• Journal of Microbiology and Biotechnology
• /
• v.32 no.4
• /
• pp.458-463
• /
• 2022

We evaluated the antibiotic susceptibilities, hemolytic activities, and technological properties of 36 Staphylococcus xylosus strains and 49 S. pseudoxylosus strains predominantly isolated from fermented soybean foods from Korea. Most of the strains were sensitive to chloramphenicol, erythromycin, gentamycin, kanamycin, lincomycin, oxacillin, tetracycline, and trimethoprim. However, 23 strains exhibited potential phenotypic acquired resistance to erythromycin, lincomycin, and tetracycline. Based on breakpoint values for staphylococci from the Clinical and Laboratory Standards Institute, >30% of the isolates were resistant to ampicillin and penicillin G, but the population distributions in minimum inhibitory concentration tests were clearly different from those expected for acquired resistance. None of the strains exhibited clear α- or β-hemolytic activity. S. xylosus and S. pseudoxylosus exhibited salt tolerance on agar medium containing 20% and 22% (w/v) NaCl, respectively. S. xylosus and S. pseudoxylosus strains possessed protease and lipase activities, which were affected by the NaCl concentration. Protease activity of S. pseudoxylosus was strain-specific, but lipase activity might be a characteristic of both species. This study confirms the potential of both species for use in high-salt soybean fermentation, but the safety and technological properties of strains must be determined to select suitable starter candidates.

• Journal of Korean Society of Environmental Engineers
• /
• v.28 no.8
• /
• pp.866-871
• /
• 2006

The nutrient recovery in phosphate crystallization process was investigated by using laboratory scale uptlow reactors, adopting sequencing batch type configuration. The industrial waste lime was used as potential cation source with magnesium salt($MgCl_2$) as control. The research was focused on its successful application in a novel integrated sludge treatment process, which is comprised of a high performance fermenter followed by a crystallization reactor. In the struvite precipitation test using synthetic wastewater first, which has the similar characteristics with the real fermentation effluent, the considerable nutrient removal(about 60%) in both ammonia and phosphate was observed within $0.5{\sim}1$ hr of retention time. The results also revealed that a minor amount(<5%) of ammonia stripping naturally occurred due to the alkaline(pH 9) characteristic in feed substrate. Stripping of $CO_2$ by air did not increase the struvite precipitation rate but it led to increased ammonia removal. In the second experiment using the fermentation effluent, the optimal dosage of magnesium salt for struvite precipitation was 0.86 g Mg $g^{-1}$ P, similar to the mass ratio of the struvite. The optimal dosage of waste lime was 0.3 g $L^{-1}$, resulting in 80% of $NH_4-N$ and 41% of $PO_4-P$ removal, at about 3 hrs of retention time. In the microscopic analysis, amorphous crystals were mainly observed in the settled solids with waste lime but prism-like crystals were observed with magnesium salt. Based on mass balance analysis for an integrated sludge treatment process(fermenter followed by crystallization reactor) for full-scale application(treatment capacity Q=158,880 $m^3\;d^{-1}$), nutrient recycle loading from the crystallization reactor effluent to the main liquid stream would be significantly reduced(0.13 g N and 0.19 g P per $m^3$ of wastewater, respectively). The results of the experiment reveal therefore that the reuse of waste lime, already an industrial waste, in a nutrient recovery system has various advantages such as higher economical benefits and sustainable treatment of the industrial waste.

• Culinary science and hospitality research
• /
• v.22 no.2
• /
• pp.78-92
• /
• 2016

This study investigated the quality characteristics of white pan bread with banana addition. This analysis was through mixograph and stickiness of dough, fermentation rate, TPA, crumbScan image analysis, color, moisture contents and acceptance test. Mixograph peak time presented 4~5 minutes on every sample. However, CON, B10 and B20 sample presented more than 60%, and B30, B40 presented less than 60% at peak value (%). The result indicated that banana addition increased as the stickiness decreased. The fermentation rate generally increased, but the sample B40 decreased after 75 minutes. The result of crust and inside color, CON was the highest on lightness L value, B40 was the highest on both red a value and yellow b value. The result of pH showed that B40 was the lowest, and more banana addition made pH decreased. Thus, adding banana influences negatively on volume and cost of the product. The image analysis through crumbScan did not show any significant difference on crust thickness and distortion of crumb fineness. On the other hand, CON value was 774.33 that was the lowest, and B40 value was 927.66 which is the highest on the density of crumb fineness. Hardness showed a significant difference; B40 was the lowest, and Control was the highest. Moisture contents generally had a noticeable difference; CON value was the highest, and banana addition increased as the value decreased. At the result of acceptance test, one of the sensory tests, B20 showed the highest grade, and B40 showed the worst. Based on the above results of characteristic difference, banana addition could influence volume of the bread negatively.

