• Food Science of Animal Resources
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• v.32 no.6
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• pp.810-819
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• 2012

This study investigated the chemical composition, meat quality and volatile flavor compounds in loin and top round of Hanwoo beef (n=126) depending on different age groups (G1, <5; G2, 6-8; G3, >9 years old). The intramuscular fat content (%) was higher for loin and top round of G1 (p<0.05) than that in the other groups. There was no difference in age groups for the top round; however, the loin of G1 had lower protein content (p>0.05). Total collagen content was lower in the top round of G3 (p<0.05). The loin and top round muscles of G1 had higher $a^*$ values and lower Warner Bratzler shear force values than that in the other age groups (p<0.05). The loin muscles of G1 were lower in percentage of cooking loss and higher in the water holding capacity than the loin in the other groups (p<0.05). The loin of G1 had lower total content of saturated fatty acids, whereas the top round of G1 had higher total content of monounsaturated fatty acids and lower total content of polyunsaturated fatty acids than that in the other age groups (p<0.05). Alanine was the highest free amino acid in the loin of Hanwoo beef, followed by glutamine, glycine, isoleucine and proline. The loin of G1 had higher contents of threonine, alanine, valine, methionine, phenylalanine, leucine and lysine than those in the other groups (p<0.05). The loin of G3 contained higher 3-methylbutanal, furfural, octanal, 1-(acetyloxy)-2-propanone, 1-octanol, 2,5-dimethylpyrazine and 2-ethyl-2,5-dimethylpyrazine in volatile flavor components than the loin in G1(p<0.05).

• Journal of Food Hygiene and Safety
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• v.35 no.5
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• pp.430-437
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• 2020

This is an approach study on the sensory properties (taste and odor) of 15 types of Korean conventional soups and stews using electronic nose and tongue. The relative sensor intensity for the taste components of the samples using electronic tongue was demonstrated. By SRS (sourness) sensor, sogogi-baechuguk (beef and cabbage soup) had the highest rate of 9.0. The STS (saltiness) sensor showed the highest score of 8.2 for ojingeoguk (squid soup). For the UMS (umami) sensor, which identifies savoriness, the sogogi-baechuguk was the highest at 10.1. The SWS (sweetness) sensors showed relatively little difference, with sigeumchi-doenjangguk (spinach and bean paste soup) at the highest of 7.3. According to the BRS sensor, which tests for bitterness, the siraegi-doenjangguk (dried radish green and bean paste soup) was the highest at 7.8. By principal component analysis (PCA), we observed variances of 56.21% in principal component 1 (PC1) and 25.23% in PC2. For each flavor component, we observed -0.95 and -0.20 for factor loading of PC1 and PC2 for SRS sensors, 0.96 and 0.14 for STS sensors, and -0.94 and 0.22 for PC1 and PC2 for UMS sensors, and PC1 and 0.22 for PC1 and PC2 loading for SWS sensors. The similarity between the samples identified by clustering analysis was largely identified by 4 clusters. A total of 25 kinds of volatile compounds in 15 samples were identified, and the ones showing the highest relative content in all samples were identified as ethanol and 2-methylthiophhene. The main ingredient analysis confirmed variances of 28.54% in PC1 and 20.80% in PC2 as a result of the pattern for volatile compounds in 15 samples. In the cluster analysis, it was found to be largely classified into 3 clusters. The data in this study can be used for a sensory property database of conventional Korean soups and stews using electronic sensors.

