• Journal of Microbiology and Biotechnology
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• v.33 no.4
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• pp.527-532
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• 2023

Brewer's spent grain (BSG) is a waste product of the beer industry, and γ-aminobutyric acid (GABA) is a physiologically active substance important for brain and neuron physiology. In this study, we used the bacterial strains Bacillus velezensis DMB06 and B. licheniformis 0DA23-1, respectively, to ferment BSG and produce GABA. The GABA biosynthesis pathways were identified through genomic analysis of the genomes of both strains. We then inoculated the strains into BSG to determine changes in pH, acidity, reducing sugar content, amino-type nitrogen content, and GABA production, which was approximately doubled in BSG inoculated with Bacillus compared to that in uninoculated BSG; however, no significant difference was observed in GABA production between the two bacterial strains. These results provide the experimental basis for expanding the use of BSG by demonstrating the potential gain in increasing GABA production from a waste resource.

• Korean Journal of Soil Science and Fertilizer
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• v.33 no.5
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• pp.311-317
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• 2000

Acid sulfate soil and potential acid sulfate soil material are worldwide in distribution and are problematic in agriculture and environment due to their present and potential acidity developed by the oxidation of sulfides. Most of them are sedimentary origin and a few cases are reported as volcanic or metamorphic origin. We report a potential acid sulfate soil material originated from volcanic activity during Mesozoic. A profile of Bongsan series-weathered nonpyritic andesite-hydrothermally altered pyrite rich andesite was studied with field examination, chemistry, and mineralogy. Once, the pyrite rich andesite was exposed to atmosphere by excavation and leveling works for a residential area and the lay out site had subsequent acidification problem of soil and surface water. The parent material and soil profile of Bongsan series had no signs of presence of pyrite and acid sulfate weathering such as yellow mottles. However, the hydrothermally altered andesite substrata contained significant amount of pyrite showing characteristics of hydrothermal origin such as cubic and pyritohedron morphology and occurrence along cracks.

• Journal of the East Asian Society of Dietary Life
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• v.22 no.5
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• pp.667-676
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• 2012

This study was conducted to investigate the quality characteristics and antioxidant activity of Kochujang following the addition of deodeok (Condonopsis lanceolata) powder. To accomplish this, 1%, 3% and 5% deodeok powder was added to Kochujang and the samples were then incubated at $30^{\circ}C$. during which time the general ingredients, water content, acidity, salinity, reducing sugar content, amino-nitrogen content and DPPH were analyzed at intervals of about two weeks. The water crude protein, crude fat and ash content were 3.61%, 8.44%, 4.62% and 8.85%, respectively. The initial acidity was 3.23~3.97%, and this increased to 4.39~44.86%. highlight please clarify this, I cannot infer your intended meaning; however, this can likely be deleted. The salinity was 7.42~7.73%, and 5% with deodeok powder producing the lowest content and showing a tendency to decrease during the storage period. The early amino-nitrogen content was 274.0~333.1%, with higher nitrogen contents being associated with large amounts of deodeok powder. The amino-nitrogen content during the storage period increased to the 4th week, then decreased. Additionally, the a value decreased sharply during the 4-week storage period. Addition of large amount of deodeok powder significantly improved the free radical scavenging activity. The free radical scavenging activity of 1%, 3% and 5% deodeok powder was higher than that of Kochujang throughout the maturation period. Overall, the results of this study indicate that there is the potential to develop functional foods by the addition of deodeok.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.12
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• pp.1799-1807
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• 2016

This study investigated the quality characteristics and antioxidant activities of espresso coffee prepared with green bean fermented by lactic acid bacteria. First, 10, 20, and 30% (w/v) green beans were fermented by Lactobacillus acidophilus KCTC 3145 at $37^{\circ}C$ for 0, 12, and 24 h, respectively. Cells of L. acidophilus gradually increased with increasing green bean content and fermentation time. After drying fermented green beans, coffee powders were prepared by roasting (city level) and grinding (<75 mesh). Then, espresso coffee was extracted using coffee powder. The pH and chromaticity (L*, a*, and b* values) of espresso coffee decreased with fermentation time, whereas total acidity, total soluble solid contents, and brown color intensity increased. The pH level decreased with increasing contents of fermented green bean and total acidity increased. However, chromaticity, total soluble solid contents, and brown color intensity remained within a limited range. The antioxidant activities, including total polyphenol content, and DPPH and ABTS radical scavenging activities increased with increasing green bean content and fermentation time. Finally, sensory evaluation -for taste, color, flavor, and overall preference- revealed espresso coffee prepared with fermentation of 30% (w/v) green bean received the highest scores. Green bean fermented by lactic acid bacteria enhanced quality characteristics and antioxidant activities of espresso coffee, showing that lactic acid bacteria fermentation has potential use in the espresso coffee industry.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.6
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• pp.478-485
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• 2017

