• Food Science and Preservation
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• v.30 no.3
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• pp.483-491
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• 2023

This study aimed to compare the bioactive compounds in Centella asiatica (C. asiatica) cultivated in a smart farm and a field and their effects on human keratinocyte cells. C. asiatica was collected in Jeju-do, Korea, and cultured in a smart farm and a field. The main bioactive compounds in the two differentially cultured C. asiatica were identified, and their activation in keratinocytes were assessed. Amplification and sequencing of the internal transcribed spacer (ITS) DNA in the nucleus and psbA-H DNA in the chloroplast were performed for species analysis. A comparison of DNA of plants reported in the NCBI GenBank was performed. The ITS DNA and psbA-H DNA sequences of C. asiatica cultivated in a smart farm and a field were consistent with No. MH768338.1 and No. JQ425422.1, respectively. Analysis of the triterpenes was performed using high performance liquid chromatography (HPLC) and as a result, C. asiatica cultured in a smart farm had more triterpenes than those cultured in a field. The effects of C. asiatica grown in a smart farm on cell proliferation and scratch recovery in HaCaT cells were greater than those grown in a field. These results suggest that C. asiatica cultivated in a smart farm can be effectively utilized as a health functional food.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.3
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• pp.358-367
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• 2017

Preservatives, as food additives, are occasionally intrinsic to natural raw materials or sometimes generated during the fermentation process as reported in many research articles. Preservative compounds in raw food materials may persist in the final food product, which is not supposed to include such preservative compounds. In this study, we validated an analytical method for preservative compounds in raw materials of functional foods. Quantification of benzoic acid and sorbic acid was determined using HPLC-PDA analysis after distillation, whereas propionic acid was quantified with GC-FID. A significant set of validation data (accuracy, precision, linearity, recovery, etc) was acquired. A total of 212 samples were collected for analysis of naturally occurred preservatives, and preservatives were detected in 85 samples. Most of the detected samples showed less 10 mg/kg of preservatives. The results of this study provide fundamental data on naturally occurring preservatives in raw materials of functional foods. Moreover, building up a database of naturally occurring preservatives could solve problems in the current scientific data.

• Journal of the Mineralogical Society of Korea
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• v.28 no.3
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• pp.245-253
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• 2015

The performance of $TiO_2$ photo-catalytic oxidation process is significantly dependent on the amount of hydroxyl radicals produced during the process, and it is an essential prerequisite to quantify its production. However, precise and accurate methods for quantification of hydroxyl radicals have not been developed so far. For this reason, this study was initiated to compare existing methods for analysis of hydroxyl radicals produced by $TiO_2$ photo-catalytic oxidation and to propose a new method to overcome the limitation of established methods. To simulate $TiO_2$ photo-catalytic oxidation process, Degussa P25 which has been widely used as a standard $TiO_2$ photo-catalyst was used with the dose of 0.05 g/L. The light source of process was UVC mercury low-pressure lamp (11 W, $2,975mW/cm^2$). The results indicate that both potassium iodide (KI)/UV-vis spectrometer and terephthalic acid (TPA)/fluorescence spectrometer methods could be applied to qualitatively measure hydroxyl radicals via detection of triiodide ion ($I_3{^-}$) and 2-hydroxyterephthalic acid which are produced by reactions of iodine ion ($I^-$) and TPA with hydroxyl radicals, respectively. However, it was possible to quantitatively measure hydroxyl radicals using TPA method coupled with high-performance liquid chromatograph (HPLC). The analytical results using TPA/HPLC method show that hydroxyl radical of 0.013 M was produced after 8 hours operation of photo-catalytic oxidation under specific experimental conditions of this study. The proposed method is expected to contribute to precise the evaluation of the performance of photo-catalytic oxidation process.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.10
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• pp.1504-1509
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• 2015

The aim of this study was to investigate a validation method for determination of pectolinarin and pectolinarigenin in fermented Cirsium setidens Nakai. For validation, the specificity, linearity, precision, accuracy, detection limits, and quantification limits of pectolinarin and pectolinarigenin were measured by HPLC. The results show that the detection limits of pectolinarin and pectolinarigenin were $4.25{\mu}g/mL$ and $2.46{\mu}g/mL$, respectively. The recovery rates of pectolinarin and pectolinarigenin were high in the ranges of 99.7~104.0% and 99.7~102.4%, respectively. Inter-day and intra-day precisions of pectolinarin and pectolinarigenin in fermented Cirsium setidens Nakai were 0.9%, 0.5% and 0.5%, 0.2%, respectively. Therefore, application of pectolinarin and pectolinarigenin was validated by an analytical method as a marker compound in Cirsium setidens Nakai.

