• The Korean Journal of Food And Nutrition
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• v.11 no.4
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• pp.369-374
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• 1998

This study was conducted to investiagte influences of cold aged dough on the quality of bagutte. After 2 hours fementing, the dough was divided 2 parts and they were stored in the refrigirated adjusted 1∼-1$^{\circ}C$. The cold aging time was 24, 48 hours respectivley. After 2 hourse fermentation, the dough's pH was 5.45 and 24, 48 hours cold aged dough were 4.99, 4.81. During cold aging, the difference of pH was not significant. The main organic acids in the baguette were lactic acid, acetic acid and malic acid, Among these organic acids, the acetic acid was the largest quantity regardlessly in different fermentation and the cold aging acids, time. Right after baking, the enthalphy of all samples were almost same even thought in different cold aging time, but during different storage periods they showed the difference of retrogradation by the increase of the enthalphy. 24 hours cold aging baguette had the best taste, aroma and texture in bread's score sheet.

• The Korean Journal of Food And Nutrition
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• v.3 no.2
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• pp.141-148
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• 1990

This studies were carried out to investigate the effects of non-volatile organic acids in the KimChi by lactic acid bacteria. The organism isolated from KimChi, Pediococcus dextrinicus, Leuconostoc mesenteroides, Lactobacillus plantarum and Lactobacillus brevis, were inoculated for preparation of KimChi. pH of all on the KimChi sample dropped sharply according as fermentation continued. pH of on optimum ripening period KimChi(4.4 and 4.2) reached 1.3 and 1.9 day at all on sample, respectively. Optimum acidity(0.5%) of KimChi were reached within 2 day all on sample. The total number of lactic acid bacteria reached 1.0X107cells/ml in 1 day and decreased slowly after 4 day. Main non-volatile organic acids were identified lactic, malic and succinic acid. The sensory score of mixed lactic acid bacteria inoculated KimChi was better than that of another KimChi.

• Korean Journal of Microbiology
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• v.3 no.2
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• pp.15-21
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• 1965

Using the synchronous culture method and the manometric technique, changes in respiratory activities, utilization of some organic acids (succinate, malate, lactate and acetate etc.) and its effect on glucose metabolism in Chlorella cells at different growing stages were measured. 1) Endogenous respiration of the cells was not active at growing stage and was almost constant throughout the early ripening, maturing and division stages. 2) Lactate was utilized as respiratory substrate better than other organic acids tested. Exogenous respiration of glucose was most active at growing and maturing stages and was decreased strikingly at division stage. 3) Succinate and citrate inhibited endogenous and glucose respiration of the cells throughout the all life cycle. 4) Malate and acetate were utilized in the cells at early growing and division stages better, and malate enhanced the glucose respiration while in case of acetate it was depressed. 5) Calcium ion inhibited not only permeability of respiratory substrate but endogenous respiration itself.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.7
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• pp.746-752
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• 2005

In this study, the effect of reaction parameters including reaction temperature, time, and pressure on sludge degradation and conversion to intermediates such as organic acids were investigated at low critical wet air oxidation(LC-WAO) conditions. Degradation pathways and a modified kinetic model in LC-WAO were proposed and the kinetics model predictions were compared with experimental data under various conditions. Results in the batch experiments showed that reaction temperature directly affected the thermal hydrolysis reaction rather than oxidation reaction. The efficiencies of sludge degradation and organic acid formation increased with the increase of the reaction temperature and time. The removal of SS at $180^{\circ}C$, $200^{\circ}C$, $220^{\circ}C$ and $240^{\circ}C$ of reaction temperatures and 10 min of reaction time were 52.6%, 68.3%, 72.6%, and 74.4%, respectively, indicating that most organic suspended solids were liquified at early stage of reaction. At $180^{\circ}C$, $200^{\circ}C$, $220^{\circ}C$ and $240^{\circ}C$ of reaction temperatures and 40 min of reaction time, the amounts of organic acids formed from 1 g of sludge were 93.5 mg/g SS, 116.4 mg/g SS, 113.6 mg/g SS, and 123.8 mg/g SS, respectively, and the amounts of acetic acid from 1 g of sludge were 24.5 mg/g SS, 65.5 mg/g SS, 88.1 mg/g SS, and 121.5 mg/g SS, respectively. This suggested that the formation of sludge to organic acids as well as the conversion of organic acids to acetic acid increased with reaction temperature. Based on the experimental results, a modified kinetic model was suggested for the liquefaction reaction of sludge and the formation of organic acids. The kinetic model predicted an increase in kinetic parameters $k_1$ (liquefaction of organic compounds), $k_2$ (formation of organic acids to intermediate), $k_3$ (final degradation of intermediate), and $k_4$ (final degradation of organic acids) with reaction temperature. This indicated that the liquefaction of organic solid materials and the formation of organic acids increase according to reaction temperature. The calculated activation energy for reaction kinetic constants were 20.7 kJ/mol, 12.3 kJ/mol, 28.4 kJ/mol, and 54.4 kJ/mol, respectively, leading to a conclusion that not thermal hydrolysis but oxidation reaction is the rate-limiting step.

