• Preventive Nutrition and Food Science
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• v.1 no.1
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• pp.46-52
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• 1996

Effective method for the preparation of Dongchimi juice was developed by addition of NaCi, sucrose and bydrolytic enzymes before fermentation and addition on Dongchimi juice during fermentation. The radish was ground and suspended in water(1:1, w/v) with addition of spices(garlic, green onion and ginger) followed by fermentation at $25^{\circ}C$. The addition of 2% NaCi and 0.5~2.0% sucrose resulted in significant increase of solid content and it was also improved by the addition of polysaccharide hydrolyzing enzyme during fermentation. When the fermented juices of pH 5.4 of 4.4 were added by 15% of total weight before(pH 5.4 juice)and during (pH 4.4 juice) fermentation, a significant increase in solid content after 24hrs of fermentation was resulted. The combined method of addition of 2% NaCI, 1.0% sucrode, 0.1% Viscozyme and 10% of fermented juice of pH 5.4 and 4.$ before and during fermentation improved solid content, reducing sugar, color and showed little effect on viscosity. The organoleptic characteristics were also improved by the combined method.

• 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.

• The Korean Journal of Food And Nutrition
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• v.12 no.1
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• pp.77-84
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• 1999

The purpose of this study is to establish a rapid preparation method of Dongchimi-juice having favor-able flavor and high antibacterial activity against undesirable bacteria in Naengmyon-broth by using high antibacterial strains of lactic acid bacteria Lactobacillus homohiochii B21 and leuconostoc mesenteroid-es subsp. mesenteroides C16 as Dongchimi starter. When the two strains of lactic acid bacteria were used as starter mixed culture was better than single culture in acid production and antibacterial activity. When starter was not inoculated in Dongchimi fermentation the numbers of Gram negatives and colifor-ms were remarkably increased in early phase and antibacterial activity could scarcely be detected. But when starter was inoculated the numbers of Gram negatives and coliforms were sharply decreased from early phase and antibacterial ctivity was high. When Dongchimi was made with heat sterilized mat-erials and starter there were no Gram negatives and coliforms and antibacterial activity was high. The antibacterial activity of starter inoculated Dongchimi was maximum in 2 days of fermentation at 2$0^{\circ}C$ and was scarcely detected in six days. In consideration of coliform counts antibacterial activity and the flavor of Dongchimi the preparation method in which all materials were heat treated at 8$0^{\circ}C$ for 15 min-utes and inoculated with mixed starter of the two strains and fermented for 2 days at 2$0^{\circ}C$ was thoug-ht to be good.

• Korean journal of food and cookery science
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• v.17 no.4
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• pp.338-343
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• 2001

This study was carried out to analyze the characteristics of Dongchimi(watery radish kimchi) juice while fermenting the samples prepared at various salt concentrations(2, 2.5, and 3 %) and fermentation temperatures(4$^{\circ}C$, 12$^{\circ}C$, and 12$^{\circ}C$ for 12 hr followed by 4$^{\circ}C$). The changes in colour, total vitamin C and free sugar contents were analyzed, and sensory evaluation was performed. As the fermentation proceeded, the “L” value was decreased and “a” and “b” values were increased in all samples. Total vitamin C contents increased up to 26-33 days and decreased thereafter in the samples fermented at 4$^{\circ}C$ and those fermented at 12$^{\circ}C$ followed by 4$^{\circ}C$. In Dongchimi fermented at 12$^{\circ}C$, vitamin C contents increased up to 12-15 days. Glucose, fructose and sucrose were detected in Dongchimi juice. The total content of free sugars in Dongchimi juice was the highest in the samples fermented at 12$^{\circ}C$ followed by 4$^{\circ}C$ . Sensory evaluation was performed for sour taste, salty taste, carbonated flavor, offensive odor, overall preference and clearance of the juice. In overall preference, Dongchimi juice fermented at 12$^{\circ}C$ followed by 4$^{\circ}C$ was the best.

