Jaeho Ha

Effective separation and quantitative analysis of major heat principles in red pepper by capillary gas chromatography

Abstract An effective analytical method for the separation and quantitative analysis of the major heat principles in red pepper has been established. Capsaicinoids were extracted with acetone, and undesirable components, such as pigments, lipoids, and lipids, were effectively removed by liquid-liquid fractionation to avoid interference of the chromatogram or contamination of the column. A moderately polar fused silica capillary column, bonded with cross-linked cyanopropylphenyldimethyl siloxane, separated capsaicinoids with good resolution, and hydrogen eluted the components within reasonable retention times.

Method validation of 16 types of structural amino acids using an automated amino acid analyzer

An analytical method for the simultaneous determination of 16 types of structural amino acids in infant formula using an automated amino acid analyzer was validated through tests of precision, accuracy and linearity. The automated analysis of the amino acids was performed on an ion-exchange packed column with a visible detector. The certificated reference material (CRM) 1546 from NIST was used as the test sample to determine the precision and accuracy of the analytical method. The regression analyses revealed good correlations [correlation coefficient (r2)] that were greater than 0.99. The recovery values of the amino acids were ranged from 87.18 to 118.08%. The limits of detection and limits of quantification were less than 0.059 mg/100 g and less than 0.198 mg/100 g, respectively. The intra- and inter-day precisions were less than 14.62% in the CRM sample.

Rapid method for the determination of 14 isoflavones in food using UHPLC coupled to photo diode array detection

A rapid method for the determination of 14 types of isoflavones in food using ultra-high performance liquid chromatography (UHPLC) was validated in terms of precision, accuracy, sensitivity and linearity. The UHPLC separation was performed on a reverse-phase C18 column (particle size 2 μm, i.d. 2 mm, length 100 mm) using a photo diode array detector that was fixed to 260 nm. The limits of detection and quantification of the UHPLC analyses ranged from 0.03 to 0.33 mg kg(-1). The intra-day and inter-day precision of the individual isoflavones were less than 11.77% and calibration curves exhibited good linearity (r(2) = 0.99) within the tested ranges. These results suggest that the rapid method used in this study could be available to determine of 14 types of isoflavones in a variety of food such as soy bean, black bean, red bean and soybean paste.

Determination of elaidic and vaccenic acids in foods using GC×GC-FID and GC×GC-TOFMS.

Trans fatty acids (TFAs) are present in meat and dairy products as m ruminant animals and in vegetable fats due to partial hydrogenation. This study aimed to discriminate between natural (N-TFA) and hydrogenated trans fatty (H-TFA) acids by GC×GC-flame ionization detection (GC×GC-FID) and comprehensive GC×GC-time-of-flight mass spectrometry (GC×GC-TOFMS). The separation of two kinds of trans fats, vaccenic acid (18:1 trans-11) and elaidic acid (18:1 trans-9), was performed using GC×GC-FID and GC×GC-TOFMS. A 100 m×0.25 mm I.D.×0.2 μm (film thickness) SP-2560 (bis-cyanopropyl polysiloxane) fused capillary column (first separation dimension, 1D) was coupled to a 1.5 m×0.18 mm I.D.×0.18 μm (film thickness) RTX-5 (5% diphenyl/95% dimethyl polysiloxane) fused capillary column (second separation dimension, 2D). The RSD of the intra-day repeatability by both GC×GC-FID and GC×GC-TOFMS for elaidic and vaccenic acids was ≤9.56% and ≤9.97%, and the RSD of the inter-day repeatability was ≤8.49 and ≤9.06%, respectively. It was found that the V/E value (vaccenic acid to elaidic acid ratio) could be used to distinguish H-TFA from N-TFA and to evaluate the quality of the fatty foods.

