• Korean Journal of Food Science and Technology
• /
• v.32 no.5
• /
• pp.1035-1042
• /
• 2000

Volatile compounds of kochujang prepared with meju and koji were analyzed by using a purge and trap method during fermentation and identified with GC-MSD. Thirteen alcohols, seventeen esters, seven acids, six aldehydes and nine others were identified. Twenty four volatile flavor detected immediately after making kochujang including 7 alcohols and 9 esters. Six volatile flavor compounds including 1 alcohol and 3 esters were more found after 30 day of fermentation and increased to forty nine of volatile compounds after 150 days. Six alcohols such as ethanol, 3-methyl-butanol, 2-methyl-1-propanol, 1-butanol and nine esters such as ethyl acetate, ethyl butyrate, ethyl caproate, ethyl carpylate and seven others were commonly found through the fermentation period. Peak area (%) of 1-butanol was the highest one among the volatile flavor compounds after 30 day of fermentation and ethanol showed the highest peak area after 60-90 day and 150 day of fermentation, and 3-methyl-1-butanol showed the highest peak area after 120 day of fermentation, 2-Methyl-1-propanol, ethyl butyrate, ethyl acetate, acetaldehyde, ethoxyethene, ethenone, methylbenzene were detected in the kochujang during the fermentation.

• Korean Journal of Food Science and Technology
• /
• v.29 no.4
• /
• pp.745-751
• /
• 1997

Volatile flavor components of kochujang made from a glutinuous rice by traditional method were analyzed by using purge and trap method during fermentation, and identified with GC-MSD. Fifty-one volatile components including 19 alcohols, 13 esters, 7 acids, 3 aldehydes, 1 alkanes, 2 ketones, 2 amines, 1 benzene, 1 alkene, 1 phenol and others were found in kochujang made by traditional method. The number of volatile components detected immediately after making kochujang were 22 and increased to 41 components after 30 day of fermentation. The most number 51 of volatile components were found after 120 day of fermentation. Twenty-two volatile components were commonly found through the fermentation period such as acetic acid ethyl ester, ethanol, butanoic acid ethyl ester, 1-butanol, 2-methyl-1-propanol, 3-methyl-1-butanol, butanoic acid and ethenone. Peak area(%) of 1-butanol was the highest one among the volatile components at immediately after mashing while ethanol showed the highest peak area after 30 day of fermentation. Although the various types of peak areas of volatile components were shown in kochujang during the fermentation days, acetic acid-ethyl ester, ethanol, butanoic acid-ethyl ester, 1-butanol, 3-methyl-1-butanol and 2-methyl-1-propanol were mainly detected during fermentation. Those might be the major volatile components in kochujang made by traditional method.

• Food Science and Preservation
• /
• v.30 no.2
• /
• pp.287-299
• /
• 2023

In vitro luwak coffee was produced using enzyme­microbial complexes. The coffee quality of non-fermented coffee beans (NFC) and fermented coffee beans (FC) was compared. The total free amino acid content was higher in FC than in NFC. The levels of glutamic acid and γ-amino-n-butyric acid in NFC were higher than those in FC; however, the contents of essential amino acids, such as lysine, leucine, and valine, in FC were higher than in NFC. During fermentation, the sucrose content decreased, whereas the fructose and glucose contents increased (p<0.001). The chromaticity of the coffee extract showed higher lightness (L), redness (a), and yellowness (b) values in FC than those in NFC. The caffeine content was significantly lower in FC (696.94±0.04 ㎍/mL) compared to that in NFC (1,130.22±1.55 ㎍/mL) (p<0.001). Conversely, the polyphenol and chlorogenic acid contents were significantly higher in NFC than in FC (p<0.001). Electronic nose analysis indicated considerable differences between the volatile aromatic components in NFC and FC. Sensory scores were significantly higher for FC than those for NFC. Therefore, the fermentation of coffee beans using enzyme­microbial complexes altered the chemical components, which promoted the Maillard reaction during the coffee bean roasting process. These results suggest the possibility of producing in vitro luwak coffee with better flavor and lower caffeine content.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.46 no.9
• /
• pp.1122-1127
• /
• 2017

