• Journal of Microbiology and Biotechnology
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• v.3 no.4
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• pp.270-276
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• 1993

We characterized the character impact compounds of flavors of the fermented Korean soy sauce manufactured with both the traditional and the improved Meju made with different strains. The whole flavor samples were obtained by extracting each volatile flavor phase from both the traditional and the improved soy sauce. To get more detailed information, each whole volatile flavor was further fractionated into the basic, acidic, phenolic and neutral fractions. Each separated peak from the whole and fractionated flavor samples on gas chromatogram was identified by GC/MS and Kovat s retention index, and likewise the aroma of each peak was investigated by a sniffing test with the exercised panel. We were able to identify 15 groups of ingredients with the characteristic soy sauce aroma from the soy sauce made with the traditional Meju and 6 groups from the soy sauce manufactured with the improved Meju made with Aspergillus oryzae. The character impact compounds the two soy sauces were different from each other.

• Journal of Microbiology and Biotechnology
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• v.3 no.4
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• pp.277-284
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• 1993

We confirmed the character impact compounds of the flavors of the soybean paste manufactured with the traditional and improved Meju, respectively, by using the following methods: gas chromatography (GC), sniffing tests and GC-mass. The soybean paste made with the traditional Meju had 12 compound groups that smelled like the soybean paste flavor, whereas the soybean paste made with the improved Meju had 7 compound groups of soybean paste flavor smell. We were easily able to determine that there is a difference of soybean paste flavor compounds between the soybean pastes made with either the traditional or the improved Mejus because the two soybean paste flavors are very different from each other.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.2
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• pp.122-129
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• 2002

In order to elucidate a responsible mechanism for the development of the odor characteristics of cooked desirable flavoring materials such as crab and shrimp, shore swimming crab flesh were extracted with various solvents and resulting extracts were evaluated organoleptically after cooking. As a result, $80\%$ aqueous methanol extract (AME) was found to produce a cooked desirable flavoring odor. After dialysis of AME, outer dialyzate was fractionated by ionexchange column chromatography, and each of the fraction obtained was subjected to cooking, fellowed by organoleptic evaluation. The outer dialyzate fraction, acidic and amphoteric fraction produced a cooked crab-like odor, On the basis of the composition of $80\%$ AME, an artificial crab extract was prepared with pure chemicals. The artificial crab extract thus obtained closely resembled $80\%$ AME in respect of the cooked odor. To elucidate the role of individual components, the artificial extracts from which certain component alone or as group was omitted were subjected to organoleptic evaluation after cooking. All of neutral, acidic, basic, and sulfur containing amino acids and quarternary base compounds were involved in the development of the cooked crab-like odor. The cooked odor of artificial extract without addition of ribose was lacking in the characteristics of cooked crab odor, and phosphorus compound accelerated the development of the cooked crab-like odor.

• Preventive Nutrition and Food Science
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• v.2 no.4
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• pp.360-367
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• 1997

The chemistry background of the Maillard reaction focused on pyrazines and factors affecting the reaction products were reviewed. The Maillard reaction, also called a non-enzymatic browning reaction, is quite complex and generates numerous reaction products. In processed foods, it is generally accepted as a key reaction to produce flavor components. Specially, pyrazines possess an important impact character on the roasted foods with other heterocyclic compounds. The Maillard reaction is initiated by condensation between reducing sugar and amino group, and N-glycosylamines are produced via Schiff base with dehydration of water. After the rearrangement of the N-glycosylamines, they follow transformation into deoxyhexosones which are reactive intermediates. Degradation and fragmentation are facilitated by rearranged compounds. By condensation, pyrazine, one of the final Maillard products, is generated as a relatively stable form to provide specific aromas. During the processes of the reaction, chemical or physical environmental parameters affect the formation of the products.

• Preventive Nutrition and Food Science
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• v.7 no.4
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• pp.405-410
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• 2002

Rice wine was prepared with medicinal plants or plant extracts to obtain a value added nutritious alcoholic tonics. Powders of ten medicinal plants (PTM) or aqueous extracts prepared from them (ATM) were added during the initial stage of fermentation. Aroma compounds of rice wine (control) and wines containing PTM or ATM were isolated by liquid-liquid continuous solvent extraction (LLCSE) and analyzed by gas chromatography-olfactometry and aroma extract dilution analysis (AEDA). Desirable aroma compounds: acetaldehyde (sweet, ethereal), benzaldehyde (sweet, fragrant), ethyl acetate (sweet) and ethyl octanoate (sweet, ethanolic) had the highest log$_3$-flavor dilution (FD) factors in ATM. Results of sensory evaluation demonstrated that intensities of undesirable aroma attributes, such as koji and yeasty notes in control, and raw medicinal herb notes in PTM, were lowest in wine with ATM. Wines made with ATM had the most attractive aroma attributes among the three different traditional Korean medicinal wines.

• 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.

• Journal of Microbiology and Biotechnology
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• v.6 no.3
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• pp.194-201
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• 1996

To develop a method appropriate for mass production in a factory, we manufactured soy sauce with Bacillus species SSA3-2M1 and fused ST723-F31 at $30^{\circ}C$ with aeration of 1/3 vvm for 40 days. The flavor components extracted from the manufactured soy sauce were fractionated to neutral, acidic, basic and phenolic fraction and identified by GC-mass. Among the 60 kinds of identified flavor components, 16 and 23 components were detected in traditional Korean soy sauce and soybean paste, respectively. There were three peak regions that smelled like soy sauce with the GC sniffing test of flavor components and 2, 6-dimethyl pyrazine, benzaldehyde, 2-methoxy phenol, phenol and benzeneethanol which were identified as character impact compounds of traditional Korean soy sauce and soybean paste were identified in the region that smelled like soy sauce. It is therefore considered possible to achieve mass production of soy sauce with standard quality by Bacillus species SSA3-2M1 and fused ST723-F31 in the factory.

• Carbon letters
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• v.10 no.2
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• pp.114-122
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• 2009

Crushed, depitted peach stones were impregnated activated with 50% $H_3PO_4$ followed by pyrolysis at $500^{\circ}C$. Two activated carbons were produced, one under its own evolved gases during pyrolysis, and the second conducted with air flow throughout the carbonization stage. Physicochemical properties were investigated by several procedures; carbon yield, ash content, elemental chemical analysis, TG/DTG and FTIR spectra. Porosity characteristics were determined by the conventional $N_2$ adsorption at 77 K, and data analyzed to get the major texture parameters of surface area and pore volume. Highly developed activated carbons were obtained, essentially microporous, with slight effect of air on the porous structure. Oxygen was observed to be markedly incorporated in the carbon matrix during the air treatment process. Cation exchange capacity towards Cu (II) and Cd (II) was tested in batch single ion experimental mode, which proved to be slow and a function of carbon dose, time and initial ion concentration. Copper was up taken more favorably than cadmium, under same conditions, and adsorption of both cations was remarkably enhanced as a consequence of the air treatment procedure. Sequestration of the metal ions was explained on basis of the combined effect of the oxygen functional groups and the phosphorous-containing compounds; both contributing to the total surface acidity character.