• Korean Journal of Food Science and Technology
• /
• v.35 no.4
• /
• pp.671-679
• /
• 2003

Effects of sun-dried, refined, seaweed, and bamboo salts on the quality of kochujang were studied by measuring enzymatic, microbial, and physicochemical characteristics of kochujang during 12 weeks of fermentation. Yeast count was low in the bamboo-salt kochujang, whereas that of aerobic bacteria was low in the seaweed-salt kochujang. Acid protease activity was high in the bamboo-salt kochujang, whereas amylase activity did not show any remarkable difference. Color change was lowest in the bamboo-salt kochujang. Water activities of all kochujangs decreased during fermentation with the lowest shown in the refined-salt kochujang. Consistency of seaweed-salt kochujang was the highest. Total sugar content was higher, whereas ORP was lower in the seaweed- and bamboo-salt kochujangs. Titratable acidity changed slightly in the bamboo-salt kochujang. Reducing sugar content was the lowest, whereas ethanol content was the highest in the refined-salt kochujang. Amino and ammonia nitrogen contents of kochujangs increased up to the middle of fermentation period then decreased with lower changes observed in the sun-dried and refined-salt kochujangs. Results of sensory evaluation indicated that the bamboo-salt kochujang was more acceptable than the sun-dried salt kochujang in taste, color, and overall acceptabilities.

• Korean Chemical Engineering Research
• /
• v.59 no.4
• /
• pp.542-547
• /
• 2021

Glass lined impellers are corrosion resistant to most chemicals, including strong acids, and also have a smooth, non-stick surface, easy to clean and free from impurities in the process. Glass lined home base impeller is a multi-purpose impeller designed to stir a wide viscosity range of liquids from low viscosity fluids to high viscosity fluids, among others, cell culture, yeast culture, and beer fermentation pots, especially used for air-water system breathable stirring. The glass lining for HB impellers, which are simple in structure and competitive in performance, is essential to have upper and lower division in order to make the joint area between the impeller and shaft as small as possible. The upper and lower division of the impeller hardly affects the mixing performance, but the aeration performance. In this study, in order to optimize the shape of the Glass Lining HB impeller, a study was conducted on the effect of the angle between the upper and lower impellers, the clearance between the impellers, and the number of baffles on the aeration power. The optimal shape and baffle plate conditions for the Glass lined HB impeller were derived through the study results that the angle and the clearance between the upper and lower impellers decreased the ration of the power consumption with aeration P_g and that without aeration P₀, P_g/P₀.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.39 no.2
• /
• pp.301-307
• /
• 2010

This study evaluates quality of Nuruk, which is a source material of Takju, collected in Daegu and Gyeongbuk and investigates fermentation characteristics of Takju made of it. Totally 7 types of Nuruk were examined and their pH and titratable acidity were 5.4~5.9 and around 0.1%, respectively. Saccharifying activity was high in D, F, G, A and E Nuruk by recording over 300 mg%. Lactic acid bacteria count was the highest in G Nuruk with $3.78\times10^8$ and yeast and total microbe count recorded the highest levels, $3.78\times10^8$ and $3.47\times10^8$, respectively in B Nuruk. When quality characteristics of Takju made of each type of Nuruk were compared, alcohol content was the highest in G Nuruk by recording 19.0% and titratable acidity was 0.44~0.86% in all samples. Hunter's color, brown color and turbidity showed different levels according to types of Nuruk and all lactic acid bacteria, yeast and total microbe counts were the highest in A and E Nuruk. For alcohol components, E and G Nuruk showed high fusel oil content levels and methanol and fusel oil contents of all samples were suitable as standards, respectively. The total organic acid content was the highest in B Nuruk at about 4,000 mg% and it was 2,000 mg% and around 1,000 mg% in A, E, F and G Nuruk and C and D Nuruk, respectively. The content of total free amino acid was the highest in B Nuruk at 3,676 mg% and it was observed to be 1,890, 1,676 and 1,531 mg% in G, E and C Nuruk in that order, respectively. Sensory preference of subjects in their 20s was high overall in G and C Nuruk and that of those in their 40s was high in F and C Nuruk. From all of these results, the types of Nuruk largely affected quality and components of Takju and an appropriate method to consider useful purpose is needed.

• Korean Journal of Microbiology
• /
• v.51 no.3
• /
• pp.271-279
• /
• 2015

Lactoferrin (LF) is a multifunctional, iron-binding glycoprotein found in physiological secretions of mammals. LF shows antibacterial, antiviral and antifungal activities. In the present study, a gene encoding the N-terminal lobe of human lactoferrin (hLF) was isolated, cloned and expressed in methylotrophic yeast, Pichia pastoris. The recombinant hLF-N (rhLF-N) protein was secreted into the culture medium at the level of $458{\mu}g/ml$ in 3 L fermentor. The size of purified hLF-N was estimated as 35 kDa when analyzed by SDS-PAGE and western blotting. The rhLF-N was further confirmed by immunodiffusion using the anti-hLF polyclonal antibody. The expression profile analysis by qRT-PCR showed that the relative mRNA expression of rhLF-N was maximal after 2-3 days of methanol induction and reduced gradually at 4 days. The purified rhLF-N showed broad antibacterial activities against the pathogens such as Staphylococcus aureus, E. coli, Pseudomonas aeruginosa, Burkholderia cepacia, and Salmonella typhimurium. However, rhLF-N showed relatively lower activity when compared to peptides derived from LF. In spite of this weak activity, the rhLF-N expressed in P. pastoris might be more advantageous for the industrial application, because rhLF-N is secreted into the culture medium and the production can also be increased by optimization of culture conditions.

