• Korean journal of food and cookery science
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• 제15권5호
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• pp.459-468
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• 1999

The purpose of this study was to evaluate the effect of bamboo(Idae) leaves on the taste and preservation of Dongchimi. Dongchimi was prepared by the method described in the literatures and fermented at 10$^{\circ}C$ for 75 days. The amounts of bamboo leaves used to cover the Donchimi was 1, 3, 5 and 7% of radish weight. Total vitamin C content increased gradually in the initial stage of the fermentation periods, and then it decreased gradually. Regardless of the amount of bamboo leves, the reducing sugar content increased gradually from the initial stage of fermentation increased rapidly after 8 days of fermentation. As the amount of bamboo leaves increased, the reducing sugar content was retained longer, which reflected the retardation of Dongchimi fermentation. The free amino acid contents in all of the Dongchimi samples were in order of arginine > glutaric acid > aspartic acid > alanine at the initial period of fermentation, but the order changed to arginine > alanine > glutamic acid > valine as fermentation proceeded over 23 days. Among the five non-volatile organic acids identified, the levels of malic acid and citric acid were decreased during fermentation, while those of lactic acid, fumaric acid, and succinic acid were increased. There was a significant increase in lactic acid, succinic acid, malic acid, and citric acid contents during fermentation. The content of water soluble pectin(WSP) was higher than other pectins at the initial stages, but the content of WSP decreased as fermentation proceeded.

• Korean Journal of Fisheries and Aquatic Sciences
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• 제21권1호
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• pp.21-29
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• 1988

This study was carried out to develop the powdered Katsuobushi (a kind of boiled, smoked, and dried fish product which is used for seasoning soup as it is.) using skipjack as a natural flavoring substance. The processing conditions of the powdered Katsuobushi and the changes of taste compounds during processing of the products were examined. In preparation of the powdered Katsuobushl, frozen skipjack was thawed, beheaded, gutted, filleted and then sliced to 1cm of thickness. The silted meats were boiled in skipjack extract for 20 minutes, and then it was smoked for, 3 times to $10\~12\%$ moisture content at $80^{\circ}C$ for 8 hours. The smoked - dried meats were followed to be 50 mesh of particle size. The effect of slicing and boiling in skipjack meat extract on enhancing flavor and on preventing lipid oxidation of product during processing were observed. The moisture content and crude lipid content of the powdered Katsuobushi was in the range of 11 to $12\%$ and 4.3 to $4.8\%$, respectively. The taste compounds of the product were nucleotides and their related compounds, 1135.8mg/100g ; free amino acid and related compounds, 2210.2mg/100g ; non-volatile organic acids, 1148.0mg/100g ; and total creatinine. 592.1mg/100g on dry basis, and small amount of betaine and TMAO. The major elements of mineral in the product were found to be K, Mg, Na, and Ca. The content of IMP was 542.0mg/100g, and major free amino acids were found to be histidine, anserine, taurine, carnosine and alanine of which occupied to $83.6\%$ of total free amino acids. In non -volatile organic acids, major ones were lactic acid, succinic acid, pyroglutamic acid and $\alpha-ketoglutaric$ acid. From the results of the chemical experiments and sensory evaluation, we may conclude that the flavor of the product from present experiment is more desirable than that of conventional products although the processing time used were much shortened than that of conventional method, and it can be commercialized as a seasoning powder.

• Korean Journal of Food Science and Technology
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• 제34권4호
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• pp.666-672
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• 2002

Changes in chemical characteristic, microflora, and sensory evaluation of fish sauce extracted at an interval of one week from fermented solution were investigated. pH was reduced from 6.0 to 4.5, and trimethylamine oxide from 132.5 to 87.2 mg/100g during fermenting periods. Trimethylamine increased from 5.6 to 50.2 mg/100g, and volatile basic nitrogen from 48.3 to 232.5 mg/100g. Bacterial flora isolated from the fish sauce were 70% Lactobacillus sp. and 13% Bacillus sp. Among the free amino acids, alanine, glutamic acid, valine, and methionine contents constitute 40% of the total free amino acids. Major non-volatile organic acid of the fish sauce was lactic acid (76%). Sensory evaluation results of the fish sauce were higher than the traditional soybean sauce after 28 days of fermentation.

