• Korean Journal of Fisheries and Aquatic Sciences
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• v.6 no.1_2
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• pp.27-36
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• 1973

The effect of water activity on degradation of pigments in dried lavers, Porphyra tenera Kjellm. was examined when stored at room temperature for fifty days. Chlorophyll pigment was extracted with methanol-petroleum ether mixture solvent(2:1 v/v), partitioned in ether, and analysed spectrophotometrically at 662 nm as chlorophyll a. The degradation products of chlorophyll were isolated on sugar-starch column(85:15 w/w) with n-propanol-petroleum ether solution(1:200 v/v) as a developing solvent. The isolated green colored zones were analysed individually at the wavelengths of 650, 662, and 667 nm as allomerized product, chlorophyll a retained, and pheophytin formed respectively. Carotenoida were also extracted with the methanol mixture solvent, partitioned in ether, and finally redissolved in acetone after the evaporation of ether in a rotary vacuum evaporator. The total carotenoid content was measured as lutein at 450 nm. From the results, it is noted that the rate of chlorophyll degradation reached a minimum at 0.11 to 0.33 water activity while progressively increased at higher moisture levels resulting in rapid conversion of chlorophyll to pheophytin. At lower activity, autocatalysed oxidizing reaction like allomerization seemed prevailing the acid catalysed conversion reaction. The loss of carotenoid pigment was also greatly reduced at the range of 0.22 to 0.34 water activity with much faster oxidative degradation at both higher and extremely lower moisture levels. These two moisture levels indicated above at which the both pigments exhibited maximum stability are considerably higher than the BET monolayer moisture which appeared 7.91 percent on dry basis at Aw=0.10 calculated from the adsorption isothermal data of the sample at $20^{\circ}C$. The rate of pigment loss in heat treated samples at 60 and $100^{\circ}C$ for 2 hours prior to storage somewhat decreased, particularly at higher moisture levels although the final pigment retention was not much stabilized.

• Bulletin of the Korean Chemical Society
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• v.30 no.10
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• pp.2413-2418
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• 2009

Rates of solvolyses of 4-nitrophenyl phenyl thiophosphorochloridate (4-N$O_2$PhOP(S)(Cl)OPh, $\underline{1}$) in ethanol, methanol, and aqueous binary mixtures incorporating ethanol, methanol, acetone, and 2,2,2-trifluroethanol (TFE) are reported. Thermodynamic parameters were determined at several temperatures in three representative solvents. The extended Grunwald-Winstein equation was applied to 29 solvents and the correlation coefficient (R) showed 0.959. The sensitivities (l = 1.37 and m = 0.62) are similar to those obtained for diphenyl thiophosphorochloridate (($PhO)_2$PSCl, $\underline{2}$), diphenyl phosphorochloridate (($PhO)_2$POCl, $\underline{3}$), diphenyl phosphinic chloride ($Ph_2$POCl, $\underline{4}$), and diphenyl thiophosphinic chloride ($Ph_2$PSCl, $\underline{5}$). The solvolytic reaction mechanism of 4-nitrophenyl phenyl thiophosphorochloridate ($\underline{1}$) is suggested to be proceeded a $S_N$2 process as previously reported result. The activation enthalpies are shown as slightly low as ${\Delta}H^{\neq}\;=\;9.62\;to\;11.9\;kcal{\cdot}mol^{-1}$ and the activation entropies are shown as slightly high negative value as ${\Delta}S^{\neq}\;=\;-34.1\;to\;-44.9\;cal{\cdot}mol^{-1}{\cdot}K^{-1}$ compared to the expected $S_N$2 reaction mechanism. Kinetic solvent isotope effects are accord with a typical $S_N$2 mechanism as shown in the range of 2.41 in MeOH/ MeOD and 2.57 in $H_2O/D_2O$ solvent mixtures.

