• Food Engineering Progress
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• v.21 no.4
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• pp.403-408
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• 2017

Acetic acid bacteria strains were isolated from a variety of fermented foods and fallen fruits. Among them, the strain MAK88, whose acetic acid fermentation ability, acid-tolerance, and alcohol-tolerance were high, was selected and identified as Acetobacter orientalis. A seed culture of A. orientalis MAK88 was inoculated into onion juice, and the optimum conditions of acetic acid fermentation was investigated. The optimum initial concentration of ethanol in onion juice was 5% (v/v) and in that condition, acidity was 4.31% at 144 h of fermentation. The optimum initial concentration of acetic acid was 1% and the final acidity was 5.32%. The optimum fermentation temperature was determined to be $28^{\circ}C$. The most appropriate preparation method of onion juice was to heat the onion at $121^{\circ}C$ for 15 min and produce juice with pressure followed by filtering, and then sterilization at $121^{\circ}C$ for 15 min. Prepared onion juice was used for fermentation without dilution.

• Journal of Life Science
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• v.34 no.4
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• pp.254-263
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• 2024

Korean jang is a food made using fermented soybeans, and the typical products include gochujang (GO), doenjang (DO), cheonggukjang (CH), and ganjang (GA). In this study, 16S rRNA metagenome analysis was performed on a total of 200 types of GO, DO, CH, and GA using next-generation sequencing to analyze the microbial community of fermented soybean foods and compare taxonomic (biomarker) differences. Alpha diversity analysis showed that in the CHAO index, the species richness index tended to be significantly higher compared to the DO and GA groups (p<0.001). The results of the microbial distribution analysis of the GO, DO, CH, and GA products showed that at the order level, Bacillales was the most abundant in the GO, DO, and CH groups, but Lactobacillales was most abundant in the GA group. Linear discriminant analysis effect (LEfSe) analysis was used to identify biomarkers at the family and species levels. Leuconostocaceae, Thermoactinomycetaceae, Bacillaceae, and Enterococcaceae appeared as biomarkers at the family level, and Bacillus subtilis, Kroppenstedtia sanguinis, Bacillus licheniformis, and Tetragenococcus halophilus appeared at the species level. Permutational multivariate analysis of variance (PERMANOVA) analysis showed that there was a significant difference in the microbial community structure of the GO, DO, CH, and GA groups (p=0.001), and the microbial community structure of the GA group showed the greatest difference. This study clarified the correlation between the characteristics of Korean fermented foods and microbial community distribution, enhancing knowledge of microorganisms participating in the fermentation process. These results could be leveraged to improve the quality of fermented soybean foods.

• Journal of the Korean Society of Food Culture
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• v.25 no.3
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• pp.241-250
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• 2010

This study was conducted to improve the kimchi intake for high school students of various kimchi sub-ingredients and foods using kimchi. The students believed that kimchi is good for health. The overall satisfaction, baechu quality and the taste and degree of fermentation of kimchi was high, but there was a low preference for offered kimchi kinds, kimchi subingredient, foods using kimchi. The types of kimchi preferred and often offered in school meals were baechu-kimchi and kkakdugi. The common kimchi sub-ingredients were radish and welsh onion in vegetables, squid and oyster in sea foods, saeu-jeot and myeolchi-jeot in salted fish, and pear and apple in fruits. The preference for kimchi sub-ingredients were high for sesame leaf and yeolmu in vegetables, saeu-sal and squid in sea foods, saeu-jeot and nakji-jeot in salted fish, and pear and apple in fruits. The foods using kimchi preferred and often offered with school meals were kimchi-jjigae, bokkeumkimchi, kimchi soup, kimchi-bokkeum-bap, and kimchi-jeon. The kimchi sub-ingredient for which students had the greatest preference was meats. Among the foods using kimchi with meats, the most preferred were kimchi-pyeonyuk bossam, doejigogi kimchi duruchigi, and kimchi galbi-jjim. Among the foods using kimchi with noodles, the most preferred were kimchi- bibimmyeon, kimchi -naengmyeon, and kimchi-cheese spaghetti. Among the foods using kimchi with vegetables, the most preferred were kimchi-pa-jeon, kimchi- deopbap and kimchi- goguma gui. Of the foods using kimchi with processed foods, the most preferred were kimchi-mandu, kimchi-bacon jumeok-bap and kimchi- cheese omelet. Among the foods using kimchi containing sea food, kimchi-haemul bokkeum-bap, kimchi-hoe-deopbap, and kimchi-saeu-jjim were most preferred. Overall, these results suggest that various kimchi sub-ingredients and foods using kimchi should be improved for kimchi intake of school meals.