Currently, the consumer trends are increasing towards "natural" in all food systems. Therefore, in the flavor industry, the production of flavor esters by "natural" methods are needed. On the other hand, "natural flavor" is expensive to produce because of the limited natural source. Recently, the flavor obtained from the enzyme or microbial could be represented as "natural flavor". Ethyl butyrate is used most frequently as a fruity aroma in drinks and the processed food industry. In this study, ethyl butyrate was synthesized enzymatically using the ester synthetase obtained from the waste of pineapple and banana peel. The ethyl butyrate production optimization was analyzed using a response surface methodology. The enzyme reaction variances were composed of the ethanol content, butyric acid content, and reaction time. As a result, in ester synthetase obtained from banana peel, the maximum predicted production amounts were 45.8199 mM at an ethanol content of 38.7050 mM, butyric acid content of 50.9019 mM, and reaction time of 4.3662 h. In ester synthetase obtained from pineapple peel, the maximum predicted production was 65.1087 mM at an ethanol content of 54.6502 mM, butyric acid content of 58.7638 mM, and reaction time of 4.7436 h. In conclusion, ethyl butyrate production was shown the more useful using the ester synthetase obtained from pineapple peel than that from banana peel.

• Journal of Microbiology and Biotechnology
• /
• v.4 no.4
• /
• pp.327-332
• /
• 1994

Optimum conditions for the production of acetoin and ammonia as the precursors of tetramethylpyrazine(TMP) were determined using Lactococcus lactis subsp. lactis biovar. diacetylactis FC1 in a modified Lactose-citrate broth containing galactose, citrate, and arginine. The cell growth and the productivity of acetoin and ammonia were remarkably increased in an aerobic culture with 10 $\mu M$ of hematin. For the optimum conditions of acetoin and ammonia production, the concentration of citrate and arginine were adjusted to 156 mM and 50 mM after 18 hr cultivation, and citrate and galactose to 156 mM and 50 mM after 36 hr cultivation, respectively. In these conditions, acetoin and ammonia were produced to the final concentration of 127 mM and 195 mM, which were the highest concentations, respectively. The optimum conditions of the TMP production were also determined as follows; 4 hours at 121, pH 8.3, and the maximal yield of TMP under these conditions was 0.81 g/l.

• Animal Bioscience
• /
• v.36 no.9
• /
• pp.1426-1434
• /
• 2023

Objective: The objective of this study was to evaluate the effect of Debaryomyces hansenii isolated from dry-aged beef on the tenderness and flavor attributes of low-grade beef during dry aging. Methods: Five D. hansenii strains were isolated from dry-aged beef samples. The rump of low-grade beef was inoculated with individual D. hansenii isolates and subjected to dry aging for 4 weeks at 5℃ and 75% relative humidity. Microbial contamination levels, meat quality attributes, and flavor attributes in the dry-aged beef were measured. Results: Of the five isolates, the shear force of dry-aged beef inoculated with SMFM201812-3 and SMFM201905-5 was lower than that of control samples. Meanwhile, all five isolates increased the total free amino acid, glutamic acid, serine, glycine, alanine, and leucine contents in dry-aged beef. In particular, the total fatty acid, palmitic acid, and oleic acid contents in samples inoculated with D. hansenii SMFM201905-5 were higher than those in control samples. Conclusion: These results indicate that D. hansenii SMFM201905-5 might be used to improve the quality of beef during dry aging.

