• Food Science of Animal Resources
• /
• v.41 no.4
• /
• pp.731-738
• /
• 2021

Herein, a novel analytical method using a high-performance liquid chromatography-fluorescence detector (HPLC/FLD) is developed for rapidly measuring an L-carnitine ester derivative in infant powdered milk. In this study, solid-phase extraction cartridges filled with derivatized methanol and distilled water were used to effectively separate L-carnitine. Protein precipitation pretreatment was carried out to remove the protein and recover the analyte extract with a high recovery (97.16%-106.56%), following which carnitine in the formula was derivatized to its ester form. Precolumn derivation with 1-aminoanthracene (1AA) was carried out in a phosphate buffer using 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC) as the catalyst. Method validation was performed following the AOAC guidelines. The calibration curves were linear in the L-carnitine concentration range of 0.1-2.5 mg/L. The lower limit of quantitation and limit of detection of L-carnitine were 0.076 and 0.024 mg/L, respectively. The intra- and interday precision and recovery results were within the allowable limits. The results showed that our method helped reduce the sample preparation time. It also afforded higher resolution and better reproducibility than those obtained by traditional methods. Our method is suitable for detecting the quantity of L-carnitine in infant powdered milk containing a large amount of protein or starch.

• Food Science of Animal Resources
• /
• v.41 no.5
• /
• pp.816-825
• /
• 2021

This study aims to validate a fast method of simultaneous analysis of 365 LCamenable and 142 GC-amenable pesticides in hen eggs by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and gas chromatography-tandem mass spectrometry (GC-MS/MS), respectively, operating in multiple reaction monitoring (MRM) acquisition modes. The sample preparation was based on quick, easy, cheap, effective, rugged, and safe (QuEChERS) extraction. Key method performance parameters investigated were specificity, linearity, limit of quantification (LOQ), accuracy, precision and measurement uncertainty. The method was validated at two spiking levels (10 and 50 ㎍/kg), and good recoveries (70%-120%) and relative standard deviations (RSDs) (≤20) were achieved for 92.9% of LC-amenable and 86.6% of GC-amenable pesticide residues. The LOQs were ≤10 ㎍/kg for 94.2% of LC-amenable and 92.3% of GC-amenable pesticides. The validated method was further applied to 100 egg samples from caged hens, and none of the pesticides was quantified.

• The Korean Journal of Food & Health Convergence
• /
• v.9 no.6
• /
• pp.9-19
• /
• 2023

Lactobacillus plantarum and Leuconostoc mesenteroides are crucial functional starters and predominant isolates in a wide range of fermented foods, particularly kimchi, whose constituents exhibit bioactive properties. We previously developed a methodology using anion exchange resins to purify peptidyl compounds from Lb. plantarum LBP-K10. Antibacterial cultures of Lb. plantarum LBP-K10 were obtained from the respective cultures' supernatants and filtrates. However, conclusive evidence of the efficacy of kimchi filtrates in eradicating pathogenic bacteria is lacking. We aimed to simulate the potential effects of antibacterial filtrates that contained antibacterial compounds which were derived from cultures of Lb. plantarum LBP-K10. We acquired the kimchi filtrates using a combination of centrifugation and filtration methodologies, without the requirement for inoculation. The filtered liquid from Chinese cabbage kimchi, inoculated with Lb. plantarum LBP-K10 as a starter culture, and the non-inoculated liquid from Chinese cabbage kimchi (referred to as CCK and CCKRef, respectively) were were examined. CCK demonstrated greater inhibitory activity and a more significant bactericidal effect against the bacterial indicator strains. The minimum inhibitory concentration demonstrated comparable outcomes in tests against both Gram-positive and Gram-negative bacteria. This research offers a groundbreaking examination that displays the effectiveness of profiling peptidyl compounds within kimchi filtrates for curing bacterial infections.

