• Journal of the Korean Society of Food Science and Nutrition
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• v.20 no.6
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• pp.559-564
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• 1991

Three different fermentation methods of dongchimi, a Korean radish roots pickle, were compared with conventional method of brining in 7% NaCl solution at $25^{\circ}C$ in order to improve the storage stability. The methods studied were addition of KCI and $CaCl_2 into the hot ($90^{\circ}C$) salt solutin (method A), addition of salts mixture of phosphates (method B) and salts mixture of phosphates, nitrite and citrate (method C) into half fermented dongchimi solution (pH 4.5~4.7) prepared by the method A. It was found from results that the method B and C reduced the decreasing rate of pH very significantly by more than 2~2.5 folds, while total a measured higher values for the method B and C. Changes in hardness of dongchimi showed little diffeence to control. The concentration of reducing sugar in the first day dongchimi solution prepared by hot brining method was measured much higher than those of control which was followed by rapid decrease. Organoleptic comparion showed a clear effect of salts mixtures by receiving the significantly higher scores in fresh dongchimi flavor and lower values in yeast moldy and sour flavor for the method B and C when those were compared to control.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.7
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• pp.921-925
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• 2007

In order to optimize microbial safety and preservation in quality retention of rice flour, commercial hot-air dry (HT, 65/15 min) and microwave dry (MT, 700 watt/30 sec) treatments were developed, and in this study, natural microflora present in rice flour exposed to different storage temperature and periods were monitored. Changes in color (E) appeared to be less on the MT rice flour than on the rice flour. Effectiveness of the MT treatment showed reduction rates for total aerobic bacteria (2.62 log CFU/g), yeasts, and molds (0.37 log CFU/g). Total aerobic bacteria showed similar growth patterns of all the treatments during storage; however, the MT treatment inhibited the growth of this organism in rice flour. In conclusion, the MT treatment was found to be a suitable drying method to substitute the HT treatment in terms of quality of rice flour and microbial safety.

• Journal of the Korean Society of Food Science and Nutrition
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• v.21 no.1
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• pp.101-108
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• 1992

Changes were evaluated in chemical and textural properties of Jeung-pyun (fermented rice cake) altered by the particle size of rice flour, amount of added Tak-ju (Korean traditional unrefined liquor) and sucrose, fermentation time and temperature, and steaming time. Particle size of polished rice flour did not affect the volume expansion during fermentation of rice dough by Tak-ju. The maximum expanded volume was noted in the dough, containing 20% sucrose (rice flour vs sucrose = 5 : 1, w/w), fermented at $35^{\circ}C$ for 3 hours. Any volume expansion was not occurred in rice dough without sucrose. The highest value of reducing power and gelatinization degree were observed in the rice dough with Tak-ju (rice flour vs Tak-ju = 2 : 1, w/v), while the lowest blue value was revealed in that case. Steaming followed after fermentation made the smaller volume of bulk by $45{\sim}50%$ of the initial volume be showed just after fermentation. Jeung-pyun prepared under the conditions could give maximum expanded volume by fermentation showed the best overall quality by sensory and textual properties.

• Food Science and Preservation
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• v.20 no.4
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• pp.475-481
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• 2013

This study was performed in order to compare the changes in fruit quality and antioxidant activity depending on the ripeness degree of the banana flesh and peel (unripe, ripe, and over ripe) when stored at room temperature for 6 days. The moisture contents showed differences such as the significantly lower maturity in the over ripe fruit peel and the moisture content increase in the fruit flesh during ripening. During the maturity stage, the L and b values decreased, while the a value increased. During ripening, the titratable acidity (TA) decreased, while the soluble solids contents (SS), sugar acid ratio (SS/TA), total sugar, and reducing sugar contents increased, respectively. Also during ripening, the glucose and the fructose contents increased considerably, thus resulting in the decrease of the sucrose content. In addition, this study revealed that the phenolic substance, which was part of the fruit skin, showed more favorable reaction to radical ability than the fruit flesh. Furthermore, the DPPH, ABTS radical scavenging ability, and reducing power showed better reaction for the fruit skin than for the fruit flesh, and there was a significant increase in the antioxidative activity as a result of the higher levels of phenolic substance. Therefore, maturity played an important role in changing the chemical composition and physiological activity of a banana. The unripe peels could be used as antioxidant ingredients and they could also enhance the biological activity in the utilization of by-products.