• Korean Journal of Food Science and Technology
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• 제14권1호
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• pp.6-10
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• 1982

To investigate the effect of organic acids on suppression of fishy odor, the change of the odor and the remaining amount of trimethyamine (TMA), selected as the representative component of fishy odor in clam pickle (15.5% NaCl) were examined by sensory evaluation and gas chromatography. The fishy odor linearly decreased as the amount of vinegar increased at ${\alpha}=0.01$, but there was no significant difference of fishness score for the changes of storage period and kinds of acid. Overall acceptability score was found to be the best when 8 ml vinegar added to 100g clam pickle. The remaining amount of TMA showed the tendency to decrease as the amount of acetic acid and storage time increased and kinds of acid were changed in order of acetic, malic and citric acid. However when $4\;{\mu}l/ml$ acetic acid (=8 ml vinegar/100g clam pickle) was added, the percentage of the remaining amount of TMA showed little decrease from about 95% for 72 hours of storage time. From the results of sensory evaluation and gas chromatography, it was considered that acids have the effect on suppression of fishy odor by producing non-volatile salts by combining with TMA chemically and that the effect of acids on suppression of fishy odor is mainly due to the masking effect at the concentration commonly used.

• Journal of Ginseng Research
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• 제27권2호
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• pp.72-77
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• 2003

The six-year old fresh ginseng collected at earlier October was stored for 10 weeks in the condition of 4$^{\circ}C$${\pm}$1$^{\circ}C$ and RH 87∼92%, and the chemical components were investigated in an interval oi one week by taking sample of it after making it to the freeze-dryed ginseng and the red ginseng. The total sugar content of the red ginseng was a little reduced as the period of storage elapsed, and the reducing sugar content was 1.48eic before it was stored and was increased to 23.33% after 10 weeks of storage. For the free sugar of the red ginseng, the content of the fructose was increased, bit the contents of the glucose and the sucrose were gradually decreased after it was a little increased. The content of the maltese was 6.62% before storage and it was gradually decreased. For the free sugar of the freeze-dryed ginseng, the contents of the fructose, the glucose and the sucrose were increased. Especially the content of the sucrose was 10.96% before it was stored and was a increased to 24.38% after 7 weeks of storage, and the content of maltose was not detected. The yield of water extract was a little high at 7-8 weeks of storage and the pH was a little high at 3-4 weeks of storage. The turbidity was not changed for the freeze-dryed ginseng but was decreased for the red ginseng The water non-soluble protein was not detected in the red ginseng, and for the freeze-dryed ginseng the water non-soluble protein was reduced and the water soluble protein was increased as the period of storage was elapsed. The contents of the phenolic compounds for the red ginseng and the freeze-dryed ginseng and have their peak values after 7 and 9 weeks of storage respectively, and the amount of phenolic compounds was larger for the red ginseng. For the content of the non-volatile organic acids, the content of the citric acid was decreased both for the red ginseng and the freeze-dryed ginseng, and the contents of the glut-matic acid and the pyruvic acid were very small for the freeze-dryed ginseng, but were detected in the red ginseng at a maximum value of 37 ${\mu}$g/g and 592 ${\mu}$g/g respectively.

• Korean Journal of Food Science and Technology
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• 제34권1호
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• pp.85-90
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• 2002

The changes in taste components of kanjang made with barley bran during fermentation time were examined. The pH was gradually decreased and total nitrogen content reached to 0.7% at 90 days fermentation. Five kinds of free sugars, three kinds of volatile organic acid, and eight kinds of non-volatile organic acid were detected. Lactic acid known as abundant component in kanjang was not detected in kanjang made with barley bran. The content of free amino acid was $422.9{\sim}803.6\;mg%$. Glutamic acid was most abundant component among the amino acids, followed by proline and phenylalanine. Essential amino acid content was revealed $34.3{\sim}37.3%$. Based on result of sensory evaluation, it was most comfortable to eat sample of fermentation $45{\sim}60$ days.

