• Korean Journal of Food Science and Technology
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• v.22 no.2
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• pp.206-214
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• 1990

Effects of commercial food grade porcine pancreatic lipase on the neutral volatile compounds in Cheddar cheese were studied The enzyme was incorporated into the cheese at two different levels of concentration and ripened at various temperatures. The production of 2-butanone increased at higher amount of lipase and higher temperature, but the production of 2-pentanone was inconsistent trends during ripening periods. The concentration of acetaldehyde was the highest among aldehydes and was increased consistently during ripening Periods. In alcohol production ethanol was the most abundant but no further consistent trend was observed after 6 wk. The production of ethyl butyrate was the most abundant ester and related io lipase activities as well as ripening temperatures. Dimethyl sulfide was the only sulfur compound and appeared not to be related to the addition of lipase or ripening temperatures . Statistical analysis suggested that ethyl butyrate was most correlated to aged Cheddar flavor during cheese ripening.

• Korean Journal of Food Science and Technology
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• v.27 no.6
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• pp.939-943
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• 1995

This study was carried out to investigate neutral volatile compounds and sensory quality of yogurt during the storage of 15 days at $10^{\circ}C$. The yogurt was manufactured with mixed culture containing Lactobacillus acidophilus, Bifidobacterium bifidum and Streptococcus salvarius subsp. thermophilus. Among the volatile compounds, acetaldehyde, acetone and ethanol increased significantly, and 2-butanone and 2-heptanone increased slightly but diacetyl did not increase during the storage periods. In sensory test, the flavor scores of yogurt were not different during the period, but those of off-flavor were significantly different (p<0.05). In correlation between the volatile compounds and sensory test, there was negative correlation between acetone and yogurt flavor, but positive correlations between ethanol and off-flavor (p<0.05). The results suggested that the volatile flavor compound may not affect the quality of yogurt during 15d storage period at $10^{\circ}C$.

• KSBB Journal
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• v.15 no.5
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• pp.501-506
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• 2000

A bench-scale air biofilter was evaluated for the removal of volatile organic compounds (VOCs) from a gas stream. Compost and peat were used as the biological attachment media. Biofilter operating parameters such as incoming VOCs concentrations, temperature, and packing materials were examined. After 26 days of acclimation periods, at 25$^{\circ}C$ and 45$^{\circ}C$, the biofilter removed more than 90% of 30 to 72 mg/㎥ of total VOC. After 40 days of operation, the concentrations of isoprene, toluene, and m-xylene were reduced to 96∼99, 91∼93, and 91∼93% of the original concentrations. VOC removal efficiency was not affected by the temperature. The medium pH was maintained near neutral (pH 6.5∼7.1). After 37 days of operation, the total bacteria count in the biofilter media increased to 1.12${\times}$10(sup)8 cells/g of medium.

• Journal of the Korean Wood Science and Technology
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• v.30 no.4
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• pp.80-86
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• 2002

Volatile compounds in three different kinds of crude vinegars obtained from oak (Quercus serrata), bamboo (phyllostachys) and pine (Pinus densiflora) species were analyzed by the solid-phase microextraction (SPME) method. A total of 264 peaks were detected on the chromatograms obtained from the polar (CBP 20) and the nonpolar (CBP 1) columns, which were used for analyzing the volatile compounds in these vinegars. The major volatile compounds identified by using the polar column were 2-butanone, acetic acid, guaiacol, phenol, cresols, 4-ethyl guaiacol, 4-ethyl phenol, and syringol. Using the nonpolar column, seven compounds could be identified: 1,2-dimethoxybenzyl alcohol, 1-hydroxy-2-butanone, 1-(2-furanyl)-1-propane, ethisolide, furfuryl acetate, 1,2-dimethoxybenzene, phenyl acetate. The volatile compounds were classified into five groups: phenols, neutral compounds, organic acids, esters and others. The phenols were the main component and comprised 49~65% of the volatile compounds of these vinegars. In the case of bamboo vinegar, the proportion of the phenols in the volatile compounds was lower than that of the two wood vinegars. However, the proportions of the neutral compounds and the organic acids were higher than those of the wood vinegars. Therefore, it seems that these differences of the proportions of the volatile compounds would make a certain difference of a smoke flavor between the bamboo vinegar and the wood vinegars.