• Journal of Food Hygiene and Safety
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• v.32 no.5
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• pp.434-442
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• 2017

The UV light in sunlight breaks down the chemical bonds in a polyolefin polymer through a process called photodegradation, ultimately causing cracking, chalking, colour changes, and loss of physical properties such as impact strength, tensile strength, elongation, and others. UV absorbers are used to prevent or terminate the oxidation of plastics by UV light. They are receptive to UV radiation and dissipate the energy harmlessly as heat. Benzotriazoles and benzophenones are used mainly in polyolefins such as polyethylene and polypropylene. In this study, we have developed a method for the analysis of 12 UV absorbers, which are Uvinul 3000, Cyasorb UV 24, Uvinul 3040, Tinuvin 312 and P, Seesorb 202, Chimassorb 81, Tinuvin 329, 234, 326, 328 and 327, migrated from the food packaging materials into four food simulants for aqueous, acidic, alcoholic and fatty foods. The UV absorbers in food simulants were determined by reversed-phase high performance liquid chromatograph-ultraviolet detector with 310 nm after solid-phase extraction with a hydrophilic-lipophilic balance (HLB) cartridge or dilution with isopropanol. The analytical method showed a good linearity of coefficient ($R^2{\geq}0.99$), limits of detection (0.049~0.370 mg/L), and limits of quantification (0.149~1.120 mg/L). The recoveries of UV absorbers spiked to four food simulants ranged from 70.05% to 110.13%. The developed method would be used as a reliable tool to determine concentrations of the migrated UV absorbers.

• Food Science and Preservation
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• v.24 no.7
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• pp.983-991
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• 2017

This study was performed to update the National Standard Food Composition Table (NSFCT) published by Korea Rural Development Administration, especially focusing on vitamin $B_{12}$ for Korean pork. Total 7 primal and 22 retail fresh cuts of Korean pork were analyzed for vitamin $B_{12}$ and the applied immunoaffinity-HPLC was validated. Vitamin $B_{12}$ assay by immunoaffinity-HPLC obtained recoveries over 95% and coefficient variations of precision below about 10%, which met the limits required for validation acceptance. Limits of detection and quantification of immunoaffinity-HPLC were 0.01 and $0.33{\mu}g/100g$, respectively. Quality control chart showed that analysis performance was excellent during the entire of study. Vitamin $B_{12}$ contents of pork cuts significantly varied depending the types of primal and its retail cuts (p<0.05). Belly, Boston butt, rib cuts showed relatively high vitamin $B_{12}$ contents compared to other primal cuts. Vitamin $B_{12}$ content of pork retail cuts were also significantly different within the same primal cuts (p<0.05). Among 22 retail cuts, the highest vitamin $B_{12}$ was observed in Tosisal in belly primal part ($0.98{\mu}g/100g$) while both Aldeungsimsal in loin and Hongdukkaesal in hide leg were the lowest by $0.33{\mu}g/100g$. This study provides reliable vitamin $B_{12}$ data for the Korean pork fresh cuts through standard sampling, method validation and analytical quality control, which would be used for update of Korean NSFCT.

