;CFU/g$ in raw soybean were disappeared after cooking process, but total aerobic bacteria were diminished from $1.9{\times}10^6\;CFU/g$ to $10^2\;CFU/g$. Aerobic bacteria of inner and outer parts of meju increased to more than $10^9\;CFU/g$. The higher viable cell counts of lactic acid bacteria in the inner parts of meju were observed than those in outer ones. On the contrary, significantly higher viable cell counts of yeasts in the outer parts of meju were found. Total nitrogen content and color density of kanjang increased by using meju with extended cultivation periods. No significant differences were observed in microbial counts between kanjang mash with aeration and non-aeration during kanajng mash maturing.

• Korean journal of food and cookery science
• /
• v.13 no.2
• /
• pp.92-98
• /
• 1997

Ethyl carbamate is an animal carcinogen and a by-product of fermentation. Since the highest level of ethyl carbamate was found in a traditional soy sauce sample in the previous study, soysauce was prepared in varying experimental conditions with three kinds of meju originated from different area of the country to investigate the factors affecting ethyl carbamate formation. The sample analysis methods included a semi-purification with solid-phase extraction and detection by GC-MS at SIM mode using m/z 62 fragment ion. Among the investigated factors, which includes source meju, bringing length, salt content, irradiation of visible light during bringing or storage, and storage length, source meju and storage length showed most profound effect on the formation of ethyl carbamate. Irradiation of visible light for 12 hours a day during storage lowered the concentration of ethyl carbamate compared to the soysauce kept in the dark. Meanwhile irradiation during the bringing as well as the degree of salt contents showed no effect.

• The Korean Journal of Mycology
• /
• v.26 no.4 s.87
• /
• pp.487-495
• /
• 1998

The mycotoxins, $Aflatoxin\;B_1(B)$ and Ochratoxin A(A), were measured from the various mejus manufactured under the artificial or natural conditions by the indirect competitive ELISA; The various fungi isolated from the Korean traditional home (KTH) made meju collected were observed to produce each mycotoxin mentioned above in the toxin producing broth, but only few in the sterilized cereals of soybean under the artificial conditions. Thus, the isolated fungi were not found to produce both A and B toxins in the artificial conditions. Particularly, the any mycotoxin was not determined at the range of 0.01 to 100 ng per gm of the mejus made under the conditions of KTH widely collected in Korea. The mycotoxins produced by the meju-fermenting fungi were seemed or speculated to be degraded in KTH's mejus under the natural conditions. The species of Mucor involved in the initial stage of fermentation were discussed to be important in the fermentations of KTH mejus.

• Korean Journal of Food Science and Technology
• /
• v.31 no.3
• /
• pp.757-763
• /
• 1999

Based on the previous studies, R. stolonifer was selected for the model system of Korean soy sauce preparation process, using the fermented soybean. The system of meju fermentation was refined; the optimal conditions of temperature and relative humidity were $25^{\circ}C$ and 90%, respectively. The optimal temperature for soy sauce fermentation was evaluated to the $25^{\circ}C$ and, in the latter half of the fermentation, some aeration was observed to positively affect the sensory evaluation of soy sauce. In the sensory evaluation, the soy sauce fermented with B. subtilis and A. sojae was showed to be better than one fermented with R. stolonifer. Conditions of the pasteurization and ultrafiltration process were also established for industrialization of the soy sauce. Finally, the standard systems using the soybean fermented was, by the industrial scales, proposed for Korean traditional soy sauces.

