• Journal of Food Hygiene and Safety
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• v.32 no.5
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• pp.389-395
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• 2017

A simultaneous determination of 5 phenolic acids (gallic acid, chlorogenic acid, caffeic acid, pcoumaric acid, trans ferulic acid) and 9 flavonoids (procyanidin b1, aspalathin, rutin, vitexin, hyperoside, isoquercitrin, luteolin, quercetin, chrysoeriol) in rooibos tea has been carried out by ultra-high performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS). A validated analysis method in this study was applied to rooibos aqueous infusions. Rooibos tea is an antioxidant-rich tea which has anti-cancer, anti-aging, anti-inflammatory, anti-diabetic effect. Extraction yield of phenolics depends on steeping time and temperature of water. Tea infusions were prepared by placing 1 g of tea leaves or 1 tea bag in 100 mL of boiled water, and then at 3, 6 and 30 minutes intervals the infused teas were taken to carry out the analysis of phenolic contents. Another tea infusion was conducted with cold water ($25-30^{\circ}C$) for 30 minuntes. As a result, the total amount of phenolics was highest in rooibos tea steeped with hot water for 30 minutes, followed by 6 minutes, 3 minutes and cold water 30minutes and the result has statistical significance.

• Korean Journal of Food Science and Technology
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• v.40 no.1
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• pp.36-41
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• 2008

This study was conducted to investigate the effects of combined osmotic dehydration and hot-air drying on the quality of dried apple products. Apple cylinders were steeped in 30% and 50% sucrose solutions at different steeping times. During the osmotic dehydration, as the concentration of the sucrose solution and steeping time increased, weight reduction and water loss increased, and the solid gain showed similar results. Osmotic dehydration in the sucrose solutions was followed by hot-air drying at 50 and $70^{\circ}C$. The experimental data were fitted successfully using the modified Page model. At the drying temperature of $50^{\circ}C$, the drying time increased from 4.15 hr for the control to 5.78 hr and 6.42 hr for the 30 and 50% sucrose solution treatments, respectively. Similar results were shown at the $70^{\circ}C$ drying temperature. The k and n values of the apple cylinders decreased by osmotic dehydration, and the k and n of the apple cylinders steeped in the 50% sucrose solution were lower than those of the samples steeped in the 30% sucrose solution. The qualities of the dried apple products were compared to samples that did not undergo osmotic dehydration. The shrinkage and rehydration capacity of the apple products decreased via osmotic dehydration, and decreased as the concentration of the sucrose solution increased. The compressibility ratios of the apple products to raw apple cylinders increased by osmotic dehydration, and increased as the concentration of sucrose solution increased. The sensory evaluation results for the apple products rehydrated in yoghurt indicate that osmotic dehydration greatly enhances the palatability of apple products in terms of appearance, taste, and texture.

• Journal of the East Asian Society of Dietary Life
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• v.26 no.5
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• pp.457-465
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• 2016

Effects of soaking time on the physicochemical and structural characteristics of waxy rice flours and starches purified from flours using the alkaline steeping method were investigated. Korean cultivar Sinseonchal waxy rice was washed and soaked in tap water (1:2 w/w) and stored at room temperature for 15 days. On each day of soaking for 0, 1,2 3, 5, 10, and 15 days, pH of soaking water was measured and rice grains were dried, ground, and passed through 100 mesh sieve. The pH was reduced to 3.90 by day 5 and increased to 4.60 by day 15. The protein and ash contents, swelling powers and solubilities of flours and starches decreased with increasing soaking time. The water-binding capacities increased while trends were not similar to soaking time. The flour particle size distribution ranged from two to four peaks with increasing soaking times. Starch granule size decreased with increasing soaking time. The peak, trough, and final viscosities of flours and starches showed similar trends until 10 days and 15 days, respectively. The starches presented higher viscosities than the flours. The branch chain length distributions of amylopectin of starches showed an increaseed DP6~12 portion and decreased DP13~24 portion with increasing soaking time of waxy rice grains.