• Korean Journal of Food Science and Technology
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• v.40 no.2
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• pp.152-159
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• 2008

The purpose of this study was to determine the accurate quantification of vitamin A in infant formula by comparing two different standard stock solutions as well as various sample weights using high performance liquid chromatography. The sources of uncertainty in measurement, such as sample weight, final smaple vloume, and the instrumental results, were identified and used as parameters to determine the combined standard uncertainty based on GUM(guide to the expression of uncertainty in measurement) and the Draft EURACHEM/CITAC Guide. The uncertainty components in measuring were identified as standard weight, purity, molecular weight, dilution of the standard solution, calibration curve, recovery, reproducibility, sample weight, and final sample volume. Each uncertainty component was evaluated for type A and type B and included to calculate the combined uncertainty. The analytical results and combined standard uncertainties of vitamin A according to the two different methods of stock solution preparation were 627 ${\pm}$ 33 ${\mu}$g R.E./100 g for 1,000 mg/L of stock solution, and 627 ${\pm}$ 49 ${\mu}$g R.E./100 g for 100 mg/L of stock solution. The analytical results and combined standard uncertainties of vitamin A according to the various sample weighs were 622 ${\pm}$ 48 ${\mu}$g R.E./100 g, 627 ${\pm}$ 33 ${\mu}$g R.E./100 g, and 491 ${\pm}$ 23 ${\mu}$g R.E./100 g for 1 g, 2 g, and 5 g of sampling, respectively. These data indicate that the preparation method of standard stock solution and the smaple amount were main sources of uncertainty in the analysis results for vitamin A. Preparing 1,000 mg/L of stock solution for standard material sampling rather than 100 mg, and sampling not more than 2 g of infant formula, would be effective for reducing differences in the results as well as uncertainty.

• Journal of Food Hygiene and Safety
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• v.37 no.3
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• pp.143-148
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• 2022

This study was to investigate an analytical method for determining dieckol content in Ecklonia stolonifera extract. According to the guidelines of International Conference on Harmonization. Method validation was performed by measuring the specificity, linearity, precision, accuracy, limit of detection (LOD), and limit of quantification (LOQ) of dieckol using high-performance liquid chromatography-photodiode array. The results showed that the correlation coefficient of calibration curve (R²) for dieckol was 0.9997. The LOD and LOQ for dieckol were 0.18 and 0.56 ㎍/mL, respectively. The intra- and inter-day precision values of dieckol were approximately 1.58-4.39% and 1.37-4.64%, respectively. Moreover, intra- and inter-day accuracies of dieckol were approximately 96.91-102.33% and 98.41-105.71%, respectively. Thus, we successfully validated the analytical method for estimating dieckol content in E. stolonifera extract.

• The Korean Journal of Pesticide Science
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• v.17 no.1
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• pp.13-19
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• 2013

Isopyrazam, a new pyrazolecarboxamide fungicide developed by Syngenta, was highly active against foliar powdery mildew pathogens on cucumber, oriental melon and various vegetables. Following foliar applications on cucumber and oriental melon, crop residues were determined using high performance liquid chromatography. For all studies, limit of quantification was 0.02 mg/kg and minimum detection level was 2.0 ng and recoveries were 83.0-88.0% on cucumber, 92.4-104.5% on oriental melon. Isopyrazam was detected 0.07-0.72 mg/kg on cucumber and < 0.02-0.68 mg/kg on oriental melon, respectively. The TMDI (Theoretical Maximum Dailly Intake) of isopyrazam on cucumber and oriental melon was estimated to less than 1.765% of ADI.

• Korean Journal of Clinical Laboratory Science
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• v.37 no.1
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• pp.22-26
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• 2005

Total homocysteine is now considered a risk factor for cardiovascular diseases. I increased interest has led to a multitude of studies requiring the determination of total homocysteine in conjunction with other factor. There are various methods for measuring total homocysteine, including HPLC, FPIA, GC-MS and LC-MS/MS. The most recent method for measuring total homocysteine uses a deuterium-labelled internal standard and tandem mass spectrometry. This development requires no derivatization and therefore leads to an increase in sample throughput compared to other techniques. We have evaluated the method for homocysteine by the LC-MS/MS method, and the correlation between the FPIA method and the LC-MS/MS method. The standard curve (0, 5, 10, 20, 50, 100 uM) was linear over the range examined (up to 100 uM). The lower limit of quantification (CV < 10 %) was 0.5 uM/L and the lower limit of detection (S/N >3) was 0.1 uM/L. Intra-assay variation and inter-assay variation were both <6 %. The comparision study for homocysteine concentration showed good correlation (r=0.9684) between the FPIA method and LC-MS/MS methods. Our conclusion is that the method showed relatively good precision, and was rapid and accurate.