• Applied Chemistry for Engineering
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• v.8 no.4
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• pp.575-581
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• 1997

UDs were synthesized from two different polyols(PTMG, PBEAG), ionic chain extender(DMPA), EDA with $H_{12}-MDI$. PU/PMMA hybrids were prepared with free radical polymerization of MMA monomer in MMA-swelled PUD. PUD particle size and film properties were investigated ionic content and polyol type. Mechanical and thermal properties of PU/PMMA hybrid film were studied in terms of PU's ionic content and the venation of PU/PMMA compositions. As DMPA content increased from 2wt% to 10wt% in PUD, particle size of PUD decreased. PUD's particle size with ester type polyol was found to be smaller then ether type polyol used. Phase separation between hard segment(HS) and soft segment(SS) with ionic contents in PU was shown by the thermal, mechanical property measurement. Although the composition of MMA was changed from 0 to 40 wt% in PU/PMMA hybrid, the particle size of the hybrid did not increase. Using the ester type polyol, tensile strength of hybrid was found to increase by 2wt% - 6wt% DPMA content, but as higher content the strength of hybrid decreased. Moreover with the ether type polyol, tensile strength of hybrid was observed to increase by 2wt% - 4wt% DMPA content, while decreasing at higher content. PU and PMMA polymer molecule being mixed in molecular level was confirmed from the pattern of $T_g$ in DSC thermogram.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.5
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• pp.591-597
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• 2012

This study was conducted to investigate the changes in chemical components and antioxidant activities of dried jujube ($Zizyphus$ $jujuba$ Miller) with different aging temperatures ($60^{\circ}C$, $70^{\circ}C$, and $80^{\circ}C$) and durations (5 days, 10 days, 15 days, 30 days, and 50 days). The browning index increased from 0.124 to 1.998 with increased aging temperature and duration. As aging duration increased, fructose, glucose, and sucrose content decreased from 24.96% to 4.96%, from 22.23% to 4.41%, and from 18.41% to 0%, respectively. Reducing sugar content decreased from 351.52 mg/g to 155.96 mg/g as aging temperature and duration increased. Total acidity slightly increased from 1.61 to 3.13%. 5-Hydroxymethyl-2-furaldehyde increased from 0.002 mg/g to 38.84 mg/g, respectively. As aging temperature and duration increased, total polyphenol content increased from 15.98 mg/g to 38.61 mg/g. DPPH and ABTS radical scavenging activities increased from 4.03 mg trolox eq/g to 22.22 mg trolox eq/g, and from 2.11 mg ascorbic acid eq/g to 13.39 mg ascorbic acid eq/g, respectively. Reducing power increased rapidly in the first stage and then slowly increased afterward.

• Preventive Nutrition and Food Science
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• v.19 no.2
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• pp.115-123
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• 2014

In the current study, wheat flour was mixed with high quality cassava flour (HQCF) in several ratios: 90:10, 80:20, 70:30, and 60:40, and used to prepare 10%, 20%, 30%, and 40% National Root Crops Research Institute (NRCRI) cassava bread, respectively. 100% wheat bread was prepared as a control (100% wheat bread). Five bread samples were prepared per group. Antioxidant assays [i.e., 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) scavenging assay, reducing power assay] revealed that the bread samples had considerable antioxidant capacities. Substitution of wheat flour with HQCF at various concentrations resulted in dose dependent decreases in the mineral and protein contents of the resulting bread samples. The crude fiber content of the bread samples was minimal, while the carbohydrate content of the bread samples ranged from 43.86% to 48.64%. A 20% substitution of wheat flour with HQCF yielded bread samples with a general acceptability that was comparable to that of 100% wheat bread. The mean bacteria counts of the bread samples ranged from $2.0{\times}10^3CFU/mL$ to $1.4{\times}10^4CFU/mL$, while the fungal counts ranged from 0 CFU/mL to $3{\times}10^3CFU/mL$. There was a positive correlation between the DPPH antioxidant activities and the reducing powers of the bread samples ($R^2=0.871$) and a positive correlation between the DPPH antioxidant activities and the flavonoid contents of the bread samples ($R^2=0.487$). The higher microbial load of the NRCRI cassava bread samples indicates that these bread samples may have a shorter shelf life than the 100% wheat bread. The significant positive correlation between total flavonoid content and reducing power ($R^2=0.750$) suggests that the flavonoids present in the lipophilic fractions of the bread samples could be responsible for the reductive capacities of the bread samples.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.10
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• pp.1533-1538
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• 2013

