• Bulletin of Food Technology
• /
• v.21 no.2
• /
• pp.55-61
• /
• 2008

본 연구에서는 발효기간 중 SAM 생성량 증진김치의 최적조건을 개발하기 위해 배추김치의 재료별 및 제조법에 따른 발효기간 중의 SAM 함량 변화를 측정하였다. 발효가 진행됨에 따라 모든 김치군의 pH는 발효초기에는 급격히 감소하다가 후기에는 pH $4.2{\sim}4.3$으로 비슷하게 나타났다. 산도는 pH와 비슷한 경향을 보이면서 발효초기에는 급격히 감소하다가 후기에는 서서히 증가하는 경향을 보였다. SAM 함량은 가장 기본적인 재료로만 제조한 표준(A)김치는 가장 낮게 나타났고, SAM이 검출되는 원 부재료에 SAM 함량이 많은 김치가 SAM 함량도 높게 나타났다. 모든 김치군 중 I김치가 가장 높은 SAM 함량을 나타냈으며, 김치별 SAM 함량이 가장 높은 발효시점은 A, K김치는 pH $4.6{\sim}4.9$, 산도 $0.38{\sim}0.57$0.57, D, H김치는 pH 6.3, 산도 $0.24{\sim}0.27$, E, G김치는 pH $6.1{\sim}6.6$, 산도 $0.05{\sim}0.14$0.14, B, C, F, I, J김치는 pH $4.3{\sim}5.3$, 산도 $0.45{\sim}1.02$에서 나타났다. 따라서 대부분의 김치는 적숙기시점이 되었을 때 B, E, G, H김치는 초기발효 때부터 SAM 함량이 높게 나타났다. 또한 발효가 진행됨에 따라 SAM 함량은 감소하는 경향을 보였다. 따라서 연구결과 주재료인 채소류와 젓갈의 함량비를 적절히 제조하여 최적의 SAM 생산능력의 발효시점과 김치맛에 영향을 끼치지 않는 관능적으로 적합하고 SAM 생성이 보다 효과적으로 유도되는 최적의 조건에 대한 실험들이 추가적으로 필요하다고 판단된다.

• Korean Journal of Food Science and Technology
• /
• v.28 no.4
• /
• pp.663-667
• /
• 1996

Acid phosphatase (EC 3.1.3.2) from Welsh onion was partially purified by Sephacryl S-200 gel filtration and CM-Sepharose CL-6B ion exchange chromatography. The optimum pH and temperature of acid phosphatase from green onion were pH 5.5 and $60^{\circ}C$, respectively. The enzyme was the most stable at pH 6.0 and unstable above pH 9.0. The activation energy of the enzyme was determined to be 4.86kcal/mole. The enzyme utilized p-nitrophenyl phosphate most as a best substrate among tested possible substrates, while 5'-GMP and 5'-IMP were poor substrates for the enzyme. $K_{m.app.}$ of the enzyme with p-nitrophenyl phosphate as a substrate was identified as 0.87mM. Among metal ions and inhibitors tested, $Cr^{+++},\;Zn^{++},\;Cu^{++}$, molybdate and metavanadate ions inhibited the enzyme reaction drastically.

• The Korean Journal of Mycology
• /
• v.31 no.2
• /
• pp.77-83
• /
• 2003

For the purpose of utilizing cellulose resources by cellulolytic enzymes of Roseofomes subflexibilis, it's cultural conditions for the production of cellulolytic enzymes in synthetic media were investigated. The results obtained were summarized as follows : The optimum temperature and pH for the enzyme production were $30^{\circ}C$ and pH 4.0, respectively. Among the carbon sources, glucose was good for the production of cellulase. The optimum concentration of saccharose as 1.2%. As a organic nitrogen source, yeast extract was good for the mycelial growth. The optimum concentration of yeast extract as 1.5%. As a inorganic nitrogen source, $NH_{4}H_{2}PO_{4}$ was good for the mycelial growth. The optimum concentration of $NH_{4}H_{2}PO_{4}$ were 1.1%. The mineral salt of $Al_{2}(SO_{4})_{3}$ was effective and the optimum concentration was 0.1 M.

• The Korean Journal of Mycology
• /
• v.25 no.4 s.83
• /
• pp.305-310
• /
• 1997

A study was conducted to obtain optimal mycelial growth conditions of Pleurotus eryngii. Mycelial growth was best on medium Lilly, temperature $25{\sim}30^{\circ}C$, and pH 6.0. Optimal carbon sources were $3{\sim}4%$ glucose and 5% dextrin. Casamino acid 0.12% in medium was good for mycelial growth as a nitrogen source.

