• Korean journal of food and cookery science
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• v.16 no.1
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• pp.57-64
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• 2000

An optional ingredient, Gatt(Brassica juncea) was adopted to improve the quality of Dongchimi during fermentation. The final weight percentage of Gatt in Dongchimi was adjusted to 0, 3, 5, 10, or 15%, per radish. Sensory and microbiological characteristics were determined during fermentation at 10$^{\circ}C$ for 45 days. The effect was varied depending on the amounts of Gatt, but Dongchimi fermented with 5% Gatt was most favored for color, flavor, taste, and overall acceptability in sensory evaluation. According to the quantitative descriptive analysis for the product, the liquid portion of Dongchimi steadily became clearer and less sour in proportion to the amount of added Gatt. The fermentation retarding action of Gatt at the initial stage of Dongchimi fermentation was clearly seen as above. However, the addition of Gatt at above 15% of Chinese radish was not desirable due to the accelerated fermentation at the later stage. The general changing patterns in typical characteristics of fermentation including microbial counts were comparable with each other depending on the treatments. And favorable Dongchimi could be prepared by fermenting with 5% Gatt at the given condition.

• Korean journal of food and cookery science
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• v.21 no.1 s.85
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• pp.1-11
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• 2005

The application of Dongchimi liquid into Naengmyon broth for the improved eating quality of Naengmyon was scientifically explored by reviewing the quality properties of the product. Primarily, the optimum fermentation conditions for Dongchimi from which the liquid portion was extracted were pursued and the optimum mixing ratio was sought on the basis of sensory and microbiological properties of the product. The liquid portions which had been periodically extracted from Dongchimi at intervals of two or five days during fermentation at $10^{\circ}C$ were added to Naengmyon broth. The treatments were prepared with three levels, namely, basic broth only('A') and the ratios of 3:7(v/v, 'B') and 5:5(v/v, 'C') of Dongchimi liquid and basic broth, respectively. According to assessments of Dongchimi liquid on taste and intensity based on sensory analyses, the organoleptic factors such as color, smell, sour taste, carbonated taste, and overall acceptability were given higher values from day 11 to day 17 in all items. As for the assessment of Dongchimi liquid on intensity, color, sour odor, moldy odor, and carbonated taste have shown the increasing scores during with high intensities while those for clearness has stayed low. Most of the phenomena observed from the Naengmyon broth substituted with $30\%$ (Treatment 'A') and $50\%$ (Treatment 'B') of Dongchimi liquids with different storage periods ensued much of the previous fermentation pattern of Dongchimi itself. Organoleptic assessment on taste and its intensity showed that better(the best) scores could be obtained at between day 16$\~$25(17) and 13$\~$20(15) for Treatments A and B, respectively. The intensity scores of taste for color, smell, carbonated taste, sour taste, and mouthfeel were increased while those for clearness, palatability, and meaty ones were decreased with lapse of fermentation. The numbers of total cell and lactic acid bacterial counts of Dongchimi has increased until day 13 and then decreased in the later stages. Total cell count and lactic acid bacterial counts of Naengmyon broth also increased until the 13th day and then they began to decrease. It was also proven that slightly over-ripened Dongchimi liquid was more preferable for adding into Naengmyon broth. Granting the optimum ripening period of Dongchimi liquid itself to be 13 days, both Treatment A and Treatment B were evenly favored using Dongchimi liquids slightly over-ripened at days 13 to 17. However, Treatment A was more favored than Treatment B when Dongchimi liquid over-ripened for 20 to 26 days was used.

• Korean Journal of Food Science and Technology
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• v.26 no.5
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• pp.573-578
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• 1994

Dongchimi as a Korean traditional fermented food was studied for the possibility of developing into as an ion beverage. Reverse osmosis process was applied to the concentration of dongchimi juice in this study. Dongchimi was prepared at different concentrations of salt and fermentation temperatures. Mineral components of concentrated dongchimi juice were analyzed and compared with those of ion beverage products. The changes of sugar contents and mineral contents were studied depending on different fermentation temperatures, periods and salt concentration. The amounts of mineral components such as $K^{+},\;Mg^{2+}\;and\;Ca^{2+}$ were increased during fermentation but slightly decreased in the last period. It was found that the concentrated dongchimi juice could be used as an improved ion beverage in future, since the electrolytic dissociation components were much more in the concentrated dongchimi juice than those in the existing ion beverages.

