• Microbiology and Biotechnology Letters
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• v.27 no.3
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• pp.236-245
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• 1999

Andong Soju is a Korean traditional distilled liquor brewed with Nuruk which is cultured with wild microorganisms. To provide useful information for scientific production and systematic quality control of traditional distilled liquor, the effects of mixed culture of the alcoholic yeasts and saccharifying molds isolated from the Nuruk, and mashes on the flavor and sensory characteristics were investigated. Distillate from mashes cocultured with Saccharomyces cerevisiae and Hansenula anomala using Mucor Nuruk was compared with distillate from mashes brewed with Andong Nuruk and with distillate from plant fermented mashes to analyze their flavor characteristics. The volatile flavor compounds in distillates were analyzed by GC and GC-MS using direct injection, solvent extraction, and purge & trap methods. Alcohols such as 3-methyl-1-butanol, 2-methyl-1-propanol, 1-propanol, and 2-phenyl ethanol; aldehydes such as acetaldehyde and 2-furancar-boxaldehyde; esters such as ethyl ester of acetic acid, hexanoic acid, octanoic acid, decanoic acid; alkanes, alkenes, ketone, sulfur, and pyrone compounds were detected. Alcohols were chief components of flavor compounds. No significant difference in overall acceptability test was shown among three experimental groups(p<0.05), but Nuruk-like aroma, Kaoliangchiew-like aroma, sweet taste, and well rounded mouthfeel showed significant differences among them(p<0.05).

• Korean Journal of Food Science and Technology
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• v.46 no.6
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• pp.734-738
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• 2014

This study was conducted to investigate whether four hot-water extraction steps could effectively remove off-flavor from bovine bone extracts and produce compounds with pleasant aroma. Experiments were performed using a mass spectrometry-electronic nose and Fourier transform-near infrared spectrometer (FT-NIR). Off-flavor compounds were removed by washing and extraction with hot water. Steaming treatment produced compounds with a better aroma, such as 4-methylthiazole. In addition, a change in flavor compounds was observed in treated samples.

• Journal of Microbiology and Biotechnology
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• v.28 no.8
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• pp.1260-1269
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• 2018

Production of good Koji primarily depends upon the selection of substrate materials and fermentative microflora, which together influence the characteristic flavor and aroma. Herein, we performed comparative metabolomic analyses of volatile organic compounds (VOCs) and primary metabolites for Koji samples fermented individually with Bacillus amyloliquefaciens and Aspergillus oryzae. The VOCs and primary metabolites were analyzed using headspace solid phase microextraction (HS-SPME) followed by gas chromatography time-of-flight mass spectrometry (GC-TOF-MS). In particular, alcohols, ketones, and furans were mainly detected in Bacillus-fermented Koji (Bacillus Koji, BK), potentially due to the increased levels of lipid oxidation. A cheesy and rancid flavor was characteristic of Bacillus Koji, which is attributable to high content of typical 'off-flavor' compounds. Furthermore, the umami taste engendered by 2-methoxyphenol, (E,E)-2,4-decadienal, and glutamic acid was primarily detected in Bacillus Koji. Alternatively, malty flavor compounds (2-methylpropanal, 2-methylbutanal, 3-methylbutanal) and sweet flavor compounds (monosaccharides and maltol) were relatively abundant in Aspergillus-fermented Koji (Aspergillus Koji, AK). Hence, we argue that the VOC profile of Koji is largely determined by the rational choice of inocula, which modifies the primary metabolomes in Koji substrates, potentially shaping its volatolome as well as the aroma characteristics.