The effect of high carbon dioxide and ethylene treatment on postharvest ripening regulation of red kiwifruit (Actinidia melanandra) was investigated during cold storage. Physio-chemical properties such as weight loss, firmness, SSC, acidity, and market quality were analysed in red kiwifruit held at $10^{\circ}C$ compared to the fruit treated with carbon dioxide and ethylene during 75 days of storage. No significant weight loss was detected in red kiwifruit treated with carbon dioxide until 75 days of storage while the most rapid loss was found in fruit treated with ethylene. In ethylene-treated fruit, the firmness was dramatically reduced from 4.2kg on the first day to 1.2 kg after 27 days of storage at $10^{\circ}C$. However, the firmness of the carbon dioxide-treated fruit was 1.8kg after 54 days of storage. The highest level of SSC(%) was investigated within the 27 storage days at $10^{\circ}C$ for fresh red kiwifruit treated with exogenous ethylene, whereas the carbon dioxide-treated fruit exhibited a greatly increased SSC after 64 days. The carbon dioxide-treated red kiwifruit maintained statistically(p<.01) higher levels of acidity compared to the control and the exogenous ethylene-treated ones during 41 days of storage at $10^{\circ}C$. The SSC/Acid ratio of fruit treated with carbon dioxide was significantly lower (p<.01) maintained than the other two treatments (ethylene-treated and control fruit)throughout the 75-day experiment. Based on the quality characteristics of postharvest red kiwifruit, it could be concluded that the carbon dioxide treatment significantly delayed the ripening process and maintained the market quality of harvested red kiwifruit, which can be a potential application for commercial use in the kiwi industry.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.12
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• pp.1798-1807
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• 2002

This study was conducted to investigate lactobacillus salivarius subsp. salivarius having probiotic properties to be used as the health adjuncts with fermented milk products. Acid- and bile-tolerant lactobacillus salivarius subsp. salivarius was isolated with lactobacilli MRS broth from faeces of 80 healthy persons (infants, children and adults). It was used as a probiotic strain in fermented milk products. The pH of fermented milk decreased from pH 6.7 to 5.0 and titratable acidity increased from 0.3% to 1.0% by L. salivarius subsp. salivarius (isolation strain 20, 35, and 37), when incubated for 36 h at 37$^{\circ}C$. The number of viable cell counts of fermented milk was maximized at this incubation condition. The SDS-PAGE evidenced no significant change of casein but distinct changes of whey protein were observed by isolated L. salivarius subsp. salivarius for titratable acidity being incubated by 0.9-1.0% at 37$^{\circ}C$. All of the strains produced 83.43 to 131.96 mM of lactic acid and 5.39 to 26.85 mM of isobutyric acid in fermented products. The in vitro culture experiment was performed to evaluate ability to reduce cholesterol levels and antimicrobial activity in the growth medium. The selected L. salivarius subsp. salivarius reduced 23-38% of cholesterol content in lactobacilli MRS broth during bacterial growth for 24 h at 37$^{\circ}C$. All of the isolated L. salivarius subsp. salivarius had an excellent antibacterial activity with 15-25 mm of inhibition zone to E. coli KCTC1039, S. enteritidis KCCM3313, S. typhimurium M-15, and S. typhimurium KCCM40253 when its pH had not been adjusted. Also, all of the isolated L. salivarius subsp. salivarius had partial inhibition zone to E. coli KCTC1039, E. coli KCTC0115 and S. enteritidis KCCM3313 when it had been adjusted to pH 5.7. The selected strains were determined to have resistances of twelve antibiotic. Strains 27 and 35 among the L. salivarius subsp. salivarius showed the highest resistance to the antibiotics. These results indicated that some of the L. salivarius subsp. salivarius (strain 27 and 35) are considered as effective probiotic strains with a potential for industrial applications, but the further study is needed to establish their use as probiotics in vivo.

• Korean Journal of Food Science and Technology
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• v.31 no.2
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• pp.410-415
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• 1999

Yakju was sterilized with high-voltage pulses of short time of a continuous pulsed electric field (PEF) system. The initial microbial counts of Yakju were $2.2{\times}10^{5}$ CFU/mL for total aerobes. The pH, acidity and electric conductivity of Yakju were 3.82, 0.37% and 1.24 mS/cm, respectively. Yakju was treated with exponential-wave formed electric pulses of 100 Hz for $0{\sim}4000{\mu}s$ under the field strength of $20{\sim}35\;kV/cm$. The lethal effect of electric fields on microorganisms was resulted from the breakdown of the cell membrane induced by the transmembrane electric potential. The critical values of the external field for the sterilization were 16.0 kV/cm for total aerobes. Logarithmic survival rates decreased linearly at low electric field strength, but curvilinearly at high electric field strength with treatment time. The sterilization of Yakju was more largely affected by the electric field strength than by the treatment time. Any changes in pH, acidity, and the growth of microorganisms were not found in the PEF treated Yakju during the storage at both $4^{\circ}C\;and\;30^{\circ}C$.

