• Korean Journal of Food Science and Technology
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• v.46 no.6
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• pp.710-715
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• 2014

To date, the quality and safety of frozen bokbunja have not been clearly assessed. To produce high-quality frozen bokbunja, the optimal freeze-thaw conditions need to be explored. The most popular cultivar (Rubus occidentalis) in Korea was selected for this study. To determine the changes in the quality of frozen R. occidentalis berries, different freezing temperatures were used. The berries were frozen at -20, -45, and $-70^{\circ}C$ immediately after harvest. The drip ratio, hardness, pH, sugar content, color, and anthocyanidin content of the frozen and thawed samples were analyzed. The drip ratio, sugar content, and hardness of the berries correlated significantly with the freezing temperatures. The color and pH of the berries were not significantly affected by the freezing conditions. Frozen leaks between cells reduced significantly with decreasing temperatures. The freeze-thawing process significantly reduced the total aerobic bacteria and inhibited the growth of yeast/mold in the berries to about 2 log scales.

• Korean Journal of Food Science and Technology
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• v.21 no.1
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• pp.109-119
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• 1989

To improve the storage method of Kimchi, optimum ripening Kimchi for an irradiation treatment(the time of around 0.3% in total acidity of Kimchi) was irradiated by doses of 1, 2, 3 kGy with Co-60 ${\gamma}-radiation$ and stored at $10^{\circ}C$. Total aerobic bacteria increased in the beginning of storage and then decrease slowly as the number of total lactic acid bacteria increased. Total lactic acid bacteria initially loaded by $10^8\;cells/ml$ in Kimchi shortly after irradiation reduced to $10^4-10^6\;cells/ml$ with 1-3 kGy doses and decreased gradually through the whole storage period. The initial load of yeast, $10^3\;cells/ml$, increased steadily during Kimchi storage and led to more than $10^4\;cells/ml$ after 30 days of storage. While it maintained tha the load in 2-3 kGy irradiated groups after 30 days of storage was less than that at the beginning of storage. pH, acidity and volatile acid in the nonirradiated group were 4.0, 0.7% and 0.06%, respectively at the 15th day after storage, but at the 30th day after storage, 2-3 kGy irradiated groups showed different values, 4.1, 0.58-0.63%, and 0.04-0.05%, respectively. The texture(firmness) of Kimchi reduced along with storage time, and 2 kGy irradiated group proved most favourable in its texture during storage. In the sensory evaluation of Kimchi, nonirradiated group was inedible after 15 days of storage, whereas 2-3 kGy irradiated groups could proling the storage-life of Kimchi over 2 times compared with the nonirradiated Kimchi, showing the good sensory quality even after 30 days of storage.

• Food Science and Preservation
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• v.22 no.3
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• pp.408-420
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• 2015

This study investigated the effect of heat treatment conditions on the quality and antioxidant activities of Korean traditional actinidia (Actinidia arguta) cultivars puree. Heat treatment on actinidia puree was conducted at $70{\sim}90^{\circ}C$ for 1 min to 5 mins, while a control sample of the actinidia puree was prepared without heat treatment. In all the samples, except for the sample treated at $90^{\circ}C$ for 5 mins, pH and Brix degree was not dramatically changed. Pulp content decreased with increasing temperature and time. L and the a value of color increased with increasing temperature and time. However, the b value showed a reverse tendency with L and the a value. Viscosity and gumminess increased as heat temperature and time increased, though cohesiveness was not significantly changed depending on temperature and time. Coliform and yeast were not detected on all samples and the number of aerobic bacteria and mold decreased as temperature and time increased. Vitamin C and total phenolic content of the puree was not changed for 1, 3, and 5 mins at $70^{\circ}C$ and for 1 and 3 mins at $80^{\circ}C$, but significantly decreased with increasing time at $90^{\circ}C$. Furthermore, the antioxidant activities of the puree, such as DPPH radical scavenging activity, ABTS radical scavenging activity, and FRAP (ferric reducing antioxidant power) showed a similar tendency with total phenolic content.