• Journal of Microbiology and Biotechnology
• /
• v.27 no.2
• /
• pp.251-261
• /
• 2017

Initially, we screened 18 Aspergillus sojae-like strains from Aspergillus spp. isolated from meju (Korean traditional fermented soybean brick) according to their morphological characteristics. Because members of Aspergillus section Flavi are often incorrectly identified because of their phylogenetic similarity, we re-identified these strains at the morphological and molecular genetic levels. Fourteen strains were finally identified as A. sojae. The isolates produced protease and ${\alpha}-amylase$ with ranges of 2.66-10.64 and 21.53-106.73 unit/g-initial dry substrate (U/g-IDS), respectively, which were equivalent to those of the koji (starter mold) strains employed to produce Japanese soy sauce. Among the isolates and Japanese koji strains, strains SMF 127 and SMF 131 had the highest leucine aminopeptidase (LAP) activities at 6.00 and 6.06 U/g-IDS, respectively. LAP plays an important role in flavor development because of the production of low-molecular-weight peptides that affect the taste and decrease bitterness. SMF 127 and SMF 131 appeared to be non-aflatoxigenic because of a termination point mutation in aflR and the lack of the polyketide synthase gene found in other A. sojae strains. In addition, SMF 127 and SMF 131 were not cyclopiazonic acid (CPA) producers because of the deletion of maoA, dmaT, and pks/nrps, which are involved in CPA biosynthesis. Therefore, A. sojae strains such as SMF 127 and SMF 131, which have high protease and LAP activities and are free of safety issues, can be considered good starters for soybean fermentations, such as in the production of the Korean fermented soybean products meju, doenjang, and ganjang.

• Microbiology and Biotechnology Letters
• /
• v.49 no.1
• /
• pp.95-100
• /
• 2021

Asparagus have anti-cancer, antioxidant, and anti-inflammatory properties. Since the high functionality of Korean traditional sauces was discovered, various studies have been conducted using asparagus. In this study, the antioxidant activity of traditional sauces containing asparagus was confirmed. The antioxidant capacity of asparagus was independent of the concentration and showed the highest activity at 70 mg/ml. For instance, concerning Meju containing asparagus, high antioxidant activity was observed in water and ethyl acetate extracts; the total polyphenol content was equivalent to 1.4 mg/g and 0.7 mg/g of tannic acid in the water and ethyl acetate fractions respectively. The DPPH and ABTS radical scavenging activities were 27.6% and 9.04%, respectively, in the water layer, and 10.7% and 52.4%, respectively, in the ethyl acetate layer. Additionally, the antioxidant activity of asparagus-containing traditional sauces was measured using 95% ethanol extracts; soy sauce showed the highest activity, retained in a wide range of concentrations.

• Microbiology and Biotechnology Letters
• /
• v.25 no.5
• /
• pp.448-453
• /
• 1997

Enzyme activities, production of killer toxin and some functionality of forty seven yeasts isolated from traditional Meju were investigated in culture broth and cell free extracts. Activities of $\alpha$-galactosidase, invertase and inulinase were detected in cell free extracts of 38 strains, 43 strains and 45 strains, respectively and acidic and neutral protease activities also were detected in culture broth of all the strains, $\beta$-Galactosidase activity was detected in cell free extracts of OE-20 and S-14 strains. Killer toxins were produced by OE-12, S-8 (Candida spp.), OE-19 (Zygosaccharomyces spp.) and S-3 (Saccharomyces spp.). Culture broth of OE-23 and S-9 showed 61.3% and 59.2% of antioxidant activity to $\alpha$, $\alpha$-diphenyl-$\beta$-picrylhydrazyl(DPPH), but nitrite-scavenging ability as well as inhibition of tyrosinase and polyphenol oxidase were not appeared in all the strains.

• Journal of the East Asian Society of Dietary Life
• /
• v.6 no.3
• /
• pp.403-410
• /
• 1996

This survey was carried out to investigate the usage of traditional fermented foods. Questionaries were answered by 283 female adults ranging from 20 to 60 ages in Daegu city and Kyungbuk province. 39.72% of total subjects answered that they made Meju and soybean paste by themselves. There were significant differences according to income, residential area, deucation level, and family size, In the results of the preference and consumption study on traditional soybean pastes, Kimchi and salted sea foods, preference of salted sea foods was the highest, whereas the consumption of salted sea foods was the lowest. The recognition of soybean pastes and traditional foods was remarkably low. However the consumption frequency of traditional fermented foods and the recognition of soybean pastes and traditional foods were significantly increased with age.