• Korean journal of food and cookery science
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• v.17 no.4
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• pp.309-315
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• 2001

The effects of soaking time of nonwaxy rice and particle size of rice flour on the properties of nonwaxy rice flour after steeping at room temperature were investigated. Nonwaxy rice was soaked at 20$^{\circ}C$ for 0, 1, 12, or 24hr, dried at room temperature and milled. Nonwaxy rice flours were passed through 45 mesh or 100 mesh sieve, and were compared for the properties depending on the particle size and soaking time. The particles of rice flour were separated into 10$\mu\textrm{m}$∼30$\mu\textrm{m}$ and 40$\mu\textrm{m}$∼80$\mu\textrm{m}$ groups, and the amount of large particle size(40$\mu\textrm{m}$∼80$\mu\textrm{m}$) was greater in the flour sieved through 45 mesh than 100 mesh sieve. The protein and ash contents decreased and amylose contents increased as the soaking time increased. The water-binding capacity increased rapidly up to 1 hr of soaking and increased slowly thereafter. The swelling power and the solubility increased with temperature rising in the range of 65$^{\circ}C$∼95$^{\circ}C$, and these two properties increased rapidly up to 12 hr of soaking. Peak viscosity and breakdown of the pastes prepared with 12 hr-soaked nonwaxy rice flour were higher than those with 1 hr-soaked ones, while the setback and viscosity at 95$^{\circ}C$ of 12 hr-soaked ones were lower than 1hr-soaked ones.

• Journal of the Korean Society of Food Science and Nutrition
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• v.12 no.4
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• pp.401-406
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• 1983

Changes in the soluble sugar content contained in the soybean, soybean milk, soybean curd and soybean whey were determined to investigate the method of reducing the introductions of soluble oligosaccharides like sucrose, raffinose and stachyose, which cause flatulence in human, to soybean curd from soybean by extending the soaking time of soybean. The soybean curd yields according to the extention of the soaking time were also determined. Markedly increased glucose, slightly reduced fructose and sucrose and noticeably reduced raffinose in soybean milk were observed with extended soaking time. Most of sucrose, raffinose and all of maltose were transferred to soybean whey. Gradual increase of soybean curd yields were obtained by extending soaking time within the experimental conditions.

• Journal of the Korean Wood Science and Technology
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• v.10 no.3
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• pp.133-134
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• 1982

This experiment has been made to investigate the absorption of watersoluble zinc chloride by Pinus densiflora S. et Z. at different moisture content, under soaking process, to decide the optimum content condition for the maximum absorption of zinc chloride by the wood tested and to investigate the concentration of zinc chloride affecting each moisture content of wood. Material was cut in the Dept. of Forest, College of Agr. S.N.U. Suwon, Korea. Sample was divided into sap and heartwood group and cut $2{\times}2{\times}2\;cm$ in size, having exact three dimensions, using the part of D.B.H. The numbers of sample were 20 pieces for each moisture content condition for both sap and heartwood. Especially, the samples were protected from exposure to keep moisture content in green condition. The ranges of moisture content tested were as the table 3 and 4. The conclusions were as follows: 1. With 3% zinc chloride solution, the rate of absorption decreased with the time increased, if the air seasoned Korean red pine (Pinus densiflora S. et Z.) was treated in steeping process. Initial absorption for 30 minutes was more than 50% of total absorpon for 24 hours. 2. Rate of absorption was same under the green condition, while rate of absorption under the moisture content 7 to 30% varied. 3. Although it was not quite proportional change in the absorption with the difference of moisture content, the great change in the absorption occured by seasoning. With exception sap green condition, sapwood twice more permeable than the heartwood in the oven dried condition and it has been observed the nearly same amount of absorption at the moisture content of 7%, 10% and 15% respectively in heartwood. 4. It was better from water in wood from view-point of absorption of zinc chloride solution, but it was difficult practically to obtain the smallest moisture content, and then it was decided that values of allowable moisture content, on the basis of mean absorption, were 15% to 20% in the sapwood, and in the heartwood, 10% to 15%. The mean absorption for each moisture content in the sap and the heartwood were as following. 5. In general, the concentration of zinc chloride after steeping was nearly same between moisture content and sap and heartwood respectively.

