• Journal of Microbiology and Biotechnology
• /
• v.22 no.2
• /
• pp.199-206
• /
• 2012

Naturally immobilized tannase (tannin acyl hydrolase, E.C. 3.1.1.20) has many advantages, as it avoids the expensive and laborious operation of isolation, purification, and immobilization, plus it is highly stable in adverse pH and temperature. However, in the case of cell-associated enzymes, since the enzyme is associated with the biomass, separation of the pure biomass is necessary. However, tannic acid, a known inducer of tannase, forms insoluble complexes with media proteins, making it difficult to separate pure biomass. Therefore, this study optimizes the production of cell-associated tannase using a "protein-tannin complex" free media. An exploratory study was first conducted in shake-flasks to select the inducer, carbon source, and nitrogen sources. As a result it was found that gallic acid induces tannase synthesis, a tryptose broth gives higher biomass, and lactose supplementation is beneficial. The medium was then optimized using response surface methodology based on the full factorial central composite design in a 3 l bioreactor. A $2^3$ factorial design augmented by 7 axial points (${\alpha}$ = 1.682) and 2 replicates at the center point was implemented in 17 experiments. A mathematical model was also developed to show the effect of each medium component and their interactions on the production of cell-associated tannase. The validity of the proposed model was verified, and the optimized medium was shown to produce maximum cell-associated tannase activity of 9.65 U/l, which is 93.8% higher than the activity in the basal medium, after 12 h at pH 5.0, $30^{\circ}C$. The optimum medium consists of 38 g/l lactose, 50 g/l tryptose, and 2.8 g/l gallic acid.

• Korean Journal of Food Science and Technology
• /
• v.12 no.2
• /
• pp.88-96
• /
• 1980

Reaction conditions in the amino-carbonyl reaction, and the effect of amino acids on the reactivity of amino-carbonyl reaction were investigated. Results obtained are as follows : 1. When the pH of the reaction mixture was increased above the isoelectric point of an amino acid, a significant increase in the color intensity was observed. 2. The color intensity increased gradually up to 1 : 1 of the molar ratio of reactants. This result was interpreted to show that sugar and free amino group combined in 1 : 1 ratio. 3. Amino-carbonyl reaction showed a significant time and temperature-dependences. The activation energy at 0.2 M glucose and 0.2 M glycine system was 37.5 Kcal/mole. 4. Among amino acids tested, glycine, lysine and $\beta$-alanine caused a significant increase in the color intensity, but acidic amino acids showed the least color intensity. The latter was interpreted to show that one of carboxyl groups of acidic amino acid has an inhibiting effect on the reactivity of the amino group. 5. The color intensity of sugars tested was in the order of xylose>arabibose>fructose>glucose>maltose>lactose.

• Asian-Australasian Journal of Animal Sciences
• /
• v.6 no.4
• /
• pp.607-617
• /
• 1993

Three experiments were carried out in which lactating Hereford ${\times}$ Friesian cattle walked up to ten kilometers a day for three periods of five days with two non-walking days between each walking period and in which the animals were fed different diets. Measurements were made of milk yield, milk constituent yields and concentrations and blood metabolite concentrations. Exercise caused significant reductions in milk yield and in the yields of lactose and milk protein. Milk fat yield was not reduced when animals were exercised. During exercise the concentrations of ${\beta}-OH$ butyrate and free fatty acids increased, whereas the concentrations of glucose, magnesium and inorganic phosphorus decreased. Diet influenced the effect of exercise on some blood metabolite concentrations.