• Journal of environmental and Sanitary engineering
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• v.18 no.1
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• pp.58-67
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• 2003

The characteristics of the commercial garbage-decomposing accelerant, Raw Material of Pomia(RMP), Pomia and Vitabio. were analyzed. In HPLC pattern, Pomia and Vitabio showed main peak of about 30kDa in 280nm wave length. RMP, Pomia and Vitabio showed three, two and two peaks in 210nm. K and Na ion content of RMP were 2,620 and 1,590ppm, respectively, and their content were the largest one among others. Ca, Mg and Mn ion content of RMP were also the largest one, but Zn ion content was the least one. $Cl^{-}$, $F^{-}$ and $NO_3^{-}$ ion content of RMP were the largest one, especially $Cl^{-}$ content was 3,553ppm. pH values of RMP and Pomia were in neutral region, but Vitabio was 9.03. Dried residue content of RMP, Pomia and Vitabio were 1.4%, 0.55% and 0.4%, respectively. The number of general bacteria on PCA plate from RMP, Pomia and Vitabio were 2.2{\times}10^{6}cfu/ml,{\;}6.5{\times}10^{3}cfu/ml{\;}and{\;}1.1{\times}10^{3}cfu/ml$, respectively. The number of facultative anaerobes of RMP was $4.4{\;}{\times}{\;}10^{4}cfu/ml$, and it was biggest one. Lactobacilli and yeasts were found less than 10cfu/ml at best. The bacterium exists in RMP in high frequency was identified as Bacillus subtilis. Volatile sulfur compound amount of garbage samples treated with Pomia and Vitabio in concentration of 1/500 at $33^{\circ}C$ for 8 days were 1,273ppb and 1,902ppb, respectively, and control showed 3,015ppb. Volatile organic compound amount of the garbage samples treated were 68,312ppb, 124,317ppb and 263,954ppm, respectively. Diethylamine that known as malodor compound were 5,107ppb, 261ppb and 11,124ppb, respectively.

• Clean Technology
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• v.28 no.2
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• pp.131-137
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• 2022

The semiconductor process currently emits various by-products and unused gases. Emissions containing pollutants are generally classified into categories such as organic, acid, alkali, thermal, and cabinet exhaust. They are discharged after treatment in an atmospheric prevention facility suitable for each exhaust type. The main components of organic exhaust are volatile organic compounds (VOC), which is a generic term for oxygen-containing hydrocarbons, sulfur-containing hydrocarbons, and volatile hydrocarbons, while the main components of alkali exhaust include ammonia and tetramethylammonium hydroxide. The purpose of this study was to determine the combustion characteristics and analyze the NO_X reduction rate by maintaining a direct combustion and temperature to process organic and alkaline exhaust gases simultaneously. Acetone, isopropyl alcohol (IPA), and propylene glycol methyl ether acetate (PGMEA) were used as VOCs and ammonia was used as an alkali exhaust material. Independent and VOC-ammonia mixture combustion tests were conducted for each material. The combustion tests for the VOCs confirmed that complete combustion occurred at an equivalence ratio of 1.4. In the ammonia combustion test, the NO_X concentration decreased at a lower equivalence ratio. In the co-combustion of VOC and ammonia, NO was dominant in the NO_X emission while NO₂ was detected at approximately 10 ppm. Overall, the concentration of nitrogen oxide decreased due to the activation of the oxidation reaction as the reaction temperature increased. On the other hand, the concentration of carbon dioxide increased. Flameless combustion with an electric heat source achieved successful combustion of VOC and ammonia. This technology is expected to have advantages in cost and compactness compared to existing organic and alkaline treatment systems applied separately.

• Journal of Life Science
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• v.17 no.2 s.82
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• pp.286-292
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• 2007

