• Korean Journal of Food Science and Technology
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• v.24 no.5
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• pp.504-510
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• 1992

Several single or mixed water-miscible organic solvent systems were investigated to develop the most effective solvent system for enzymatic synthesis of N-benzoylaspartame(BzAPM). The BzAPM was prepared by immobilized thermolysin with using N-benzoyl-L-aspartic acid(Bz-Asp) and L-phenylalanine methyl ester(PheOMe). The solubilities of BzAPM and L-phenylalanine were highest in 4.5% methanol(1.89 and 1.79%, respectively) among the solvents system investigated while a mixed solvent system of 25% dimethyl sulfoxide(DMSO) and 20% polyethylene glycol(PEG) 200 showed relatively high values. The synthetic activity of BzAPM as well as initial reaction rate were found to be high in 45% methanol, 45% DMSO and a mixed solvent of 25% DMSO and 20% PEM 200. The imobilized thermolysin was most stable in 25% DMSO and 20% PEG 200 during storage at $40^{\circ}C$ for 42 days. PheOMe in the same solvent system was also found fairly stable against non-enzymatic decomposition at $40^{\circ}C$. Based on the synthetic efficiency and stability, the solvent system containing 25% DMSO and 20% PEG 200 was selected to be appropriate for the enzymatic synthesis of BzAPM.

• Korean Journal of Food Science and Technology
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• v.27 no.4
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• pp.564-570
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• 1995

N-Benzoyl-L-aspartyl-L-phenylalanine methyl ester(BzAPM), a novel aspartame precursor, was investigated for its enzymatic synthesis by immobilized thermolysin using a water-miscible organic solvent system. The substrate used were N-benzoyl-L-aspartic acid(BzAsp) and L-phenylalanine methyl ester (PheOMe). Synthetic conditions such as substrates concentration, temperature, pH, and some metallic ions were varied to study their effects on BzAPM synthesis. The synthetic reaction rate increased linearly as the PheOMe concentration increased at a constant concentration of BzAsp(100 mM), and the maximum reaction rate was obtained at BzAsp concentration of 200 mM when 300 mM PheOMe was used. The optimum pH and temperature were found to be 6.1 and $40^{\circ}C$, respectively. The metallic ions such as $Zn^{2+},\;Mg^{2+},\;Mn^{2+},\;Fe^{2+},\;Pb^{2+}\;and\;Cu^{2+}$ at 5 mM level showed inhibitory effect on BzAPM synthesis, while $Co^{2+}$ and $Ca^{2+}$ ion increased synthesis. $Co^{2+}$ ion was also found to have synergistic effect with $Ca^{2+}$ ion. Benzoic acid, L-phenylalanin and NaCl showed inhibitory effect.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.4
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• pp.573-578
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• 2015

This study was performed to elucidate the fermentation and sensory characteristics of Korean traditional rice wine, makgeolli, made from GABA rice, which has a high content of GABA (gamma-aminobutyric acid). GABA rice is a brown rice that is not easily fermented by general makgeolli manufacturing methods. Thus, the Geupchungju method, which is a Korean traditional manufacturing method for makgeolli using a fermentation starter and additional malt, was considered for making makgeolli from GABA rice. We confirmed that Geupchungju method showed a high saccharification and stable alcohol fermentation ability in the early stages of fermentation. However, malt addition more than 2% resulted in a lower score in the sensory evaluation of the final product. It was also confirmed that GABA content of GABA makgeolli was higher than that of commercial makgeolli by 2.3-fold. Our result provides useful information toward improving quality of brown rice makgeolli.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.180-185
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• 2003

The increase of traffic over a bridge has been emerged as one of the most severe problems in view of bridge maintenance, since the load effect caused by the vehicle passage over the bridge has brought out a long-term damage to bridge structure, and it is nearly impossible to maintain operational serviceability of bridge to user's satisfactory level without any concern on bridge maintenance at the phase of completion. Moreover, bridge maintenance operation should be performed by regular inspection over the bridge to prevent structural malfunction or unexpected accidents front breaking out by monitoring on cracks or deformations during service. Therefore, technical breakthrough related to this uninterested field of bridge maintenance leading the public to the turning point of recognition is desperately needed. This study has the aim of development on automated inspection system to lower surface of bridge superstructures to replace the conventional system of bridge inspection with the naked eye, where the monitoring staff is directly on board to refractive or other type of maintenance .vehicles, with which it is expected that we can solve the problems essentially where the results of inspection are varied to change with subjective manlier from monitoring staff, increase stabilities in safety during the inspection, and make contribution to construct data base by providing objective and quantitative data and materials through image processing method over data captured by cameras. By this system it is also expected that objective estimation over the right time of maintenance and reinforcement work will lead enormous decrease in maintenance cost.