• Korean Journal of Organic Agriculture
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• v.19 no.4
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• pp.589-602
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• 2011

In this study, experiments were conducted to determine the effect of different compost teas on plant growth reponses and yield of leaf lettuce. Compost tea is a liquid extract of compost obtained by mixing compost and water for a defined period of time. The pig manure and spent mushroom compost were made by steeping compost in water. Compost tea was aerated from 24 hours and molasses and kelp were added as supplements. The four types of compost were tested growth of lettuce. EC of animal manure compost tea was higher than that of spent mushroom compost tea. Mineral nutrients were significantly higher in animal manure compost tea compared with spent mushroom compost tea. Compost tea contains nutrient and a ranges of different organisms. The beneficial fungi and actinomycetes were prominent in a spent mushroom compost tea. Compost tea from animal manure had the higher numbers of total bacteria. The actinomycetes densities were high in spent mushroom compost tea. But actinomycetes were not founded in animal manure compost tea. The growth characteristics of lettuce in animal manure compost tea were higher than those of spent mushroom compost tea. And also SPAD value in leaf was high in plot treated with animal manure compost tea. The fresh yield of lettuce in animal compost tea was higher by 181% that of control plot. The effect of compost tea on growth of lettuce was largely attributable to mineral nutrient.

• Applied Biological Chemistry
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• v.32 no.3
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• pp.203-208
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• 1989

Eight samples of Korean two-rowed barley, 9 samples of North American barley and 3 samples of Korean six-rowed barley were analysed for 1,000 kernel weight, steeping time, germinative capacity, and protein content. The barley samples were malted with the same malting schedule and analyzed for malting loss, protein content, soluble protein, percent extract, wort viscosity, and diastatic power. The American barleys were higher in germinative capacity, percent extract and diastatic power than the Korean two-rowed barleys. The protein content ranged from 11.8 to 14.2% for the North American barleys and 9.7 to 15.5% for Korean barleys. The three Korean six-rowed barleys were lower in germinative capacity, percent extract and diastatic power, but were higher in wort viscosity than the Korean two-rowed barleys.

• The Korean Journal of Pharmacology
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• v.15 no.1_2 s.25
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• pp.13-19
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• 1979

Circadian susceptibility of sleeping induced by pentobarbital was observrd in male DDO mouse treated with phenobarbital and ginseng saponin. The pentobarbital elimination rate was also measured in the same animal. The mouse had been maintained for one week under 12 hours of artificial illumination extending from 06:00 to 18:00 hours alternating with 12 hours of darkness. During the period the animals were administered intraperitoneally with 100mg/kg of phenobarbital for three days or 10mg/kg and 100mg/kg of ginseng saponin for seven days. At 24 hours after last injection pentobarbital sleeping time and elimination rate were measured following intraperitoneal administration of 50mg/kg of pentobarbital sodium. In a control group treated with saline, the duration of pentobarbital-induced sleep varied with circadian rhythmicity, which had a trough at 02:00 hours of light phase and a crest at 14:00 hours of dark phase. And the elimination rate measured at 02:00 hours was faster than that at 14:00 hours. Pretreatment with phenobarbital markedly shortened the pentobarbital steeping time and abolished the circadian rhythmicity. Those were correlated with the increased pentobartital elimination by phenobarbital throughout light and dark phases examined. Ginseng saponin, given for seven days in a dose of 10mg/kg or 100mg/kg, did not affect the circadian rhythmicity of sleeping and the elimination rate. Sleeping time during light phase, however, was somewhat shortened in ginseng treated animals, which was not matched with the finding of unaltered elimination rate. It seemed that the central nervous system stimulating effect of ginseng saponin might be involved in the findings observed.

• Journal of the Korean Wood Science and Technology
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• v.33 no.3 s.131
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• pp.64-71
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• 2005

In this study, we attempted to apply ultrasonic treatment for the preservative treatment of two softwood species, Korean pine and Japanese red pines to evaluate its effectiveness. Wood samples were submerged in oilborne preservative, copper naphthenate (NCU) and waterborne preservative, alkyl ammonium compound (AAC) and then treated with ultrasonic wave of 40 kHz, 400 W. After the treatment, the retention and penetration depth of these preservatives in the specimens were measured as a function of treatment time. Both the retention and penetration depth were continuously increased with increasing the treatment time up to 120 hours, where the retention reached about 95% by the application of AAC and the penetrating depth of 95% and 83% by the application of NCU, respectively for both species. The results of electronic microscopic observation showed that the improved retention capacity could be attributed to air deflation, wood extractive deflation working of ultrasonic wavelength, and destruction of wood pits which served as the pathway of preservatives. The results suggested that the use of ultrasonic treatment could be applied to thick wood veneers for the production of laminated wood products.