• Korean Journal of Food Science and Technology
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• v.21 no.6
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• pp.788-794
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• 1989

This study was attempted to investigate the effects of blanching temperature and cooking methods on the changes in the proportions of vitamin C of fresh potato and potatoes with different storage time. Sensory evaluation of fresh potato by different cooking methods was also conducted. The contents of residual ascorbic acid(AA) and total ascorbic acid(TAA) of fresh potato were maximum at $40^{\circ}C$ followed by rapid decrease at $50-65^{\circ}C$ while leached AA and TAA showed steady increase as the blanching temperature increased. Oxidized AA and dehydroascorbic acid(DHA) hydrolyzed increased at $50-65^{\circ}C$. From these results, it was considered that AA was lost mainly by oxidation up to $65^{\circ}C$ and leaching of AA was the major mode of loss above $65^{\circ}C$. In the case of potatoes stored for 1-4 weeks, they showed similar changes in the proportions of vitamin C as that of fresh potato. However, at $40^{\circ}C$ the content of residual TAA decreased and those of leached TAA and DHA hydrolyzed increased redundant during storage. At $65^{\circ}C$, the content of DHA hydrolyzed decreased The residual TAA of fresh potato by different cooking methods decreased in the order of pressure cooking (PC) > microwave cooking (MC)>boiling. Leached TAA were 49.5% and 36.4%, during boiling and MC, respectively. While DHA hydrolyzed were 22.3% and 4.2%, respectively Leached TAA and DHA hydrolyzed during PC were not determined. From these results, it was considered that AA was lost mainly by leaching during cooking. Residual TAA of stored potatoes by different cooking methods decreased during storage. But leached TAA and DHA hydrolyzed did not show any steady increase or decrease. Overall eating quality of fresh potato by different cooking methods decreased in the order of PC>MC>boiling(p<0.05).

• Korean Journal of Soil Science and Fertilizer
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• v.6 no.2
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• pp.115-127
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• 1973

Leaf discoloration of IR667 lines (tropical) and leading locals (temperate) in fields was classified according to the probable causes and nutritional disorder due to soil reduction in 1972 was investigated. 1. The causes of leaf discoloration in IR667 were low air temperature, soil reduction, seed born, insect bite, nitrogen depression, overdose pesticide, strong wind, early senescence and unknown one. 2. Leaf discoloration due to soil reduction which has been called Sageumbyeong by famers, was caused by the heavy application of $Ca(OH)_2$, compost and poor drainage followed by Zn and K deficiency and Fe toxicity. 3. About 30 days after transplanting deficiency concentration of K and Zn in leaf blade appears to be less than 2.0% and 20ppm respectively, and greater than 200ppm, 500ppm, and 1.0% respectively for toxicity or excess of Fe, Mn and Ca. and in the shoot 2.4% for K, 30ppm for Zn and 800ppm for Fe. The value of K/Ca should be greaterthan 2.0 for health. 4. When plants were damaged by soil reduction the contents of N, P, Ca, Mg, Fe, Mn, Na in shoot were increased and those of K, Zn, Si were decreased. 5. IR667 lines show in shoot higher content of N, P, Ca, Mg, Si, Na, and lower content K, Zn, Fe, Mn and lower root activity than local leading varietles in either healthy or disieased case, indicating IR667 lines are likely more suseptible to soil reduction damage. 6. Normal soil was less than 6.5 of pH and greater than -50 mv of Eh, but pH of problem soil was ranged from 6.7 to 7.4 and Eh from -100 to -190. 7. The root activity (${\alpha}$-naphthylamine oxidation) decreased at early stage of soil redudtion damage, then increased with severity and at the end it decreased again, but IR667 lines showed always lower root activity than local ones.

• Food Science of Animal Resources
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• v.30 no.2
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• pp.277-285
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• 2010

The objective of this study was to manufacture spent layer chicken meat products by natural freeze-drying. The spent layers of chickens that were slaughtered at 80 wk were obtained from a local slaughter house and separated into two halves of carcasses. The samples were divided into the following groups: 1) control (non-curing), 2) curing, and 3) curing with 2% trehalose before drying. The cured meats were placed at $2^{\circ}C$ for 7 d and then transferred to a natural drying spot located in Injae City, Gangwondo, Korea. The experiment was conducted from January to March in 2008. The average temperature, RH, and wind speed were $-1.5^{\circ}C$, 63%, and 1.8 m/sec, respectively. The cured treatments showed higher pH, lower Aw and lower shear force value compared with the control. Based on the results of TBARS (2-thiobarbituric acid reactive substances) level and volatile basic nitrogen value, lipid oxidation and protein deterioration were inhibited in curing treatments during drying. Trehalose acted as a humectant because it maintained a lower water activity despite the relatively higher moisture content during drying. The polyunsaturated fatty acids content and sensory attributes were higher in cured treatments than in the control during drying. Most of the bacterial counts in the treated groups were lower by 2 Log CFU/g after 1 mon of drying, and Salmonella spp. and Listeria spp. were not found in any treatment. There was also no microbial safety problem associated with dried meat products. Based on the results of this experiment, dried meat products could be manufactured from precured spent layer chickens by natural freeze-drying during winter.

