• Journal of the Korean Society of Food Culture
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• v.6 no.3
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• pp.237-244
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• 1991

This study was undertaken to examine the effects of ginseng on the acceptability of kimchi for 9 days at $20^{\circ}C$. Kimchi was analyzed for the measurement of acidity, pH, saltiness, reducing sugar, hardness by Instron and organic acids by HPLC. Ten highly trained panelists were involved in the sensory evaluation. The data analysis revealed followings; 1. While saltiness was maintained at around 2.3% level during the entire fermentation periods, kimchi containing 2% and 4% ginseng showed higher pH, reducing sugar, hardness by Instron, and lower acidity than without ginseng. 2. Results from analysis of organic acids contained by HPLC revealed that all three groups contained relatively high concentration of oxalic acid, lactic acid and malic acid. It was also found that, as fermented progressed, the amounts of lactic acid and acetic acid increased, and those of tartaric acid and malic acid decreased while the concentration of oxalic acid did not change significantly. 3. A result of sensory evaluation revealed that kimchi containing 2% and 4% ginseng was higher in hardness, savory taste and carbonated taste, and lower in sour taste, moldy off flavor than kimchi without ginseng, thus scoring high in overall eating quality. Considering all results obtained throughout this experiments, it can be concluded that the addition of small amount of ginseng to kimchi improve overall acceptability and retard rancidity, thus increasing the period during which is eatable.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.11
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• pp.1425-1430
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• 2007

This study investigated alcohol and acetic acid fermentation conditions for the quality control of pomegranate vinegar In the alcohol fermentation process, alcohol content was the highest at a pomegranate juice concentration of $16^{\circ}Brix$, but suitable to fruit vinegar standards at a concentration of $12^{\circ}Brix$. In the concentrated pomegranate juice alcohol fermentation free sugars, fructose and glucose were detected at the beginning of fermentation; at day 4 of fermentation only glucose was detected and decreased as time passed. Organic acids were also detected, including oxalic, lactic, acetic, and citric acid, and they did not change greatly during the alcohol fermentation process. In the acetic acid fermentation process, total acidity increased from 1.56% to 5.54%, where acetic acid increased; however, oxalic, lactic, and citric acids changed only slightly. In conclusion, pomegranate vinegar can undergo alcohol and acetic acid fermentation processes using concentrated pomegranate juice of $12^{\circ}Brix$.

• Korean Journal of Food Science and Technology
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• v.20 no.1
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• pp.100-105
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• 1988

Composition of organic acids and fatty acids in three edible mushrooms, Pleurotus ostreatus, Lentinus edodes and Agaricus bisporus were analyzed by gas-liquid chromatography and compositional differences of these components depending on species, sizes and portions (pileus and stipe) were investigated. Lactic, oxalic. fumaric. citric and pyroglutamic acid were identified in each of the three mushrooms and the major organic acids were malic, citric and pyroglutamic acid, respectively. The total organic acid contents were in the range of 2.4-4.0% in Pleurotus ostreatus, 1.7-3.6% in Lentinus edodes and 1.9-3.1% in Agaricus bisporus. Especially oxalic and pyroglutamic acid in Pleurotus ostreatus, malic and citric acid in Lentinus edodes and fumaric acid in Agaricus bisporus were higher in pileus than stipe. The total organic acid contents decreased as the size of pileus developed and especially the decrease of citric acid were marked. On the other hand, the major fatty acids in three mushrooms were linoleic, palmitic and oleic acid. But fatty arid compositions were not significantly different depending on species, sizes and portions.

• Korean Journal of Food Science and Technology
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• v.30 no.2
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• pp.306-312
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• 1998

Free sugar, organic acid, naringin, hesperidin and inorganic elements change of six varities of Cheju citrus fruits; Citrus natsudaidai, C. grandis, C. platymamma., C. sudachi, C. aurantiun and C. unshiu Marc. var. miyagawa by harvest date were investigated. Changes in free sugar of citrus fruits on the different harvesting stages and varieties showed a little differencies. The content of sucrose, glucose and maltose in citrus juice were $44.9{\sim}66.0%,\;15.7{\sim}25.7%\;and\;17.5{\sim}30.1%$, respectively. As the fruits were matured, free sugar was increased, but organic acid was decreased gradually. The major organic acids from the fruit juice were citric acid, malic acid and oxalic acid. Citric acid content exceeded 90%, oxalic acid ranged less than 3.58% and malic acid ranged $0.98{\sim}9.45%$ in total organic acids. Both naringin and hesperidin content showed markedly high in immature fruits, and in rind compare to fruit juice. Naringin and hesperidin content decreased as peel coloration progressed. It was estimated that fully matured fruits would be useful for making processed products, which lead to less turbity and less bitterness.