• Korean journal of food and cookery science
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• v.20 no.6 s.84
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• pp.598-606
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• 2004

The application of Dongchimi liquid to Naengmyon broth to improve its eating quality was scientifically explored by reviewing the quality of the product properties. Primarily, the optimum fermentation conditions for Dongchimi from which the liquid portion was extracted were pursued and the optimum mixing ratio sought on the basis of the product physicochemical properties. The liquid portions, periodically extracted from Dongchimi at intervals of two or five days, during fermentation at $10^{\circ}C$, were added to Naengmyon broth. The treatments were prepared at three levels namely, basic broth only ('A') and with ratios of Dongchimi liquid to basic broth of 3:7 (v/v, 'B') and 5:5 (vfv, 'C'). As a typical phenomenon of kimchi fermentation, a gradual decrease in the pH with increasing total acidity was observed as the fermentation of the Dongchimi progressed. At $10^{\circ}C$, the optimum ripening was obtained from day 8, and continued until day 15, when the pH was maintained at about 3.8 to 4.0. The total vitamin C and reducing sugar contents increased until the 13th-day of fermentation, but then decreased thereafter. The turbidity and solid content of the Dongchimi liquid increased with progression of the fermentation. With respect to the color values, the lightness (L) decreased, with increases in the redness (a), yellowness (b) and total color difference $({\Delta}E)$ during fermentation. Most of these observed phenomena for the Naengmyon broth substituted with $30\%$ (Treatment 'A') and $50\%$ (Treatment 'B') Dongchimi liquid, with different storage periods, confirmed the previous fermentation patterns of Dongchimi. A decrease in the pH with increasing total acidity, as well as gradual increases in the total vitamin C and reducing sugars (glucose and fructose) up to the 13th-day of fermentation were accompanied by subsequent declining patterns. The turbidity and solid content of the mixed broth also increased with increasing Dongchimi liquid fermentation period. With respect to the color of the mixed broth, the lightness was decreased, while the redness, yellowness and total color difference increased with increasing Dongchimi liquid fermentation period. It was also proven that the addition of slightly over-ripened Dongchimi liquid to the Naengmyon broth was more preferable.

• Korean journal of food and cookery science
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• v.16 no.6
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• pp.557-567
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• 2000

An optional ingredient, jasoja(Perillae semen), was adopted to improve the quality of Dongchimi. The final weight percentage of jasoja in Dongchimi was adjusted to 0, 0.25, 0.5, 0.75, or 1.0%, per radish, and sensory and microbiological characteristics were determined during fermentation at 10 for 45 days. The effect was varied depending on the amounts of jasoja, but Dongchimi fermented with 0.5% jasoja was most favored for color, flavor, taste, texture, and overall acceptability in sensory evaluation. According to a quantitative descriptive analysis for the product, the liquid portion of Dongchimi steadily became clearer and less sour in proportion to the amount of added jasoja. However, a strong off-taste was detected from 1.0% treatment. The viable cell numbers of total and lactic acid bacteria drastically increased during the first 2 days, and then gradually increased to their maximum values during fermentation and slowly decreased at the later stage. Dongchimi with 0.5% treatment showed a distinctive high number of microorganisms at the 15th-day of fermentation and this trend was maintained until the completion of fermentation. The lactic acid bacteria isolated and identified from Dongchimi were; Lactobacillus brevis, Lactobacillus plantarum, Leuconostoc mesenteroides, Lactococcus faecalis, and Lactococcus lactis. The combined number of Lactobacillus brevis and Lactobacillus plantarum began to increase right after preparation to as much as 10$\^$7/CFU/㎖, then decreased to 10-10$^3$CFU/㎖ afterward. This study showed that the addition of jasoja retarded the initial fermentation of Dongchimi; however, too much jasoja at above 1% weight level per Chinese radish might accelerate fermentation at the later fermentation stage and shoud be avoided. A comparable fermentation pattern was observed among the samples; however, more acceptable Dongchimi could be prepared by fermenting for 11 to 30 days at 0.5% jasoja concentration per radish.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.6
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• pp.1021-1027
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• 1997

$CO_2$production in fermentation of dongchimi was measured and interrelated with changes in pH and titratable acidity. The effects of salt content and temperature on $CO_2$production rate were analysed. Fermentation of dongchimi showed drastic pH decrease in early stage and subsequent levelling off around 3.9, with linearly increased acidity up to 0.3~0.4% optimum quality. $CO_2$production of dongchimi could be analysed to consist of two consecutive stages of constant rate. The first stage $CO_2$production of higher rate moved to the second stage of lower rate when acidity rose beyond 0.3%. When compared to those of 1 and 2% salt content, dongchimi of 3% salt showed lower $CO_2$production rate in the 1st stage and slower acidity change through the whole fermentation period. However, it resulted in the product of highest $CO_2$accumulation at optimal ripeness because of consistent $CO_2$production of longer 1st stage period and relatively high $CO_2$production rate in 2nd stage. $CO_2$production depended on temperature less compared to acidity change(activation energy: 57.3 and 44.3kJ/mol for $CO_2$production of 1st and 2nd stages, respectively; 79.3kJ/mol for acidity change), which means higher ratio of $CO_2$production rate relative to acidity increase at lower temperature. Slower increase in acidity at low temperature also was shown to extend the period of 1st stage $CO_2$production. Therefore, low temperature fermentation was effective in producing the high $CO_2$content dongchimi at adequate acidity, which is desirable organoleptically.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.2
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• pp.392-398
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• 2004

