• Journal of the East Asian Society of Dietary Life
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• v.17 no.3
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• pp.409-416
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• 2007

This study investigated changes in the catechin and alkaloid contents of Bosung green tea during different manufacturing processes and storage periods, using HPLC and UV-VIS spectrophotometer analysis. For changes in the catechin and alkaloid contents by roasting technique, we found that EGCG, CG and GCG decreased just slightly by processes performed before roasting, rather than after roasting. In addition, theobromine, caffeine, and ECG changed minimally throughout all the processes. For changes in the catechin and purine alkaloid contents of the green tea leaves during storage, EGCG, ECG, and CAF decreased considerably in the green tea stored at temperatures of $5^{\circ}C$ and $25^{\circ}C$, and they decreased by $20{\sim}30%$ after storage for 1 year. However, a quantitative difference was hardly observed in the catechin and alkaloid contents regardless of storage temperature.

• Journal of the Korean Applied Science and Technology
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• v.35 no.4
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• pp.1073-1080
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• 2018

There are several types of petroleum products used for the fuel oil, according to their respective quality standards, grades and usage. Depending on the degree of oil tax rate by country, even the same petroleum products will have price gap. The illegal mixing of cheap petroleum products, which are subject to the lower tax rate, with relatively expensive transportation fuel causes problems such as tax evasion, environmental pollution and vehicle breakdown. In order to prevent illicit production and mixing of these different petroleum products, a small amount of markers are legally added to specific petroleum products. In Korea, markers are introduced and used to prevent illegal activity that kerosene used as fuel for house and commercial boiler are mixed with automotive diesel fuels, and marker contents are analyzed to use UV-Vis spectrophotometer and high performance liquid chromatography (HPLC). In this study, we have developed a method to qualitatively and quantitatively determine the marker added to petroleum products by gas chromatography-mass spectrometry (GC-MS) without adding developing reagent or sample pre-treatments.

• Analytical Science and Technology
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• v.37 no.3
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• pp.155-165
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• 2024

This study aimed to assess whether plant-based meat substitutes can effectively replace animal meat products in terms of amino acid composition and zinc bioavailability. The evaluation was conducted in response to the growing demand for meat substitutes, driven by the increasing vegan population and the expansion of vegan culture. For this purpose, a chicken product and two plant-based meat substitutes in tender form were selected. The amino acid content and composition were measured using HPLC, while the levels of trace elements like zinc and calcium were determined through ICP-AES. Additionally, the presence of phytic acid, which inhibits zinc bioavailability, was extracted and quantified using UV-Vis spectroscopy. The results were analyzed in the context of daily product consumption. The findings revealed that certain essential amino acids, such as valine and lysine, were found to be deficient in plant-based meat substitutes compared to animal meat products. It was challenging to meet the recommended daily intake of these amino acids solely through the use of meat substitutes. Regarding zinc bioavailability, the inhibitory effect of calcium on zinc bioavailability was expected to be minimal. The zinc bioavailability of the meat substitutes varied significantly depending on the zinc and phytic acid content of the ingredients. Therefore, ingredients of plant-based meat substitutes should be carefully modulated to reach appropriate zinc bioavailability by selecting and processing plant materials with high zinc and low phytic acid content.

• Journal of Conservation Science
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• v.31 no.3
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• pp.299-308
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• 2015

Aim of this study is to identify dyestuff of the Dallryeong(official's robe in Joseon Dynasty, 16th century) excavated from Yuryang-dong, Cheonan, in 1996. For this purpose, extracted dyestuffs from Dallryeong fabric and from natural dyestuffs for red color(safflower, Sapanwood, Madder) which are presumed to have been used in the Dallryeong, are analyzed and compared by high performance liquid chromatography(HPLC). As a result, HPLC chromatogram of extracts of the Dallryeong's dyestuff and safflower are showed a peak at 17.5 minutes. The UV/Vis spectra of the samples are showed the maximum absorption wavelength at 519nm. This result is identical with the analysis of the previous studies on red dyestuff of safflower. In addition, the analysis of Mass Spectrometry(MS) showed the identical result of the peak with m/z 910. Following these results, excavated pink Dallryeong were considered to have been dyed with safflower.

