• Food Science and Biotechnology
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• v.14 no.3
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• pp.375-379
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• 2005

Physicochemical properties, intestinal microbial growth, and inhibitory effects of alcohol-insoluble polysaccharide (AIP) extracted from cucumber peel were investigated. AIP was composed of 14.54% crude protein, 1.04% crude lipid, 13.74 % crude ash, 9.1% soluble dietary fiber, and 41.2% insoluble dietary fiber. AIP showed low bulk density (0.18 g/mL) and water-holding capacity (6.39 g/g), and high oil-holding capacity (3.96 g/g). Pectic substance fractions [water-soluble pectic substance (WSP), ethylenediaminetetraacetic acid-soluble pectic substance (ESP), and alkali-soluble pectic substances (ASP)] and hemicellulose fractions [1 M KOH-soluble hemicellulose (KHP1) and 4 M KOH-soluble hemicellulose (KHP4)] were obtained from sequential chemical fractionation of AIP. WSP showed higher total sugar contents than total uronic acid contents, whereas opposite results were observed in ESP and ASP. Molecular weight distributions of three pectic substance fractions were in order of ASP>ESP>WSP. Ion exchange chromatogram pattern of WSP was different from those of ESP and ASP. Major component of WSP was fraction eluted by 0.05 M ammonium acetate buffer, whereas that of ESP and ASP was fraction eluted by 0.2 M NaOH. WSP and ASP showed growth-promoting activities against Lactobacillus brevis, Bifidobacterium bifidum, and B. longum, whereas B. bifidum and B. longum for ESP. KHP1 and KHP4 fractions had significant growth-promoting activities against B. bifidum.

• Journal of the Korean Society of Food Science and Nutrition
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• v.25 no.3
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• pp.470-477
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• 1996

This study was intended to observe the changes of pectic substances and enzyme activities, texture, microstructure of anchovy added kimchi during fermentation for 4 weeks at 4$^{\circ}C$. Content of alcohol insoluble solid(AIS) and HCl soluble pectin(HClSP) were decreased, whereas content of hot water soluble pectin(HWSP) was increased during fermentation. Content of HClSP was higher and HWSP was lower in anchovy added kimchi than control. Activity of pectinesterase(PE) was decreased, whereas activity of polygalacturonase(PG) was increased during fermentation. In anchovy added kimchi, PG activity was lower than control. Changes in microstructure of Chinese cabbage and kimchi during fermentation was lower than control. Changes in microstructure of Chinese cabbage and kimchi during fermentation was observed ; in the raw cabbage, parenchyma cells, intercellular space and middle lamella were clearly shown. But in salted cabbage, middle lamella became separated. In the late stage of fermentation, parenchyma cell walls were wrinkled and collapsed. Puncture forces of kimchi were decreased, whereas cutting forces of kimchi were increased as fermentation proceeded. The firmness was slightly higher in anchovy added kimchi than control at the late stage fermentation, which may be explained by the PG activity.

• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.1
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• pp.29-34
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• 1998

This study was investigated to know changes of the cell wall components, cell wall degrading enzyme activities and contents of soluble protein of strawberry during ripening and softening. The contents of water soluble substances were slightly increased during ripening, but the contents of alcohol-insoluble substances were not changed. The contents of pectin were not changed at green mature and turning stage, while decreased after mature stage. The contents of alkali-soluble hemicellulose and cellulose were increased during ripening and softening. The contents of water-soluble and saltsoluble protein were not changed, but the content of cell wall protein was slightly decreased during ripening. The content of total protein was increased at turning stage, it is not changed after turning stage. $\beta$-Galactosidase activity was increased during ripening, and pectinmethylesterase activity was decreased at turning. Phenylalanine ammonia-lyase activity was changed up to mature stage, but decreased at overripening stage. Polygalacturonase and cellulase activities were not detected at all of ripening stages.

