• Korean Journal of Environmental Agriculture
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• v.14 no.1
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• pp.15-22
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• 1995

This study was carried out to investigate the deposition aspect of acid precipitation in rural area of Chonbuk province by analysis of the chemical components in the precipitation at National Honam Agricultural Experiment Station, RDA in the suburbs of Iri from Jan. to Dec. in 1992. The results are summarized as follows: 1. The frequency of acid precipitation was 82.5% in 1992 and the month of the lowest frequency of 17% was June. 2. The pH range of the most precipitation amount was pH $4.5{\sim}5.0$ of 54.0% and the amount and ratio of the precipitation below pH 4.0 were 9.6 mm and 1.1%, respectively. 3. The seasonal acidity of precipitation was Summer(4.78)>Fall(4.59)>Spring(4.52)>Winter(4.16). 4. The components showed significant correlation with pH value were $SO_4^{2-}$ and $NO_3$ and the equivalence ratio between two components was 2.85 : 1. 5. The order of the major ion concentration in the precipitation was $SO_4^{2-}$>$NH_4^+$>$Cl^-$>$Ca^{2+}$>$NO_3^-$>$Na^+$>$H^+$>$K^+$>$Mg^{2+}$ and the equivalence ratio of total anion to cation was 1.20. 6. Deposition amount of nitrogen ($NO_3-N$ + $NH_4-N$) and potassium ($K_2O$) were 1.19 and 0.53 kg/l0a/year, respectively.

• 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.

• Korean Journal of Food Science and Technology
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• v.36 no.3
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• pp.448-455
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• 2004

Changes in quality characteristics of Bijijang (fermented soybean curd residus) prepared at $35^{\circ}C\;and\;40^{\circ}C$ for 0, 12, 24, 36, and 48 hr were investigated. Acidity of Bijijang increased, whereas pH and Hunter's color values decreased during fermentation. Immediately after Bijijang preparation, ${\alpha}-and\;{\beta}-amylase$ activities were very low, ${\beta}-Amylase$ activity during fermentation increased rapidly, with those fermented at $40^{\circ}C$ higher than at $35^{\circ}C$. Neutral pretense activity was significantly higher than acidic pretense activity, and increased gradually after 12 hr. Change in total nitrogen content in Bijijang was insignificant, whereas contents of amino-type and water-soluble nitrogens increased significantly during fermentation. Major free amino acids of Bijijang were Arg, Pro, Glu, Thr, Ser, and Lys at initial fermenting stage, and, as fermentation progressed, contents of Cys, Met Glu, Ile, Leu, and Phe increased. Reducing sugar contents of Bijijang fermented at $40^{\circ}C$ were higher than those fermented at $35^{\circ}C$. Sucrose content decreased and glucose content increased. Glucoside (genistin and daidzin) contents decreased and aglycone (genistein and daidzein) contents increased during preparation of Biji and fermentation of Bijijang. Contents of free sugars and isoflavones were higher in Bijijang fermented at $40^{\circ}C$ than at $35^{\circ}C$. Based on these results, fermentation at $40^{\circ}C$ for 48 hr was determined to be optimum fermentation condition for Bijijang.

• Korean Journal of Food Science and Technology
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• v.36 no.3
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• pp.385-392
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• 2004

Physicochemical and sensory characteristics of commercial Oiji, Korean pickled cucumbers (six commercial and three traditionally made products) were investigated. Saltiness values for commercial and traditionally made products were 3.424-4.47 and 3.92-7,23%, and acidity and pH were 3.43-3.85 and 0.39-0.75%, respectively, Commercial products showed lower L and higher b values than traditionally made products. Redness of both products ranged from -1.47 to -3.71. Numbers of total microbial, lactic acid bacteria, and yeast in traditionally made products ($1{\times}10^{7}-1.3{\times}10^{9},\;4{\times}10^{6}-4.7{\times}10^{8},\;and\;1.3{\times}10^{6}-3{\times}10^{8}\;cfu/mL,\;respectively$), were higher than those of commercial products ($1{\times}10^{4}-2{\times}10^{7},\;1{\times}10^{4}-6{\times}10^{6},\;and\;1{\times}10^{4}-6{\times}10^{6}cfu/mL\;respectively$). Texture analysis revealed fracturability (2,103-3,010 g) and hardness (409-890 g) varied among the products above. Overall acceptability scores of commercial products C1 and C2 were highest at 7.6-8.0 compared to other products (p<0.05). From the principal component analysis, the first principal component (PC1, 79.94%) and the second principal component (PC2, 19.94%) could describe the majority of the variability. Commercial product C1, C2, C3, and C7 having high negative loadings on the PC2 axis are closely related to over-all acceptability, over-all taste, savory taste and hardness. From Pearson correlation analysis, hardness and chewiness correlated positively with saltiness, whereas over-all acceptability, positively correlated with savory and overall taste, respectively (p<0.05).

