Jung-Hun Kim

Mercury contamination and exposure assessment of fishery products in Korea

In this study, total (T-Hg) and methyl mercury (Me-Hg) contamination was investigated in fishery products including canned fish, fish sauces, dried bonito and frozen tuna sashimi, collected from retail markets in Korea, to assess dietary exposure. Direct mercury analyser and gas chromatography-electron captured detector were employed to measure T-Hg and Me-Hg, respectively. The highest T-Hg and Me-Hg contamination was present in tuna sashimi, followed by dried bonito, respectively. Canned tuna showed more frequent detection and higher content than other canned fishery products. The weekly exposure estimate indicates that exposure to mercury from fishery products is safe, showing 2.59% provisional tolerable weekly intake (PTWI) for T-Hg, 1.82% PTWI for Me-Hg and 4.16% reference dose for Me-Hg. However, it should be addressed to monitor the mercury contamination in fish and fishery products regularly, to safeguard vulnerable population such as children, to limit intake of these food products.

Contents of Sodium and Potassium for Restaurant Dishes in Seoul

To determine the contents of sodium (Na) and potassium (K) for restaurant dishes, 194 cases clas- sified 26 kinds of restaurant dishes were collected from restaurants in Seoul and were analysed using the atomic absorption spectroscopy. Average contents of Na and K in Kimchi among restaurant dishes were highest as 554.9 ± 155.5 mg/100 g, 225.1 ± 69.1 mg/100 g, while average contents of Na and K were lowest in Seolleongtang as 24.2 ± 5.8 mg/100 g, 12.7 ± 3.9 mg/100 g respectively. The contents between Na and K in restaurant dishes had a strong cor- relation of positive linear judging from 0.782 (p-value < 0.01) of the correlation coefficient. The Na/K ratio of Bul- gogi was appropriate as 1.17 ± 0.44, while those of Udon, banquet noodles, Kalguksu were very high as shown more than 10. The contents of Na and K were examined 5 dish groups as Gook/Tang, Jjigae/Jeongol, stir-fried dish, noodle and Kimchi. Average contents of Na and K classified by dish groups were significantly difference (p-value < 0.001). Average content of Na among dish groups was highest in Kimchi as 554.9 ± 155.5 mg/100 g followed by Jjigae/Jeon- gol, Gook/Tang, stir-fried dish and noodle. Similar to Na content, average content of K was highest in Kimchi as 225.1 ± 69.1 mg/100 g followed by stir-fried dish, Jjigae/Jeongol, Gook/Tang and noodle. The ratio of Na/K by clas- sified groups of dishes was shown as significantly difference (p-value < 0.001). Stir-fried dish was 1.18 ± 0.44 close to 1 followed by Kimchi, Jjigae/Jeongol, Gook/Tang, and noodle.

Toxic metal content in 52 frequently prescribed herbal medicines on the Korean market

This study was conducted to investigate the toxic metal content (Pb, As, Cd and Hg) of 52 frequently prescribed herbal medicines and to identify herbal medicines that exceed the Korea Food and Drug Administration (KFDA) maximum limits. A total of 3534 samples, including 1966 domestic samples and 1568 imported samples, were analysed using an Inductively Coupled Plasma-Mass Spectrometer (ICP-MS). Total amounts of Pb, As, Cd and Hg were significantly different between domestic (0.63 mg kg−1) and imported (0.81 mg kg−1) medicines (p < 0.05). Among the 52 kinds of samples, 4 kinds of herbs required quality control for Pb and 12 kinds of herbs required quality control for Cd. No sample contained As and Hg above the limits.

Study of the Characteristics of Roasted Coffee Bean in Seoul

This study was performed to survey and evaluate the contents of pH, total acidity, caffeine, harmful metals (Pb, Cd) and total polyphenol in coffee extraction. In total, coffee bean. Total fifty coffee samples were analy- sed. A 5 g portion of roasted ground coffee samples were extracted in coffee-maker with 100 mL of distilled water and the extraction were used in all experiments. The pH range was 4.72~5.25 (mean value = 4.99). According to increase of the roasting temperature, the pH were shown a tendency to increase. The contents of total acidity was 0.72~2.25% (mean value = 1.59%). According to increase of the roasting temperature, the contents of total acidity were shown a tendency to decrease. The contents of harmful metals (Pb, Cd) in coffee extractions were determined by ICP. The aver- age contents of Pb and Cd were 0.0112 and 0.0011 mg/kg, respectively. The contents of caffeine in coffee extractions were determined by HPLC, the range of detection was 0.51~20.28 mg/mL (mean value = 12.29 mg/mL). According to increase of the roasting temperature, the contents of caffeine were shown a tendency to increase. The contents of total polyphenol in coffee extractions were determined by spectrophotometer, the range of detection was 18.88~ 43.90 mg/mL (mean value = 31.94 mg/mL). According to increase of the roasting temperature, the contents of total polypenol were shown a tendency to decrease.