• Korean Journal of Food Science and Technology
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• v.32 no.5
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• pp.985-990
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• 2000

${\zeta}-Carotene$ was subjected to ozonolysis in ice-cold dichloromethane. The ozonolysis products were fractionated with a silica column and the carbonyl fraction was analyzed by ODS-HPLC with a photodiode array detector. ${\zeta}-Carotene$ was solubilized in toluene, and then oxidized by incubating at $37^{\circ}C$, 72 hr under atmospheric oxygen. Carbonyl compound and acidic compound were produced. In comparison with autoxidation and ozonolysis, each compound showed the same retention time and UV-vis spectra were identical to the reference cleavage products prepared by ozonolysis of ${\zeta}-carotene$. Absorption spectrum of acidic compound was similar to that of standard 4,5-didehydrogeranyl geranyl acid which is known to possess biological activity. Thus, eccentric cleavage of ${\zeta}-carotene$ was confirmed to occur in vitro under oxidation condition.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2020.08a
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• pp.32-32
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• 2020

High-quality and high-phytonutrient watermelon fruits have strong market opportunities besides their health related benefits. Hence, investigating quality and nutritional related traits of watermelon genetic resources could provide important baseline data in breeding for increased lycopene content thereby increasing the marketability of watermelon. To this end, we have examined some fruit morphological traits and lycopene content of 105 genetic resources. The morphological characters were recorded on the field and inside laboratory and lycopene was measured using spectrophotometric and HPLC methods. Watermelon fruits have shown a diverse morphological characters. Red and pink fleshed fruits dominated in the entire collections. Fruits with higher thickness of rind were found to exhibit less soluble solid content (SSC). Korean origin fruits were characterized by intermediate SSC while USA, RUS, TJK, TKM, TWN, and URY originated fruits had the highest SSC. The lycopene content varied between 41.37 and 182.82 ㎍/g, 2.81 and 163.72 ㎍/g, and 3.54 and 255.47 ㎍/g using HPLC, UV-Vis, and microplate reader instrumnets, respectively. Red- and pink-fleshed fruits had the highest levels of lycopene content compared to the yellow- and orange-fleshed. Lycopene content had a significant positive correlation with SSC, however, no correlations were detected between lycopene and other quantitative fruit morphological characters.

• Food Science of Animal Resources
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• v.32 no.5
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• pp.571-577
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• 2012

This study was carried out to develop an analytical method for the determination of vitamin D in infant formula. Vitamin D was determined by column-switching high-performance liquid chromatography (HPLC) equipped with a reversed phase column and UV detector after saponification and extraction of the formula with an organic solvent. A preseparation column ($C_8$), focusing column ($C_{18}$), analytical column ($C_{18}$) and UV-Vis detector (254 nm) were used. The limits of detection (LOD) and the limits of quantification (LOQ) for vitamin D were estimated to be $1.51{\mu}g/kg$ and $4.95{\mu}g/kg$, respectively. The linearity, recovery, precision and accuracy of the analytical method for vitamin D were evaluated through the application of a SRM (Standard Reference Material) 1846 (National Institute of Standard & Technology, USA). The linearity of this method was calculated with a value of the coefficient of determination ($r^2$) ${\geq}0.9999$. The recovery of vitamin D was $85.20{\pm}3.00%$. The intra-assay precision for vitamin D was between $1.68{\pm}0.03%$ and $5.75{\pm}0.33%$, and the inter-assay precision for vitamin D ranged from $1.73{\pm}0.03%$ to $2.96{\pm}0.09%$. The intra-assay accuracy for vitamin D was between $100.03{\pm}2.77%$ and $102.01{\pm}0.59%$, and the inter-assay accuracy for vitamin D ranged from $99.00{\pm}1.53%$ to $102.01{\pm}3.04%$. The proposed method is optimal for the separation and quantification of vitamin D from infant formula.