• Korean Journal of Microbiology
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• v.52 no.1
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• pp.98-109
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• 2016

The study was aimed to investigate the mixing ratio of kiwi and persimmon juices for the production of good quality wine by Saccharomyces cerevisiae Y28. Firstly, the optimum condition of rapidase treatment for the kiwi and persimmon juices was established, thereafter various mixing ratio (10:0, 9:1, 8:2, 7:3, 6:4, 5:5) of kiwi and persimmon was investigated regarding physiochemical properties and flavor compounds of wine. As the result, the optimum conditions were obtained as 0.3% rapidase for 1 h in kiwi and 0.3% rapidase for 3 h in persimmon. According to higher ration of persimmon, the pH of wines increased from 3.69 to 3.77, while the acidity of wines decreased from 2.07% to 1.51% at 14 days fermentation. The ranges of brix and reducing sugar in wines were decreased which ranges around 9.6 to 8.8 and 6.07 to 6.90 g/L, respectively, after fermentation. Major organic acid in wines were identified as tartaric acid, malic acid, and citric acid. A small amount of free sugar such as sucrose and glucose were detected in wines, but fructose was completely absent. The soluble phenolic contents were decreased that ranges around 1.00 to 1.25 g/L, in contrast, browning degree were increased ranges around 0.212 to 0.412 after fermentation. The major flavor components were identified as ethyl acetate and hydrazine, and 1,1-dimethyl. Importantly, phenylethyl alcohol was detected from the all wines that have a typical rose like flavor. But sensory test results and preference of kiwi-persimmon (7:3) mixing wine was better than the other wines.

• Clean Technology
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• v.21 no.1
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• pp.76-82
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• 2015

Volatile organic compounds (VOC) free adhesives have been interested by many scientists and engineers due to environmental regulations and the safety of industrial workers. In this work, a series of composites composed with bisphenol A epoxy resin used as solvent, dicyandiamide, and promoter were prepared to investigate the most appropriate molar ratio for steel-steel adhesion. The cured test specimen of each composite were measured with universal testing machine (UTM) to figure out mechanical properties such as tensile strength, Young’s modulus, and elongation. Furthermore, the lap shear strength of the specimen was tested with UTM while impact resistance was measured with Izod impact tester. The composite whose molar ratio of epoxy resin to curing agent is 1 : 0.9 (sample 3), showed better tensile strength, coefficient of elastic modulus, elongation, and impact strength than other composites did. The highest tanδ from dynamic mechanical analysis (DMA) was observed from sample 2 (epoxy resin: dicy = 1 : 0.7) while sample 3 showed slightly lower tanδ than that of 2. The morphology of the fracture surface of the cured composites from SEM showed that the number of subtle lines on the surface caused by impact increase as the contents of amine curing agent accrete. Furthermore, the viscosity change of sample 5 (epoxy resin: dicy = 1 : 1.3) was observed to confirm its storage stability.

• Analytical Science and Technology
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• v.26 no.3
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• pp.165-173
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• 2013

To establishment of PT Program for Indoor air quality field that manufacture of confidential development PTMs (proficiency testing materials) and examined of proficiency testing evaluation included sampling process whether or not that is valid. Confirmation of homogeneity and stability of PTMs prepared. PTMs were confirmed to be homogeneous enough to be used as proficiency testing materials since withinbottle homogeneities of the RMs were lower than 0.3 times of targeted standard deviation of proficiency testing. The result of this study showed that the Robust RSD of proficiency testing for VOCs (volatile organic compounds) appeared 23~43% in concentration of 50~320 ${\mu}g/m^3$ for Method A(Distribution by adsorption in Tenax-tube of VOCs), but less 13~42% in concentration of 200~1200 ${\mu}g/m^3$, 16~31% in concentration of 100~450 ${\mu}g/m^3$ for Method B (distribution by VOCs of gas phase in 10L Tedalr bag), C (directly sampling of cylinder with high pressure) respectively. The result of this study showed that method C with sampling is most adequate to the proficiency testing for VOCs in indoor air.