• Microbiology and Biotechnology Letters
• /
• v.15 no.6
• /
• pp.436-440
• /
• 1987

Pullulanase gene (pul) of Klebsiella pneumoniae NFB-320 which was cloned previously in Escherichia coli with plasmid pBR322. The gene was analyzed with various restriction enzymes. The cloned gene was contained within n 10 kb BamHI DNA fragment. We constructed the restriction map of the hybrid plasmid pYKL451. The optimum temperatures for pullulanases produced in E. coli (pYKL451) and K. pneumoniae NFB-320 were almost the same, 50-55 $^{\circ}C$. The optimum pHs for the reaction of the enzymes produced by E. coli (pYKL451) and K. pneumoniae NFB-320 was 6.0. Both enzyme preparations were stable under the range of pH 5.0 to 10.0 when those were kept at 40 $^{\circ}C$ for 90 min and were stable until 40 $^{\circ}C$ when allowed to stand for 1hr at various temperatures.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.14 no.1
• /
• pp.131-138
• /
• 2006

In this study, the optimum condition of pH was investigated on the hydrogen gas production under anaerobic fermentation process. The results of the experiment showed that the optimum condition was observed at pH 6, resulting in 1175.87 mL/L of hydrogen gas production rate and 22.51% theoretical hydrogen conversion ratio. Hydrogen gas production rate and theoretical hydrogen conversion ratio were 901.77 mL/L and 17.48 % respectively at pH 5. At pH 7 and 8, the production rate of hydrogen gas was little low as 82.15 mL/L. Among the organic acids from the sucrose fermentation, propionate was observed as the dominant acid at pH 7 and 8 but butyrate was the dominant at pH 5 and 6.

• Analytical Science and Technology
• /
• v.21 no.1
• /
• pp.20-24
• /
• 2008

A chemiluminescence method has been developed to determine vitamin $P_1$ in aqueous solution which is based on the enhancement of the intensity of lucigenin using lucigenin-$H_2O_2$ as chemiluminogenic system. The effects of experimental parameters such as concentrations of lucigenin, pH and concentrations of $H_2O_2$ were studied. The present method allows the determination of vitamin $P_1$ over the range $7.5{\times}10^{-6}{\sim}5.0{\times}10^{-4}mol/L$. The detection limit was $5.7{\times}10^{-7}mol/L$. The relative standard deviation was 0.75 % for 10 determinations of $7.5{\times}10^{-5}mol/L$ vitamin $P_1$. The correlation coefficient of the working curve was 0.9984 (S/N=3).

• Korean Journal of Food Science and Technology
• /
• v.29 no.2
• /
• pp.343-347
• /
• 1997

Effect of culture conditions on the fermentation of wheat flour solution by mixed lactic acid bacteria of Lactobacillus brevis, L. fermentum and L. plantarum was investigated. The optimum temperature for the fermentation of wheat flour solution was $35^{\circ}C$ because pH decreased the lowest value and TTA (total titrable acidity) increased the highest value at this temperature. In aerobic condition, fermentor was purged with air at 1.0 vvm and was purged with nitrogen gas at 1.0 vvm in anaerobic condition. The decrease of pH and the increase of TTA in aerobic condition were higher than those in anaerobic condition. In aerobic condition, the optimum condition of oxygen supply was found to be oxygen transfer rate coefficient of $60\;hr^{-1}$ which corresponded to agitation speed of 250 rpm in a 5 L fermentor. Repeated fed-batch cultures were performed using pH-stat in order to increase the productivity of fermented wheat flour. With increasing the repeated fraction of culture volume, mean cycle time increased but maximum operation time decreased. However, the volume of produced broth per culture volume per time and total volume of produced broth per culture volume were maximum at the repeated fraction of culture volume of 20%. In a repeated fed-batch fermentation of wheat flour solution using mixed lactic acid bacteria, the culture condition was optimum at temerature of $35^{\circ}C$, aeration rate of 1.0 vvm, oxygen transfer rate coefficient of $60\;hr^{-1}$, and repeated fraction of culture volume of 20%.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.11 no.8
• /
• pp.3112-3118
• /
• 2010

The pH control agent in PWRs, to insure the integrity of steam generator, was changed from ammonia to ethanolamine(ETA) which decreased pH at condensate system and low pressure feedwater heater drain system, so that several amines were investigated for the selection of the optimum amine. There was no single alternative amine to meet the optimum condition. The more volatile ammonia provides the higher pH in condensate, while the less volatile ETA increases the pH in wet steam area. Thus, the combined amine of ammonia and ETA is able to equally raise the pH in both region so that the flow accelerated corrosion be reduced in the every system of the secondary side and the integrity of steam generator be also improved in pressurized water reactors (PWRs).

• KSBB Journal
• /
• v.16 no.2
• /
• pp.174-178
• /
• 2001

Soybeans contain the phytoestrogens genistein and daidzein, their glucosides genistin and daidzin and coumesterol. These isoflavonoid compounds are capable of producing an estrogenic response in a number of diverse species. This study determined optimum conditions for the extraction of the main isoflavones(daidzin, genistin, daidzein, genistein) in defatted soybean meal using high-performance liquid chromatography. The best optimum extraction was achieved at 75% ethanol, $80^{circ}C$, pH4 and a three hour contact time. In addition, isoflavones with high purity were separated by adding up to 4%(w/v) of calcium chloride dihydrate. Most soybean extracts were composed of $beta$-glucosidic conjugate(daidzin, genistin) which is difficult to adsorb in body. Therefore, $beta$-glucosidase was used to convert as conjugate to aglycone form (daidzein, genistein) which is easy to adsorb. The optimal conditions of enzyme reaction involved to be 8.4 units of enzyme concentration, pH5.0, $40^{circ}C$ and 40 minutes.