• Proceedings of the SCSK Conference
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• 2003.09a
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• pp.178-191
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• 2003

OMC is essentialiy necessary compound in sun goods as organic UV protecting products. But the skin-trouble problem is raising because of skin penetration of OMC. In this study, non-capsulated pure OMC was compared with Organic-Inorganic-Nano-hybrid OMC for skin penetration force and SPF degree. Organic- Inorganic Nano-Hybrid OMC is OMC trapped in the pore of the mesoporous silica synthesized by the sol-gel method after OMC is nanoemulsified in the system of the hydrogenated Lecithin/ Ethanol/caprylic/capric triglyceride/OMC/water. OMC- nano- emulsion was obtained by a microfluidizing process at 1000bar and then micelle size in the nanoemulsion solution is 100-200nm range. Mesoporous silica nano-hybrid OMC was prepared by the process; surfactant was added in dissolved OMC-Nanoemulsion, then the rod Micelle was formed. OMC-nanoemulsion was capsulated in this rod Micelle and then silica precursor was added in the OMC-nanoemulsion solution. Through the hydrolysis reaction of the silica precursor, mesoporous silica concluding OMC-Nanocapsulation was obtained. The nano-hybrid surface of this OMC-Nanoemulsion-Inorganic system was treated with polyalkyl-silane compound. OMC-Mesoporous silica Nano-hybrids coated with polyalkyl-silane compound show the higher sun protecting factor (SPF Analyzer: INDEX 10-15) than pure OMC and could reduce a skin penetration of OMC. The physico-chemical properties of these nano-hybrids measured on the SPF index, partical size, strcture, specific surface area, pore size, morphology, UV absorption, rate of the OMC dissolution using SPF Analyzer, Laser light scattering system, XRD, BET, SEM, chroma Meter, HPLC, Image analyzer, microfluidizer, UV/VIS. spectrometer.

• Analytical Science and Technology
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• v.13 no.3
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• pp.378-384
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• 2000

This Study has been carried out to develop a method of analysis of 8 permitted synthetic food colors [including Brilliant Blue FCF(B1), Indigocarmine (B2), Fast green FCF(G3), Amaranth (R2), Erythrosine (R3), Allura red (R40), Tartrazine (Y4), Sunset Yellow FCF (Y5)] in Korean foods by HPLC. After adjusting to 0.5% HCl, each of the food colors extracted was eluted by Sep-pak $C_{18}$ cartridge. Eluates were then determined by high performance liquid chromatograph with a UV-VIS detector. Recoveries of the 8 synthetic food colors were found to be 81.2-98.0% for soft drinks, 80.6-96.1% for candy, 79.8-96.3% for chewing gum, 76.5-91.7% for cereals, 79.9-93.8% for ice cream and 78.6-94.7% for jelly, respectively. The detection limits were $0.05-0.1{\mu}g/g$.

• Korean Journal of Food Science and Technology
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• v.32 no.1
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• pp.25-30
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• 2000

Phytoestrogen has been used as a suppliment of estrogen in order to treat osteoporosis. The representative phytoestrogens, isoflavones, are daidzein, genistein and formononetin which were present highly in our traditional soybean foods. The quantitative analysis of the isoflavone was done with a high performance liquid chromatography(HPLC) using a UV/VIS detector for the contents of the isoflavones in Astragali Radix, soybean sprouts, bean-curd(Tofu), soybean, soybean oil, pea, kidney pea, black bean(Yak-kong), soybean sauce(Ganjang). soybean paste(Doenjang), and fermented soybean(Maejoo). The content of free daidzein in soybean sprouts was $43.49{\pm}3.41\;mg/kg$$ which was much higher than that in soybean, $14.52{\pm}0.58\;mg/kg$, although total daidzein of fermented soybean was lower than that in soybean (Table 2. P<0.01). The amounts of free genistein in soybean sprouts, fermented soybean. and soybean paste were $27.63{\pm}1.66\;mg/kg,\;291.52{\pm}6.81\;mg/kg,\;and\;18.75{\pm}1.33\;mg/kg$, respectively. The level of free formononetin in soybean paste was the highest among the soybean products (P<0.01). The content of formononetin in Aatragali Radix, $9629.73{\pm}0.57\;{\mu}g/kg$, was about 160 times higher than that in soybean. Thus Korean traditional soybean products, black bean(Yak-Kong) and Astragali Radix can be a good choice of phytoestrogens.