• Korean Chemical Engineering Research
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• v.59 no.4
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• pp.548-556
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• 2021

This study was conducted to investigate the applicability of lignocellulosic fiber and coconut shell activated carbon (CSA) for the production of a particulate matter (PM)-reducing air-filter as raw materials to solve the environmental problems of non-woven fabrics. CSA had a good potential to use as a raw material of air-filter for reducing volatile organic compounds as well as noxious metals, and reduction capability of the CSA was 5 times higher than that of wood fiber. Natural adhesives formulated with proteinaceous wastes mostly were applied successfully to fabricate air-filters with the shape of fiberboard. The air-filter fabricated with the minimum target density of 200 kg/m³ and the maximum CSA-content of 40 wt% in fiberboard had a good manageable strength. However, the fiberboard filters was required to make vent-holes for improving an air-permeability of the filters. Size of the CSA particles was adjusted to greater than 2 mesh with the consideration of strength and formability of the fiberboard. Three-layers fiberboard that only wood fiber and the mixture of wood fiber and CSA were formed in the surface and middle layers, respectively, was determined to the optimal condition for the production of air-filters. In addition, traditional Korean paper handmade from mulberry trees (TKP) showed a good PM-reducing property as an air-filter. It is concluded that air-filtering set composed of fiberboard with vent-holes and TKP instead of conventional air-filters made with non-woven fabrics can be used as a filter for reducing the concentrations of PM, VOC and noxious metals existed in indoor and outdoor spaces.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.5
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• pp.572-580
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• 2019

In view of the numerous discussions on global environmental issues, policies have been implemented to limit emissions in the field of marine transport, which accounts for a major part of international trade. In this study, a ship's emissions were calculated by applying the engine load factor to determine the total quantity of emissions based on the ship's speed reduction. For ships entering and leaving the Busan North Port from 1 January to 31 December 2017, emissions were calculated and analyzed based on the ship's type and its speed in the reduced speed zone (RSZ), which was set to 20 nautical miles. The comparison of the total amount of emissions under all situations, such as cruising, maneuvering, and hotelling modes revealed that the vessels that generated the most emissions were container ships at 76.1 %, general cargo ships at 7.2 %, and passenger ships at 6.8 %. In the cruising and maneuvering modes, general cargo ships discharged a lesser amount of emission in comparison with passenger ships; however, in the hotelling mode, the general cargo ships discharged a larger amount of emission than passenger ships. The total emissions of nitrogen oxides (NOx), sulphur oxides (SOx), particulate matter (PM), and volatile organic compounds (VOC), were 49.4 %, 45 %, 4 %, and 1.6 %, respectively. Furthermore, the amounts of emission were compared when ships navigated at their average service speed, 12, 10, and 8 knots in the RSZ, respectively. At 12 knots, the reduction in emissions was more than that of the ships navigating at their average service speed by 39 % in NOx, 40 % in VOC, 42 % in PM, and 38 % in Sox. At 10 knots, the emission reductions were 52 %, 54 %, 56 %, and 50 % in NOx, VOC, PM, and Sox, respectively. At 8 knots, the emission reductions were 62 %, 64 %, 67 %, and 59 % in NOx, VOC, PM, and Sox, respectively. As a result, the emissions were ef ectively reduced when there was a reduction in the ship's speed. Therefore, it is necessary to consider limiting the speed of ships entering and leaving the port to decrease the total quantity of emissions.

• Korean Journal of Remote Sensing
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• v.39 no.5_1
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• pp.563-576
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• 2023