• Korean Journal of Food Science and Technology
• /
• v.45 no.6
• /
• pp.693-699
• /
• 2013

A simple, sensitive, and specific method for quantifying the nicotine content of synthetic favoring substances (SFS) was developed using high performance liquid chromatography (HPLC) with a photo-diode array detector (PDA). Nicotine was extracted from SFS samples by using an acid-base liquid-liquid extraction method with dichloromethane and distilled water. The nicotine content was quantified by HPLC/PDA (261.9 nm) with a $C_{18}$ column under a gradient of 10% acetonitrile with 20 mM ammonium formate (ammonia solution adjusted to pH 8.7) to 100% acetonitrile. The calibration curve, analyzed from concentration standards between 0.1 to 2 mg/L, presented linearity with a correlation coefficient ($r^2$)>0.9999. The limit of quantitation (LOQ) of nicotine in SFS was 0.4 mg/kg, and the average recoveries ranged from 76.4% to 96.3%. The repeatability of measurements, expressed as the coefficient of variation (CV%), ranged from 1.74 to 5.12%. This newly developed method for nicotine quantification in SFS can be considered an analytical method with an acceptable level of sensitivity and repeatability.

• Journal of Korean Clinical Nursing Research
• /
• v.22 no.1
• /
• pp.20-27
• /
• 2016

Purpose: The purpose of this study was to compare the fluid intake and output (I&O) measurement methods in order to figure out more effective and easier method for medical patients Methods: 71 hospitalized patients participated in the study. In "liquid only (LO)" method, all amount of water was summed up including any liquid types of food and IV fluids. In "whole food(WF) intake," all liquid and solid food intake and IV fluids were added up. Results: The average amount of fluid intake was 2105.29 ml for LO method and 2523.54 ml for WF method. The average amount of fluid output was 2148.98 ml. The intra-class correlations (ICC) between the intake and output measures by the two different methods was 0.803 and 0.826, respectively. The correlation between the differences of intake/output and body weight change in two different methods was r=.347 (p=.003), and r=.376 (p=.001), respectively. Conclusion: The results of this study indicate that both LO and WF method may be useful in monitoring patients' fluid balance. Given the comparability of using LO over WF, it is suggested that measuring just liquid only intake as the indicator of patient's intake is applicable in clinical setting.

• The Korean Journal of Food And Nutrition
• /
• v.33 no.3
• /
• pp.339-346
• /
• 2020

Although aronia (Aronia melanocarpa (Michx.) Elliott) contains higher levels of polyphenols and more antioxidant activity than other berries, it is a berry that is difficult to eat raw due to its strong astringent taste and lack of sweetness. Therefore, in this study, we investigated the effect of tannin reduction of aronia by bioconversion method using mushroom mycelia cultures. Aronia and liquid cultures of Lentinula edodes and Phellinus linteus mycelia were mixed and then treated for 48 hours at 60℃. Tannin content, total polyphenol, total flavonoid and antioxidant activities (DPPH, ABTS radical-scavenging activities and FRAP activities) were investigated. The tannin content decreased from 64.2 mg ECE/g to 57.9 mg ECE/g (9.8% reduction) when treated with liquid culture of L. edodes and from 77.3 mg ECE/g to 47.9 mg ECE/g (38.1% reduction) from treatment with a liquid culture of P. linteus. Therefore treatment with mushroom mycelia culture solution may improve the palatability of aronia reducing the astringent taste.

• Membrane and Water Treatment
• /
• v.6 no.3
• /
• pp.237-249
• /
• 2015

In this study we investigate a laboratory scale vacuum membrane distillation system to produce pure water from model oil in water emulsion. Experimental determination of liquid entry pressure (LEP) of a commercial Durapore$^{TM}$ GVPH flat sheet membrane using model emulsions in various oil concentrations has been carried out. Two different methods of liquid entry pressure determination - a frequently used, so-called static and a novel dynamic method - have been investigated. In case of static method, LEP value was found to be 2.3 bar. No significant effect of oil content on LEP was detected up to 3200 ppm. In contrast, LEP values determined with dynamic method showed strong dependence on the oil concentration of the feed and decreased from 2.0 bar to a spontaneous wetting at 0.2 bar in the range 0-250 ppm, respectively. Vacuum membrane distillation tests were also performed. The separation performance is evaluated in terms of flux behavior, total organic carbon removal and droplet size distribution of the feed and final retentate. No significant effect of oil content on the flux was found ($5.05{\pm}0.31kgm^{-2}h^{-1}$) up to 250 ppm, where a spontaneous wetting occurred. High separation performance was achieved along with the increasing oil concentration between 93.4-97.0%.

