• Asian-Australasian Journal of Animal Sciences
• /
• v.4 no.1
• /
• pp.67-71
• /
• 1991

The purpose of this study was to investigate the possibility of using the buffer index curve as a criterion of silage quality evaluation. The buffer index (or buffer capacity, $\beta$) value is the amount of 0.1N NaOH consumed in titrating from the beginning to the end of the chosen pH step. This value equals the slope of the titration curve at the chosen pH range (${\beta}={\Delta}NaOH/{\Delta}pH$). There were two patterns of buffer index curve. Poorly preserved silages had a peak at pH 5.0, whereas with well preserved silages the peaks tended to rise to the pH 3.75 or 4.00. Well preserved, wilted silages with high pH also appeared to have peak values at pH 3.75 or 4.00. There was a high positive correlationship between the concentration of lactic acid and peak value of good quality silage (r = 0.994, p < 0.01). Also a high positive correlationship (r = 0.899, p < 0.001) was found between the sums of concentration of acetic and butyric acids and the peak values of poor quality silages. The results of these experiments verified the value of the buffer index method as a criterion of silage quality evaluation.

• Korean Journal of Veterinary Research
• /
• v.34 no.1
• /
• pp.99-105
• /
• 1994

Clotridium bovis sp. nov, is described on the basis of 5 strains isolated from the feces of Holstein cattle. The isolate are gram-positive, motile, strict anaerobic spore forming rods. They differ from all the validly described related species of the genus Clostridium in carbohydrate fermentation pattern, G+C mol% and DNA homologies. Acid is produced from arabinose, xylose, glucose, mannose, fructose, galactose, sucrose, maltose, cellobiose, lactose, trehalose, melibiose, raffinose, inulin and salicin. Major end products in PYFG broth are large amounts of butyric acid and lactic acid, and trace amounts of acetic and succinic acids. The G+C mol% of DNA from the type strain is 26 mol%. The type strain of Clostridium bovis is Catt $66^T$ strain.

• Journal of Microbiology and Biotechnology
• /
• v.13 no.2
• /
• pp.175-181
• /
• 2003

The production of a carotenoid astaxanthin, a growth-associated principal pigment, is limited in a batch cultivation, because a high glucose concentration severely inhibits the cell growth and also influences the carotenoid production. Therefore, a fermentation strategy including effective chemicals for the high-level production of cells and astaxanthin by a mutant strain Phaffia rhodozyma AJ-6-1 was developed in a fed-batch culture. First, a production medium for maximizing the cell and astaxanthin yields was formulated and optimized. Using this optimized medium, the highest cell and astaxanthin concentrations obtained were about 38.25 g/1 and 34.77 mg/1, respectively. In addition, an attempt was made to increase the amount of astaxanthin using effective chemicals such as ethanol and acetic acid, which are known at an inducer and/or precursor of carotenoid synthesis. When either 10g/1 ethanol or 5 g/1 acetic acid was added to investigate the resulting astaxanthin content, a relatively high astaxanthin concentration or 45.62 mg/l and 43.87 mg/1, respectively, was obtained, and the cell concentrations also increased slightly under these conditions. Therefore, these results imply that a fed-batch culture of the mutant strain P. rhodozyma AJ-6-1 could be effectively employed in the commercial production of astaxanthin, although the factors affecting the productivity remain to be elucidated.

• Journal of the Korean Society of Industry Convergence
• /
• v.26 no.3
• /
• pp.371-380
• /
• 2023

This study aimed to present data for the industrialization of Omija added onion fermented beverage (OOFB) development by analyzing the volatile flavor components. A total of 55 compounds, including 4 terpene derivatives, 9 esters, 5 aromatic compounds, 6 alcohols, 7 ketones, 3 aldehydes, 11 acids, 1 sulfur-containing compound, 8 furans and 1 other, were identified in OOFB. The content of fragrance components was high with 37.8% of acids and 29.0% of furans. 2,5-dimethyl thiophene, a sulfur compound, is a compound produced during the acetic acid fermentation of onion, and is thought to affect the onion flavor of OOFB.