• Korean Journal of Food Science and Technology
• /
• v.37 no.3
• /
• pp.449-455
• /
• 2005

To reduce saft content of kochujang, various combinations of sub-materials such as ethanol mustard and chitosan were added to kochujang, and their effects on microbial characteristics, enzyme activities, and physicochemical characteristics of kochujang were investigated after 12 weeks of fermentation. Activities of ${\beta}$-amylase and pretense were low in ethanol-mustard-chitosan-added kochujang, whereas no significant difference was observed in ${\alpha$-amylase activity among all groups. Number of viable yeast cells decreased remarkably in mustard-added kochujang during late aging period, and anaerobic bacterial counts decreased in sub-material-added groups. Consistency of kochujang increased by addition of sub-materials, and oxidation-reduction potential was low in chitosan-added group. Mustard-chitosan-added kochujang showed lowest increase in total color difference(${\Dalta}E$) and decrease in water activity. PH of kochujang wns highest in mustard-chitosan-added kochujang, resulting in significantly increased titratable acidity. Addition of sub-material increased reducing sugar contents of kochujang, whereas ethanol production was significantly repressed in mustard-chitosan-added kochujang. Amino nitrogen content was Highest in mustard-chitosan-added kochujang during late aging period, whereas ammonia nitrogen content was lower in ethanol-mustard-added kochujang. Results of sensory evaluation indicated ethanol-mustard-added kochujang was more acceptable than other groups in taste and overall acceptability.

• Microbiology and Biotechnology Letters
• /
• v.25 no.4
• /
• pp.386-390
• /
• 1997

The characteristics of alcohol dehydrogenase (ADH, EC 1.1.1.1, alcohol:NAD oxidoreductase) of thermotolerant alcohol-producing yeasts, Saccharomyces cerevisiae RA-74-2 and Kluyveromyces marxianus RA-912, were compared with that of mesophilic S. cerevisiae D, an industrial strain. Under anaerobic culture condition, both S. cerevisiae RA-74-2 and D had similar level of ADH activity at 30$\circ$C, and the activity of S. cerevisiae RA-74-2 at 37$\circ$C was the same level at 30$\circ$C. However, the level of ADH activity of S. cerevisiae D at 37$\circ$C decreased about 70% of that at 30$\circ$C. The level of enzyme activity of K. marxianus RA-912, which showed lower alcohol productivity than S. cerevisiae RA-74-2 and D, was about 43% of those strains at 30$\circ$C, and decreased somewhat at 37$\circ$C. The results showed a good correlation between the alcohol productivities and the level of ADH activities of these strains grown at 30$\circ$C and 37$\circ$C. And the higher heat stability of ADH of S. cerevisiae RA-74-2 than that of S. cerevisiae D seemed to reflect the ability of high temperature fermentation. Despite of its fermentation ability even at 45$\circ$C, however, the ADH of K. marxianus RA-912 showed lower heat stability than that of S. cerevisiae D. Both S. cerevisiae RA-74-2 and D showed similar patterns of two bands of ADH isozyme, and the low band of S. cerevisiae RA-74-2 moved slightly faster than that of S. cerevisiae D. The staining intensity of the bands of S. cerevisiae D at 37$\circ$C was weaker than those at 30$\circ$C. However, S. cerevisiae RA-74-2 showed no differences in total intensity of the bands of 30$\circ$C and 37$\circ$C. As the patterns of cellular proteins and ADH isozyme of K. marxianus RA-912 were different from S. cerevisiae RA-74-2 and D, K. marxianus might have its own characteristic ADH system.

• The Korean Journal of Food And Nutrition
• /
• v.13 no.6
• /
• pp.578-584
• /
• 2000

Three kinds of the mashes of 15%, 20% and 25% of boiled wax gourd containing 20% of sugar were fermented by yeast at 5~1$0^{\circ}C$ for 100 days. After fermentation, total sugar content of the 15% mash was 8.0%, 20% mash 8.6%, and 25% mash 8.3%, respectively. Also, it revealed that in reducing sugar content, 15% mash was 7.4%, 20% mash 7.6%, and 25% mash 7.4%, respectively, In protein content, 15% mash was 10.3mg/ml, 20% mash 9.8mg/ml, and 25% mash 11.3mg/ml, and in amino acid content, 15% mash was 0.13 $\mu$mo1/ml, 20% mash 0.03 $\mu$mo1/ml, and 25% mash 0.03 $\mu$mo1/ml, each. In case of pH, 15% mash was 3.88, 20% mash 3.99, and 25% mash 3.97, respectively. In acidity, 15% mash was 0.37, 20% mash 0.44. and 25% mash 0.43, respectively. In the number of yeast cell, 15% mash was 8.33 logCFU/ml, 20% mash 8.56 logCFU/ml, and 25% mash 8.57 logCFU/ml. respectively. In ethanol content, 15% mash was 13.4%, 20% mash 14.9%, and 25% mash 15.5%, respectively. In organic acid content, acetic acid, pyruvic acid, citric acid, and lactic acid were produced, and succinic acid content ranges from 1,407~1,800 mg/l. Five-grade scoring test of sensory evaluation showed that in its taste degree, 15% mash was 3.93, 20% mash 3.66 and 25% mash 3.40, respectively.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.35 no.4
• /
• pp.277-282
• /
• 2015

