• Korean journal of food and cookery science
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• v.29 no.6
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• pp.661-669
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• 2013

This study was performed to determine the optimal composition of Cheonggukjang added with garlic. The experiment utilized a central composite design (CCD). The evaluation was carried out by means of response surface methodology (RSM), which included 18 experimental points with three independent variables : the content of the garlic (1.3~9.7%, $X_1$), the steaming time of garlic (0~15.1 min, $X_2$), and the fermentation time of Cheonggukjang (48.2~71.8 h, $X_3$). The viscous substance ($Y_1$), acidity ($Y_2$), amino-type nitrogen ($Y_3$), ${\gamma}$-GTP activity ($Y_4$) and ABTS radical scavenging activity ($Y_5$). were assessed in four replicates with five dependent variables. The maximum content of the viscous substance was 13.02% at 6.53% ($X_1$), 6.81 min ($X_2$) and 55.18 h ($X_3$). The acidity was increased when the fermentation time was longer, and the minimum acidity point was 0.50% at 7.75% ($X_1$), 3.42 min ($X_2$) and 58.60 h ($X_3$), respectively. The content of the amino-type nitrogen at the experimental range studied was was 80.58~158.82 mg%, and the stationary point was at saddle point. Using ridge analysis, the maximum point was 156.97 mg% at 6.21% ($X_1$), 14.85 min ($X_2$) and 58.04 h($X_3$). The optimum conditions of ${\gamma}$-GTP activity was 5.73% ($X_1$), 6.99 min ($X_2$) and 57.96 h($X_3$), respectively, at the maximum point was 353.66 mU/mL. The maximum point of ABTS radical scavenging activity was 76.43% at 3.78% ($X_1$), 14.28 min ($X_2$) and 57.99 h($X_3$) at the saddle point, when the garlic steaming time was longer.

• Food Science and Preservation
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• v.22 no.3
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• pp.369-376
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• 2015

This study was performed to develop the maufacturing processes of Makgeolli using red ginseng starch (RGS). After the fermentation of RGS with koji, nuruk, and yeast, the different temperature effects on the number of the yeast cells, the content of organic acid, free sugars, and total acid, and pH were investigated. There were no changes in the composition of the yeast cell number and content of organic acid amd during 20 days at $4^{\circ}C$. The content of free sugars (sucrose, glucose and mannose) and the pH value of red ginseng Makgeolli decreased during storage at $4^{\circ}C$. This meant that the total acid content and pH value increased after organic acid was produced from fermentation. Therefore, red ginseng Makgeolli is highly acidic and sour. Since high acidity helps improve storage conditions, so this developed red ginseng Makgeolli is considered safe for consumption. Furthermore, the total content of ginsenoside was 2.47 mg/mL, which was differentiate Makgeolli using red ginseng starch, with others. Therefore, new red ginseng Makgeolli is rich in organic acid, free sugars, and ginsenoside. As a result, its storage, taste, and flavor improved.

• KSBB Journal
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• v.23 no.6
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• pp.519-524
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• 2008

Monacolin-K is a strong anti-hypercholesterolemic agent produced by Monascus sp. via polyketide pathway. High-yielding mutants of monacolin-K were developed through rational screening strategies adopted based on understanding of monacolin-K biosynthetic pathway. Through the experiments for investigating various amino acids as putative precursors for the monacolin-K biosynthesis, it was found that production level of monacolin-K was remarkably increased when optimum amount of cysteine was supplemented into the production medium. We suggested that these phenomena might be related to the special roles of SAM (S-adenosyl methionine), a putative methyl group donor in the biosynthetic pathway of monacolin-K, demonstrating close interrelationship between SAM-synthesizing primary metabolism and monacolin-K synthesizing secondary metabolism. Namely, increase in the intracellular amount of SAM derived from the putative precursor, cysteine which was extracellularly supplemented into the production medium might contribute to the significant enhancement in the monacolin-K biosynthetic capability of the highly mutated producers. On the basis of these assumptions derived from the above fermentation results, we decided to construct efficient expression vectors harboring SAM synthetase gene (metK) cloned from A. nidulans, with the hope that increased intracellular level of SAM could lead to further enhancement in the monacolin-K production through overcoming a rate-limiting step associated with monacolin-K biosynthesis. Hence, in order to overcome the plausible rate-limiting step associated with monacolin-K biosynthesis by increasing intracellular level of SAM, we transformed the producer mutants with an efficient expression vector harboring gpdA promoter of the producer microorganism, and metK gene. Notably, from the resulting various transformants, we were able to screen a very high-yielding transformant which showed approximately 3.3 fold higher monacolin-K productivity than the parallel nontransformed mutants in shake flask cultures performed under the identical fermentation conditions.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.4
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• pp.481-487
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• 1999