• Korean Journal of Food Science and Technology
• /
• v.17 no.3
• /
• pp.197-202
• /
• 1985

In order to evaluate the aptness for the preparation of liquid-yogurt, microbiological properties of 8 Lactobacilli isolated from 7 Korean liquid-yogurts were investigated. To accelerate acid-producing ability in skim milk, L. bulgaricus D, L. casei A and L. casei E need to supply with glucose, and L. Casei A and L. csaei E also need milk-protein hydrolyzate, but L. jugurti B, L. jugurti C, L. jugurti G, L. helveticus F and L. acidophilus B did not need those supplements. In cultivation in skim milk supplemented with glucose, L. jugurti B, L. jugurti C, L. jugurti G. L. helveticus F and L. bulgaricus D showed rapidity in acid development and weakness in cell viability, but L. acidophilus B, L. casei A and L. casei E showed slowness in acid development and highness in cell viability. Liquid-yogurts made by L. casei A or L. casei E had no sedimentation during storage but those made by L. jugurti B, L. jugurti C, L. jngurti G, L. helveticus F, L. bulgaricus D, or L. acidophilus B had much sedimentation. In sensory evaluation, Liquid-yogurts made by L. casei A or L. casei E had good response but those made by L. jugurti B, L. jugurti C, L. jugurti G, L. helveticus F, L. bulgaricus D or L. acidophilus B did not. Among 8 Lactobacilli examined, L. casei A and L. casei E were thought to have more suitable properties for the preparation of liquid-yogurt though they required a long period of cultivation.

• Analytical Science and Technology
• /
• v.34 no.4
• /
• pp.160-171
• /
• 2021

Synthetic azo dyes are used extensively in herbal medicines to render the medicines more visually attractive to consumers. This study developed and validated a rapid high-performance liquid chromatography (HPLC) method to determine whether synthetic colorants such as Tartrazine, Auramine O, Metanil yellow, Sunset yellow, and Orange II are used extensively in Typha orientalis. To increase the recovery of the synthetic dyes, this method employed containing 50 mM ammonium acetate in 70 % methanol at first extraction and 100 mM HCl in 70 % methanol at second extraction. Five synthetic pigments in Typha orientalis were separated by gradient elution with a mobile phase consisting of acetonitrile and 50 mM ammonium acetate in distilled water at ultra-violet (UV) detection 428 nm or 500 nm. Additionally, this study established the liquid chromatography tandem mass spectrometry (LC-MS/MS) method to confirm positive samples suspected by HPLC results. The HPLC-UV method had good linearity, indicating r²> 0.999. The recoveries of the samples spiked with three different concentration ranged from 73.8~91.5 %, and relative standard deviation values indicated 0.2~5.2 %. The established LC-MS/MS could successfully identify the synthetic pigments in herbal medicine samples. The study demonstrates that Typha orientalis adulterated by yellowish synthetic dyes can be successfully distinguished when using the HPLC-UV method.

• Analytical Science and Technology
• /
• v.30 no.4
• /
• pp.174-181
• /
• 2017

Bio-liquid is a liquid by-product of the hydrothermal carbonization (HTC) reaction, converting wet biomass into solid hydrochar, bio-liquid, and bio-gas. Since bio-liquid contains various compounds, it requires efficient sampling method to extract the target compounds from bio-liquid. In this research, fatty acid methyl ester (FAME) in bio-liquid was extracted based on hollow fiber supported liquid phase microextraction (HF-LPME) and determined by Gas Chromatography-Flame Ionization Detector (GC-FID) and Gas Chromatography/Mass Spectrometry (GC/MS). The well-known major components of biodiesel, including methyl myristate, palmitate, methyl palmitoleate, methyl stearate, methyl oleate, and methyl linoleate had been selected as standard materials for FAME analysis using HF-LPME. Physicochemical properties of bio-liquid was measured that the acidity was 3.30 (${\pm}0.01$) and the moisture content was 100.84 (${\pm}3.02$)%. The optimization of HF-LPME method had been investigated by varying the experimental parameters such as extraction solvent, extraction time, stirring speed, and the length of HF at the fixed concentration of NaCl salt. As a result, optimal conditions of HF-LPME for FAMEs were; n-octanol for extraction solvent, 30 min for extraction time, 1200 rpm for stirring speed, 20 mm for the HF length, and 0.5 w/v% for the concentration of NaCl. Validation of HF-LPME was performed with limit of detection (LOD), limit of quantitation (LOQ), dynamic range, reproducibility, and recovery. The results obtained from this study indicated that HF-LPME was suitable for the preconcentration method and the quantitative analysis to characterize FAMEs in bio-liquid generated from food waste via HTC reaction.