• Korean Journal of Food Science and Technology
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• v.31 no.6
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• pp.1596-1603
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• 1999

Dongchimi (Korean-style fermented radish with juice) products were frozen to prevent further acidification and softening of texture by restraining microbial growth and enzyme activity during storage. Dongchimi juice and radish were separated prior to freezing process. Dongchimi radish was frozen at $-20^{\circ}C,\;-70^{\circ}C$ and immersed in liquid nitrogen and dongchimi juice was frozen at $-20^{\circ}C\;and\;-70^{\circ}C$. Frozen dongchimi samples were thawed with ambient temperatures of $4^{\circ}C\;and\;27^{\circ}C$ and with 915 MHz-microwave, respectively. Dongchimi radish immersed in liquid nitrogen and thawed with 915 MHz-microwave showed the highest pectinesterase activity and hardness, and the lowest polygalacturonase activity and color change, indicating that this quick freezing-quick thawing method can be used for the long-term storage of dongchimi products. Dongchimi juice frozen at $-70^{\circ}C$ and thawed with 915 MHz-microwave retained its pH and titrable acidity, and showed a largest reduction in total aerobic count and lactic acid bacteria.

• Korean journal of food and cookery science
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• v.11 no.2
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• pp.113-118
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• 1995

A preferable mixing ratio of a six-vegetable juice was suggested in this study. The vegetables used for preparation of mixed vegetable juice were carrot(Ct), cabbage(Cg), pear(Pr), cucumber(Cr), celery (Cy) and dongchimi(Di). The characteristics of pH, titratible acidity, reducing sugar, turbidity, solids, color and acceptability were compared to determine the mixing ratio. The vegetables showed a wide ranHe of pH of 3.70-6.01, acidity of 28.92 uv~74.40 nd and reducing sugar of 1.20ft~ 12.69fo. Celery juice showed the higest suspension stability and "b" value and the lowest values in Hunter "L" and "a" values among the 6 vegetable juice. The preferable mixing ratio of two-vegetable juice selected were Ct-Di(1 : 4), Cg-Pr(1 : 3) and Cr-Cy(3 : 1). From the various ratio of the three of biary mixtures of Cg-Pr(1 : 3): Ct-Di(1 : 4): Cr-Sy(3 : 1), two ratio of 5.0 : 2.5 2.5(V-6A) and 6.0 : 2.0 : 2.0(V-6B) were suggested as the most prefered six-vegetable juice. Pear, dongchimi and cucumber were found to be influential on the preference. The pH and titratible acidity of the two juices with different ratios were in the range of 4.92~4.98 and 36.g∼37.4 ml, respectively.

• Korean journal of food and cookery science
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• v.13 no.5
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• pp.578-584
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• 1997

Fermentation temperature and salt concentration of Dongchimi were studied for the development of low salt Dongchimi juice. The juice was prepared by soaking the radish in brine solution of 0.3∼3.0% and fermented at the temperature range of 10∼30$^{\circ}C$. The fermentation proceeded faster at higher temperature. However, the salt concentration effect was dependent on the temperature. Fermentation in 3.0% NaCl solution resulted the fastest reach to pH 3.8 followed by 0.5% NaCl at 10 and 20$^{\circ}C$, while higher NaCl concentration caused a decrease in the fermentation rate at 30$^{\circ}C$. Comparison of flavor of the juice of pH 3.9 showed that fresh sourness was high in the juice prepared at 20$^{\circ}C$ and in 0.5% NaCl. The preference test also showed the juice of pH 3.8∼4.0 fermented in 0.5% NaCl at 20$^{\circ}C$ to be the most preferable one. The salt concentration lower than 0.5% at 20$^{\circ}C$ resulted in faster fermentation and high values in turbidity. However 0.5% NaCl was scored high in flavor acceptability.