• Applied Biological Chemistry
• /
• v.14 no.3
• /
• pp.191-200
• /
• 1971

As a series on the soy-bean protein and their related substances 9 samples were collected from 9 places such as straws (Rice) to obtain bacterial strains which produce protease. From these samples total of 23 strains were isolated by the use of dilution pour plate method. For all isolated strains primary screening of productivity of protease was performed and useful straines with regard to protease productivities were identified. Optimum conditions for enzyme action of protease from isolates $D_9$, $F_{20}$ strains were pH 7.5 and $40^{\circ}C$. Chung-Kook-Jang is one of the characteristic foods in Korea made from soy-bean by fermentation. The chief bacterium is Bacillus subtilis and the chief change which takes place in soy-bean during fermentation is degradation of protein. Three kinds of Chung-Kook-Jang were prepared using three different strains of Bacillus natto, $D_9\;and\;F_{20}$ from isolated. Water soluble-N, TCA soluble-N, amino-N and peptide-N were measured about the steamed soybean, Chung-Kook-Jang prepared with three strains of bacteria. Water soluble-N decreased very largely in steamed soybean, but in Chung-Kook-Jang it increased to 85% of raw soy-bean.

• Korean Journal of Food Science and Technology
• /
• v.47 no.3
• /
• pp.328-335
• /
• 2015

The objective of this study was to evaluate the quality characteristics of the Korean rice wine, makgeolli, supplemented with omija berries (Schizandra chinensis Baillon) during the fermentation. The changes in pH, total acidity and contents of ethanol, amino acid, total soluble solids, reducing sugar, and total sugar after the completion of fermentation were determined. In comparison with control, omija-supplemented makgeolli showed significantly lower pH (3.46), lower contents of alcohol (17.2%), amino acids (1.85 g/L), and total sugar (17.5 g/L), and higher acidity (12.8 g/L). Moreover, supplementation with omija resulted in significantly higher antioxidant capacity of 1,1-diphenyl-2-picrylhydrazyl (DPPH) and hydroxyl radical scavenging activities, superoxide dismutase-like activity and reducing power, and higher levels of total polyphenol and flavonoid. Sensory evaluation revealed no significant difference on the overall acceptance, although better appearance and refreshing taste of omija-supplemented makgeolli were observed. Our results indicate that omija represents an effective natural additive for enhancing the biological activities of makgeolli.

• Korean journal of food and cookery science
• /
• v.24 no.4
• /
• pp.517-524
• /
• 2008

This study made Soy-Sauce-Kimchi and investigated its pH, acidity, microorganism, salinity, chromaticity, viscosity and taste to revive traditional Soy-Sauce-Kimchi using Soy-Sauce instead of salt and to report its fermentation characteristics. As one of studies on traditional Kimchi, it tried for practical use of traditional Soy-Sauce-Kimchi which had been eaten in the middle region of Korea, especially in Seoul but currently has been prepared by only a few people and has disappeared gradually. According to the results of this study, among three groups of Soy-Sauce-Kimchi-I(s1), Soy- Sauce-Kimchi-II(s2) added by 2.5% sucrose and the control group(C), acidity of s2 was sharply increased after 24 hours and 72 hours at $20^{\circ}C$ and $10^{\circ}C$ respectively and there was few difference in salinity by temperature. In the case of s2 group, addition of 2.5% sucrose was considered to lead to increase of salinity. For chromaticity, while the L value and b value became larger after 48 hours, the a value tended to decline. Viscosity of s2 grew after 24 hours at all of $20^{\circ}C$, $10^{\circ}C$ and $1^{\circ}C$ and that was thought to be because propagation of bacteria such as Leuconostoc mesenteriodes following addition of 2.5% sucrose secreted dextransucrose so sucrose was transferred into dextran to increase viscosity. The total number of microorganisms was recorded to be largest after 48, 36 and 72 hours at $20^{\circ}C$, $10^{\circ}C$ and $1^{\circ}C$ respectively and the number of lactic acid bacteria was the largest at $1^{\circ}C$ after 72 hours compared to those at other temperatures. That was considered to be because microorganisms such as Leuconostoc mesenteriodes are psychrotropic lactic acid bacteria. For sensory evaluation, all appearance, chromaticity and odor of C were higher by $3{\sim}4$ points than those of s1 and s2(p < 0.001) and their feel also showed a similar tendency(p < 0.05). Considering the results of sensory evaluation, more researches were needed to overcome difference of taste for Soy-Sauce-Kimchi according to age due to characteristic flavor and smell of soy-source.