Determination of 22 Ginsenosides in Ginseng Products using Ultra-High-Performance Liquid Chromatography

A reverse-phase ultra-high-performance liquid chromatography (u-HPLC) method was developed for the rapid quantification of 22 ginsenosides in ginseng products. The proposed method for the analysis of ginsenosides is based on a heating-block method without further treatment. The u-HPLC separation was performed on a reversed C18 column (100 × 2 mm id, particle size 2 µm) followed by ultraviolet detection at 203 nm. Aqueous 50% methanol was used as the extraction solvent. The optimum amount of extraction solvent and the optimum extraction time were 20 mL and 20 min (extracted twice with 10 mL), respectively. The method validation parameters yielded good results for linearity, precision, accuracy and recovery. The recovery of ginsenosides from ginseng powder was greater than 98.1% and the limits of detection and quantification of the u-HPLC analysis were >0.6 and >1.8 mg/kg for ginsenosides. The calibration graphs for ginsenosides were linear from approximately 2.6 to 40.4 mg/kg for u-HPLC. The inter-day and intra-day precisions (relative standard deviation values) were <14.6 and 14.7%, except for Rg2(R) + Rh1(R).

Analysis of E,E-farnesol and squalene in makgeolli using stir bar sorptive extraction coupled with gas chromatography-mass spectrometry

The aim of this study was to establish an analytical method for the determination of E,E-farnesol and squalene in makgeolli, which is a traditional type of Korean fermented rice wine. E,E-farnesol and squalene in makgeolli were extracted using stir bar sorptive extraction (SBSE) coupled with gas chromatography-mass spectrometry. SBSE was found to be an effective method for analyzing the E,E-farnesol and squalene levels in makgeolli. The linear dynamic range of the SBSE method for detecting E,E-farnesol and squalene ranged from 0.5 to 200 ng/mL with R 2 =0.9974 for E,E-farnesol and 100 to 50000 ng/mL with R 2 =0.9982 for squalene. The limit of detection and the limit of quantification using the SBSE method were 0.1 and 0.5 ng/mL for E,Efarnesol and 15.0 and 40.0 ng/mL for squalene, respectively. The average recoveries obtained were, quantitatively, 101-107% for E,E-farnesol and 98-103% for squalene, respectively, supporting the accuracy of the SBSE-GCMS method.

Rapid Method for Determination of Anthocyanin Glucosides and Free Delphinidin in Grapes Using u-HPLC

A rapid method for the determination of anthocyanin glucosides and free delphinidin in food using ultra-high-performance liquid chromatography (u-HPLC) was validated through tests of precision, accuracy and linearity. The u-HPLC separation was performed on a reversed-phase C18 column (particle size 2 µm, i.d. 2 mm, length 100 mm) with a photodiode array detector. The limits of detection and quantification of the u-HPLC analyses ranged from 0.07 to 0.65 mg/kg for nine types of anthocyanin glucosides and from 0.08 to 0.26 mg/kg for delphinidin aglycone. The intra-day and inter-day precision of individual anthocyanin glucosides and delphinidin aglycone were less than 9.42%. All calibration curves showed good linearity (coefficient of determination = 0.99) within the tested ranges. The rapid and simultaneous u-HPLC method presented in this study significantly improved the speed, sensitivity and resolution of the analyses of nine types of anthocyanin glucosides and free delphidinin aglycone in grapes.

Chemical Characteristics and Flavors of Bamboo-shoot Vinegar

Bamboo Resource Research InstituteAbstract We assessed the quality of a bamboo shoot vinegar produced in Damyang-gun in terms of parameters thatincluded acidity, mineral contents, amino acids, and flavonol aglycones. The flavor compounds of the bamboo shootvinegar were also analyzed using the stir bar sorptive extraction (SBSE) method. The acidity of the bamboo shoot vinegarwas 4.49%, which was the lowest value among the commercial vinegars studied. The bamboo shoot vinegar had a lowerconcentration of Na (8.36 mg/100 g) than the other commercial vinegars. There was a relatively large amount of tyrosineand lysine in the bamboo shoot vinegar. The concentration of quercetin, a flavonol aglycone, was 3.29 mg/100 g. Theresults of the flavor analysis showed that hexanal, 2-furancarboxaldehyde, and benzaldehyde were high in the bambooshoot vinegar. Oleamide, a compound that is known to induce sleep, was first found in bamboo shoot vinegar using theSBSE method.Keywords: bamboo shoot, vinegar, flavor, stir bar sorptive extraction, oleamide