• Journal of the Korean Society of Tobacco Science
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• v.22 no.2
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• pp.176-183
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• 2000

This study was conducted to compare the volatile components of lamina(cutter group) and midrib of flue-cured tobacco leaves by two analytical methods, Curie-Point pyrolysis and Purge & Trap headspace technique. The pyrolysis of lamina and midrib part of tobacco leaves was performed at the temperature of $330^{\circ}C$, $650^{\circ}C$, and $920^{\circ}C$ by Curie-Point Pyrolyzer, and 33 compounds were identified in the pyrolyzates by GC/MSD. The composition of the components identified showed a quite difference between lamina and midrib. However, the amount of the pyrolyzed products from the both of lamina and midrib was increased with temperature increase except that of acetic acid, furfural, and nicotine. The content of phenolic compounds including phenol, 4-methyl phenol, and 3-methyl phenol was higher in midrib than in lamina, while that of furan compounds such as 2,3-dihydrobenzofuran, 5-hydroxymethyl furfural, was high in lamina. Interestingly, acetamide, 2-propenamide and 3-acetoxy pyridine were not defected in the pyrolyzates of lamina. By Purge & Trap headspace technique, 28 volatile components were identified in both lamina and midrib. The composition of the identified compounds and their chromatograpic patterns also showed the complete difference between the two. The content of solanone, $\beta$-damascone, $\beta$-damascenone, and megastigmatrienones, key components of tobacco aroma, was much higher in lamina than in midrib. The results indicate that lamina contains much more carbonyl compounds known to enhance the smoke taste of cigarette, whereas midrib takes nitrogenous and phenolic compounds, which are known to cause a deteriorate effect of smoke such as irritation.

• Korean Journal of Food Science and Technology
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• v.31 no.5
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• pp.1337-1344
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• 1999

Lactic acid bacteria fermented foods were prepared from egg white powder, casein and growth stimulating agent. pH change and growth of Lactbacillus acidophilus(KCTC 2182) during freeze drying were studied. The effects of freeze drying on sensory evaluation. hardness and volatile aroma compounds in freeze dried sample or reconstituted sample were also studied. Freezing and freeze drying did not affect pH of fermented samples. Number of viable cells in original fermented samples was markedly reduced during freezing or freeze drying. When number of viable cells in original fermented sampler was considered at 100%. survival ratio of viable cells after freezing was $72.0{\sim}82.4%$ and that after freeze dying $10.0{\sim}20.4%$. When sensory properties of original fermented samples were compared with those of freeze dried/reconstituted samples, sensory properties of original samples were generally better than those of freeze dried/reconstitute samples. However, the reconstitution property and the acceptability of freeze dried samples were good. Volatile aroma compounds in original fermented samples were reduced during freeze drying. The reduction degree of volatile aroma compounds varied with sample.

• Korean Journal of Food Science and Technology
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• v.32 no.4
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• pp.881-888
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• 2000

Lactic acid bacteria(LAB) fermented food was prepared with milk or egg white powder(EWP) and added with freeze drying protectant(FDP). 0.2% of Tween 80 or 1% of ascorbate was added to milk sample and 3% of raffinose or 1% of ascorbate was added to EWP sample. Effects of FDP on sensory property, volatile aroma compounds and physical property of LAB fermented food were investigated. In case of non-freeze dried samples, sensory properties of milk sample with ascorbate were slightly better than those of reference sample(milk), while sensory properties of EWP sample or EWP sample with FDP were slightly inferior to reference sample. Sensory properties of all of the freeze dried/reconstituted samples were not different. Sensory properties of milk sample with ascorbate were reduced by freeze drying/reconstitution, while those of sample with ascorbate were not changed. Although all of the volatile aroma compounds were reduced by freeze drying, the residual ratio was slightly different between milk samples and EWP samples. Difference in volatile aroma compounds between milk samples and EWP samples before freeze drying was relatively large, while difference between two sample groups after freeze drying/reconstitution was relatively small. Rheological properties of milk samples were markedly changed by freeze drying/reconstitution, while those of EWP samples were changed slightly.