• Journal of Life Science
• /
• v.23 no.4
• /
• pp.560-568
• /
• 2013

Chungkookjang was fermented by B. subtilis MC31, a ${\gamma}$-amino butyric acid (GABA) producing microorganism. The characteristics of Chungkookjang were investigated while fermenting. Twenty four amino acids were detected in Chungkookjang, leucine was the highest of them all. Total cell populations of B. subtilis MC31 phase were between log $9.52{\pm}0.5$ ~ log $9.049{\pm}0.5$ CFU/g at stationary phase. Contents of moisture, crude ash, crude protein, crude lipid and crude fiber are $61.07{\pm}0.01%$, $1.52{\pm}0.01%$, $17.66{\pm}0.04%$, $8.96{\pm}0.03%$ and 2.61%, respectively. Contents of ammonia type nitrogen, amino type nitrogen and reducing sugar were increased during fermentation at $40^{\circ}C$ for 72 hr, however those of titratable acidity and total sugar were decreased. pH was slowly alkalized during fermentation. Viscous substance and protease contents in Chungkookjang were $4.7{\pm}0.05%$ and $0.519{\pm}7.36$ g/l, apiece. When the fibrin plate and Robbin method for fibrinolytic activity were applied, B. subtilis MC31 showed high activity. These results suggested that B. subtilis MC31 is suitable to be used as a starter to enhance the quality of Chungkookjang.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.12 no.3
• /
• pp.225-229
• /
• 1983

The change of free amino acids was identified during fermentation of kimchis (Ixeris sonchifoliaH.) added fermented anchovy. The results were summarized as follows; In fresh roots and leaves of Ixeris sonchifolia H., 8 kinds of free amino were determined respectively. Among them, argine, cysteine and glutamic acid were abundant in fresh roots, while arginine, valine, isoleucine and phenylalanine in fresh leaves, especially arginine was dominant in fresh both roots and leaves. The amount of total amino acids in fresh leaves was about 2.5 times of that of roots. After fermentation, 15 kinds of free amino acids were determined in kimchis, and the characteristic favor of in was attributed to such amino acids as threonine, glutamic acid, alanine, leucine and cysteine. The content of total free amino acids in kimchi leaves was increased to about 5 times of that in fresh (9,435,6mg % on dry base), but in kimchi roots, 11 times of that in fresh was contained (7,079,1mg % on dry base) In kimchi'es extract, 16 kinds of free amino acids were determined, and threonine, glutamic acid, alanine, cysteine and leucine were abundant.

• Korean Journal of Food Science and Technology
• /
• v.44 no.6
• /
• pp.779-784
• /
• 2012

Characteristic chemical compositions of jujube wine using different preparation methods including fermentation were investigated. Fermentation for jujube wine started using whole fruit (JW1), seed-removed fruit (JW2) and whole fruit heated at $100^{\circ}C$ for 2 h and then extracted (JW3). The free amino acids and flavors were analyzed quantitatively by HPLC and GC-MS. A total of 18 amino acids were identified in all samples. The amount of total free amino acids was detected from 141-210 ppm (JW1), 147-342 ppm (JW2), and 336-362 ppm (JW3). Large amounts of proline, aspartate, glutamate, arginine and alanine were detected in jujube wine. Thirteen kinds of volatile compounds including six alcoholic compounds (ethyl alcohol, iso-butyl alcohol, n-butyl alcohol, iso-amyl alcohol, n-amyl alcohol, and phenethyl alcohol), four ester (ethyl acetate, hexyl acetate, ethyl caprylate, and phenethyl acetate) and three aldehydes (diethylacetal, furfural, and benzaldehyde) were detected. Ethyl alcohol (30.50-33.95% peak area), benzaldehyde (2.55-15.97% ratio), furfural (0.07-15.28% ratio), iso-amyl alcohol (1.04-14.73% ratio), and phenethyl acetal (0.78-9.28% ratio) were abundant in jujube wine.

• Korean Journal of Food Science and Technology
• /
• v.34 no.4
• /
• pp.666-672
• /
• 2002

Changes in chemical characteristic, microflora, and sensory evaluation of fish sauce extracted at an interval of one week from fermented solution were investigated. pH was reduced from 6.0 to 4.5, and trimethylamine oxide from 132.5 to 87.2 mg/100g during fermenting periods. Trimethylamine increased from 5.6 to 50.2 mg/100g, and volatile basic nitrogen from 48.3 to 232.5 mg/100g. Bacterial flora isolated from the fish sauce were 70% Lactobacillus sp. and 13% Bacillus sp. Among the free amino acids, alanine, glutamic acid, valine, and methionine contents constitute 40% of the total free amino acids. Major non-volatile organic acid of the fish sauce was lactic acid (76%). Sensory evaluation results of the fish sauce were higher than the traditional soybean sauce after 28 days of fermentation.