The objective of this study is to select an effective microbial strain to enhance the sensory qualities and functionalities of fermented ginseng soymilk. For this purpose, soybean were ground with water extracts of ginseng and fermented with five Lactobacillus strains. All strains grew well in ginseng soymilk, and viable cell counts reached greater than 8 log CFU/mL after 18 h of fermentation. The contents of total ginsenosides were higher in soymilk fermented with L. casei ATCC 393 than those in the other strains. The sensory qualities of the fermented soymilk were observed to increase with the intensity of sourness and showed the best sensory acceptability of soymilk fermented with L. kefir ATCC 35411. Moreover, the antioxidant activities, superoxide and hydroxyl radical scavenging activities were significantly enhanced by 2~4 and 4~5 times, respectively, compared to the non-fermented soymilk. In particular, the antioxidant activities of the fermented soymilk by L. kefir ATCC 35411 were the highest among the samples. This result suggests that soymilk fermented by L. kefir ATCC 35411 allowed obtaining a soymilk with enhanced sensory quality and antioxidant activity was able to contribute to the health benefit.

• Journal of Life Science
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• v.25 no.11
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• pp.1311-1318
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• 2015

The effects of fruit maturation on changes in the total phenolics, flavonoids, and carotenoids of methanolic extracts of Citrus sudachi, in addition to its antioxidant and antidiabetic activities, were determined. Generally, the concentration of these chemical constituents increased as C. sudachi reached maturity. C. sudachi contained high levels of total phenolics, flavonoids, and carotenoids at maturity, contributing 6339.5 mg of gallic acid equivalent per 100 g, 2364.2 mg of rutin equivalent per 100 g, and 678.7 mg/ml, respectively. The scavenging activities of 1,1-diphenyl-2-picryl hydrazyl (DPPH), hydrogen peroxide and nitric oxide radicals and the reducing power of mature fruits were significantly higher at all data points than those of immature fruits (p<0.05). In contrast, the ferrous ion chelating activity of mature and immature C. sudachi fruits was similar. The 50% effective concentrations (EC₅₀) of mature fruits were 4.1±0.10 mg/ml for scavenging DPPH radicals, 3.1±0.02 mg/ml for scavenging hydrogen peroxide, 3.9±0.01 mg/ml for scavenging nitric oxide, and 3.8±0.02 mg/ml for chelating ferrous ion. The antidiabetic activity of C. sudachi was studied in vitro using the α-glucosidase inhibitory method. The inhibitory activity of mature C. sudachi fruits on α-glucosidase was higher than that of immature fruits. These results suggest that the content of bioactive compounds and the antioxidant and antidiabetic activities of C. sudachi change during maturation. These findings can be further extended to exploit them for their possible application for the preservation of food products, as well as their use as health supplements and nutraceuticals.

• Korean journal of food and cookery science
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• v.27 no.1
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• pp.43-54
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• 2011

Job's tears (Coixlachryma-jobi L.) and Chungkukjang (soybean-fermented food) were abundant source of phenolic compounds. In this study, almond cookies were prepared with different concentration(5%, 10%, 15%), of Job's tears Chungkukjang powder. The total phenolic contents were measured by the Folin-Ciocalteu method, total flavonoids contents were measured, and antioxidant activities were evaluated by DPPH assay. Antioxidative activity was highly correlated with the total phenolic and total flavonoids contents of Job's tears Chungkukjang almond cookies (r=0.867, r=0.647). In addition, the quality characteristics of the Job's tears Chungkukjang almond cookies were estimated based on the bulk density and pH of the dough, spread factor, color, texture profile analysis, proximate composition, and sensory evaluations. The spread factor, hardness, a value and b value, total polyphenolic contents, and DPPH free radical scavenging activity of cookies significantly increased with increasing content of Job's tears Chungkukjang powder (p<0.01), whereas the L values of the cookies decreased with the increasing Job's tears Chungkukjang powder content (p<0.05). The acceptability scores for the 5-15% Job's tears Chungkukjang almond cookie groups were ranked higher than those of the other groups in appearance, texture, and overall preference. The results of this study were shown that Job's tears Chungkukjang powder was a good ingredient for increasing the consumer acceptability and the functionality of cookies.

• Journal of the Korean Chemical Society
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• v.41 no.7
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• pp.337-342
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• 1997