• Journal of The Korean Society of Grassland and Forage Science
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• v.19 no.4
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• pp.347-354
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• 1999

This experiment was carried out to determine the effect of maturity at harvest and inoculants on the quality of round baled rye(Secale cereale L.) silage at the experimental field of Grassland and Forage Crops Division, National Livestock Research Institute, RDA, Suwon in 1998. The experiment was consist of split-plot design with 3 replications. The main plots were 3 harvesting stages such as boot(20 April), heading(29 April), and flowering stages(14 May). The subplots wered inoculant treatments : control (untreated), inoculant A, and inoculant B. Acid detergent fiber(ADF), neutral detergent fiber(NDF), and in vitro dry matter digestibility (IVDMD) of rye silage were significantly increased with delayed harvesting date, but there was not significant difference between inoculants. Mean silage pH at flowering stage was the lowest(4.35), but the highest at early harvest(4.91). Inoculants significantly reduced acidity of silage compared with control. Dry matter(DM) content of the control was higher than that of inoculants. Ammonia-N as proportion of total N was below 10% which was maximum level of high quality silage. The addition of inoculants reduced ammonia-N. There were significant difference in organic acid contents between harvesting stages and inoculants. Lactic acid was increased with inoculants, but acetic and butyric acids were decreased. Various treatments increased colony forming unit(CFU) of lactic acid bacteria by 2 or 3 times compared with the control and the highest at flowering stage with inoculant B treatment. Results of this study indicate that use of microbial inoculant and harvesting after heading stage will improve the silage fermentation and quality of round baled rye silage.

• Korean Journal of Food Science and Technology
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• v.41 no.5
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• pp.541-546
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• 2009

The objectives of this study were to evaluate the physico-chemical and sensory characteristics of a Korean traditional alcoholic beverage (yakju) prepared using different nuruk (Korean-style koji) concentrations and yeasts such as the fusant FA776 and Saccharomyces cerevisiae KOY-1, respectively. The fusant FA776, which has alcohol-fermenting and starch-utilizing properties, was formed by Saccharomyces cerevisiae KOY-1 and Saccharomyces diastaticus KCTC1804. The fermentation trial was conducted in a 5 L lab-scale jar at $25^{\circ}C$. The maximum alcohol production of the K-100 and F-50 reached levels of 135.0 mg/mL and 119.4 mg/mL, respectively. The pH values were in a range of 4.3-4.5. Total acidity was in a range of 0.47-0.60%. Organic acids and amino acids were analyzed in order to evaluate variations in its composition and content via HPLC analysis. Organic acids including lactic acid, citric acid, malic acid, and pyruvic acid, and 16 kinds of amino acids, including aspartic acid, were detected in all treatments. K-100 showed the highest amino acid contents, whereas F-50 exhibited the lowest amino acid contents. Volatile flavor components such as phenylethyl alcohol, isoamyl alcohol, 2-methylthiophane, isobutyl alcohol, and ethyl succinate were detected as a major component in all treatments, as determined via gas chromatography. The results of our sensory evaluation demonstrated that Yakju fermented by the FA776 fusant yielded more favorable results than S. cerevisiae KOY-1.

• Applied Biological Chemistry
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• v.23 no.3
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• pp.157-165
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• 1980

Kojis were prepared from the different starch raw materials such as glutinous rice, barley rice, wheat flour and sweet potato, and were tested in an effort to reduce production cost and to improve quality of Kochuzang(red pepper paste). During the starting period of Koji preparation, there were less significant changes in pH; however, pH decreased somehow in the case of sweet potato, whereas it increased for the other Kojis. In general, the highest acidity was obtained after 72 hours of Koji preparation. Total nitrogen, soluble nitrogen and amino-nitrogen content increased in order of wheat flour, barley rice, and glutinous rice; Kojis they were markedly produced between 72 and 96 hours of Koji preparation. The maximum amount of reducing sugar was observed between 48 and 72 hours of Koji preparation during this period the reducing sugar content varied widely depending on starch source. Sweet potato Koji produced the highest level of ethyl alcohol content after 72 hours of Koji preparation; for the other Koji the same trends were observed after 24 hours. The starch liquefying activities have reached the highest level after 96 hours and for glutinous rice and barley rice; however, they kept on increasing until 120 hours for wheat flour and sweet potato. Koji Starch liquefying and saccharogenic amylase activities tended to increase in order of sweet potato, glutinous rice, barley rice and wheat flour. Kojis Various protease activities were measu-red during the Koji preparation, and they increased in order of alkali, neutral and acidic protease.