The application of Dongchimi added with Wasabi for the improvement of quality was scientifically explored by reviewing the optimum level and its effect on the physicochemical property of product of fermentation. The final weight percentage of Wasabi in Dongchimi was adjusted to 0, 3, 5, 7 and 9%, per radish, each respectively. Following the fermentation of Dongchimi, the 7% treatment contained the highest pH and the lowest total acidity. The total vitamin C and reducing sugar content increased initially to the certain time of fermentation depending on the level of Wasabi, and the 7% treatment decreased later. The optimum levels of Wasabi in Dongchimi obtained through experiments were 5% and 7% per added radish weight, preferably 7% for fermentation-retarding effect of the product.

• The Korean Journal of Community Living Science
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• v.15 no.4
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• pp.3-10
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• 2004

The physicochemical and microbiological studies were conducted to examine the effect of Prunus mume extract on the Dongchimi fermentation. Dongchimi with the addition of various levels (0, 0.05, 01, 0.2 or 0.3%) of Prunus mume extract was fermented at $10^{\circ}C$ for 30 days. The pH of the product decreased in the course of fermentation and it was between 3.8~4.2 at 6~8 days fermentation. Total acidity was decreased by the addition of Prunus mume extract. A more rapid decrease in pH and an increase in total acidity were observed in the control Dongchimi than in that with added Prunus mume extract. The content of vitamin C increased for up to 10 days of fermentation and then gradually decreased. Reducing sugar content increased for up to 10 days, and the highest of sugar content was shown in the Dongchimi with 0.3% of added Prunus mume extract. As Prunus mume extract levels increased, the total viable cell number and the Lactobacillus cell number decreased. Dongchitni in which Prunus mume extract was added gained it,j optimum taste after 10 days of fermentation. The results of this study indicate that Prunus mume extract causes a delay in the fermentation of Dongchimi by slowing down pH drop and inhibiting the Lactobacillus cell growth.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.8
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• pp.1057-1063
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• 2006

The Dongchimi added with Wasabi (Wasabia japonica Matsum) for the improvement of quality was scientifically explored by reviewing the optimum level and its effect on the microbiological and sensory characteristics of product fermentation. The final weight percentage of Wasabi in Dongchimi was adjusted to 0, 3, 5, 7 and 9%, per radish, respectively. Microbiological and sensory characteristics were determined during fermentation at $10^{\circ}C$ for 55 days. The viable cell counts of total and lactic acid bacteria had increased to their maximum values during fermentation until they began to drop at the later stage. Here, the 7% treatment showed a distinctive low and high numbers of total cells and lactic acid bacteria, respectively, during the later stage of fermentation. As for the sensory evaluation results of the fermented Donchimi with Wasabi, the 7% treatment was most favored for the color, the smell, the sour taste, the hot taste, the carbonated taste, the texture, and the overall acceptability of the products. The optimum levels of Wasabi in Dongchimi were estimated between 5 and 7% per added radish weight, and the 7% level was more preferred when the fermentation-retarding effect of the product was considered.

• Korean journal of food and cookery science
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• v.20 no.1
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• pp.42-48
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• 2004

The effect of xylitol on the Dongchimi fermentation was investigated by measuring the sensory, physicochemical and microbiological properties during fermentation of up to 30 days. Dongchimi with 0, 1, 2, 3 and 4％ w/v xylitol was fermented at 10$^{\circ}C$. The addition of 1％ xylitol gave the highest scores in terms of the overall acceptability, texture, ripeness, sweet taste and smell. During the fermentation, the total acidity increased, while the pH gradually decreased. The reducing sugars showed the highest content with the addition of 1％ xylitol. The vitamin C was increased in the early stage of fermentation, but reduced gradually after 5 days. The vitamin C content of the Dongchimi with 2％ xylitol addition was shown to be the highest. The total viable cells and lactic acid bacteria increased between 2 and 5 days of fermentation, but were gradually reduced thereafter. The numbers of lactic acid bacteria with 1％ xylitol addition were more numerous than with the other percentage additions. The current study showed that the application of 1％ xylitol to the fermentation of Dongchimi enhanced the sensory values of the fermented product.