Acryloylmethylbenzo-15-crown-5 was prepared from the reaction of 4'-hydroxymethylbenzo-15-crown-5 with acryloyl chloride. And, poly(acryloylmethylbenzo-15-crown-5) [poly(AMB15C5)] was synthesized by radical polymerization using AIBN as initiator in benzene. Coated wire lead(II) ion-selective electrodes ($Pb^{2+}$-CWISEs) using either poly(AMB15C5) or B15C5 as neutral carrier were prepared, respectively. $Pb^{2+}$-CWISEs gave linear responses with slopes of 28$\pm$ 1mV per decade within the concentration range of $10^{-5} M{\sim}10^{-1}$ M, respectively. Also, the detection limits were $10^{-6}$ M and response times were either 3 or 5 min. for B15C5 and poly(AMB15C5), respectively. $Pb^{2+}$-CWISE base on B15C5 was rather unstable than poly(AMB15C5)'s due to solubility of the B15C5 in water. The selectivity coefficients of a variety of interfering ions such as $Mg^{2+},\; Ca^{2+},\; Co^{2+},\; Ni^{2+},\; Cu^{2+},\; Zn^{2+}$ and $Cd^{2+}$ were small ($10^{-4}{\sim}10^{-5}$), while those of $Na^+$ and $K^+$ were large (0.1∼0.01). In addition, the electrode responses depended upon the pH of test solution and the composition of the membrane. In the range pH 3∼6 of test solution, potentials of Pb2+-CWISEs were hardly changed. The optimal contents of B15C5 and poly(AMB15C5) were 7.7 wt% and 13.1 wt%, respectively.

• Korean journal of food and cookery science
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• v.28 no.1
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• pp.17-24
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• 2012

The present study was performed to expand the application of mechanically impacting technology reported in our previous studies. Several parameters were analyzed to research Korean indigenous pigmented rice. The proximate composition of Korean indigenous rice was the following; 12.0-13.4% moisture, 74.1-77.3% carbohydrate, 6.8-8.7% crude protein, 1.68-3.25% crude lipid, 0.78-1.38% crude ash, with a 6.6-7.07 pH value. The phenolic compound content of red rice was twice that of black rice. Moreover, antioxidative activity was estimated by DPPH radical-scavenging activity (IC50 = 0.15-1.04 mg/mL). Anthocyanin and chlorophyll in each pigmented rice type were detected by spectrophotometer. Garaedduk samples were prepared with non-waxy rice, salt, 24% water, and/or 15% indigenous pigmented rice(red, green and black, w/w of total swelling non-waxy rice) and adapted with or without mechanically impacting technology. Hardness, as a main texture profile parameter of Garaedduk was maintained up to 3 days under storage at $20^{\circ}C$. The results suggest that Korean indigenous pigmented rice can be applied for functional Garaedduk adapted with mechanically impacting technology.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.6
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• pp.752-758
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• 2012

We conducted this study to investigate the quality and antioxidant properties of saccharified strawberry gruel with different ratios of strawberry rice mash. Different samples of saccharified strawberry gruel with different ratios of strawberry puree were prepared, and the proximate composition, sweetness, pH, acidity, color difference, texture, free sugar, sensory evaluation, and physiological activities of the sample were measured. With increasing strawberry puree content, the proximate compositions, sweetness, and total acidity of the strawberry gruel increased, and pH decreased significantly (p<0.05). Saccharified strawberry gruel prepared with 15% to 45% strawberry puree displayed significantly lower viscosity. As the amount of strawberry puree increased, the Lvalue, and b-value decreased, whereas the a-value increased. The free sugar content of fructose, glucose, maltose, sucrose, and total free sugar increased significantly (p<0.05). Strawberry gruel with 30% added strawberry puree was the most preferred for, its color, flavor, taste, texture, and overall acceptability preference. With increasing strawberry puree content, the total polyphenol contents, total flavonoid contents, DPPH, and ABTS radical scavenging of strawberry gruel increased significantly (p<0.05). From these results, we found that adding 30% strawberry puree was the best way to make gruel with high sensory qualities.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.8
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• pp.1114-1121
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• 2016

This study investigated the food components and antioxidant activities of dried Jerusalem artichoke (Helianthus tuberosus L.) with white and purple colors. For the proximate composition of dried Jerusalem artichoke, regardless of color, carbohydrate content was highest, followed by crude protein, ash, and moisture contents, and breed-specific differences were not detected. The highest mineral content of dried Jerusalem artichoke was potassium, followed by calcium, magnesium, sodium, and iron. The major minerals of white color sample were calcium, magnesium, and zinc, whereas those of the purple color sample were potassium, sodium, copper, and manganese, and no significant differences between the samples were detected. The main amino acid of dried Jerusalem artichoke was arginine, regardless of color, followed by asparagine, aspartic acid, and ${\gamma}-amino-n-butyric$ acid in order. Cysteine, leucine, and tyrosine were significantly (P<0.05) more abundant in the purple color sample than in the white color sample. In contrast, phosphoethanolamine was significantly (P<0.05) higher in the white color sample than in the purple color sample. Antioxidant activity was higher in the purple color sample than in the white color sample for all activities except the 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) assay methodology. Ferric-reducing antioxidant power and oxygen radical absorbance capacity assays at low concentrations of extracts found no differences between the two samples, although the purple sample at high concentration showed relatively high antioxidant activities.