• Journal of the East Asian Society of Dietary Life
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• v.18 no.1
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• pp.87-94
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• 2008

In this study, a nanatural fermentation starter formulation was developed for manufacturing bread products by substituting baker's yeast with naturally fermented raisin extract and sourdough. Four experimental groups containing 2.5, 5.0, 7.5, 10% naturally fermented raisin extract per 2,000 g of flour were compared based on quality characteristics, including the fermentation power on dough expansion, specific volume, baking loss, water activity, color, textural characteristics, and internal surface appearance. The activities of the naturally fermented raisin extract were examined in terms of pH changes, total titratable acidity, brix, and viable yeast counts. The raisin extract, which was cultured for 7 days at 30$^{\circ}C$, smelled of alcohol and produced $CO_2$. Yeast were also found in the extract after separation. As the incubation time of the raisin extract and sourdough increased, pH decreased, while total titratable acidity increased. The brix of the raisin extract increased until the $2^{nd}$ day of fermentation, and viable yeast counts increased until the $5^{th}$ day however, these gradually decreased by the $7^{th}$ day. The fermenting power on dough expansion increased in the bread with increasing incubation time. The bread samples containing 7.5% and 10% raisin extract had significantly higher specific volumes than the other samples. Baking loss was minimal with the 2.5% extract substitution. In analyzing the crumb, water activity, redness, and yellowness were highest in the 10.0% raisin extract bread samples, and lightness was maximal in the 5.0% group. In terms of textural characteristics, hardness was lowest with the 2.5% extract substitution. Gumminess, springiness, and chewiness were not significantly different among the bread samples. Cohesiveness was highest at the 7.5% extract substitution level, and resilience was lowest at the 10% level. In conclusion, based on the results, a natural fermentation starter formulated with 2.5% naturally fermented raisin extract (1 part raisins and 1.5 parts water) and 70% sourdough (1 part rye flour and 1 part water) has high potential as a baker's yeast substitute for making naturally fermented bread.

• Journal of the Korean Applied Science and Technology
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• v.41 no.2
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• pp.375-385
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• 2024

The purpose of this study is to manufacture ice cream with perilla leaves fermented extract(5%, 10%, 15%, and 20% w/v) fermented by Lactobacillus acidophilus KCTC 3164 strain as functional additives. The physical and chemical properties(color, viscosity, pH, total acidity, melting rate, overrun) and antioxidant activity of ice cream with perilla leaves fermented extract were evaluated. The addition of perilla leaves fermented extract affected the color of the ice cream, and the melting rate increased with increasing addition of perilla leaves fermented extract. In contrast, viscosity showed a gradual decrease. Overrun increased gradually with higher levels of perilla leaves fermented extract, while pH decreased significantly, and total acidity increased. The DPPH radical scavenging activity and total polyphenol content of ice cream with perilla leaves fermented extract significantly increased with higher concentrations of fermented perilla leaves extract. The results of this study indicate that the ice cream sample with 10% fermented perilla leaves extract has a potential as a functional ice cream since it exhibited high overrun, a low melting rate, the desired viscosity, and high DPPH radical scavenging activity and total polyphenol content.

• Korean Journal of Soil Science and Fertilizer
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• v.22 no.3
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• pp.173-179
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• 1989

Characterization and classification of the potential acid sulfate soils found on flood-plains in Yeongnam area were summarized as follows: 1. The "Potential acid sulfate soil" layer(s) were appeared in the around 2-4m substrata of soil profiles and characterized by the fine texture, high reduction and physical unripened soft mud deposits or having higher contents of organic matter with dark color. 2. The contents of total sulfur (T-S) in those soils were ranged around 0.45-0.9% and the materials exhibited a strong acidity upon the oxidation with $H_2O_2$. Although the T-S contents was low as much as 0.15%, the sulfidic materials were also acidified strongly by the oxidation with $H_2O_2$ in the condition of lower content of carbonates. As defined in Soil Taxonomy of USDA, most of the sulfidic materials contained less than 3 times carbonate ($CaCO_3$ equivalent wt. %), but there were some which abundant in shell fragments, contained more than 3 times carbonate by weight percentage and that not much acidified by the oxidation with $H_2O_2$. 3. The contents of T-S correlated negatively with the pH oxidized by $H_2O_2$ and with the fizzing time (minutes) due to addition of $H_2O_2$. 4. The potential acid sulfate soils could be defined as soil materials that had sulfidic layer(s) more than 20cm thick within 4m of the soil profile and contained more than 0.15% of T-S with less than 3 times carbonate ($CaCO_3$ equiv. %). A tentative interpretative soil classification system was proposed, i.e., "Weak potential acid sulfate (T-S, 0.15-0.5%)", "Moderate potential acid sulfate (T-S, 0.5-0.75%)", and "Strong potential acid sulfate (T-S, more than 0.75%)". Finally, it was proposed that the "Detailed soil survey with high intensity" should be carried out in the areas of agricultural engineering works such as arableland readjustment works, in advance.