• Food Science and Preservation
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• v.17 no.4
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• pp.563-570
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• 2010

We sought to ferment wine from mulberry (Morus alba) juice. The soluble solid content was $9.5{\sim}14.5^{\circ}brix$ on day 6 of fermentation, and gradually fell later; sugar was not further consumed when $3^{\circ}brix$ was attained. Alcohol content rose dramatically on day 6 of fermentation, being 4.5% (v/v) at fermentation temperatures of 16C and 18C, 6.5% (v/v) at 20C, and 8.0% (v/v) at 25C, rising further to 10.5~11.5% (v/v) on day 48, at higher culture temperatures. Citric acid, malic acid, and oxalic acid were present in mulberries. The levels of both citric and oxalic acid fell after fermentation, whereas malic acid concentration increased. All of fructose, glucose, maltose, and sucrose were fermented. Electron-donating ability (EDA) was elevated to over 90% of the control value in mulberry juice diluted to 40% (v/v). SOD-like activities in juice and wine were 80.1% and 72.1% of the control value. Nitrite-scavenging abilities (NSAs) were 86.2% and 85.2% of control in undiluted juice and wine, respectively. Mulberry juice had an activation level higher than that of mulberry wine, but functionality neither rose nor fell after fermentation. Insensory evaluation, the overall wine score was better than average, at 5.00, demonstrating the commercial potential of mulberry wine.

• Journal of the Korean Society of Food Science and Nutrition
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• v.22 no.1
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• pp.78-84
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• 1993

This study was conducted to investigate the effect of various polyethylene (PE) film packaging on the quality of strawberry during storage at low temperature. Gas composition in film was changed rapidly at early stage of storage and then kept at the level of 5~10% $CO_2$and 1~3% $O_2$. Weight loss and decay rate were low at 0.08mm PE film packed strawberries. Titratable acidity, pH and soluble solids were changed slightly during storage but its large difference according to film thickness was not observed. Decrease of flesh firm-ness and a value was restrained by PE film packaging. Free sugar of strawberry was composed of glucose and fructose in similar content and it was decreased a little during storage but the difference according to film thickness was not observed. The organic acids in strawberry were citric acid, malic acid, succinic acid, ascorbir acid, oxalic acid, tartaric acid and pyruvic acid and the major organic acid was citric acid. The contents of citric acid, malic acid, succinir acid and ascorbic acid were decreased and oxalic acid and tartaric arid were not changed during storage but pyruvic acid was increased in early stage and then decreased. These changes of organic acid were slight in packaged with 0.08mm PE film strawberry.

• Economic and Environmental Geology
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• v.40 no.2 s.183
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• pp.141-151
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• 2007

This study was focused on iron removal from illite by L-ascorbic and oxalic acids. Iron has been shown as a secondary mineral such as iron oxides and hydroxides in illite ores. It is also known as a primary agent to degrade brightness index of the ores. Methods such as physical separation and chemical leaching with strong inorganic acids have been widely used to remove the iron from the ores. However, these methods are expensive and give rise to environmental problems. In this study, we examined an alternative method using solutions with different set of combination of sulfuric, hydrochloric, L-ascorbic, and oxalic acids. Compared to chemical treatments with only inorganic acids, our results demonstrate that an addition of L-ascorbic acid in inorganic acids results in decreasing both total concentrations of the inorganic acids and time for the treatments. The treatment with 0.15 M L-ascorbic acid and 0.25 M sulfuric acid in solution for 60 min significantly improved the brightness index from 42.4% to 74.4%. This improvement is similar to that of treatment with only 2.5 M sulfuric acid alone for 150 min. Mineralogical and chemical analyses were performed to compare the effect of acid leaching on illite powders. No obvious differences are observed in the mineralogical characteristics and particle size distributions of the samples. These results suggest that the treatment with the addition of L-ascorbic acid in sulfuric acid could effectively remove iron without modifying the physicochemical properties of illite under conditions used in this study.