The optimal conditions of enzymatic hydrolysis for preparation of rapid salted and fermented anchovy sauce (SFAS) using various pretenses such as trypsin, chymotrypsin, crude enzyme from squid liver and viscera, Alcalase, Neutrase and Protamex were studied. SFAS prepared with squid viscera had higher level of VBN (173.6 mg/100 g) when stored for 70 days than other samples, and peroxide values were almost equal among all samples during fermentation period. Total amino acids and nonprotein nitrogenous compounds remarkably increased as SFAS treated with Alcalase or Protamex which exhibited higher the hydrolysis rate of $57\%$ at 60 day than others. The optimal pHs of trypsin, chymotryosin, Alcalase, Neutrase and Protamex on anchovy actomyosin were 7.5, 6.5, 6.5, 7.0 and 5.0, respectively. Optimal temperatures of trypsin, chymotryosin, Alcalase and Neutrase were 55, 45, 60 and $55^{\circ}C$, respectively. Otherwise, Protamex activity increased as temperature increased from 20 to $70^{\circ}C$. Protamex had higher $K_m$ (3.545) and $V_{max}$ value (2.688) than others. Protamex affected less by NaCl had $52.5\%$ activity at the fermentation condition of $20^{\circ}C$ and $25\%$ NaCl. Protamex appeared to be very effective for the hydrolysis of crude actomyosin from ancnovy.

• Food Science and Preservation
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• v.30 no.1
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• pp.155-169
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• 2023

Jerusalem artichoke (JA, Helianthus tuberosus L.) has a great potential to enhance the quality of yakju due to the plentiful inulin content which is functional and indigestible carbohydrate in human. In this study, the optimal preparation conditions such as the added amount and steam treatment of JA were investigated to improve the quality of yakju. As the amount of JA added to yakju increased, alcohol production decreased, whereas fermentation was performed well when the steam-cooked JA was added to yakju. The pH and total acidity of yakju decreased and increased, respectively, when the amount of JA added to yakju increased, whereas pH and total acidity of yakju increased and decreased, respectively, when the steam-cooked JA was added to yakju. The free sugar and organic acid contents of yakju increased and decreased, respectively, when the amount of JA added to yakju increased, whereas those of yakju decreased when the steam-cooked JA was added to Yakju. Amino acid content of JA decreased as the amount of JA added to yakju increased and that of JA significantly decreased when the steam-cooked JA was added to yakju. In the sensory evaluation analysis, the addition of 10% unsteam-cooked JA to yakju was the best when considering sweetness, flavor, sourness, and overall preference of yakju supplemented with JA. Consequently, utilizing JA to yakju may contribute to the improvement of the quality of yakju.

• Journal of Food Hygiene and Safety
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• v.23 no.2
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• pp.113-120
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• 2008

The influence of incubation temperature, pH and media components on bacteriocin production by Lactobacillus plantarum K11 were investigated. The highest activity was observed in MRS broth, but no bacteriocin activity was obtained in TSB. The bacteriocin was produced from the exponential growth phase and its activity also reached a maximum in MRS broth, but then dropped after 16 hr because of degradation by extracellular proteolytic enzymes or exhaustion of medium nutrients. The optimal temperature and pH for production of bacteriocin were $37^{\circ}C$ and pH 7.0 in MRS broth, respectively. The addition of 0.5 or 1.0% glucose and $0.5{\sim}1.5%$ lactose to MRS resulted in the increase of the bacteriocin production. With 0.5% NaCl and $K_2HPO_4$, the activities were significantly higher than that of control, respectively. However, increasing nitrogen sources such as beef extract, casein, and tryptone and salts such as $NH_4PO_4$, $MgSO_47H_2O$, and $MnSO_4H_2O$, had detected a negative influence upon the bacteriocin production. Consequently, because the bacteriocin produced by L. plantarum K11 was affected by various incubation conditions, the bacteriocin activity of L. plantarum K11 applied in food as a novel starter will be dependent on environmental factors such as fermentation conditions and food ingredients.

• Food Science and Preservation
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• v.23 no.1
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• pp.131-138
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• 2016

This study was conducted to investigate the change in the quality of early season Fuji apples that were subjected to eight different storage conditions using the developed controlled atmosphere (CA) storage system. Early season Fuji apples grown at Mungyeong, in the South Korea, were harvested in September 2014 for storage studies. Flesh firmness, titratable acidity, total soluble solid content, weight loss, and internal browning disorder were used as quality indicators for the stored apples. Flesh firmness and weight loss were better than that of the control after 70 days of storage. However, there was no significant difference in the titratable acidity or total soluble solid content among the apple samples from eight chambers after storage. The internal browning disorder of apple samples in CA chambers occurred when exposed to 1% $CO_2+2%$ $O_2$ and 1% $CO_2+0.5%$ $O_2$, resulting in a higher incidence rate of 2 and 8% after 70 days of storage than that in the control. In addition, the CA storage conditions at 3, 4 and 5% $CO_2+2%$ $O_2$ increased the rate of internal browning disorder by 26%. Therefore, CA storage can be used to maintain the quality of the apple if the optimal gas concentrations in the CA are applied to the storage strategy.