Determination of 2-Propenal Using Headspace Solid-Phase Microextraction Coupled to Gas Chromatography–Time-of-Flight Mass Spectrometry as a Marker for Authentication of Unrefined Sesame Oil

Ascertaining the authenticity of the unrefined sesame oil presents an ongoing challenge. Here, the determination of 2-propenal was performed by headspace solid-phase microextraction (HS-SPME) under mild temperature coupled to gas chromatography with time-of-flight mass spectrometry, enabling the detection of adulteration of unrefined sesame oil with refined corn or soybean oil. Employing this coupled technique, 2-propenal was detected in all tested refined corn and soybean oils but not in any of the tested unrefined sesame oil samples. Using response surface methodology, the optimum extraction temperature, equilibrium time, and extraction time for the HS-SPME analysis of 2-propenal using carboxen/polydimethylsiloxane fiber were determined to be 55°C, 15 min, and 15 min, respectively, for refined corn oil and 55°C, 25 min, and 15 min, respectively, for refined soybean oil. Under these optimized conditions, the adulteration of unrefined sesame oil with refined corn or soybean oils (1–5%) was successfully detected. The detection and quantification limits of 2-propenal were found to be in the range of 0.008–0.010 and 0.023–0.031 µg mL−1, respectively. The overall results demonstrate the potential of this novel method for the authentication of unrefined sesame oil.

Determination of capsaicinoids in red pepper powder using ultra high performance liquid chromatography

Abstract: The efficiency of the two extractions (refluxing extraction and heating-block extraction) was comparedto develop the simple analytical method for the determination of capsaicinoids, including capsaicin anddihydrocapsaicin in red pepper powder. For the method development, the parameters, including particle size,extraction time and sample size, were evaluated using ultra high performance liquid chromatography (u-HPLC).It was found that the most effective extraction time of the refluxing extraction was 3 hr. The higher extractionefficiency was obtained with the fine particle of a mild red pepper powder, while the particle size did notaffect the extraction efficiency in case of the hot red pepper powder. The higher extraction efficiency wasobtained with the small size of sample taken because of the ratio of the large extracting solvent to sampleamount. The extraction efficiency of the refluxing method was 3-9% higher than that of the heating-blockmethod, however, the heating-block method could be applied to the determination of capsaicinoids in the redpepper powder for the purpose of quality control of the product. 요약: 고춧가루의 매운맛을 나타내는 capsaicinoids인 capsaicin과 dihydrocapsaicin을 초고속액체 크로마토그래피로 간편하게 측정하기 위하여 고춧가루의 입도, 추출시간에 따른 추출율 비교하고 환류추출법과 가열블록법을 비교하였다. 환류추출법의 경우 3 시간 추출하는 것이 효율적이었으며 capsaicinoids 추출율은 덜 매운 고춧가루의 경우 입도가 고울수록 높았으나 매운 청량고추의 경우는 추출율이 입도에 영향을 덜 받았다. 시료량을 달리한 경우 용매의 사용을 동일하게하면 시료를 적게 사용하는 것이 추출율이 높았다. 환류추출법으로 3시간 추출한 것은 가열블록법으로 1 시간 추출한 것에 비하여 추출효율이3-9% 높았으나 품질관리의 목적인 경우 신속간편 방법인 가열블록법으로 고춧가루의 capsaicinoids를 측정하는 것이 가능하였다. Key words: u-HPLC, red pepper powder, capsaicinoids, refluxing extraction, heating-block method