• Journal of Food Hygiene and Safety
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• v.39 no.3
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• pp.281-287
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• 2024

This study investigated the total sugar and low-calorie sweetener content in 72 alcoholic beverages. The samples included 10 takjus, 6 yakjus, 5 cheongjus, 5 beers, 12 fruit wines, 5 sojus, 5 general distilled alcoholic beverages, 9 liqueurs, and 15 other alcoholic beverages. Sugar and allulose content were analyzed using HPLC-RI, and the content of five sweeteners was analyzed using HPLC-UV and LC-MSMS. The average sugar content in the alcoholic beverages was 4.13±5.16 g/100 g. When categorized by type, the sugar content ranged from 0.00 to 8.92 g/100 g, 0.00 to 30.55 g/100 g, and 0.14 to 17.02 g/100 g in fermented (takju, yakju, cheongju, beer, and fruit wine), distilled (soju, general distilled alcoholic beverages, and liqueur), and other alcoholic beverages, respectively. Sugar content was the highest in liqueur, with the average content being 12.41±9.66 g/100 g. Among low-calorie sweeteners, acesulfame potassium, sodium saccharin, aspartame, and sucralose were detected in concentrations ranging from 28.6-121.5, 42.3, 34.1-141.5, and 23.3-88.1 mg/kg, respectively. Cyclamate and allulose were not detected in any of the alcoholic beverages. Sweeteners were detected in 24 out of the 72 alcoholic beverages, and their content complied with the standards stipulated for food additives.

• Journal of Food Hygiene and Safety
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• v.13 no.2
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• pp.121-128
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• 1998

Ochratoxin A (OA) is a mycotoxin produced by Aspergillus ochraceus as well as other molds. It is a natural contaminant of mouldy food and feed. OA has a number of toxic effects, the most prominant being nephrotoxicity. Futhermore, OA is immunosuppressive, genotoxic, teratogenic and carcinogenic. OA inhibits protein synthesis by competition with phenylalanine in the phenylalanine-tRNA aminoacylation reaction. Recently, lipid peroxidation induced by OA has been reported, indicating that the lesion induced by this mycotoxin could be also related to oxidative pathway. Since it seems impossible to avoid contamination of foodstuffs by toxigenic fungi, detoxification and detoxication of OA are needed. In this study we investigated the protective effects of aspartame (Asp), phenylalanine (Phe), polyphenol 70S (PP) and aloe extract (AE) on the nephrotoxicity induced by subacute exposure to the OA. Asp and Phe are structural analogues of OA. PP, an ingredient of Green Tea and AE have been known as antioxidant and radical scavenger. Phe (40 mg/kg, i.p.) and Asp (25 mg/kg, p.o.) were administered to Sprague-Dawley rats simultaneously with OA (2.0 mg/kg, p.o.) for 2 weeks. PP (200 mg/kg, p.o.) and AE (50 mg/kg, i.v.) were pretreated before administration of OA, for 2 weeks and 3 days, respectively. Using enzymuria, BUN level, creatinemia and histophathologic examination as indices of renal damage, we observed that all of four compounds prevented the nephrotoxic effects induced by OA. It seems that structural analogues of OA such as Asp and Phe have better protective effect on the nephrotoxicity of OA than antioxidants. These results indicate that 1) formation of free radical and lipid peroxidation are likely to be involved in the nephrotoxicity of OA in vivo, 2) Asp, PP and AE might be used for prevention of renal lesions in cases of ochratoxicosis.

• Journal of Food Hygiene and Safety
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• v.32 no.4
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• pp.314-320
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• 2017

This study was carried out to investigate and evaluate total sugar and artificial sweetener contents in health functional foods. In this study, HPLC with evaporative light scattering detector (ELSD) and HPLC-UV were used to determine the contents of total sugar and artificial sweetener in health functional foods. Sixty-six chewable products and sixty red ginseng products were collected from markets in Seoul. The average content of 126 samples per daily intake portion was 1.96 g ranging from not-detected (N.D.) to 12.61 g. The mean total sugar content per serving of chewable product was 1.26 g and N.D. to 10.39 g. The average amount of total sugar per daily intake of ginseng and red ginseng was 2.70 g and N.D. to 12.61 g. The average amount of sugar per daily intake of chewable products was 2.10 g for children, 1.43 g for nutrients, and 0.35 g for functional raw material. For children's products, the content of sugar per serving was ranged from 1.03 g to 5.33 g, from N.D. to 10.39 g for nutrients and from N.D. to 2.61 g for functional raw materials. The average content of sugar per daily intake of ginseng and red ginseng product was 4.25 g in liquid product, 1.51 g in concentrate product and 1.49 g in powder product. The contents of sugar per the daily intake of the liquid product ranged from N.D. to 10.80 g, from 0.01 g to 12.61 g for the concentrated product, and from 0.06 g to 5.64 g for the powdered product. Analysis of artificial sweeteners showed that artificial sweeteners were detected in three cases. No artificial sweeteners were detected in ginseng and red ginseng products. Two of the chewable products and one of the functional raw materials were detected. The detected artificial sweeteners were aspartame, 3.09 g/kg in nutrients and 1.09 g/kg in functional raw material.