• Food Science of Animal Resources
• /
• v.37 no.5
• /
• pp.698-707
• /
• 2017

This study was performed to investigate the impacts of irradiation sources on quality attributes of low-salt sausage during refrigerated storage. Control sausage was prepared with 1.5% sodium chloride (NaCl), whereas low-salt sausage was formulated with 0.75% NaCl (a 50% reduction; L-control). Sausage samples were vacuum-packaged, and low-sausages were irradiated with gamma-ray, electron-beam and X-ray at 5 kGy, respectively. The samples were stored at $4^{\circ}C$ for 28 d to determine changes in quality attributes. The pH of low-salt sausages was unaffected by irradiation at 5 kGy (p>0.05). Higher redness values were found at irradiated low-salt sausages compared to control (p<0.05). The hardness, gumminess and chewiness of control sausage were higher than those of low-salt sausages (p<0.05). However, there were no significant differences in the textural parameters between low-salt sausage treatments. The overall sensory acceptability score of irradiated/low-salt sausages were lower than L-control due to decreased scores for cooked meat flavor but increased radiolytic off-flavor (p<0.05). The initial 2-thiobarbituric acid-reactive substances (TBARS) values of irradiated/low-salt sausages were higher than control and L-control (p<0.05). However, the TBARS values of irradiated treatments were significantly lower than control at the end of storage. Irradiation could effectively inhibit the microorganism growth (total aerobic bacteria, coliforms, Enterobacteriaceae, and Pseudomonas spp.) in low-salt sausages (p<0.05). Therefore, our findings show that irradiation could be to improve microbial safety of low-salt sausages, and suggest that further studies should be necessary to reducing radiolytic off-flavor of irradiated/low-salt sausages.

• Research in Plant Disease
• /
• v.10 no.4
• /
• pp.285-289
• /
• 2004

The bloody watermelon exhibiting dark red and fermentation off-flavor results in a great economic loss. As an effort to clarify the cause of the bloody watermelon, relationship between the fermentational off-flavor and the presence of endophytic bacteria was studied. The number of endophytes was 2.2-37.0 ${\times}10^3$ cfu/g fw (fresh weight) in normal watermelons, compared to 1.26-1.75 ${\times}10^6$ cfu/g fw in bloody ones. Seventeen bacteria among 56 isolates from bloody watermelons could induce bloody watermelons. The bacteria responsible for bloody watermelons were mainly Gram negative: aerobic Pseudomonas spp and some anaerobic bacteria. The results in this study strongly suggested that the bloody watermelons were produced by abnormal fermentation and growth of endophytic Gram negative bacteria.

• Korean Journal of Food Science and Technology
• /
• v.32 no.6
• /
• pp.1358-1364
• /
• 2000

A mixed culture of bacteriocin-producing lactic acid bacteria and yeast was used to prepare unique fermented fruit and vegetable beverage which contains bacteriocin. Fruit and vegetable broth fermented by Lactococcus lactis 11454 showed inhibitory activity against foodborne pathogens such as Listeria monocytogens and Staphylococcus aureus, and Streptococcus mutans which is a major causative agent for dental caries. Bacteriocin was detected at the end of fermentation of fruit and vegetables and its antimicrobial activity was stable for 5 weeks during storage at $4^{\circ}C$. These results suggest that the presence of bacteriocin in beverages during fermentation and storage will provide a safeguard against foodborne pathogens and spoilage bacteria. To improve flavor of the fermented broth, post-fermentation of the fermented broth was carried out at $4^{\circ}C$ by using yeast isolated from raw material mixture. Total acidity of the post-fermented broth was slightly decreased, but significant increase in the concentration of succinic acid was observed in the post-fermented broth. It was also observed that bitter and disagreeable taste compounds such as phthalates were decreased, and mild acidic and fruity flavor esters and alcohols were increased by the post-fermentation of the fermented broth with yeast.

• Journal of the Korean Society of Food Culture
• /
• v.33 no.3
• /
• pp.283-290
• /
• 2018

This study examined the quality characteristics and anti-oral microbial activity of bamboo leaf jelly prepared with different 5 levels (0, 10, 20, 30, and 40%) of bamboo (Phyllostachys nigra var. henonis) leaf extract. The sugar contents of bamboo leaf jelly were increased significantly by increasing the level of bamboo leaf extract. The luminance and Hunter's a values of the jelly samples increased with increasing bamboo leaf extract, but the 40% bamboo leaf jelly had the lowest Hunter's b values. The hardness, adhesiveness, gumminess, and chewiness increased significantly with increasing bamboo leaf extract. Among the mechanical properties, only the flavor of the jelly with 30 and 40% bamboo leaf extract were increased significantly. The extract of bamboo leaves had strong antimicrobial activity against S. mutans, S. sobriuns, P. gingivalis, and P. intermedia at a concentration of 40%. These results suggest that bamboo leaf extract can be useful in the production of high quality jelly.