A Study on Contents of Sugars and Sugar Alcohols in Processed Foods Met to Children's Taste

In this study, HPLC-RI was used to determine sugars and sugar alcohols contents in 102 different kinds of processed foods met to childrens taste. The average amount of sugars per 100 g of candies was 70.25 g, of processed cocoa products was 65.34 g, of processed chocolate products was 47.53 g, of breads was 25.66 g, of cookies was 22.28 g, of ices was 12.47 g, of snacks was 9.74 g. Processed cocoa product items had relatively higher sucrose contents (56.80 g/100 g) than any other items. The average amount of sucrose per 100 g of candies was 44.20 g, of processed chocolate products was 32.89 g, of breads was 23.11 g. When the contents of sugars in processed foods met to childrens taste per on serving size were compared to WHO guidelines, the percentages were 5.84~28.52 about rec- ommended daily intake of total sugar of 50 g. The result for the analysis of confectioneries showed that 13 samples of 102 were detected and the sugar alcohols content of samples investigated varied between 0.01~15.06%.

Quality inspections of active components in oxidative hair coloring products by UPLC

To identify oxidative hair dyes in hair-coloring products, the thin-layer chromatography (TLC) screening method was used in accordance with Korean Quasi-drug Codex. However, the TLC method is not reliable when there are very small amount of materials to be tested or when values of several components are similar. In this study, Ultra Performance Liquid Chromatography (UPLC) with a rapid sample preparation method was developed for the reliable and sensitive identification of active components contained in oxidative hair-coloring products. Hexane-distilled water was used for the extraction of active components contained in the products prior to UPLC analysis. The limit of detection of active components was 6.7-77.9 , and the limit of quantitation was 22.3-259.7 . Except for -naphthol, the range of recovery ratio was 96.2-101.5%. From this study, we demonstrated that oxidative active hair-coloring components can easily be analyzed by rapid extraction method followed by UPLC analysis.

Analysis and Risk Assessment of Benzo(a)pyrene in Edible Oils

ABSTRACT - To assess the health risk for benzo(a)pyrene by the intake of edible oils, 288 cases of edible oilscollected from food markets were analysed using the high performance liquid chromatography with fluorescencedetector. The levels of benzo(a)pyrene were from non-detection to 4.78µg/kg, and the average was 0.11µg/kg. Thechronic daily exposures of benzo(a)pyrene for total population group and consumer-only group were estimated usingthe food consumption data in the fifth Korea National Health and Nutrition Examination Survey in 2011. The esti-mated daily intake of benzo(a)pyrene was 4.26 × 10 −3 ng/kg b.w./day for total population group and 7.64 × 10 −3 ng/kgb.w./day for consumer-only group. The MOE (margin of exposure) of benzo(a)pyrene for total population group andconsumer-only group was 7.28 × 10 7 ~1.74 × 10 8 and 3.95 × 10 7 ~9.42 × 10 7 , respectively. Accordingly, the health riskfrom benzo(a)pyrene caused by the intake of edible oils was considered as a very low level.Key words : benzo(a)pyrene, edible oils, risk assessment, margin of exposure

Simultaneous Determination of Non-steroidal Anti-inflammatory Drugs and Corticosteroids Added to Foods as Adulterants using LC-ESI-tandem Mass Spectrometry

The objective of present study was to develop a simultaneous determination method of 5 medical compounds, including beclomethasone, dexamethasone, prednisolone, ketoprofen, phenylbutazone in foods, using LC-MS/MS. To optimize MS analytical condition of 5 compounds, each parameter was established by MRM mode. The chromatographic separation was achieved on a C18 column successfully, with a mobile phase made up of A (0.1% formic acid) and B (0.1% formic acid in acetonitrile), at a flow rate of 0.3 mL/min for 17 min with a gradient elution. LOD and LOQ of 5 compounds were in the range of 0.40~4.60 ng/mL and 0.81~11.46 ng/mL, respectively. As a result of analyzing the three concentrations of the standard mixture added to blank samples, the results showed that the mean recovery rate of 5 compounds was in the range of 81.52~103.83%, and RSD (%) of Intra- and Inter-day assay were 0.52-10.45. Since relatively fine selectivity, accuracy and reproducibility were shown in this qualified experimental method, it could be utilized efficiently to investigating those 5 compounds to see if it is added to food products illegally.