• Food Science and Preservation
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• v.20 no.4
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• pp.539-545
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• 2013

Effects of RS4 type resistant corn starch on the quality characteristics of cookies were investigated by physicochemical, instrumental and sensory evaluation. The resistant starch was made by cross-linking of corn starch as following; corn starch slurry was annealed at pH 2.0 and $50^{\circ}C$ for 2 h followed by the cross-linking reaction. The cross-linking reaction was performed at $50^{\circ}C$ for 12 h in the presence of 1.2%/st.ds NaOH, 10%/st.ds sodium sulfate and 10%/st.ds of sodium trimetaphosphate (STMP)/sodium tripolyphosphate (STPP) mixture. Dietary fiber content of the resistant starch was estimated to be 73.8% by the AOAC method. For quality characteristics, dough pH decreased with the increase of the resistant starch content and spread factor decreased a little at 20% of the resistant starch. The moisture content and L value of cookies increased with the increase of the resistant starch content. However, the hardness and fracturability decreased with the increase of the resistant starch content. In the sensory evaluation, no significant differences were observed between the two cookies with or without the resistant starch. The results of this study suggest that the RS4 type resistant corn starch can be a good ingredient to increase dietary fiber content in cookies without changes of their qualities.

• Korean Journal of Food Science and Technology
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• v.20 no.2
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• pp.140-147
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• 1988

The pysicochemical and bacteriological properties of yogurts made by single or mixed cultures of L. bulgaricus FRI025 and S. thermophilus CHI were investigated. L. bulgaricus FRI025 which was isolated from raw milk was selected as starter culture among 22 strains of lactic culture by measuring viscosity, flavor, growth and acid production ability. The acid production and number of viable cell were increased by using L. bulgaricus FRI025 and S. thermophilus CHI together in ratio of apporximately 1:1. The pH, titratable acidity, viable cell number and viscosity of yogurt were 4.08, 1.14%, $2.5{\times}10^{10}/ml$ and 2100 cp after 9 hours incubation at $40^{\circ}C$, respectively. The pH and viable cell number were decreased on the other hand titratable acidity and viscosity were increased after 7 days of storage at $4^{\circ}C$. The changes of quality did not show significantly after storage. The selected starter was much higher than commercial yogurt starter in the acid production and growth of starter. The yogurt nanufactured with selected starter was better than with commercial yogurt in sensory evalution such as taste, texture, flavor and overall acceptability.

• Journal of the Korean Society of Food Culture
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• v.28 no.6
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• pp.664-673
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• 2013

This study was conducted to investigate the physicochemical properties of mung bean starch and the quality characteristics of mung bean starch gels supplemented with gelatin and isolated soy protein (0, 2, 5%) during storage at $5^{\circ}C$ for 0, 24, 48, and 72 hours. The swelling power of mung bean starch supplemented with gelatin did not significantly change, whereas those supplemented with isolated soy protein (ISP) significantly increased. The solubility of mung bean starch supplemented with gelatin and ISP, however, significantly increased with increasing concentration. In addition, the soluble amylose and soluble carbohydrate of mung bean starch supplemented with gelatin and ISP significantly decreased with increasing concentration. In terms of pasting properties measured by the Rapid Visco Analyzer (RVA), the pasting temperature of mung bean starch supplemented with gelatin and ISP was not significantly different, whereas peak viscosity, minimum viscosity, final viscosity, breakdown, and consistency decreased. DSC thermograms showed that the onset temperature of mung bean starch supplemented with gelatin and ISP did not significantly change, whereas the enthalpy increased with the addition of 5% ISP. The lightness (L) and redness (a) of mung bean starch gels supplemented with gelatin, ISP, and without additives increased during cold storage, whereas the yellowness (b) decreased. The addition of gelatin and ISP suppressed changes in L, a and b of mung bean starch gel during cold storage. Synereses of mung bean starch gel supplemented with gelatin and ISP was lower than that without additives, with the addition of gelatin suppressing synereses more than ISP. The addition of gelatin and ISP also suppressed increases in hardness, chewiness, and gumminess of mung bean starch gels during cold storage. In the sensory evaluation, the addition of gelatin and ISP suppressed increases in hardness and brittleness of mung bean starch gels during cold storage. The addition of 2%, 5% gelatin and 2% ISP also suppressed a decrease in the overall acceptability of mung bean starch gels during 24-48 hr cold storage. Thus, the addition of 2-5% gelatin and 2% ISP to mung bean starch is appropriate for suppressing the quality deterioration of 24-48 hr cold-stored mung bean starch gels.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.9
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• pp.1467-1474
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• 2013