• Journal of the Korean Society of Food Science and Nutrition
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• v.22 no.1
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• pp.53-57
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• 1993

The compositions of non-volatile organic acids, mineral, fiber and fatty acids of leaf mustard were investigated. Non-volatile organic acid contents were higher in leaf than in leaf stalk. Of non-volatile organic acids assayed malic acid was the most abundant in both leaf (79.1 mg%) and leaf stalk (46.4mg%), followed by L-ascorbic, oxalic, citric and succinic acids. Mineral contents were also higher in leaf than in leaf stalk. Both leaf and leaf stalk contained calcium most, followed by magnesium, sodium, iron, zinc and copper. It has also been found that leaf mustard contains more iron than any other Cruciferous vegetables reported. The major fatty acid of total lipid was $\alpha$-linolenir acid (63.2% in leaf, 55.3% in leaf stalk). The ratios of polyun-saturated fatty acids to saturated fatty acids (P/S ratio) were 4.1 in leaf and 2.9 in leaf stalk. The content of pectic substances, in terms of alcohol-insoluble solid, of leaf was 9.4% which was 1.4-fold higher than that of leaf stalk. Of pectic substances, hot soluble pectins (HWSP) were present most and followed by sodium hexametaphosphate soluble (HXSP) and HCI soluble pectins (HSP). Total dietary fiber content of mustard leaf was 2.68% and in general, higher content of total dietary fiber than leaf had. Neutral detergent fiber content was higher than acid detergent fiber, and cellulose was higher than hemicellulose by 2.1-fold in leaf stalk.

• Applied Biological Chemistry
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• v.34 no.4
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• pp.366-372
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• 1991

The volatile components, normal hydrocarbons, organic acids, and nonvolatile fatty acids in the various parts of Luffa cylindrica(L.) Roemer(sponge-gourd) were analyzed by GC and GC/MS. More than 150 volatile components were separated and thirty seven components were identified and quantified. The contents of essential oil were 0.05%, 0.05%, and 0.08% on a dried weight base in leaves, stem, and seeds respectively. Fruit juice and sap contained 0.06% and 0.03% oil on the fresh weight base. Twenty six components of normal hydrocarbons in leaves, stem, seed, and unripe fruit were separated, identified, and quantified. The total concentrations of the hydrocarbons were $75.5\;{\mu}g/g$ in leaf, $52.0\;{\mu}g/g$ in stem, $46.6\;{\mu}g/g$ in fruit juice, and $32.8\;{\mu}g/g$ in seed fractions. The major hydrocarbons in leaves, stem, and fruit juice were $nC_{25}$, $nC_{27}$, $nC_{29}$, and $nC_{31}$, $nC_{16}$, $nC_{17}$, $nC_{18}$, and $nC_{19}$ were abundant in seeds mainly. The concentration of malonic acid among the five organic acids was highest in leaves, stem, and flowers. Unripe fruit contained 24.5 mg/g of the five organic acids and malic and citric acids were higher. The concentrations of palmitic, linoleic, and linolenic acids were higher concentration in the various parts of sponge-gourd and palmitic acid was distributed in the most parts. The concentrations of organic and fatty acids in the sap were negligible.

• KSBB Journal
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• v.19 no.6 s.89
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• pp.484-488
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• 2004

Fermentation studies were conducted in batch and continuous flow cell-recycle reactors with food by-products as substrates. The genus Propionibacterium acidipropionici ATCC 4965 was utilized in the production of organic acids. Good performance was achieved in the batch fermentation using hydrol as a carbon source and corn steep liquor (CSL) as nitrogen and vitamin sources. Product yields and productivity based on maximum values were 0.80 g total acids/g glucose and 0.26 g total acids/L/h, respectively, when $3\%$, (w/v) of hydrol and $2.5\%$, (w/v) of CSL were utilized. Continuous fermentation with cell-recycling system using the optimum amounts of substrates resulted in dramatic increase in cell concentration (X) and maximum productivity (P). Compared to the batch fermentation, X and P were increased by as much as 21 and 13 times, respectively, at the dilution ratio of $0.2\;hr^{-1}$, indicating that cell recycling fermentation of food by-products provides valuable means for the mass production of organic acids as well as utilizing cell mass as good nutrient resources.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.18 no.5
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• pp.417-423
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• 1985

