• Korean Journal of Food Science and Technology
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• v.51 no.3
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• pp.200-206
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• 2019

A potentially functional yogurt co-fermented with Monascus-fermented soybean powder (MFSP) was prepared, and its quality and antioxidant properties were investigated. Skim milk powder with (SMP+MFSP, 1:1, w/w) or without MFSP (SMP; control) was fermented by probiotic cultures consisting of L. delbrueckii subsp. bulgaricus KCTC 3635 and S. thermophilus KCTC 5092. The functional yogurt fermented with MFSP contained significantly (p<0.05) higher levels of ${\gamma}-aminobutryric$ acid (GABA; $107.22{\pm}3.06{\mu}g/g$), isoflavone aglycone (daidzein+genistein; $201.21{\pm}6.29{\mu}g/g$), and ubiquinone ($39.05{\pm}0.08{\mu}g/g$) than the control yogurt. During fermentation at $36^{\circ}C$ for 48 h, the functional yogurt displayed higher titratable acidity, viable cell numbers, and radical scavenging activity and a lower pH than the control yogurt (p<0.05). These results indicate that MFSP has great potential for enriching the free isoflavones, GABA, and ubiquinone contents in yogurt.

• Korean Journal of Food Science and Technology
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• v.54 no.2
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• pp.185-195
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• 2022

To enable the widespread use of buckwheat and create novel consumer demands through improved food processing techniques, we compared the quality characteristics of roasted groats following different processing and brewing methods for common and tartary buckwheat. The various processing steps resulted in significant reductions in rutin content for both buckwheat species, while the quercetin content increased in the tartary buckwheat. The fully processed tea products showed dramatic differences in rutin content, which varied based on the buckwheat species, formulation, and brewing method. Tartary buckwheat contained an average of 61 times more rutin than common buckwheat. The tartary buckwheat variety, Hwanggeum-miso, was used to determine an optimal roasting temperature of 70-80℃. Finally, we suggest that consumers who want buckwheat tea rich in rutin would prefer hand-drip-extracted tea, while those who want tea with less bitterness, sweetness, and good flavor would prefer the cold-brewed method.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.32 no.6
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• pp.231-238
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• 2022

To secure the mechanical strength of porous Al₂O₃ ceramics, which can be utilized for filters and catalyst supports is essential for their functionality and durability. Superior mechanical strength would be obtained by tailoring the densification and grain growth during sintering. This study deals with grain growth behavior of a freeze-casted Al₂O₃ with addition of La₂O₃. In a temperature range between 1400 and 1600℃, variations of average grain size with sintering time and temperature were observed and analyzed with G_tⁿ-G₀ⁿ = kt and with k = k₀exp(-E_a/RT). As a result, n value and activation energy (E_a) for grain growth were calculated as 3 and 489.09 kJ/mol, respectively. These commonly confirms retardation effect of the La addition during sintering of Al₂O₃ porous structure. More accurate analysis on the La effect can be followed to provide useful guidance for the selection of additives for better mechanical strength in Al₂O₃ porous structures.

• Journal of the Korea Organic Resources Recycling Association
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• v.31 no.3
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• pp.35-41
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• 2023

In this study, silicon sludge generated in semiconductor manufacturing process is recycled and applied as materials for pigments and paints. In detail, metallic impurities are removed from silicon sludge to obtain plate-like silicon sludge powder (SW-sludge), which is then coated with titanium dioxide via sol-gel method (TCS-sludge). SW-sludge and TCS-sludge are dispersed in hydrophilic transparent varnish and sprayed onto glass substrates to observe the possibility for the application as materials for pigments and paints. Notably, the applicability of TCS-sludge-based paint is improved compared to SW-sludge-based paint after the titanium dioxide coating. Moreover, the color of TCS-sludge-based paint turns into white. Accordingly, it is confirmed that the applicability and hydrophilicity are improved by the presence of outer titanium dioxide layer. In this regard, it is expected that the recycled TCS-sludge may be a future material for the application as pigments and paints.