To develop a starter culture system for the fermentation of mukeunji, we introduced lactic acid bacteria and yeast isolated from mukeunji into kimchi fermentation as a single or a mixed culture. On evaluating mukeunji flavor, we found that the mixed starter kimchi prepared with two strains, ML17 and MY7, gave the best sensory score. These strains were identified as Lactobacillus (Lb.) curvatus ML17 and Saccharomyces (S.) servazzii MY7 by molecular identification method. The fermentative characteristics of starter kimchi were investigated by measuring changes in the physicochemical and microfloral characteristics during the fermentation. The decrease in pH and increase in acidity in the starter kimchi were faster compared to respective values of control kimchi. There was a gradual decrease in hardness of starter kimchi, which was still slow compared to hardness decrease in control kimchi. Microbial analysis of starter kimchi revealed that Lb. curvatus ML17 and S. servazzii MY7 were the dominant organisms during the entire fermentation period. The lactic acid and citric acid contents of starter kimchi were higher than those of the control kimchi after 90 days of fermentation. By sensory evaluation, the starter kimchi scored higher in appearance, mukeunji flavor, sourness, carbonated flavor, savory taste, texture, and overall acceptability, but lower in off-flavor than the control kimchi.

• Korean Journal of Environmental Biology
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• v.31 no.4
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• pp.471-477
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• 2013

Biochar amendment to agricultural soil is regarded as a promising option to mitigate climate change and enhance soil quality. It could sequester more carbon within the soil system and increase plant yield by changing soil physicochemical characteristics. However, sustainable use of biochar requires comprehensive environmental assessment. In this sense, it is important to measure additional greenhouse gas emission from soils after biochar addition. We investigated emissions of $CO_2$, $N_2O$, and $CH_4$ from incubated soils collected from rice paddy and cultivated grassland after amendment of 3% biochar (wt.) produced from rice chaff. During incubation, soils were exposed to three wet-dry cycles ranging from 5~85% soil gravimetric water content (WC) to investigate the changes in effect of biochar when influenced by different water levels. The $CO_2$ emission was reduced in biochar treatment compared to the control at WC of 30~70% both in rice paddy and grassland soils. This indicates that biochar could function as a stabilizer for soil organic carbon and it can be effective in carbon sequestration. The $N_2O$ emission was also reduced from the grassland soil treated with biochar when WC was greater than 30% because the biochar treated soils had lower denitrification due to better aeration. In the rice paddy soil, biochar addition resulted in decrease in $N_2O$ emission when WC was greater than 70%, while an increase was noted when WC was between 30~70%. This increase might be related to the fact that available nutrients on biochar surface stimulated existing nitrifying bacterial community, resulting in higher $N_2O$ emission. Overall results imply that biochar amendment to agricultural soil can stabilize soil carbon from fast decomposition although attention should be paid to additional $N_2O$ emission when biochar addition is combined with the application of nitrogen fertilizer.

• Applied Biological Chemistry
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• v.50 no.1
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• pp.42-47
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• 2007

Effect of chlorine dioxide ($ClO_2$) treatment on the microbial and physicochemical changes of fish paste was investigated. Fish paste samples were treated with 5, 10, and 50 ppm of $ClO_2$ solution, respectively, After $ClO_2$ treatment, fish paste samples were individually packaged and stored at 4$^{\circ}C$. The initial microbial loads of samples were 3.8 log CFU/g in total bacterial count, and 2.5 log CFU/g in yeasts and molds. Microbial growth of fish paste during storage showed that populations of total bacteria, yeast and mold were significantly reduced by $ClO_2$ treatment. In particular, the treatment of 50 ppm $ClO_2$ decreased total bacterial count the most significantly among the $ClO_2$ treated fish pastes. The pH and VBN of fish paste decreased with increasing $ClO_2$ concentration. Thiobarbituric acid reacted substance (TBARS) values of treated fish paste increased during storage, regardless of $ClO_2$ concentration. This study showed that 50 ppm chloride dioxide was the optimum dose level to extend the shelf-life of fish paste.