This study was conducted to investigate the effect of novel Lactobacillus plantarum KCC-10 and KCC-19 on the quality and fermentation characterization of rye silages. The study was conducted at the National Institute of Animal Science, Cheonan province in Korea and consisted of three treatments: control without lactic acid bacteria, treatment with L. plantarum KCC-10 and treatment with L. plantarum KCC-19. The amounts of acid detergent fiber and neutral detergent fiber as well as the in vitro dry matter digestibility in KCC-10 and KCC-19 were similar to the control. The pH of rye silage in L. plantarum KCC-10 and KCC-19 treatments decreased compared to the control (p<0.05). The amount of lactic acid in L. plantarum KCC-10 and KCC-19 treatments increased (p<0.05), but the amounts of acetic acid and butyric acid in KCC-10 and KCC-19 treatments decreased (p<0.05). In addition, the number of lactic acid bacteria in L. plantarum KCC-10 and KCC-19 treatments increased compared to the control (p<0.05). Therefore, we suggest that rye silage was improved by the addition of L. plantarum KCC-10 and KCC-19.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.40 no.9
• /
• pp.1292-1299
• /
• 2011

This research aimed to determine the quality characteristics of kochujang made of sword bean chunggukjang. The effects of chunggukjang addition were compared in products fermented for 90 days. During the fermentation period of kochujang, sword bean chunggukjang was added at 0, 2, 5, 8, and 10%. The moisture content ranged from 40.24 to 42.83% (w/w). After 90 days of fermentation, sodium chloride was at around 10.2 to 10.3%, which was not much different from that of control kochujang (SBC 0) before and after fermentation. The color values were not significantly different between SBC kochujang and traditional kochujang. The microbial counts in 0, 2, 5, 8, and 10% SBC kochujang fermented for 90 days were around $5.42{\times}10^7$ to $9.59{\times}10^7$ CFU/g for aerobic viable cells, $1.14{\times}10^2$ to $9.73{\times}10^2$ CFU/g for yeast, and $8.49{\times}10^2$ to $1.25{\times}10^3$ CFU/g for Bacillus cereus. Sensory evaluation of kochujang showed that the comprehensive preference was 5.40, 5.15, 6.30, 6.10, and 6.95, respectively, for SBC 0, 2, 5, 8, and 10%. In conclusion, the quality difference between SBC and traditional kochujang was not significant, and sensory evaluation of kochujang showed that SBC 10% received the highest score.

• Korean Journal of Agricultural Science
• /
• v.27 no.2
• /
• pp.117-124
• /
• 2000

Three kinds of the mashes of 15%, 20% and 25% of boiled wax gourd containing 15% of sugar were fermented by yeast at $5{\sim}10^{\circ}C$ for 100 days. After fermentation, total sugar content of 15% mash was 7.3%, 20% mash 5.0% and 25% mash 4.0% respectively. Also, it revealed that in reducing sugar content, 15% mash was 4.5%, 20% mash 3.4% and 25% mash 4.0%, respectively. In protein content, 15% mash was 10.1mg/ml, 20% mash 13.9mg/ml, 25% mash 10.9mgl/ml, and in amino acid content, 15% mash was $0.27{\mu}mol/ml$, 20% mash $0.51{\mu}mol/ml$, and 25% mash $0.31{\mu}mol/ml$, each. In case of pH, 15% mash was 3.85, 20% mash 3.76, and 25% mash 3.51. In acidity, 15% mash was 0.34%, 20% mash 0.84%, and 25% mash 1.35%, respectively. In the number of yeast cell, 15% mash was 0.34%, 20% mash 0.84%, and 25% mash 1.35%, respectively. In the number of yeast cell, 15% mash was 6.30 logCFU/ml, 20% mash 6.85 logCFU/ml, and 25% mash 8.45logCFU/ml, respectively. In ethanol content, 15% mash was 11.4%, 20% mash 12,4%, and 25% mash 11.5%, respectively. Succinic acid content ranges from 1,128~1,385mg/l. In Acetic acid, 20% mash showed 2,806 mg/l and 25% mash 4,952 mg/l by acidification. Five-grade scoring test of sensory evaluation showed that in its taste degree, 15% mash was 3.26, 20% mash 3.00 and 25% mash 2.46, respectively.