• Korean journal of food and cookery science
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• v.20 no.1
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• pp.86-94
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• 2004

The purpose of this study was to investigate the changes of hardness and microstructure of Dongchimi cooked with various source of water(distilled water, purified water, Cho Jung Carbonated Natural water). This study was conducted to observe the changes of pH, total acidity, salt content, turbidity, texture and microstructure. Dongchimi cooked with source of water of water was fermented at 10$^{\circ}C$ for 46 days. The changes of pH on Dongchimi cooked with various source of water decreased in all samples during fermentation period, and then showed a slowly decrease after 12 days of fermentation. The total acidity of Dongchimi cooked with Cho Jung Carbonated Natural water was arrived slowly at best tasting condition 0.3 ∼ 0.4 point compared with other conditions. So Dongchimi cooked with Cho Jung Carbonated Natural water was continued to the best tasting condition for end of fermentation. At early stage of fermentation, the changes of turbidity of Dongchimi used Cho Jung Carbonated Natural water showed highly as compared with other test condition for 12th days of fermentation. The maximum cutting force of chinese radish of Dongchimi showed the highest value among all at the 25th day of ripening and then decreased gradually. The maximum cutting force of chinese radish of Dongchimi used Cho Jung Carbonated Natural water was the highest compared with other conditions at 25th day of fermentation. The calcium content of Dongchimi juice used Cho Jung Carbonated Natural water was observed hish at the early stage of fermentation and showed the highest value at 25th day of ripening. The calcium content of chinese radish and Dongchimi juice of Dongchimi cooked with water purifier was lower than that of Dongchimi cooked with Cho Jung Carbonated Natural water, and was higher than that of Dongchimi cooked with Distilled water at the early stage of fermentation. The magnesium content in all samples increased gradually from the early stage of fermentation. The microstructure showed disintegration appearance of middle lamella and cell wall during fermentation period.

• Korean Journal of Food Science and Technology
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• v.29 no.4
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• pp.730-736
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• 1997

Pasteurization of low salt dongchimi juice was studied for the effect of heating temperature and time on total viable counts and some physicochemical and sensory properties. The juice was prepared by fermentation of the radish at $20^{\circ}C$ in 0.5% NaCl solution. Heating the juice (pH 3.8) at $60{\sim}100^{\circ}C\;for\;5{\sim}30$ min caused little changes in pH and total acidity while the lightness (L value) was decreased and the turbidity, a and b values of color were increased as the heating temperature and time increased. The total viable counts of microorganisms was significantly decreased to 18 at $60^{\circ}C$ and 6 at $70^{\circ}C$ after 30 min heating and was not detected after heating at 90 and $100^{\circ}C$ for 10 min. The sensory test showed that heating up to $70^{\circ}C$ for 20 min caused a little cooked off-flavor. After storage of the pasteurized juices at $30^{\circ}C$ for 10 days, the pH, total acidity and color were changed little while the unheated juice changed significantly. The total viable counts of microorganisms was also remained initial level after pasteurization. Therefore pasteurization at $60^{\circ}C$ for 30 min or $70^{\circ}C$ for 20 min was recommendable in the aspects of storage stability and quality characteristics.

• Food Science and Preservation
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• v.6 no.4
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• pp.456-462
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• 1999

The radish juice inoculated with mixed culture of Leuconostoc mesenteroides and Lactobacillus brevis was fermented and stored. Radish juice was heat-treated for 30 min at 65$^{\circ}C$ and 15 min at 80$^{\circ}C$, and stored for 8 weeks at 25$^{\circ}C$, 15$^{\circ}C$, and 5$^{\circ}C$, respectively. When the radish juice was heat-treated, any bacteria were not detected and any quality changes were not occured. On the other hand non-heated radish Juice, pH was decreased and acidity was increased during storage. The turbidity of the heat-treated radish juice was higher than that of the non-heated juice when it stored at 5'E. From the sensory evaluation, the pasteurization condition of 15 min at 80$^{\circ}C$ was not appropriate because the fresh smell of Dongchimi was decreased and the cooked smell was increased. The radish juice stored at 5$^{\circ}C$ without heat-treatment was evaluated to have the best quality. The storage period of the non-heated radish juice was shown to be extended over 8 weeks at 5$^{\circ}C$.