• Food Science and Preservation
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• v.23 no.3
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• pp.402-412
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• 2016

Generation of biogenic amines (BAs) and physiological activities of Makgeolli, Korean rice wine, were investigated during fermentation under different temperatures (20, 25, and $30^{\circ}C$) and time (3, 5, and 7 days). The pH was 3.96~4.36 during fermentation and the acidity increased proportionally with temperature and time. Alcohol and total phenolic contents peaked on day 5 at 25 by 9.0~9.8% and $3.01{\pm}0.07mg/g$, respectively. The organic acid mostly produced was lactic acid, which increased gradually with temperature and time. Formation of biogenic amines comprised of tryptamine and putrescine was observed during fermentation: 6.91, 11.70, and 15.63 mg/mL of tyramine on day 7 at 20, 25, and $30^{\circ}C$, respectively. Antioxidant activities from DPPH and FRAP assay were high in the order of $25^{\circ}C$>$20^{\circ}C$>$30^{\circ}C$ while that from ABTS assay was high regardless of temperature. Processed at 1 mg/mL and $30^{\circ}C$, the inhibitory effect on ${\alpha}$-amylase was $67.99{\pm}0.11$, $73.64{\pm}0.43$, and $75.51{\pm}0.26%$ on days 3, 5, and 7, respectively, which increased proportionally with temperature and time. Inhibitory activity on lipid accumulation in 3T3-L1 adipocytes was the highest in Makgeolli fermented on day 5 at $25^{\circ}C$. This study shows that fermentation at $25^{\circ}C$ for 5 days yields Makgeolli of the best quality with high bioactivities but no biogenic amines.

• Food Science and Preservation
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• v.17 no.1
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• pp.50-57
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• 2010

To develop a new functional kimchi with antioxidative properties, salted baechu was soaked in black rice water extract for 6 h at room temperature. The antioxidative property of the water extract was $78.75{\pm}1.18%$ that of the control (0.1% [w/v] alpha-tocopherol). The black rice gel was added to the baechu kimchi preparation. The color of baechu kimchi treated with black rice water extract changed to dark violet and/or black. Control kimchi and black rice water-treated kimchi were stored at $4^{\circ}C$ for 30 days. No significant differences were detected between the control and the black rice water-treated group in the early stages of fermentation. As fermentation time increased, pH decreased and titratable acidity increased rapidly in control kimchi. However, such marked changes were not evident in test kimchi. The hardness value of black rice water-treated kimchi was higher than that of control kimchi after the midpoint of the fermentation period. The storage life of baechu kimchi treated with black rice water extract was prolonged by up to 5 days compared with control samples, owing to a decline in lactic acid bacteria and yeast levels during the final fermentation period in black rice water-treated kimchi. The total phenolic levels and the antioxidative capacity of black rice water-treated kimchi (83%) were approximately 1.5-fold higher than in control kimchi (57%). In sensory evaluation, black rice water-treated kimchi scored higher than did control kimchi using a blind test protocol.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.5
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• pp.598-604
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• 2012

Four types of mixed citrus and carrot juice (CCJ) were prepared with citrus-pressed juice and cake, and carrot-pressed juice. Their physicochemical properties and antioxidative activities were investigated. The four types of juices were created using different ratios of citrus-pressed juice, carrot-pressed juice, citrus-pressed cake, and additives. The mixing ratios of the four CCJ were as follows (all ratios given in the order of citrus-pressed juice : carrot-pressed juice : citrus-pressed cake : additives; 70:30:0:0 for CCJ-1, 65:30:0:5 for CCJ-2, 65:30:5:0 for CCJ-3, and 60:30:10:0 for CCJ-4. Acidity was low in CCJ-3 and -4 at 0.82 and 0.80, respectively, compared with 0.95 in CCJ-1. The fructose, glucose, and sucrose content was 2.11~5.76 g/100 g, 1.20~2.75 g/100 g, and 3.00~4.21 g/100 g, respectively. Total phenolic content was 1.17 and 1.22 times high as 863 and 898 mg% in CCJ-3 and -4, respectively, compared with 735 mg% in CCJ-1. DPPH radical scavenging activities of methanol extracts of CCJ-3 and -4 were 3.05 and 3.29 times as high as 58.7% and 63.3%, respectively, compared with 19.2% in CCJ-1. Superoxide anion scavenging activities were also 1.67 and 1.80 times higher in CCJ-3 and -4 than that of CCJ-1. Inhibition of NO production in methanol extracts of CCJ-4 were 1.15 and 1.57 times as high as 20.9% and 28.5%, respectively, compared with 18.2% in CCJ-1. Based on the sensory evaluation, CCJ-3 was more preferable in terms of color, flavor, taste, and overall preference than CCJ-1, -2, and -4. It was concluded that CCJ-3 made with 65% citrus-pressed juice, 30% carrot-pressed juice, and 5% citrus-pressed cake were high in antioxidative activity and the inhibition of NO production, and more preferable in terms of sensory attributes.