• Journal of the Korean Society of Food Science and Nutrition
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• 제38권5호
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• pp.594-600
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• 2009

Quality characteristics of white lotus leaf tea (LLT) fermented with or without mycelial Paecilomyces japonica were investigated. Extraction yield and browning index of hot water extract from non fermented and fermented LLTs were higher than those of ethanol extract (p<0.05). In all LLTs, nutritional components such as total free sugar, free amino acids and minerals of hot water extracts were higher than those of ethanol extracts except for total organic acids (p<0.05). Contents of total free sugar and organic acids were markedly increased through fermentation process of mycelial Paecilomyces japonica. in the same solvent extracts (p<0.05). Contents of most taste components of fermented LLT were increased by mycelial solid fermentation (p<0.05), but total free amino acids of two extracts were decreased in the range of $37.1{\sim}67.2%$ as compared to non-fermented LLT. Fifty-nine volatile compounds were identified by GC and GC-MS, including 11 aldehydes, 14 alcohols, 11 ketones, 11 hydrocarbones and 12 acids. Aldehyde and ketone compounds were more identified in fermented LLT than in non-fermented LLT being abundant alcohol compounds by simultaneous steam distillation and extraction. The most abundant compounds of LLT identified in this study were curcumene followed by 2,6-bis(1,1-dimethylethyl)-4-methyl-phenol and cyclohexen. Main compounds of fermented LLT were 2,6-bis(1,1-dimethylethyl)-4-methyl-phenol, butanoic acid, furfural, benzaldehyde, hexanoic acid and 2(3H)-furanone.

• Transactions of the Korean hydrogen and new energy society
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• 제22권6호
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• pp.765-771
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• 2011

This study was conducted to investigate the effect of heat treatment on the start-up performance for anaerobic hydrogen fermentation of food waste. The result showed that hydrogen production was $0.61{\pm}0.31$ mol $H_2$/mol hexose with heat-treatment of food waste at $70^{\circ}C$ for 60 min whereas it was $0.36{\pm}0.31$ mol $H_2$/mol hexose without heat-treatment of one. The heat treatment of food waste enhanced hydrogen yield due probably to the increase of hydrolysis as well as the decrease of non-hydrogen fermentation microorganisms. The removal efficiency of carbohydrate in reactors regardless of heat treatment of food waste maintained over 90%. The hydrogen conversion efficiency from food waste was 1.7-6.3% with heat-treatment whereas it was 0.7-4.5% without heat-treatment. At the time of switchover from batch to continuous operation, lactate concentration was high compared to the n-butyrate concentration in anaerobic hydrogen fermentation reactor without heat-treatment. Anaerobic hydrogen fermentation of food waste with heat treatment was stable in start-up periods because lactate concentration could be maintained at a relatively low compared to n-butyrate concentration due to the decrease of non-hydrogen fermentation microorganisms.

• Journal of the Korean Society of Food Science and Nutrition
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• 제24권1호
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• pp.141-146
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• 1995

The study was conducted for optimum fermenting conditions of Dongchimi(pony tailed chinese radish kimchi) in production of ion beverage. The changes of pH and total acidity were increased as the temperature increased. Non-volatile organic acids, such as lactic acid, citric acid, malic acid and succinic acid were produced in Dongchimi fermentation. The amount of lactic acid was increased higher, followed by citric acid and malic acid. However succininc acid was produced a little of amount at $0^{\circ}C$. Lactic acid producing bacteria number increased in initial period and then decreased in last period of fermentation. During lactic acid producing bacteria was increased, the amouont of lactic acid was increased. The flavor components were tentatively identified as methyl pentane, ethyl thioethene 2, 3-diazaindolizine, dimethyl disulfide. The optimum fermenting conditions of Dongchimi for production of ion beverage were 24~29 days at $0^{\circ}C$, 9~12dyas at $5^{\circ}C$ and 16~22days at $10^{\circ}C$, respectively.

• Korean Journal of Food Science and Technology
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• 제23권3호
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• pp.267-271
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• 1991

The chemical and organoleptic properties of dongchimi studied for their changes during fermentation at $4{\sim}35^{\circ}C$ in 7% NaCl solution with seasonings. It was found that pH decrease showed three variation points in its slope at about pH 5.2, 4.7 and 4.1 during fermentation. A negative linear relationship between total acidity and logarithmic value of pH was obtained. The slope of the relationship curve was increased as the fermentation temperature increased. The reducing sugar was increased until pH reached$4.0{\sim}4.2$ followed by a small decrease and its amount was lowered as the temperature increased from $4\;to\;25^{\circ}C$ The major nonvolatile organic acids were lactic and citric acids. The increase in lactic acid were more marked at $25^{\circ}C$ than at $4^{\circ}C$. As fermentation proceeded the fresh radish odor significantly decreased while sourness and yeast-moldy odor increased. The crispness of the radish decreased slightly during fermentation.