• Food Science and Preservation
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• v.24 no.2
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• pp.221-229
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• 2017

The effect of sweet potato on the quality of Doenjang was investigated during fermentation. Viable cells of yeast decreased gradually after 4 weeks of fermentation, but those of aerobic bacteria increased in the late stage. Amylase activity of Doenjang was higher in the late stage of fermentation, while neutral protease maintained high activity during fermentation. Hunter L and b values of Doenjang decreased gradually during fermentation, while a value was increased. The pH of Doenjang decreased gradually until 10 weeks of fermentation, and the titratable acidity was low in the sweet potato added groups. The acid value was low in the Shinyulmi sweet potato added Doenjang. Water activity and oxidation-reduction potential of Doenjang decreased during fermentation. Reducing sugar of Doenjang decreased in the middle stage of fermentation, and it was low in sweet potato added groups. The alcohol content of Doenjang decreased after 2 weeks of fermentation. Amino and ammonia-type nitrogen of Doenjang increased during fermentation and reached the maximum after 10 and 12 weeks of fermentation, respectively. After 12 weeks fermentation, 8% of Shinyulmi sweet potato added Doenjang was more favorable taste, flavor and overall acceptability (p<0.05) than the control or the Yeonwhangmi sweet potato added groups.

• Food Science and Preservation
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• v.21 no.5
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• pp.652-660
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• 2014

To maintain the microbiological safety of Prunus mume fruit before it is processed, it was treated with a combination of 0.5% citric acid and 0.1% Tween 20, and stored at $4{\pm}1^{\circ}C$ for seven days. The combined treatment reduced total aerobic bacteria, yeast, and mold populations in the fruit by 2.20 and 1.70 log CFU/g, respectively, compared to those in the control. Organic acid contents and the Hunter $L^*$, $a^*$, and $b^*$ values were not affected by the treatment during the storage. In addition, the dried Prunus mume fruit prepared with 40% red algae extract (RAE) or maltodextrin (MD) treatment and hot-air drying were compared with respect to the fruit's physicochemical properties such as color, total phenolic and flavonoid content, and microstructure. The hot-air dried samples had undesirable color changes and inferior textures. The RAE-treated samples had a higher total phenolic content (225.15 mg gallic acid equivalent (GAE)/100 g) and total flavonoid content (49.25 mg quercetin equivalent (QE)/100 g) than the other treatments. The treatment of Prunus mume fruit with RAE can provide better-dried products than can MD treatment or hot-air drying. These results suggest that the combined treatment with citric acid and Tween 20 can be effective in preserving the microbiological safety of Prunus mume fruit, and its dehydration using RAE is an efficient drying method.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.7
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• pp.1072-1078
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• 2015

To maintain high quality and microbiological safety of paprika during storage for export, paprika samples after harvest were treated with 75 ppmv chlorine dioxide ($ClO_2$) gas and stored at $8^{\circ}C$, which is the optimal storage temperature, for 30 days. $ClO_2$ gas treatment reduced initial populations of total aerobic bacteria in samples by 1.62 log CFU/g as well as yeast and molds by 1.45 log CFU/g compared to those of the control. During storage, weight loss of all samples increased, and samples treated with $ClO_2$ gas showed lower weight loss than the control. In addition, total soluble solid and total phenolic contents were not significantly different between the samples during storage, whereas vitamin C content and hardness of all samples decreased. Hunter L, a, and b values of paprika samples were not significantly different between the treatments. These results suggest that $ClO_2$ gas treatment can be effective for improving microbiological safety and maintaining high quality of paprika during storage.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.11
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• pp.1715-1724
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• 2015

The combined effects of a sanitizer mixture solution and antimicrobial ice on the quality of salted Chinese cabbages were examined. Salted Chinese cabbages were treated with a sanitizer mixture (comprised 50 ppm aqueous $ClO_2$ and 0.5% citric acid), packed in 2% brine and antimicrobial ice, and stored for 12 days at 4 and $10^{\circ}C$. Microbiological data on the salted Chinese cabbages after washing with the sanitizer mixture indicated that the populations of total aerobic bacteria, and yeast and molds decreased by 2.20 and 1.28 log CFU/g after treatment with the sanitizer mixture. In addition, coliforms population of salted Chinese cabbage after 12 days storage at $4^{\circ}C$ in the combined mixture of the sanitizer and antimicrobial ice was 3.22 log CFU/g, which was a significantly different from that of control (5.46 log CFU/g). The combined treatment of sanitizer mixture, antimicrobial ice, and low temperature at $4^{\circ}C$ suppressed reduction of pH and elevation of titratable acidity, resulting in delaying the growth of lactic acid bacteria. Differences in salinity, hardness, and Hunter's $L^*$, $a^*$, and $b^*$ values among treatments were negligible during storage at $4^{\circ}C$. Therefore, this study suggests that a combination of sanitizer mixture, antimicrobial ice treatment, and low temperature storage could improve the microbial safety and quality of salted Chinese cabbages during storage.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.9
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• pp.1292-1299
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• 2011