• Journal of Life Science
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• v.25 no.8
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• pp.917-924
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• 2015

This study aimed to evaluate the protective effect of Orostachys malacophyllus (OM) and fermented O. malacophyllus (FOM) in Sprague-Dawley rats who had been intoxicated with 1% (w/w) orotic acid (OA) for 10 days. The activities of several hepatic enzymes, aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), lactate dehydrogenase (LDH), and cholinesterase, were increased when OA was given, but these parameters were significantly decreased by FOM treatment. In addition, OA treatment resulted in an increased lipid peroxidative index (thiobarbituric acid-reactive substances, TBARS). A worsened antioxidant status (reduced glutathione) in the liver and serum was also observed. FOM treatment improved the antioxidant status of OA-induced fatty-liver rats, which was evaluated by decreased levels of the lipid peroxidative index and improved antioxidant status in the liver and serum. The contents of liver non-heme iron were increased with OA treatment and significantly decreased with FOM treatment, which suggested that the lipid peroxidation contents were inversely correlated with liver non-heme iron content. Based on these results, FOM is considered a material with significant potential for development into a functional health food that can improve fatty-liver conditions.

• Korean Journal of Environmental Agriculture
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• v.38 no.4
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• pp.262-268
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• 2019

BACKGROUND: To investigate mineralization characteristics of organic resources in the soil, five materials (rice straw, cow manure sawdust compost, microorganism compost, mixed oil-cake, and amino acid fertilizer) were treated according to the nitrogen content, and an indoor incubation experiment was conducted for 128 days. The results of this analysis were applied to determine the nitrogen mineralization pattern of these organic resources. METHODS AND RESULTS: During the constant temperature incubation period, the nitrogen net mineralization rate of the organic resources was the highest in the amino acid fertilizer with the highest nitrogen content, and the lowest in the rice straw with the lowest nitrogen content. A positive correlation (0.96) was observed between the potential nitrogen mineralization rate and total nitrogen content. The mineralization rate constant, k, was negatively correlated with the organic matter (-0.96) and carbon content (-0.97). The nitrogen mineralization rate during the first cropping season, as estimated by the model, was 6.6%, 11.6%, 30.9%, 70.7%, and 81.0% for the rice straw, the cow manure sawdust compost, the microorganism compost, the mixed oil-cake, and the amino acid fertilizer, respectively. CONCLUSION: The nitrogen mineralization rate varies depending on the type of organic resources or the nitrogen content; thus, it can be used as an index for determining the nitrogen supply characteristics of the organic resource. Organic resources such as compost with low nitrogen content or those undergoing fermentation contain organic nitrogen. Organic nitrogen is stabilized during the composting process. Therefore, as the nitrogen mineralization rate of these resources is lower than that of non-fermented organic resources, it is desirable to use the fermented organic materials only to improve soil physical properties rather than to supply nutrients for the required amount of fertilizer.

• Food Science of Animal Resources
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• v.38 no.1
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• pp.189-202
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• 2018

This study was conducted to evaluate the effects of fermenting temperature on the applicability of Lactobacillus plantarum for production of fermented sausages as starter cultures, and its applicable efficiency was also compared with those inoculated with commercial starter culture or non-inoculated control. The L. plantarum isolated from a naturally-fermented meat, identified by 16S rDNA sequencing and again identified by de novo Assembly Analysis method was used as a starter culture. Six treatments: 3 with L. plantarum at different fermenting temperatures (20, 25 and $30^{\circ}C$), and other 3 treatments (1 with commercial starter culture, 1 with its mixture with L. plantarum and 1 non-inoculated control) fermented under the same conditions ($25^{\circ}C$) were prepared. Results revealed that the fermenting temperature considerably affected the pH change in samples added with L. plantarum; the highest pH drop rate (1.57 unit) was obtained on the samples fermented at $30^{\circ}C$, followed by those at $25^{\circ}C$ (1.3 unit) and $20^{\circ}C$ (0.99 unit) after 4 days fermentation. Increasing the temperature up to $30^{\circ}C$ resulted in significantly lower spoilage bacteria count (5.15 log CFU/g) and lipid oxidation level in the products inoculated with L. plantarum. The sensory analysis also showed that the samples added with L. plantarum at $30^{\circ}C$ had significantly higher odor, taste and acceptability scores than those fermented at lower temperatures. Under the same processing condition, although the L. plantarum showed slightly lower acidification than the commercial starter culture, however, it significantly improved the eating quality of the product.