• Korean Journal of Microbiology
• /
• v.27 no.3
• /
• pp.188-193
• /
• 1989

Gene for lactose catabolism in Lactobacillus casei SW-M1 was encoded by a 60Kb metabolic plasmid. A derivative of only 10kb, pPlac 15 of recombinant plasmid, was constructed by introducing into pBR322 and was cloned into E. coli using restriction endonuclease Pst I. A 10kb insery DNA in plasmid pBR322 was identified as a gene encoded phospho-$\beta$-galactosidase by the determination of enzyme activity. Phospho-$\beta$-galactosidase was apparently expressed in E. coli. The enzyme activities of cell-free extract from transformant E. coli HB101 carrying pPLac 15 DNA were not different from that of L. casei as a donor strain on the basis of enzyme properites. However, specific activity of phospho-$\beta$-galactosidase in the cloned strain with Lac $Y^{-}$ phenotype of E. coli HB101 was lower than that in L. casei strain.

• Applied Chemistry for Engineering
• /
• v.19 no.1
• /
• pp.129-132
• /
• 2008

The purposes of this study were to investigate the physicochemical properties and component values of bamboo oil from Phyllostachys nigra var. henonis obtained by refining process. The tar concentration in the refined bamboo oil (RBO) was decreased to about 78% compared to crude Bamboo oil (CBO). The chromaticities of light, red, and yellow in RBO were 92.4 and 3.0, respectively. This result indicates that the chromaticity of light was increased with the decrease in the tar concentration in the Bamboo oil. The total concentrations of organic acid and phenolics compound in RBO were decreased to about 63% and 80%, respectively. The total concentration of free sugars was decreased to about 78% in RBO and the concentration of free sugar was in the order of lactose, fructose, and glucose. The palmitoleic acid and stearic acid concentrations were higher than that of other fatty acids. The concentration of total organic acid was decreased to about 88% through RBO. Among the various organic acids, the formic acid concentration was highest in the RBO. The minerals concentrations in the CBO were in the order of Ca, K, Na, and Fe. On the other hand, in the case of RBO, it was in the order of Ca, Fe, K, and Na.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.39 no.3
• /
• pp.421-427
• /
• 2010

This study was conducted to compare and analyze the active and general components between mulberry leaf tea (MLT) and fermented mulberry leaf tea (FMLT). Among the general ingredients, the crude lipids of FMLT contained higher than that of MLT, while the level of carbohydrates was higher in the MLT. Although free sugar of FMLT was a lower concentration than MLT, the value of maltose was higher in the MLT. In FMLT, maltose was not analyzed but small amount of lactose was analyzed. In addition, the level of total free amino acid of MLT was higher than that of FMLT. The level of glutamic acid was highest in MLT, while that of cystine was highest in FMLT. The value of $\gamma$-aminobutyric acid (GABA) was greater in the derivatives of amino acids, and the content was similar for both MLT and FMLT. FMLT also contained a lower level of unsaturated fatty acids than MLT. In addition, the content of total mineral was higher in FMLT, and the level of K was the highest and similar in both teas.

• Food Science and Preservation
• /
• v.17 no.6
• /
• pp.853-860
• /
• 2010

We quantitated the major chemical components of ramie leaves (Boehmeria nivea L.) powder. The proximate compositions (all w/w) was 5.42% moisture, 28.15% crude protein, 6.95% crude fat, 15.27% crude ash, and 54.79% carbohydrate, respectively. The total, insoluble, and soluble dietary fiber contents were $39.66{\pm}1.84g/100g$, $20.32{\pm}2.02g/100g$, and $19.34{\pm}2.84g/100g$, respectively. The major free sugars were glucose, galactose and lactose. Seventeen amino acids were isolated. Essential amino acids constituted 44.65% of the total. When free amino acid levels were evaluated, 25 kinds of components were detected, of which 18.15% were essential. Only caproic acid methyl ester and pentadecanoic acid were detected when fatty acid examined. The contents of vitamin A, vitamin E and vitamin C were 0.0194 mg%, 0.0184 mg%, and 0.1833 mg%, respectively. The mineral contents of were in order of Cu

• Journal of Dairy Science and Biotechnology
• /
• v.21 no.2
• /
• pp.81-87
• /
• 2003