• Journal of Microbiology and Biotechnology
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• v.24 no.10
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• pp.1397-1404
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• 2014

A few starters have been developed and used for doenjang fermentation but often without safety evaluation. Filamentous fungi were isolated from industrial doenjang koji, and their potential for mycotoxin production was evaluated. Two fungi were isolated; one was more dominantly present (90%). Both greenish (SNU-G) and whitish (SNU-W) fungi showed 97% and 95% internal transcribed spacer sequence identities to Aspergillus oryzae/flavus, respectively. However, the SmaI digestion pattern of their genomic DNA suggested that both belong to A. oryzae. Moreover, both fungi had morphological characteristics similar to that of A. oryzae. SNU-G and SNU-W did not form sclerotia, which is a typical characteristic of A. oryzae. Therefore, both fungi were identified to be A. oryzae. In aflatoxin gene cluster analysis, both fungi had norB-cypA genes similar to that of A. oryzae. Consistent with this, aflatoxins were not detected in SNU-G and SNU-W using ammonia vapor, TLC, and HPLC analyses. Both fungi seemed to have a whole cyclopiazonic acid (CPA) gene cluster based on PCR of the maoA, dmaT, and pks-nrps genes, which are key genes for CPA biosynthesis. However, CPA was not detected in TLC and HPLC analyses. Therefore, both fungi seem to be safe to use as doenjang koji starters and may be suitable fungal candidates for further development of starters for traditional doenjang fermentation.

• Food Science and Biotechnology
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• v.16 no.6
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• pp.1011-1017
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• 2007

Saeujeot (salted and fermented shrimp) and kimchi are traditional Korean fermented foods. Even though shrimp have often induced severe allergic reactions in sensitized individuals, few studies have investigated the allergenicity of shrimp. The aim of this study was to observe the changes of pH and allergenicity of raw shrimp (Acetes japonicus) and saeujeot in cabbage kimchi during fermentation using competitive indirect enzyme-linked immunosorbent assay (Ci-ELISA). Fermentation was carried out at different temperatures (25, 15, and $5^{\circ}C$). The pH of cabbage kimchi added with raw shrimp or saeujeot slowly decreased at lower temperature ($5^{\circ}C$) at the end stage of the fermentation process. The binding ability of serum obtained from patients allergic to raw shrimp against shrimp tropomyosin and saeujeot in kimchi rapidly decreased during longer fermentation periods and higher temperature ($25^{\circ}C$). In conclusion, the allergenicity of both raw shrimp and saeujeot in kimchi decreased during fermentation but the decrease in allergenicity of saeujeot was greater than observed for raw shrimp.

• YAKHAK HOEJI
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• v.4 no.1
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• pp.53-55
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• 1959

In order to confirm on production of vitamin $B_{12}$ during the kimchi fermentation period, the variation of its content is studied in this paper As a sample of kimchi for this fermentation study due to the seasonal condition, nabakkimchi which is aseasonal one in early spring, is prepared by author. The content of vitamin $B_{12}$ is estimated by the microbiological assay method using lactobacillus leichmannii A Tee 7830. Details for assay are indicated in the original part. And the pseudo-vitamin $B_{12}$ substances as thymidine which is active to the growth of lactobacillus leichmannii, are eliminated by the alkali treatment method of sample solution, According to the results shown in table 2 and 3 and figures 1 to 4, the following conclusions are summerized; 1. Vitamin $B_{12}$ produced during the fermentation period of kimchi. And the content of this vitamin during its optimum fermentation period, is much higher content compared with the theoretically calculated amount from its materials, This has been confirmed at the repeated experiment. The trend of variation during its period is indicated at the figures. 2. The sterilized kimchi inhibited the fermentation by sterilization at the preparation, did not increased its content showing only its theoretically calculated amount.