• Journal of the Korean Wood Science and Technology
• /
• v.44 no.3
• /
• pp.389-397
• /
• 2016

In this study, ethanol was produced from a biomass hydrolysate that had been treated by electrodialysis (ED) and Amberlite XAD resin to remove fermentation inhibitors. Most of the acetic acid (95.6%) was removed during the ED process. Non-ionizable compounds such as total phenolic compounds, 5-hydroxymethyl furfural, and furfural were effectively removed by the XAD resin treatment. Ethanol production was improved when the ED-treated hydrolysate was treated with XAD-4 resin for a short reaction time. The highest ethanol production from ED-treated hydrolysate was $6.16g/{\ell}$ (after 72 h of fermentation) when the treatment with XAD-4 resin was for 5 min. Among the lignin-derived fermentation inhibitors tested, syringaldehyde in low concentrations (1 and 2 mM) in the hydrolysate increased ethanol production, whereas a high concentration (5 mM) inhibited the ethanol production process. A synthetic medium containing syringaldehyde and ferulic acid was prepared to investigate the synergistic effect of inhibitors on ethanol fermentation. Ethanol production decreased in the mixture of 1 mM syringaldehyde and 1 mM ferulic acid, implying that the effect of ferulic acid on ethanol fermentation is comparable to that of syringaldehyde.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.45 no.1
• /
• pp.155-159
• /
• 2016

The objective of this study was to investigate the effect of fermentation temperature on quality characteristics of apple wine. Apple wine mashes were fermented in 15, 20, and $25^{\circ}C$ water bathes for 9 days. The pH levels of all samples were below 4 from 24 h of fermentation until the end. Total acidities of 0.05% acetic acid solution were 7.8, 7.4, and 7.0% in the 15, 20, and $25^{\circ}C$ fermented samples, respectively. The evaporation of esters generated by combining alcohol and organic acids might be the reason for lower total acidity for high temperature fermentation. Alcohol contents of the 20 and $25^{\circ}C$ fermented samples were 6.5 and 6.6% (v/v), respectively, whereas that of the $15^{\circ}C$ fermented sample was 5.6% (v/v) and significantly lower than the others (P<0.05). Methanol contents were 0.68, 0.82, and 1.69 mg/L in the 15, 20, and $25^{\circ}C$ fermented samples, respectively. Fermentation at higher temperatures generated higher methanol content in apple wine. On the other hand, acetaldehyde contents were 3.43, 2.39, and 1.02 mg/L in the 15, 20, and $25^{\circ}C$ fermented samples, respectively, due to the lower boiling point of acetaldehyde ($20.2^{\circ}C$). Based on the results, a fermentation temperature of $20{\sim}25^{\circ}C$ is effective for apple wine fermentation.

• Food Science and Preservation
• /
• v.18 no.6
• /
• pp.875-883
• /
• 2011

Brown rice vinegar was made from brown rice mash with different brewing starter addition rates in static culture, and its quality characteristics were investigated. As a result, the amounts of alcohol produced in the fermentation process were shown to be 9.1, 8.8, 8.6 and 8.5% in the Nuruk 75 : crude enzyme 25 (B), Nuruk 50 : crude enzyme 50 (C), Nuruk 25 : crude enzyme 75 (D) and Nuruk 0 : crude enzyme 100 (E), respectively. The higher the percentage of crude enzyme added was, the lower the alcohol content that was produced. Nuruk 100 : crude enzyme 0 (A) was appeared to contain the lowest alcohol content (7.7%). In addition, the titratable acidity in all the groups was about 0.7%. The final titratable acidity (BV) of brown rice vinegar made with static culture was the highest (approximately 5.2%). The initial pH appeared to be between 3.6~4.0 and steadily decreased as the fermentation progressed, and the pH was almost unchanged after 15 day fermentation. The examination of the changes in the organic acids showed that the acetic acid content was similar in all the groups, and that the single starter added (AV, EV) group had much more other organic acids than the mixed starters added (BV, CV, DV) group. From these results, the mixed starters (Nuruk and crude enzyme) added group appeared to be superior to the single starter added in terms of alcohol production ability and vinegar quality. As the future aging process, however, is expected to change the flavor components and sensory characteristics, studies on various quality factors of vinegar are needed.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.42 no.3
• /
• pp.441-449
• /
• 2013