• Applied Chemistry for Engineering
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• v.34 no.3
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• pp.285-290
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• 2023

Poly-lactic acid (PLA) is the most promising polymer in additive manufacturing as an alternative to acrylonitrile butadiene styrene (ABS). Since it is produced from renewable resources such as corn starch and sugar beets, it is also biocompatible and biodegradable. However, PLA has a couple of issues that limit its use. First, it has a comparatively low glass transition temperature of around 60 ℃, such that it exhibits low thermal resistance. Second, PLA has low impact strength because it is brittle. Due to these problems, scientists have found methods to improve the crystallinity and ductility of PLA. Polyethylene glycol (PEG) is one of the most studied plasticizers for PLA to give it chain mobility. However, the blend of PLA and PEG becomes unstable, and phase separation occurs even at room temperature as PEG is self-crystallized. Thus, it is necessary to investigate the optimal mixing ratio of PLA-PEG at the molecular scale. In this study, molecular dynamics will be conducted with various ratios of L-type PLA (PLLA) or DL-type PLA-PEG (PDLA-PEG) systems by using BIOVIA Materials Studio.

• Food Science and Preservation
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• v.30 no.4
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• pp.654-662
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• 2023

The Aster glehni extract has many therapeutic and medicinal values. Therefore, it is essential to set appropriate conditions for enzyme treatment to efficiently extract A. glehni. In this study, changes in the quality of A. glehni extract depending on the concentration and time of enzyme treatment was investigated to increase its effective utilization. Compared to the control, the pH of the extract of A. glehni its soluble solid content increased with the enzyme treatment. The color of the A. glehni extract changed from green-yellow to reddish-yellow with the increase in treatment duration. The fructose and sucrose contents of the extract were the highest at 7.73% and 6.78%, respectively, in the control group without the enzyme treatment. Glucose and maltose contents were 6.91% and 4.44% in the C group (3.2% enzyme concentration and 60 min for enzyme treatment), respectively. Total polyphenol content, which shows antioxidant activity, was the highest at 7.38 mg GAE/g in the E group (1.6% of enzyme concentration and 120 min for enzyme treatment). 2,2-diphenylpicrylhydrazyl (DPPH) and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid (ABTS) showed the highest radical scavenging activity in the C group (3.2% of enzyme concentration and 60 min for enzyme treatment). These results enable setting appropriate conditions of enzyme treatment in terms of enzyme concentration and time for the production of dry powders using A. glehni extract.

• Journal of Aquaculture
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• v.5 no.1
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• pp.69-79
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• 1992

The muscle extracts of the ascidian, Halocynthia roretzi cultured for two and three years old on the southern coast near Chungmu and the eastern coast near Pohang of Korea, were analyzed for extractive nitrogen (EN), free amino acids (FAA), combined amino acids (CAA), nucleotides and related compounds (NRC), quaternary ammonium bases and guanidino compounds using specimens collected in February 1989 and in April 1989, and compared for those contents with each other. As for the amount of EN, no remarkable difference was found between two- and three-year-old samples collected at St. 1 in the spring and winter seasons, while at St. 2 in the spring season the two-year-old sample was distinctly lower than the three-year-old one. Taurine, proline, glutamic acid, glycine and alanine were the major FAA in every sample. The amount of taurine, the most prominent FAA, was higher in three-year-old sample than in two-year-old one regardless of sampling station and season. Most of the other major FAA showed a similar tendency to EN at both sampling stations in both seasons. Adenosine 5'-triphosphate (ATP), adenosine 5'-diphosphate (ADP), adenosine 5'-monophosphate (AMP), inosine 5'-monophosphate (IMP), inosine (Ino) and hypoxanthine (Hyp) were detected in all the samples and ATP, ADP and AMP were the major ingredients. The amounts of total NRC were in parallel with those of EN and total FAA. As for the contents of betaines, two- and three-year-old samples collected in the winter season exhibited a great discrepancy each other, the former being clearly lower than the latter, but no remarkable difference was observed between two samples of two groups in the spring season. In proximate composition of the muscles, the two-year-old sample was considerably higher in moisture content and lower in protein and glycogen contents than the three-year-old one at St. 2 in the spring season. The large discrepancies observed between two- and three-year-old samples from St. 2 seems to be attributable to the difference in size of samples rather than to the difference in age.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.1
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• pp.75-82
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• 1999