• Toxicological Research
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• v.31 no.3
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• pp.289-297
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• 2015

Ethyl carbamate (EC) classified as a probable human carcinogen (Group 2A) is naturally formed in alcoholic beverages and fermented foods during fermentation process and/or during storage. The objective of this study was to analyze EC in 34 food items including 14 alcoholic beverages and 20 fermented foods sold in Korea. Each food was collected from 18 supermarkets in 9 metropolitan cities in Korea, and then made into composite. According to food composition and alcohol content, samples were divided into four matrices such as apple juice, milk, Soju (liquor containing about 20% alcohol), and rice porridge. The maximum EC value of $151.06{\mu}g/kg$ was found in Maesilju (liquor made from Maesil and Soju). Whisky and Bokbunjaju (Korean black raspberry wine) contained $9.90{\mu}g/kg$ and $6.30{\mu}g/kg$, respectively. EC was not detected in other alcoholic beverages. Of 20 fermented foods, Japanese-style soy sauce had highest level of $15.59{\mu}g/kg$ and traditional one contained $4.18{\mu}g/kg$. Soybean paste had $1.18{\mu}g/kg$, however, EC was not found in other fermented foods.

• Journal of Microbiology and Biotechnology
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• v.32 no.10
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• pp.1219-1225
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• 2022

Microorganisms involved in food fermentation not only improve the aroma and taste of the food, but also enhance its preservation. Thus, they are added as starter cultures to boost the final product quality of commercial fermented foods. Although these microorganisms originate from fermented foods and have a long history of consumption, the European Union recently applied the concept of Qualified presumption of Safety (QPS), which is a safety evaluation system for microorganisms used in food or feed in Europe. The QPS system is a species-level safety system and shares results with the European Novel Food System, a strain-level safety evaluation system. In the United States, microorganisms added to fermented foods are considered as food additives or Generally Recognized as Safe substance. In Korea, food microbe lists are presented at the species level. Moreover, the nation has established a strain-oriented evaluation system that applies temporary safety evaluation methods for food raw materials as well as new raw materials. However, when it comes to microorganisms isolated from traditional fermented foods and other fermented food products, there is no definition of the term "species," and there is a lack of an evaluation system at the species level. Therefore, such an evaluation system for microbial species used in Korean fermented foods is necessary.

• Journal of Life Science
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• v.26 no.5
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• pp.571-583
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• 2016

Biogenic amines are produced primarily by microorganisms found in fermented foods and are often implicated in poisoning incidents in humans. In this study, 620 strains of microorganisms were isolated from traditional Korean fermented food in Sunchang in order to screen for non-biogenicamine-producing microorganisms present in these foods. One strain was identified and named Bacillus subtilis SCJ1, by using 16S rRNA sequencing and biochemical characterization. We investigated the cell growth of this organism in order to understand its potential for industrial application. To this end, we optimized the culture medium constituents by using the response surface methodology. The Plackett-Burman experimental design was used for screening of the medium constituents, such as molasses, yeast extract and peptone, for improving cell growth. In order to determine the optimal concentration of each constituent, we used a central composite design. Consequently, the optimized concentrations of molasses, yeast extract and peptone were predicted to be 27.5 g/l, 7.5 g/l and 17.5 g/l, respectively. By model verification, we confirmed that a 1.49-fold increase in dry cell weight compared to the basal medium-from 1.32 g/l, to 1.9722 g/l-was achieved.

• Korean Journal of Food Science and Technology
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• v.25 no.6
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• pp.655-665
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• 1993

The added levels of dongdong-ju, soy bean and fermentation time were selected as factors affecting the quality of Jeung-pyun (Korean fermented steamed rice cake) through pretest. The standing height ratio was significantly raised after the 1st and 2nd fermentation by the soy bean treatment. As the amount of dongdong-ju and soy bean were increased, the values of specific volume and expansion ratio for Jeung-pyun were increased. The effects of fermentation time did not show any significant differences. The pH of Jeung-pyun dough was significantly higher when the amount of dongdong-ju decreased and the amount of soy bean increased. Reducing sugar content of Jeung-pyun significantly augmented with raised amount of soy bean. As the amount of soy bean was increased, the hardness, springiness and cohesiveness of Jeung-pyun measured by rheometer significantly decreased. The optimum conditions for Jeung-pyun preparation were found to be 30g dongdong-ju, 2g soy bean solid and 180 minutes of fermentation time per 100g rice flour basis. Soy bean treatment had primary influence on Jeung-pyun preparation.