• Journal of the Korean Society of Food Science and Nutrition
• /
• v.31 no.2
• /
• pp.204-210
• /
• 2002

The quality characteristics and sensory evaluation of chungkookjang were investigated. The samples were prepared and fermented by the inoculation of Bacillus strains; B. subtilis, B. natto and B. licheniformis as a single starter, and mixed culture of B. natto and B. licheniformis on the industrialized model system. It was shown that microbial growth, protease activity, contents of amino-and ammonia-nitrogen and contents of organic acid were higher in B. subtilis inoculated sample, and were lower in B. licheniformis inoculated one. General quality characteristics of sample inoculated by mixed culture of B. natto and B. licheniformis took a middle position between each B. natto and B. licheniformis inoculated one. Fifty eight species of odor components were identified. Ethanol, 3-methyl-1-butanol, acetic acid, benzaldehyde and alkyl pyrazines were identified in all samples and most of other flavor components were strain specific. The contents of unpleasant smell components, alkyl pyrazines and benzaldehyde, were lower in B. licheniformis inoculated sample. The sensory evaluations showed that chungkookjang manufactured from mixed culture of B. natto and B.licheniformis was most acceptable. Therefore, results indicated that chungkookjang manufactured from mixed culture of B. natto and B. licheniformis induced better sensory quality than that of the control.

• Korean Journal of Food Science and Technology
• /
• v.32 no.3
• /
• pp.507-512
• /
• 2000

The headspace flavors of roasted tea, prepared with steamed and nonsteamed polygonatum roots, were absorbed in solid-phase microextraction(SPME) fiber coated with $65\;{\mu}m$ of carbowax/divinylbenzene(CW/DVB) and analysed by GC-MS. The absorption conditions of SPME fiber for equilibrated headspace were selected as $60^{\circ}C$ and 30 min. In a comparison for both samples roasted at $130^{\circ}C$ for 15 min, gas chromatograms showed a similar pattern in overall profiles between steamed and nonsteamed samples before roasting, but some differences were observed in peak characteristics. From 40 separated peaks, 25 compounds were identified with both GC-MS and retention time comparison. The pyrazines including 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one, 2,5-dimethyl-4-hydroxy-3(2H)-furanone, 2-acetyl-1-pyrroline, etc. were higher in their contents in nonsteamed-roasted sample than steamed-roasted one. In particular, steamed-roasted polygonatum showed higher contents of acetic acid(8.17%) and hexanoic acid(5.43%) than the corresponding compounds of nonsteamed-roasted one, 2.40% and 2.00%.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.45 no.2
• /
• pp.104-113
• /
• 2012

Crab-like flavorants (CFs) were made from snow crab cooker effluent (SCCE) using response surface methodology (RSM) and reaction flavoring technology (RFT). Type A CF was made from SCCE via RSM, RFT, adding starch syrup, centrifugation, and microfiltration. Type B was made from type A by adding the food additives dimethyl sulfide, ethyl valerate and fish sauce. The stability of the CFs was evaluated in terms of the color values, sensory evaluation, and flavor profiles after storage for 90 days at three different temperatures: 10, 20, and $30^{\circ}C$. The compounds, ethanol and 3-methyl-1-butanol, were considered key components of off-flavor and a decrease in dimethyl-2-vinylpyrazine affected the occurrence of off-flavor. It may be a microbial metabolite arising from contamination and lab-scale micro-filtration. At the lowest temperature ($10^{\circ}C$), the decrease in volatile compounds, such as pyrazines, was not as dramatic as at $20^{\circ}C$ and $30^{\circ}C$ and alcohol formation was prevented or delayed. Therefore, it is necessary to store CFs at < $10^{\circ}C$ with suitable sterilization to preserve volatile flavor compounds and prevent off-flavor from occurring.

• Korean Journal of Food Science and Technology
• /
• v.39 no.4
• /
• pp.366-371
• /
• 2007

The volatile components in Eoyuk-jang, a traditional Korean fermented food, were isolated using solvent extraction, and analyzed by gas chromatography-mass spectrometry (GC-MS). A total of 36 components, including 11 aliphatic hydrocarbons, 4 acids, 2 ketones, 5 phenols, 7 alcohols, 1 pyrazines, 4 pyrones and furanones, and 2 miscellaneous components, were found in Eoyuk-jang; among them, butanoic acid was quantitatively dominant. In addition, the aroma-active compounds were determined by gas chromatography-olfactometry (GC-O) using aroma extract dilution analysis (AEDA). A total of 20 aroma-active compounds were detected by GC-O. Butanoic acid (rancid) and methional (cooked potato-like) were the most potent aroma-active compounds with the highest FD factors $(Log_3$, FD), followed by 2-methyl-2-butanol (soysauce-like), 3-hydroxy-2-butanone (buttery), and 2-furanmethanol (burnt sugar-like).