• Korean Journal of Food Science and Technology
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• v.29 no.3
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• pp.595-600
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• 1997

The antioxidant activity of the solvent fractions extracted from onion skin was examined. The antioxidant activity of methanol extract at the cencentration of 0.02% and 0.03% was stronger than that of mixed tocopherol. The antioxidant activity of the fractions of methanol extract increased in the order of butanol> ethyl acetate> ethyl ether> water fraction. The antioxidant activity of each fractions was strongly related with total phenol content and HDA. Further separation of butanol fraction by TLC yielded 6 fluorescent bands with Rf values of 0.20, 0.33, 0.49, 0.60 and 0.94. The total phenol content and HDA of fluorescent band, Rf 0.96, were remarkable higher than those of the other band and exhibited a strong UV absorption at 255 nm and 317 nm, which would be specifically produced by flavonol. Spectral analyses indicated that the major antioxidant component was quercetin aglycone (3,3',4',5,7-pentahydroxyflavone).

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.4
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• pp.717-720
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• 2001

Chemical compositions and physiological activities of Platycodon grandiflorum roots grown for 4 and 24 years were investigated. Chemical compositions of P. grandiflorum roots grown for 24 years were moisture 82.7%, crude protein 1.6%, crude lipid 2.1% crude ash 0.7%. total sugar 6.0% total dietary fiber 2.3% crude saponin 3.4mg% and ascorbic acid 3.0 mg%. Contents of each components in 24 years old roots were higher than that in 4 years old roots and the most abundant mineral was potassium being 879.9mg/kg. Physiological activities of solvent extract from P. grandiflorum roots grown for 4 and 24 years were high in order of ethanol methanol and water extract. The electron-donating abilities and nitrite-scavenging effect of solvent extract of 24 years were high in order of ethanol methanol and water extract. The electron-donating abilities and nitrite-scavenging effect of solvent extract of 24 years old roots were higher than those of 4 years of old roots in the range of 10~40% respectively.

• Korean Journal of Food Science and Technology
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• v.31 no.6
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• pp.1613-1618
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• 1999

Extracts of Citrus sudachi juice and peel were obtained by several organic solvents such as hexane, acetone, ethyl acetate and methanol. Their antimicrobial spectrum were determined against 14 strains of gram positive and 4 strains of gram negative bacteria by paper disk method and minimal inhibitory concentration (MIC) was also obtained. Antimicrobial activities of solvent extracts from Citrus sudachi juice showed stronger than those of solvent extracts from peel. Acetone extract from juice showed the strongest antimicrobial activity among extracts, but the hexane extract did not show antimicrobial activities on tested target strains. The MIC was differant among tested strains; i.e. 0.5% (v/v) to Bacillus subtilis, 1% to Pseudomonas fragi, 1.5% to Listeria monocytogenes and Escherichia coli O157:H7, 2% to Propionibacterium acnes and Salmonella typhimurium, and 2.5% to Staphylococcus aureus.

• Food Science and Preservation
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• v.7 no.2
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• pp.177-183
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• 2000

A supercritical fluid extraction was performed for the extraction of phenolics from grape seeds which up to now have been discarded. The optimum condition for extraction process was predicted through response surface methodology using central composit experimental design. The extraction amount of grape seed phenolics was increased by increasing extraction temperature, pressure, and concentration of co-solvent (ethanol). The optimum extraction conditions were 84.83$^{\circ}$C, 51.50MPa and 1.27% ethanol. The yield of phenolics using SFE was higher with 3 folds than ethanol and 4 folds than hexane but less than 80% methanol. In the respects of food poisoning, the approved solvents were restricted to ethanol and hexane. So, SFE for extraction of phenolics could be powerful alternative method for solvent extraction.

• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.3
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• pp.406-412
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• 1998

Such extraction conditions as the kinds of solvent, extracting temperature, extracting time, ratio of material to solvent and particle size of material, were studied to maximize the extraction of oleoresin from chipi. Larger amount of soluble solids were extracted from seeds with nonpolar solvents (hexane, pentane, ether) for extraction, because the seeds contained large amount of crude fats and monoterpene(limonene) volatile compounds. Larger amount of soluble solids were extracted from peel with polar solvents(methanol, ethanol) of extraction because of large amount of water soluble colors, sugars and oxygenated terpene bolatile compounds in the peel. The application of the solvents in intermediate polarity (dichloromethane, acetone) resulted in more effective extraction of soluble solid and volatile compounds. Expecially, dichloromethane was an excellent solvent in extraction of volatile compounds. In the concern of volatile compound recovery yield, the optimum extraction conditions, such as temperature, time, mixing ratio of material to dichloromethane and mean particle size, were $25^{\circ}C$, 10min, 1:10(w/v), 355~250${\mu}{\textrm}{m}$ for chopi peels and 3$0^{\circ}C$, 10min, 1:8(w/v), 355~250${\mu}{\textrm}{m}$ for chopi seeds, respectively.

• YAKHAK HOEJI
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• v.40 no.1
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• pp.52-58
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• 1996

Solvent fractions were prepared from traditional herbal drugs which of methanol extracts inhibited $CCl_4$-induced cytotoxicity in primary cultured rat hepatocytes and c ontinuously assayed their effects. Ethylacetate and n-buthanol fractions from Cibotii Rhizoma and chloroform fraction from Gelatina Nigra inhibited the release of LDH and GPT from $CCl_4$-treated hepatocytes, respectively. Water fraction (WAR) among solvent fractions from Astragali Radix showed the most potent inhibitory effect on the release of GOT or GPT by treatment with $CCl_4$. All of solvent fractions prepared from Eucommiae Cortex had no effect on $CCl_4$-induced cytotoxicity. Chloroform and ethylacetate fractions from Rehmanniae Radix Preparata increased the release of GPT from $CCl_4$-treated hepatocytes. n-Hexan, chloroform or ethylacetate fraction from 5 herbal drugs increased the release of LDH, GOT or GPT from normal hepatocytes at the dose of 1.Omg/ml. Administration of WAR suppressed the elevation of GOT, ALP activities and MDA contents in the serum as well as in the liver tissue of $CCl_4$-intoxicated rats. Based on these results, isolation of antihepatotoxic substances from WAR is under the process.

• Food Science and Preservation
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• v.9 no.1
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• pp.97-101
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• 2002

Antimicrobial and antioxidative activities of various solvent extracts from different parts of the loquat were investigated to process it as the functional food. The extraction yield showed higher in butanol fraction of 4.95% in peel and 4.42% in seed than others, but water fraction showed high extraction yield of 3.89% in leafs 23.6% in the seedless fruit and 21.1% in fresh, In the antimicrobial activity test, ethyl acetate fraction that leaf and fruit excluded seed inhibited higher 19, 15 mm and 16, 15 m in clear zone far Staphylococcus aureus and Escherichia coli in each. Ethyl acetate fraction that extracted from a series of polar and nonpolar solvent fractionation of methanol extracts showed better results in the hydrogen donating activity of 82% in leaf, 74% in seedless fruit, 68% in seed, 52% in peel and 30% in fresh.

• Journal of the Korean Society of Food Science and Nutrition
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• v.22 no.6
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• pp.815-822
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• 1993

This experiment was carried out to determine the separation condition of 1-dimethylaminonaphthalene-5-sulfony(Dansyl) derivatives of amino acids by reverse-phase high performance liquid chromatography with Nova-Pak C18 column. Determined solvent system was solvent A(200mA phosphate buffer pH 6.8 15%, acetonitrile 11%, water 74%) and solvent B(acetonitrile 65%, methanol 28%, water 7%). Linear gradient of solvent B was applied from 12% to 80% for 50min. Complete separation of 20 amino acids including asparagine and glutamine which constitute protein was achieved within 50min. As the detection limit was the range of picomole, the resolution power was excellent. Reproducibility of the retention time was less than mean $\pm$0.05min. According to the above optimum chromatographic conditions, the amino acid composition of some food and human blood was examined. The most affluent amino acid was alanine in human blood, aspartic acid and glutamic acid in soy sauce, alanine and threonine in soy milk and proline in milk and yoghurt.