This study was conducted to correlate the quality depending upon sensory evaluation of ESL(extended shelf life) and non-ESL milk during the shelf life. The most important quality assurance is sensory evaluation for dairy products. ESL and non-ESL milk were stored at $5^{\circ}C$ and $10^{\circ}C$ for 14 days. In order to compare physicochemical and sensory properties, pH, TA(titratable acidity), protein, fat, lactose, FFA(free fatty acid), and other organoleptic characteristics were measured. The results showed that physicochemical properties were not significantly changed during storage. On the other hand, the freshness was affected by storage conditions. The most freshness depending upon sensory evaluation was monitored at 5 days storage. Descriptive and acceptability analysis showed that more acceptable milk was ESL milk than non-ESL milk because of off-flavor and after taste of non-ESL milk. According to these results, it was shown that the freshness of milk products depends on sensory. And ESL milk was fresher than non-ESL milk after storage.

• The Korean Journal of Mycology
• /
• v.50 no.1
• /
• pp.65-73
• /
• 2022

This study aimed to isolate wild yeasts from seawaters and soils samples of the Haeundae and Mongdol beaches on the southern coast of Korea, and to characterize these unrecorded wild yeast strains. In total, 41 strains, representing 37 different species of wild yeast were isolated from 70 samples collected from the beaches. Among these, 14 strains were isolated from the alkalophilic medium of yeast extract-peptone-dextrose (YPD) medium (pH 9.0), and 27 strains were isolated concurrently on general YPD medium (pH 6.5). Among the 41 isolated wild yeast strains, Candida insectorum HUD 16-3(JSL-KSS-002) and Metschnikowia citriensis HUD 12-5(JSL-KSS-001) had not previously been recorded. We investigated the microbiological characteristics of these two unrecorded yeast strains and three other strains-, Cystobasidium lysinophilum JSC 52-2(JSL-GGU-019), Candida takata NMD 11-1(JSL-GGU-017) and Candida panamensis ASG 58M-2(JSL-GGU-018) from Jangseoncheon in Jellabuk-do and Jangtaesan in Deajeon city. All five previously unrecorded yeasts were oval and did not form spores. All strains grew well in YPD and yeast extract-malt extract media in a vitamin-free medium. Two strains, including C. insectorum HUD 16-3(JSL-KSS-002) grew well in a 15% NaCl-containing YPD medium. Three strains, including Cys. lysinophilum JSC52-2(JSL-GGU-019) assimilated lactose, and all strains assimilated starch.

• Journal of the East Asian Society of Dietary Life
• /
• v.25 no.5
• /
• pp.867-879
• /
• 2015

To confirm basic nutrient contents of Korean honey as a food material, we assessed New Zealand Manuka honey by measuring proximate components, vitamin C and minerals of 16 kinds of honey harvested in South Korea. The proximate composition of each honey sample was as follows: moisture content 18.45~29.84%, crude protein 0.10~0.95% (vs Manuka honey 0.23%), crude fat 0.02~0.60% (vs Manuka honey 0.34%), crude ash 0.01~.52% (vs Manuka honey 0.24%) and carbohydrate 67.90~80.94% (vs Manuka honey 79.39%), respectively. In the case of free sugars analyze by HPLC, fructose showed a content of 26.12~49.84% which was highest in acacia honey and lowest in sorbus honey. Content of glucose was 19.38~36.12% and lowest in chestnut honey, whereas sucrose, lactose, maltose were absent. Total sugar contents were 64.16% which was less than Manuka honey (70.23%) and vitamin C was not detected in all samples. Minerals were detected 15~25 kinds, including K, Ca, Mg, Zn, Fe, Cu, Mo and so on. Ca was high in order of linden > canola > codonopsis > hedysarum honey, and K was higher than in Manuka honey in order of chestnut > hedysarum > codonopsis > jujube honey. Especially, these results suggest that Korean honey have a better nutrient content profile than Manuka honey.