The hydrolysate of desalinated tuna boiled extract (TBE) were prepared by continuous hydrolysis of TBE using a membrane reactor. TBE and tuna boiled extract hydrolysate (TBEH) were isolated depending on molecular weights. The major molecular weight distributions of TBEH-l0K, TBEH-5K and TBEH-lK were 9,800Da, 3,000Da and 990Da, respectively. The amounts of nucleotides and their related compounds of TBE were 3.47 $\mu$mole/g AMP, 23.75 $\mu$mole/g IMP, 9.07 $\mu$mole/g inosine and 1.89 $\mu$mole/g hypoxanthine. Total content of amino acids having desirable taste (glycine, glutamic acid, alanine, proline, aspartic acid, serine) was about $63\%$ of total amino acid from TBE and about $62\%$ from TBEH. The natural seasoninings were prepared with TBE and TBEH. From the results of sensory evaluations, complex seasoning containing TBEH-1K was almost equal to the shellfish complex seasoning obtained from the market. The mixed sauce which was made by mixing of $50\%$ TBEH sauce and $50\%$ fermented soy sauce was similar to the tradition soybean sauce in product quality and it showed the possibility to be used for the substitute product for acid hydrolyzed soysauce.

• Journal of Life Science
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• v.19 no.7
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• pp.983-993
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• 2009

The effects of Monascus-fermented Korean red ginseng (MFRG) on the contents of serum lipids and tissues lipid peroxidation was investigated in alcohol feeding rats (AC group). Serum contents of total lipid and free fatty acid in alcohol feeding rats were significantly increased, but these increases tended to decrease in the AMFRG group. Serum triglyceride content was also significantly decreased in the AMFRG group compared to other groups. Serum content of total-cholesterol was significantly increased in AC group compared to normal control (NC) group, whereas there was no significant difference between the AC and AMFRG groups. Content of HDL-cholesterol in serum was slightly increased in the AC group compared to the NC group, but this increase in the AC group was more significantly increased in the AMFRG group. At the same time, atherogenic index (AI) was also significantly decreased in the AMFRG group compared to the AC group. Contents of thiobarbituric acid reactive substances (TBARS) in the liver, heart, spleen and testes were significantly increased in the AC group compared to the NC group, but these increases were significantly less in the AMFRG group. Contents of liver nonheme ion was increased in the AC group and was significantly decreased in the AMFRG group, which suggested that lipid peroxidation contents are inversely correlated with liver nonheme ion content. Hepatic glutathione concentration was significantly decreased in the AC group, but this content was significantly increased in the AMFRG group and it showed the antioxidant abilities of glutathione. These results suggested that Monascus-fermented Korea red ginseng has anti-atherogenic index (AI) effects as well as antioxidative activities through reduced tissue oxidative stress in alcohol feeding rats.

• Analytical Science and Technology
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• v.29 no.4
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• pp.170-178
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• 2016

Accuracy and precision of ID methods for different spike isotopes of ⁷⁶Se, ⁷⁷Se, and ⁷⁸Se were compared for the analysis of Selenium using quadrupole ICP/MS equipped with Octopole reaction cell. From the analysis of Se inorganic standard solution, all of three spikes showed less than 1 % error and 1 % RSD for both short-term (a day) and long-term (several months) periods. They showed similar results with each other and ⁷⁸Se showed was a bit better than ⁷⁶Se and ⁷⁷Se. However, different spikes showed different results when NIST SRM 1568a and SRM 2967 were analyzed because of the several interferences on the m/z measured and calculated. Interferences due to the generation of SeH from ORC was considered as well as As and Br in matrix. The results showed similar accuracy and precisions against SRM 1568a, which has a simple background matrix, for all three spikes and the recovery rate was about 80% with steadiness. The %RSD was a bit higher than inorganic standard (1.8 %, 8.6 %, and 6.3 % for ⁷⁸Se, ⁷⁶Se and ⁷⁷Se, respectively) but low enough to conclude that this experiment is reliable. However, mussel tissue has a complex matrix showed inaccurate results in case of ⁷⁸Se isotope spike (over 100 % RSD). ⁷⁶Se and ⁷⁷Se showd relatively good results of around 98.6 % and 104.2 % recovery rate. The errors were less than 5 % but the precision was a bit higher value of 15 % RSD. This clearly shows that Br interferences are so large that a simple mathematical calibration is not enough for a complex-matrixed sample. In conclusion, all three spikes show similar results when matrix is simple. However, ⁷⁸Se should be avoided when large amount of Br exists in matrix. Either ⁷⁶Se or ⁷⁷Se would provide accurate results.