This study was conducted to ferment high quality vinegar by using Omija fruit. Strains of bacteria producing acetic acid were isolated from spoiled Omija wine (OV1 and OV2) and traditional rice vinegar (RA). The bacterium was from optimally-oxidized Omija wine containing 6.0% ethanol and from Omija vinegar with 5.21% acetic acid by 14 days of fermentation. The Omija vinegar got the highest sensory score (5.80) among several commercial vinegars. The Omija vinegar showed a potent antibacterial activity against Staphylococcus aureus, Bacillus subtilis, Escherichia coli, and Pseudomonas fluorescens by the paper disc test, while Omija wine had limited antibacterial activity against S. aureus and P. fluorescens. The diameter of the clear zone formed by the paper disc test using Omija vinegar was not less than 9.5 mm. The DPPH free radical-scavenging activity of Omija wine was higher than that from Omija water extracts. The nitrite scavenging ability of Omija wine (36.98% of all nitrites present) and vinegar (31.14%) was higher than that from Omija water extracts (22.53%). Omija vinegar exhibited strong antibacterial and antioxidant activities. In conclusion, we prepared high quality vinegar from dried Omija.

• Applied Biological Chemistry
• /
• v.46 no.2
• /
• pp.94-100
• /
• 2003

Preparation method and characteristics of high quality Korean pickled cucumber made with acetic acid-treated cuttle bone powder (KPCCP) were examined and compared to those of Korean pickled cucumber prepared by traditional methods (control). Optimal concentration of acetic acid-treated cuttle bone powder for KPCCP preparation was revealed as 10%. Salt concentration of KPCCP fermented for 3 days was 4.5%, slightly higher than that of the control, whereas that of KPCCP fermented for over 6 day was about 4.8%, similar to that of the control. The pH, greenness, and hardness of korean pickled cucumber decreased during fermentation, with the control showing a greater extent of decrease than KPCCP Total acidity and alcohol insoluble calcium contents increased during fermentation, with KPCCP showing higher extent of increase. These results indicate that quality of KPCCP is superior to that of Korean pickled cucumber prepared by traditional methods.

• Korean Journal of Food Science and Technology
• /
• v.39 no.6
• /
• pp.593-599
• /
• 2007

In this study, we examined the volatile flavor components in the mashes of takju prepared using different yeasts such as Saccharomyces coreanus, S. ellipsoideus, S. carlsbergensis, S. cerevisiae (Baker's yeast), and S, rouxii by GC and GC-MS. Fourteen alcohols, 13 esters, 5 acids, 3 aldehydes, 7 amines, and 2 other compounds were identified in the mash after 6 days of fermentation. On day 6, the takju fermented by S. coreanus had the greatest variety of volatile flavor components. Fifteen flavor components, including ethanol, isobutyl alcohol, isoamyl alcohol, methyl pentanol, 1,3-butanediol, 3-methylthio-1-propanol, benzeneethanol, ethyl lactate, acetic acid, acetaldehyde, and 1,3-cyclohexane diamine, were typically detected in all the treatments. The relative peak areas of the volatile components were as follows: alcohols (96.758-99.387%), esters (0.081-0.968%), acids (0.040-0.640%), aldehydes (0.266-0.959%), and amines (0.011-0.047%). In particular, 1-propanol, isobutyl alcohol, 3-methyl-1-butanol, 2,3-butanediol, trimethyl benzylalcohol, heptene-2,4-diol, ethyl lactate, diethyl succinate, ethyl nonanoate, methyl hexadecanoate, linoleic acid, hexadecanoic acid, and acetaldehyde were hish in the takju made by S. coreanus. Also, ethyl stearate was high in the takju made by S. carlsbergensis, and hexanoic acid was high in the takju made by S. cerevisiae. Finally, methyl pentanol, 1,3-butanediol, 3-methylthio-1-propanol, benzene ethanol, ethyl octadecanoate, acetic acid, pentanal, and 1,3-cyclohexane diamine were high in the takju made by S. rouxii.