Free amino acids and volatile compounds of fresh garlic and its liqueur were investigated to search elution profile of those components as basic data for development of garlic liqueur. The garlic was soaked in 20% alcohol solution and then sampled every week for 5 weeks. The major free amino acids were L-aspartic acid, L-glutamic acid, L-arginine, L-alanine, L-proline, L-asparagine and L-serine. Neutral amino acids such as L-threonine, L-proline, L-valine and L-leucine, and aromatic amino acids such as tyrosine and phenylalanine were eluted over 80% of those content in fresh garlic after 3 weeks of soaking, but acidic, basic and sulfur containing amino acids were below 80% even after 5 weeks. Sulfide compounds such as diallyl trisulfide, diallyl disulfide, methyl allyl disulfide, 2-vinyl-4H-1,3-dithi in, 3-vinyl-3,4-dihydro-1,2-dithiin, 3,5-diethyl-1,24-trithiolane, isobutyl isothiocyanate and diallyl sulfide were identified as major volatile compounds of fresh garlic by using GC/MS. Among volatile compounds of fresh garlic, allyl alcohol, diallyl disulfide, 3,5-diethyl-1,2,4-trithiolane, diallyl trisulfide and 3,4-dimethoxy furan were eluted to liqueur, but those compounds except 3,5-diethyl-1,2,4-trithiolane were lowered in liqueur during soaking. Furfural, 5-methylfurfural, 5-hydroxymethylfurfural, dimethyl pyrazine, furfuryl alcohol, 3-hydroxy-2-bytanone and 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyr-an-4-one were generated newly and their content increased in liqueur during soaking.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.8
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• pp.1205-1211
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• 2003

This study was designed to examine the effect of microencapsulated iron-fortified Cheddar cheese and L-ascorbic acid as a bioavailable helper of iron on chemical and sensory aspects. Coating material was PGMS, and ferric ammonium sulfate and Lascorbic acid were selected as core materials. The highest efficiency of microencapsulation of iron and L-ascorbic acid were 72 and 94%, respectively, with 5:1:50 ratio (w/w/v) as coating to core material to distilled water. TBA absorbance was significantly lower in microencapsulated treatments than those in uncapsulated treatments during ripening. The productions of short-chain free fatty acid and neutral volatile compound were not significantly different among treatments during ripening periods. In sensory aspects, bitterness, astrigency and sourness were higher in Cheddar cheese fortified with microencapsulated iron and uncapsulated L-ascorbic acid than others. The present study indicated that fortification of iron as well as L-ascorbic acid did not show any defect problem to Cheddar cheese, and suggested the possibility of iron fortification of Cheddar cheese.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.3
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• pp.409-416
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• 2003

This study was carried out to find a cholesterol removal rate, flavor development and bitter amino acid productions in Cheddar cheese treated with $\beta$-cyclodextrin (CD): 1) Control (no homogenization, no $\beta$-CD), and 2) Milk treatment (1000 psi milk homogenization, 1% $\beta$-CD). The cholesterol removal of the cheese was 79.3%. The production of short-chain free fatty acids (FFA) increased with a ripening time in both control and milk treated cheese. The releasing quantity of short-chain FFA was higher in milk treated cheese than control at 5 and 7 mo ripening. Not much difference was found in neutral volatile compound production between samples. In bitter-tasted amino acids, milk treatment group produced much higher than control. In sensory analysis, texture score of control Cheddar cheese significantly increased with ripening time, however, that in cholesterol-reduced cheese decreased dramatically. Our results indicated that the cheese made by $\beta$-CD treated milk with low pressure homogenization showed an effective cholesterol reduction and a rapid cheese ripening, while no capture of flavor compounds by $\beta$-CD.

• Journal of the Korean Society of Food Science and Nutrition
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• v.21 no.5
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• pp.557-565
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• 1992

Volatile components of domestic Meju and Doenjang were extracted by simultaneous steam distillation extraction, and analyzed by GC-MS. Sixty-four kinds of compounds were identified from neutral fraction. The contents of pentanal, hexanal and 1-octen-3-ol were high in cooked soybean while those of 3-methylbutanal and 1-butanol were high in Meju. In the case of Doenjang, so many compounds including acetic acid, ethylester were identified which was not appeared in Meju. The main compounds in Meju were 3-methyl-1-butanol, 2-furancarboxyaldehyde, 1-octen-3-ol, benzeneacetaldehyde, methyloctadecadienoate and methyloctadecenoate. Of the eleven compounds identified from basic fraction, the contents of 2,6-dime-thylpyrazine, trimethylpyrazine and tetramethylpyrazine were high in Meju and Doenjang. Nine kinds of compounds were identified from phenolic fraction and appeared that 4-vinylphenol and p-ethylguaiacol were major compounds in Meju and Doenjang. Fifteen kinds of volatile compounds were contained in acidic fraction. Only four acidic compounds were identified in cooked soybean and Meju, but in Doenjang ten compounds were identified which did not appeared in other samples. Among them pentadecanoic acid was major compound.