• Journal of Microbiology and Biotechnology
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• v.21 no.11
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• pp.1184-1192
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• 2011

A bacterial isolate (strain JS-2) characterized as Bacillus sp. was challenged with high concentrations of toxic selenite ions. The microbe was found to transform the toxic, soluble, colorless selenite (${SeO_3}^{2-}$) oxyions to nontoxic, insoluble, red elemental selenium ($Se^0$). This process of biotransformation was accompanied by cytoplasmic and surface accumulation of electron dense selenium ($Se^0$) granules, as revealed in electron micrographs. The cells grown in the presence of selenite oxyions secreted large quantities of extracellular polymeric substances (EPS). There were quantitative and qualitative differences in the cell wall fatty acids of the culture grown in the presence of selenite ions. The relative percentage of total saturated fatty acid and cyclic fatty acid increased significantly, whereas the amount of total unsaturated fatty acids decreased when the cells were exposed to selenite stress. All these physiological adaptive responses evidently indicate a potentially important role of cell wall fatty acids and extracellular polymeric substances in determining bacterial adaptation towards selenite-induced toxicity, which thereby explains the remarkable competitiveness and ability of this microbe to survive the environmental stress.

• Food Science and Preservation
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• v.1 no.1
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• pp.1-7
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• 1994

To investigate the effect of several bactericides and fungicides against fruit & vegetable decay grapefruit seed extract(GFSE) was tested in a dilution solution. GFSE was shown to be effective against decay and rind breakdown and to extend the shelf-life of fruits and vegetables during storage and tiansport. Antimicrobial efficiency of GFSE on a wide spectra of gram + & - bacteria, moulds and yeasts was demonstrated by the measurement of minimal inhibitory concentrations performed (Bacteria 10-500ppm, Fungi:250-1,000ppm, Yeasts:100-250ppm). GFSE was separated and extracted into water-soluble fraction, water-insoluble and non-dialyzed fraction to isolate the antimicrobial substances. The water-soluble fraction showed the most active antimicrobial effect. The antimicrobial substances were isolated by gas chromatography. As the result of the isolation using GC, Peak-D was found to be the antimicrobial compound in GFSE. The identification of the most antimicrobial substance was carried out by using GC-MS.

• Korean journal of food and cookery science
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• v.5 no.1
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• pp.43-47
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• 1989

For identifying the cause of the difference from the texture of mealy potatoes-Namjak and soomi- and soggy Potatoes-Daeji and Dowon-, starch and pectic substances and their relating materials were analyzed, and polygalacturonase(PG) activity was measured. The shape and size of Namjak and soomi starch granules were circular and diameter ranged from 0.02 to 0.024 mm. In the meanwhile, Daeji and Dowon had two sizes of starch granules; larger one tend to be oval in shape and diameter of longer side ranged from 0.04 to 0.045 mm, that of narrower side ranged from 0.02 to 0.03 mm and smaller one was rather circular in shape and average deameter was below 0.005 mm. Oval shaped potato starch grancules under polarized light showed dark cross of V-shape, whereas circular granules showed cross shape. Total sharch contents of Namjak and soomi were higher than that of Daeji and Dowon. The changes of pectic substances were the decrease of the insoluble pectin and the increase of the soluble pectin, and the reduction of the total pectic substance content after cooking. This phenomena were more prominent in Namjak and Soomi than in Daeji and Sowon. PG activities of Namjak and Soomi were greater than Daeji and Dowon. Calcium contents of Namjak and Soomi were lower than Daeji and Dowon. Phytic acid contents of Namjak, Soomi, Daeji and Dowon were 0.093%, 0.096%, 0.078%, and 0.081%, respectively. Hardness of Namjak and Soomi were less than Daeji and Dowon. The mealy potatoes had higher starch contents, higher tendency to pectin solubilization, higher PG activities, lower calcium contents and less hardness than the soggy Potatoes.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.6
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• pp.1006-1012
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• 1997