• Journal of the Korean Society of Food Culture
• /
• v.28 no.1
• /
• pp.78-88
• /
• 2013

Marinated beef galbi is a traditional Korean dish cooked with soy sauce, pear juice, onion, sesame oil, and sugar. However, there are many differences in beef galbi, including flavor and physicochemical aspects, depending on cooking conditions. Therefore, the physicochemical characteristics of marinated beef galbi prepared through various recipes was evaluated for its effects on pH, texture, aging, proteolysis, heating conditions, cooking time, and flavor compounds (pyrazines, IMPs, or FAAs). There were significant differences in salt concentration (0.8~3.03%), pH (4.89~6.22), and solid soluble contents (1.34-6.31 Brix) between recipes in this study. In the Pearson assay for sensory evaluation, overall preference correlated well with texture (a well-known sensory attribute in meat evaluation). Controlling the pH of meat through soaking in lemon solution, alkali water, phosphate, and baking powder solution, improved water holding capacity as much as 9 to 15% compared with the control. The myofibril index (MFI) of marinated meat stored at $4^{\circ}C$ increased 32% with 24 hours of aging and reached 39% at 48 hours of aging, and its fragmentation was observed through microscopy. SDS-PAGE showed hydrolysis of acid-soluble collagen by the pear juice, possibly related to meat tenderness. On the basis of surface temperature, the cooking time was estimated to be 8 minutes with pan heating at $170^{\circ}C$, 6 minutes at $270{\sim}300^{\circ}C$, and 4 minutes with charcoal at $700{\sim}900^{\circ}C$. Different pyrazine compounds, such as 2-methyl-3-phenylpyrrol(2,3-b) pyrazine (the typical product of the browning reaction) was mainly detected, and IMP (one of the main taste compounds in beef) was in higher amounts with the charcoal treatment, potentially related to its flavor preference among treatments. Our results demonstrate an effective case study and cooking system for beef galbi.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.43 no.1
• /
• pp.102-109
• /
• 2014

Crab-like flavoring base (CFB) was made from a concentrated snow crab cooker effluent (SCCE) containing five food additives (proline, glycine, arginine, methionine, fructose) using reaction flavor technology (RFT). The volatile flavor compounds in CFB were compared between raw (SCCE) and control (without food additives) samples using solid phase microextraction (SPME) and gas chromatography with mass selective detector. A total of 74 compounds were detected in all samples (30 raw samples, 34 control samples, 55 CFB samples). A total of 22 nitrogen-containing compounds, including 19 pyrazines and 3 pyridines, were formed through RFT and increased 27 times compared to the control. Dimethyl trisulfide and dimethyl disulfide were predominant sulfur-containing compounds that increased through RFT, while aromatic compounds decreased through RFT. Seven compounds, tetramethylpyrazine, 2-ethyl-3,5,6-trimethylpyrazine, 2,3,5-trimethyl-6-(3-methylbutyl)pyrazine, 2-ethyl-3,5-dimethylpyrazine, 2,5-dimethyl-3-(3-methylbutyl)pyrazine, 2-ethyl-3,6-dimethylpyrazine, and 2-decanone potentially have a role in CFB odor by Pearson's correlation analysis.

• Journal of Life Science
• /
• v.11 no.6
• /
• pp.517-522
• /
• 2001

To Confirm the repression of off-odor and improvement of food quality in small black bean chungkugjang (SBC), some taste compounds of SBC added with kiwi and radish homogenate and fermented fro 3 days at 42$^{\circ}C$ were investigated. Contents of free amino acids in SBC were lower than that of soybean chungkugjang (SC) and were increased by adding kiwi and radish homogenate to black bean, indicating that two materials were effective to the enzymatic digestibility of soy protein. Of organic acids, citric acid was the most abundant, followed by acetic acid and lactic acid. Fatty acid composition was high in the order of linoleic acid (50.82~54.51%), oleic acid (17.76%~22.10%) and plamitic acid(12.13~13.79%). There were no significant difference in compositions of organic acids and fatty acids of chungkugjang. Major volatile compounds of SBC were indole , 2-5-dimethyl pyrazine and trimethyl pyrazine. Contents of alkyl pyrazines that contribute the characteristic aroma and flavor of SBC added and fermented with kiwi and radish homogenate were 3 times lower than those of SC. Uracil and UMP were major nucleic acie-drlated compounds in all four chungkugjangs. Contents of the other nucleic acid-related compounds were a similar trend in all chungkugjangs.