In succession to the previous paper, the present study was directed to investigate the nonvolatile organic acids composition in raw and belied-dried products of oyster, sea-mussel, baby clam and hen clam by gas liquid chromatography. The results obtained are summarized as follows : In four kinds of the samples examined, eight kinds of organic acids were identified and determined in oyster, sea-mussel and baby clam, and nine kinds in hen clam. The major organic acids in oyster were pyroglutamic, succinic and malic acid which was $94.2\%$ of total quantity of organic acid, and those in sea-mussel, baby clam and hen clam were succinic and malic acid which were $90.8\%,\;89.7\%\;and\;86.4\%$ of total acids, respectively. The most abundant organic acid in sea-mussel, baby clam and hen clam was succinic acid that was $80.6\%,\;84.9\%\;and\;73.2\%$ in total acids, repectively. And that of oyster was pyroglutamic acid which marked $38.8\%$ in total acids, and the next one was succinc acid marked $34.4\%$. In the total quantity of organic acid, the highest was 913.0 mg/100g in oyster which showed 4.5 times as much as in hen clam, followed by 478.4 mg/100g in sea-mussel, 246.3mg/100g in baby clam, and the least was 201.2 mg/100g in hen clam. The decreasing rate of total quently of organic acids by boiled-dried procersing was the highest in oyster, $54.7\%$, followed by $46.5\%$ in sea-mussel, $37.1\%$ in hen clam and $29.4\%$ in baby clam. The decreasing rate of each organic acid shelved much difference according to the samples examined, in general, great in malic, fumaric and proglutamic acid ana less in succinic, lactic and oxalic acid.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.6
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• pp.910-919
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• 2012

The role of inorganic nitrogen assimilation in the production of amino acids, organic acids and soluble sugars is one of the most important biochemical processes in plants, and, in order to achieve normally, nitrate uptake and assimilation is essential. For this reason, the characterization of nitrate assimilation and metabolite composition from leaves, roots and xylem sap of tomato (Solanum lycopersicum) was investigated under different nitrate levels in media. Tomato plants were grown hydroponically in liquid culture under five different nitrate regimes: deficient (0.25 and 0.75 mM $NO_3{^-}$), normal (2.5 mM $NO_3{^-}$) and excessive (5.0 and 10.0 mM $NO_3{^-}$). All samples, leaves, roots and xylem sap, were collected after 7 and 14 days after treatment. The levels of amino acids, soluble sugars and organic acids were significantly decreased by N-deficiency whereas, interestingly, they remained higher in xylem sap as compared with N-normal and -surplus. The N-excessive condition did not exert any significant changes in metabolites composition, and thus their levels were similar with N-normal. The gene expression and enzyme activity of nitrate reductase (NR), nitrite reductase (NIR) and glutamine synthetase (GS) were greatly influenced by nitrate. The data presented here suggest that metabolites, as a signal messenger, existed in xylem sap seem to play a crucial role to acquire nitrate, and, in addition, an increase in ${\alpha}$-ketoglutarate pathway-derived amino acids under N-deficiency may help to better understand plant C/N metabolism.

• Journal of the Korean Society of Food Science and Nutrition
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• v.29 no.2
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• pp.211-217
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• 2000

To standardize quality characteristics of commercial doenjang prepared by traditional method, general components, organic acids, amino acids and fatty acid composition were investigated. Moisture, crude protein, crude lipid, titratable acidity (expressed as milliliter of 0.1 N NaOH), acid value and salinity were 54.7%, 13.8%, 8.0%, 14.4mL, 45.7mg/g and 11.8%, respectively. The content of amino type nitrogen was 345.3mg% (w/w) in the range of 207.6 to 443.5mg% being 1.1~2.2-fold for all samples. Average value of Hunter color for L(lightness), a(redness) and b(yellowness) were 37.4, ＋9.7 and ＋21.3, respectively. Browning index value(expressed as optical density at 425 nm) of water-soluble compound(2.58) was above 7.1 times higher than that of the water-insoluble compound(0.38). Total contents of free and total amino acid were 3.81 and 9.72%, respectively, and then the former(1.1~3.7 times) was more different in all samples tested than that of the latter(1.1~2.0 times). Among amino acids, glutamic acid was abundant and its content of free and total amino acids was 0.57 and 1.24%, respectively. Of organic acids, lactic acid was the most abundant being 0.34%(average) and ranged from 0.15 to 0.86%. Linoleic acid(52.17%, as area%) was the highest content of the total fatty acids. Unsaturated and polyunsaturated fatty acids were 83.89 and 61.189%, respectively. Polyunsaturated fatty acid was markedly different among all samples and ranged from 51.52 to 64.91%.