To observe the food quality of Baik-kimchi which is known as a watery Chinese cabbage pickles without fish sauce and red pepper paste, the changes of dietary fibers and pectic substances during fermentation at 5$^{\circ}C$ and $25^{\circ}C$ were studied. Baik-kimchi fermented at $25^{\circ}C$ showed a greater changes in pH and acidity than those of 5$^{\circ}C$ during storage. Ripened Baik-kimchi products fermented at 5$^{\circ}C$ could be prepared on 9~12 days of fermentation, and those had a pH range from 4.25 to 4.40 and acidity of 0.34~0.53. But in the case of $25^{\circ}C$ fermentation, Baik-kimchi ripened for 3 days showed a pH of 4.02 and acidity of 0.54. The pH and acidity of the Baik-kimchi juice changed more rapidly than those of the Baik-kimchi solid regardless of fermentation temperatures. The content of soluble dietary fiber(SDF) was ranged from 3.06 to 4.87% at 5$^{\circ}C$ and a wide variation in SDF was observed in the sample fermented at $25^{\circ}C$(4.15~11.22%). Insoluble dietary fiber(IDF) were increased from 21.66% to 28.42% in solid of Baik-kimchi during fermentation at 5$^{\circ}C$ and ranged from 21.37% to 24.65% for sample fermented at $25^{\circ}C$. A notable amount of pectin had been dissolved in juice of Baik-kimchi till the best ripening time and showed the level of 223.2mg/100ml at 5$^{\circ}C$ on the day of 9 and 207.3mg/100ml at $25^{\circ}C$ on the day of 2. In contrast, the contents of pectin in solid Baik-kimchi decreased, whereas contents of sodium hexametaphosphate soluble pectin(HXSP) and HCl soluble pectin(HClSP) increased with fermentation period.

• The Korean Journal of Mycology
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• v.21 no.2
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• pp.106-111
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• 1993

Pectolytic enzymes were extracted in apple fruits rotted by Botryosphaeria dothidea, and their activities and change of pectic substances were investigated. Exo-polygalacturonase(exo-PG), exo-polymethylgalacturonase(exe-PMG), polygalacturonate-trans-eliminase(PGTE) and pectin-methyl-trans-eliminase(PMTE) were produced by the pathogen. Activities of exo-PG and exe-PMG extracted from rotten apple fruits were high to 21.15 and 24.65 units/mg protein in specific activity at seven days after inoculation, respectively. Activities of PGTE and PMTE showed 5.60 and 7.90 units/mg protein, respectively, but they were lower than those of the exo-type enzymes. Water-soluble and versene-soluble pectins were 11.50 mg/100 mg-AIS and 7.31 mg/100 mg-AIS at 14 days after inoculation, namely, they were increased by 4.23 and 2.16 mg/100 mg-AIS over those of sound apples, respectively. Total soluble pectic substances of rotten apple were 72.4% of total pectic substances and it was higher by 24.8% than sound apple. Insoluble pectic substance was notably decreased from 15.32 to 7.16 mg/100 mg-AIS according to progress of decay while total pectic substances were not changed remarkably.

• 한국생물공학회:학술대회논문집
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• 2003.04a
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• pp.595-599
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• 2003

Arabinose is five-carbon sugar that have been used a precursor of chemical synthetic pharmaceutics and an additives for an diet foods. Its contents in the hemicellulose among varied cellulosic materials is approximately $0.2%\;{\sim}\;4.0%$. In previous papers, it was focused in the production of xylose. But this study was subjected to an effective production of arabinose. High arabinose yield and selectivty was achieved at 0.6% sulfuric-acid concentration and $100^{\circ}C$. We will present how to remove an insoluble substances and the process for arabinose separation.

• Applied Biological Chemistry
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• v.2
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• pp.9-14
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• 1961

The formation of sulfide from sulfate has been discussed from the thermodynamic principles. No mechanism of the reaction has been presented. From the stoichiometric and Nernst equations for the conversion of sulfate into sulfide, it was concluded that the formation of sulfide from sulfate can take place more readily if pH of a medium is low. The difficulty of this conversion increases with increasing pH. As pH of a medium increases, the degree of dissociation of H₂S into S= increases and this, in turn, renders the chance of precipitation of sulfide as FeS easier. Higher the pH of a soil or medium, greater is the S= concentration. The concentration of ferrous ion required to remove dissolved sulfide in a medium by forming insoluble FeS decreases with increasing pH. From the theory it was pointed out that an application of lime and iron rich foreign substances to a soil may be effective in causing the removal of dissolved sulfide from solution.