• Journal of the Korean Wood Science and Technology
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• v.39 no.1
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• pp.75-85
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• 2011

The main purpose of this study is to evaluate the potential of producing bioethanol from yellow poplar ($Liriodendron$ $tulipifera$) wood chips by oxalic acid pretreatment and to examine the pretreatment conditions by response surface methodology (RSM). Based on $2^3$ factorial design, adjusted variables were reaction temperature ($^{\circ}C$), residence time (min), and acid loading (g/g), and a series of distinct 15 experimental conditions was organized with duplication at central point (total 16 performances). After pretreatment, simultaneous saccharification and fermentation (SSF) was subjected on solid fraction with yeast strain $Pichia$ $stipitis$. Maximum ethanol yields of the most samples were measured at 72 hours and applied to RSM as a dependent variable. 9.7 g/${\ell}$ of ethanol was produced from the solid pretreated at $180^{\circ}C$ for 40 min with 0.013 g/g of oxalic acid loading. According to the response surface methodology, it was determined that the temperature is the most governing factor via statistic analysis.

• Korean Journal of Food Science and Technology
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• v.7 no.2
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• pp.74-81
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• 1975

Nonvolatile organic acids were determined in raw Chinese cabbage, Kimchis fermented at $6^{\circ}{\sim}7^{\circ}C$ and at $22^{\circ}{\sim}23^{\circ}C$. Total acids were isolated by ion-exchange chromatography and quantitative determination of individual acids was performed by silicic acid partition column chromatography. Acids were identified qualitatively by paper chromatography. Palatability of Kimchis was evaluated by nine pannels. Results were as follows: Maleic, fumaric, lactic, succinic, malonic, oxalic, glycolic, malic, citric, tartaric, sulphuric and phosphoric acid were found in raw Chinese cabbage. Kimchis fermented at $6^{\circ}{\sim}7^{\circ}C$, and at $22^{\circ}{\sim}23^{\circ}C$. In raw Chinese cabbage, most of organic acids were in salt form and malic acid was highest in amount. In Kimchi fermented at $6^{\circ}{\sim}7^{\circ}C$, the amount of lactic acid and succinic acid was higher than that in Kimchi fermented at $22^{\circ}{\sim}23^{\circ}C$, and, tartaric, oxalic, malic, malonic, maleic, glycolic and fumaric acids were less than those in Kimchi fermented at $22^{\circ}{\sim}23^{\circ}C$. Kimchi fermented at $6^{\circ}{\sim}7^{\circ}C$ had a more flavorous sour taste than Kimchi fermented at $22^{\circ}{\sim}23^{\circ}C$. It is assumed that large amount of lactic acid and succinic acid in Kimchi fermented st $6^{\circ}{\sim}7^{\circ}C$ have a connection with flavorous sour taste.

• Korean Journal of Food Science and Technology
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• v.4 no.2
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• pp.134-139
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• 1972

The contents and their seasonal changes of non-volatile organic acids and sugars of various fruits in Korea, apricot(maesil), peach, grape, apple and pears were measured. The organic acid contents were determined by gas chromatography and the free sugars were detected by thin layer chromatography. The results were as follows: 1) The common non-volatile organic acids found in those fruits were oxalic, fumaric, succinic, maleic, tartaric and citric acids: though their contents varied from almost none to 3430mg/100g. 2) Malic acid was contained in all above fruits with generally the highest contents ranging $18{\sim}3430mg/100g$ among different fruits. In every fruits oxalic was the least contained among other organic acids, almost none to trace except apricot(maesil) which contained 10.8mg/100g. 3) It seemed that generally all the non-volatile acids contents decreased after ripening except maleic acid and the cases of an apple and a pear varieties where they increased. 4) Glucose and fructose were detected in all fruits both matured and unripened by thin layer chromatography. Maltose was found in apricot(maesil), peach, grape and apple. Sucrose was detected in apricot(maesil), peach, grape, apple and pear.