This research aimed to determine the quality characteristics of kochujang made of sword bean chunggukjang. The effects of chunggukjang addition were compared in products fermented for 90 days. During the fermentation period of kochujang, sword bean chunggukjang was added at 0, 2, 5, 8, and 10%. The moisture content ranged from 40.24 to 42.83% (w/w). After 90 days of fermentation, sodium chloride was at around 10.2 to 10.3%, which was not much different from that of control kochujang (SBC 0) before and after fermentation. The color values were not significantly different between SBC kochujang and traditional kochujang. The microbial counts in 0, 2, 5, 8, and 10% SBC kochujang fermented for 90 days were around $5.42{\times}10^7$ to $9.59{\times}10^7$ CFU/g for aerobic viable cells, $1.14{\times}10^2$ to $9.73{\times}10^2$ CFU/g for yeast, and $8.49{\times}10^2$ to $1.25{\times}10^3$ CFU/g for Bacillus cereus. Sensory evaluation of kochujang showed that the comprehensive preference was 5.40, 5.15, 6.30, 6.10, and 6.95, respectively, for SBC 0, 2, 5, 8, and 10%. In conclusion, the quality difference between SBC and traditional kochujang was not significant, and sensory evaluation of kochujang showed that SBC 10% received the highest score.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.4
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• pp.450-458
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• 2017

In this study, the antimicrobial activity of black garlic pomace extract (BGPE) was examined, and its washing applicability to spinach was investigated. BGPE had antimicrobial activity against both Gram-positive (Listeria monocytogenes and Staphylococcus aureus) and Gram-negative (Escherichia coli O157:H7 and Salmonella Typhimurium) food-borne pathogens. In particular, antimicrobial activities of BGPE against Gram-positive bacteria were higher than those against Gram-negative bacteria. Spinach samples were treated with 0.5% BGPE to determine the effect of BGPE on reducing naturally existing microorganisms on the surface of spinach leaves. BGPE treatment reduced populations of total aerobic bacteria and yeast/molds in spinach by 1.23~1.35 log CFU/g and 0.82~1.12 log CFU/g during 9 days of storage, respectively, compared with those of control samples. After treatment, there were no significant differences in color quality such as Hunter L, a, and b values and total color difference (${\Delta}E$). These results clearly indicate that BGPE treatment can be useful for improving microbiological safety and maintaining color quality of spinach during storage.

• Journal of Dental Rehabilitation and Applied Science
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• v.31 no.3
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• pp.212-220
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• 2015

Purpose: Candida albicans can cause mucosal disease in many vulnerable patients. Also they are associated with denture-related stomatitis. Electrolyzed water is generated by electric current passed via water using various metal electrodes and has antimicrobial activity. The aim of this study was to investigate antifungal activity of electrolyzed water on C. albicans biofilm. Materials and Methods: C. albicans was cultured by sabouraud dextrose broth and F-12 nutrient medium in aerobic and 5% $CO_2$ condition to form blastoconidia (yeast) and hyphae type, respectively. For formation of C. albicans biofilm, C. albicans was cultivated on rough surface 6-well plate by using F-12 nutrient medium in $CO_2$ incubator for 48 hr. After electrolyzing tap water using various metal electrodes, the blastoconidia and hyphal type of C. albicans were treated with electrolyzed water. C. albicans formed blastoconidia and hyphae type when they were cultured by sabouraud dextrose broth and F-12 nutrient medium, respectively. Results: The electrolyzed water using palladium electrode (EWP) exhibited antifungal effect on blastoconidia of C. albicans. Also, the EWP significantly has antifungal activity against C. albicans biofilm and hyphae. In the electrolyzed water using various metal electrodes, only the EWP have antifungal activity. Conclusion: The EWP may use a gargle solution and a soaking solution for prevention of oral candidiasis and denture-related stomatitis due to antifungal activity.