• Journal of Microbiology and Biotechnology
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• v.5 no.3
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• pp.143-148
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• 1995

A strain producing soybean paste flavor was isolated from traditional Korean soybean paste. The isolate was identified as Bacillus subtilis PM3. The neutral fraction representing the traditional soybean paste aroma was obtained from the whole volatile components produced by B. subtilis PM3 in cooked soybean. Each separated peak from the neutral fraction of gas chromatogram was identified by gas chromatography-mass spectrometry (GC/MS) and Kovat's retention index, and the aromas of each peak were investigated by a sniffing test with the exercise panel. The twenty-nine components, including six character impact compounds and twelve components of flavors of Korean soybean paste, were confirmed. Some regions of gas chromatogram represented the soybean paste odor. It has been confirmed that traditional Korean soybean paste can be manufactured with the strain B. subtilis PM3.

• The Korean Journal of Food And Nutrition
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• v.10 no.2
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• pp.145-150
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• 1997

This study was performed to compare the changes of quality in citron(Citrus junos Sieb) juice between sampleII stored at 5$^{\circ}C$ for 1 year after extraction and sampleI made from raw citrons by the belt-pressing extraction method. Compared with sampleI, the soluble solid of sampleII was decreased more than 1$^{\circ}$brix, and the moisture increased 3%. The acidity reduced from 5.83 to 5.23 at the pH rose from 2.68 to 2.84. Although it decreased more than 50% in vitamin C and over 20~30% in amino acid, the changes of the other proximate components, amino nitrogen and free sugar content were very little at the range 0.1~1.0%. Volatile compounds in citron juices between sampleI and II were analyzed by GC and GC-MS. Sample I and II showed about 70 of volatile compounds. But only 13 compounds were identified by mass spectrometer. Major volatile compounds were aromatic compounds of limonene, terpinene, terpineol and terpinolene. Amounts of volatile compounds in citron juices depended on the storage period. The recovery of volatile compounds of citron juices, reduced 30~50% after storage for 1 year and the trace component disappeared during storage. The sensory characteristics including color, aroma, taste and overall acceptability and sugar recipe were not significantly.

• Journal of the Korean Society of Tobacco Science
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• v.35 no.1
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• pp.20-27
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• 2013

An Electronic Nose(E-Nose) and Gas Chromatography/Mass Spectroscopy (GC/MS) are meanwhile conventional technique to analyze volatile materials in many industries (e.g., food, medicine, environment) and have broad acceptance in the analysis of tobacco products. In this study, an experiment where tin oxide gas sensor array responses and GC/MS profiles are used to characterize the volatile compounds of different cigarettes at the same time is performed and the measurements of two instruments are compared for cigarette samples with a known chemical information. E-Nose and GC/MS were employed to differentiate and match flavored cigarettes with commercial tobacco flavoring agents (lavender, vanilla, peppermint, orange, star anise). For verifying reliability of two systems, the analyses were conducted in terms of amount of flavors in each cigarettes using partial least squares (PLS) and with the principal components analysis (PCA). Various chemical sensors and GC/MS data was reduced into two principal factors (PC1, PC2) for being distinguished with visualized regions. Both systems provided adequate results for odor characteristics of cigarettes in this study with each instrument having its own advantages and disadvantages.

• The Korean Journal of Food And Nutrition
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• v.14 no.1
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• pp.10-14
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• 2001

The volatile components of umbelliferous herbs having a characteristic spicy aroma were investigated. The essential oils of herbs were isolated by simultaneous steam distillation and extraction and the volatile components were identified by capillary GC and GC/MS. Forty-nine volatile compounds were identified from the herbs. The major compounds of chervil (Anthricus cerefolium) leaf oil were methyl chavicol, 1-allyl-2,4-dimethoxy benzene, and of coriander (Coriandrum sativum) leaf oil were ${\beta}$-sesquiphellan drene, germacrene B, nerolidol, selinene-4-ol, and of coriander seed oil were linalool, decanal, ${\gamma}$-terpinene, $\rho$-cymene.