In this study nitrogen dioxide (NO₂), formaldehyde (HCHO) from the Ozone Monitoring Instrument (OMI) and TROPOspheric Monitoring Instrument (TROPOMI), OMI/ Microwave Limb Sounder (MLS) tropospheric column ozone (TCO), and Airkorea ground-based O₃ data were analyzed to examine the photochemical reaction relationship between tropospheric ozone and its precursors nitrogen oxides (NOx) and volatile organic compounds (VOCs). As a result of analyzing the trend of long-term changes from 2006 to 2020 using OMI satellite data, TCO showed an increasing trend, NO₂ steadily decreased, and HCHO continued to increase in Northeast Asia. In addition, formaldehyde nitrogen dioxide ratio (FNR; HCHO/NO₂ ratio), an indicator of ozone sensitivity, is gradually increasing, which means that the VOC-limited regime is decreasing. This study conducted a sensitivity analysis of ozone generation using TROPOMI FNR and ground-based ozone (O₃) over the recent years (2019~2022) to identify the possible cause for the continuous increase of ozone in Korea. Similar to the previous studies, VOC-limited and transitional regimes appeared in megacities, and VOC-limited regimes also appeared in areas where major power plants were located. In VOC-limited regimes, in other words, areas where NOx is excessively saturated, the reduction in NOx emissions may have weakened the ozone titration and thus led to the increase of ozone. Therefore, VOC emissions should be reduced in the short term rather than NOx emissions to reduce ozone concentrations under the VOC-limited regime.

• Analytical Science and Technology
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• v.28 no.6
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• pp.385-397
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• 2015

Harmful and potentially harmful constituents (HPHCs) are chemical compounds in tobacco smoke that cause harm to smokers and non-smokers. This study established and validated methods for the analysis of HPHCs from mainstream cigarette smoke. The analyzed HPHCs were categorized into seven groups: aromatic amines, volatile organic compounds (VOCs), heavy metals, tobacco specific nitrosamines (TSNAs), benzo[a]pyrene (B[a]P), ammonia, and carbonyl compounds. The methods were validated by specificity, linearity, limit of detection (LOD), accuracy, precision, and recovery. These validated methods were then applied to the reference cigarettes (1R5F, 3R4F). The correlation coefficients (r²) for the calibration curves of the seven groups were over 0.995. The LODs showed values of 0.01-0.04 ng/cig cig for aromatic amines, 0.01-0.16 μg/cig for VOCs, 0.01-1.27 ng/cig for heavy metals, 0.06-0.28 ng/cig for TSNAs, 0.04 ng/cig for benzo[a]pyrene, 0.08 μg/cig for ammonia, and 0.78-1.77 μg/cig for carbonyl compounds. The precisions obtained from the intra and inter-day batches were less than 15%. The accuracy and the recovery range were less than 15% and 79.2-117.5%, respectively. The proposed methods can therefore be applied for determining HPHCs in tobacco mainstream smoke.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.6
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• pp.799-805
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• 1998

In present paper, we examined the flayer constituents and functionality of two stage enzyme hydrolysates (TSEH) of purplish clam and oyster, and also examined reappearance of oyster flavors through repreparation of individual flayer constituents. Total free amino acid contents in TSEH was $1943.0mg\%$ for purplish clam and was $5066.2 mg\%$ for oyster, respectively, Major free amino acids in purplish clam extracts were taurine, glutamic acid, glycine, alanine, Iysine and arginine, and in oyster extracts were taurine, asparagine, glutamic acid, valine, leucine, alanine, Iysine and arginine. As for nucleotides and related compounds, AMP was the principal component though small amounts in TSEH of purplish clam and oyster, and also contents of TMAO, total creatinine, and betaine were $41.2 mg\%,\;35,9 mg\%$ and $220.9 mg\%$ for that of purplish clam and $3.51 mg\%,\;33.4 mg\%$ and $380.9 mg\%$ that of oyster, respectively. The major inorganic ions in TSEH of both samples were Na, K, P, Cl and $PO_4$, and major non-volatile organic acid was succinic acid. The TSEH of purplish clam and oyster revealed very higher inhibition effect ($84.1\%,\;77.0\%$) in ACE inhibition than that ($0\~44.7\%$) of water and autolytic extract. A synthetic oyster extract prepared from pure chemicals on the basis of the analytical data on the TSEH, satisfactorily reproduced the taste of the natural extract except for a slight lack of mildness and odor. From the omission test the major taste compounds of oyster extract were free amino acid and inorganic ions. The quaternary ammonium bases, nucleotides and related compounds seemed to net an auxiliary role in taste of that.