• Korean Journal of Food Science and Technology
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• v.32 no.2
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• pp.238-245
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• 2000

This study was investigated to compare the changes of flavors in sesame oil with roasting temperature $(110^{\circ}C{\sim}230^{\circ}C)$. In the results of analyzing the volatile flavor compounds of sesame oil with GC and GC/MS, 26 pyrazines, 11 pyridines, 9 thiazoles, 6 furans, 8 pyrroles, 5 phenols, 8 aldehydes, 8 hydrocarbons, 7 alcohols, 2 indoles, 3 ketones, 10 acids, 4 nitriles, 7 esters, and 5 others were isolated, identified, and quantified. The total amount of flavor compounds was increased with roasting temperature. Detected flavors could be devided into top(peak No. $1{\sim}91$), middle$(92{\sim}197)$ and last note$(198{\sim}224)$ by rentention time. The top notes(initial content 19.87 ppm) which contain pyrazines and provide representative roasted flavors were increased significantly with roasting temperature. Initial content of middle note(17.72 ppm) was increased to 36.71 ppm at $170^{\circ}C$, to 95.61 ppm at $220^{\circ}C$, and to 138.62 ppm at $230^{\circ}C$. Last note was almost unchanged up to $170^{\circ}C$ and increased at $190^{\circ}C$, whereas it indicated a tendency to decrease at $230^{\circ}C$. Pyrazines such as methylpyrazine, 2,5-dimethylpyrazine, 2,6-dimethylpyrazine, trimethylpyrazine, 2-ethyl-3,5-dimethylpyrazine which indicate the major components among volatile flavors were increased slightly up to $150^{\circ}C$ and revealed the higher increase than any other components above $170^{\circ}C$. This tendency was also similar to pyridines, thiazoles, and furans. Most of these compounds are assumed to be developed by thermochemical reactions of sesame components by roasting above $170^{\circ}C$. It seemed that a lot of increase in phenols above $210^{\circ}C$ resulted from the production of guaiacol. Acids were almost unchanged up to $190^{\circ}C$, increased at $210^{\circ}C$, and then decreased above $220^{\circ}C$. It seemed to be resulted from pyrolysis of free fatty acids formed from thermal oxidation of oil.

• Journal of Life Science
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• v.28 no.12
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• pp.1489-1500
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• 2018

Honey is made from flower nectar by honey bees. In this study, 120 honeys from various flowers and across eight different provinces in Korea were collected and their components, antioxidants, and hemolytic activities against red blood cell were evaluated. Our results show that total polyphenol (TP) varied widely across the samples, with chestnut honey showing the highest TP ($77.1{\pm}8.4mg/100g$), protein content ($25.9{\pm}0.9mg/100g$), and absorbance at 400 nm ($A_{400}$ : $0.156{\pm}0.036$). In contrast, the acacia honey and sugar honey had a TP of 9.5~30 mg, 12~15 mg/100g of, and the lowest $A_{400}$ of $0.06{\pm}0.02$. High amounts of total flavonoid were quantified in the jujube and chestnut honeys at $8.73{\pm}7.31$ and $8.39{\pm}3.02mg/100g$, respectively. No samples demonstrated hemolytic activity up to 1 mg/ml. Antioxidant activities determined by DPPH, ABTS, and nitrite scavenging placed the chestnut honey highest, followed by jujube, styrax, multi-floral, citrus, acacia and sugar honey. Analysis of parameter correlations indicated that the components and bioactivity of the honey are dependent on the origin of the flower rather than on bee-farming regions. A positive correlation between TP content and antioxidant activity was identified. The correlation coefficients between $A_{400}$ and the TP, ABTS scavenging, and reducing power values were 0.804, 0.772 and 0.741, respectively. We therefore suggest that $A_{400}$ could be used as a noble, economic and simple factor for honey quality evaluation. Our results can potentially be used to develop functional honey for the food and pharmaceutical industries.

• Journal of the East Asian Society of Dietary Life
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• v.21 no.1
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• pp.74-81
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• 2011

This study was carried out to investigate the effect of red wine on the color, hardness, springiness, chewiness, pH, volatile basic nitrogen (VBN) content, thiobarbituric acid reactive substances (TBARS) value, and total bacterial number of pork meat stored at $4^{\circ}C$ for 10 days. Pork meat was treated with 25% water (control), 20% water and 5% red wine (RW5), 15% water and 10% red wine (RW10), or 10% water and 15% red wine (RW15). The lightness ($L^*$), redness ($a^*$) and yellowness ($b^*$) values tended to decrease with longer storage period (p<0.05). The $L^*$ values of RW10 and RW15 were higher than those of control and RW5 on the first day of storage, whereas the control and RW5 had higher $L^*$ values compared to RW10 and RW15 after 10 days (p<0.05). Hardness of RW5 was the lowest after 10 days of storage (p<0.05). The pH levels were not significantly different among the samples. The VBN contents increased with longer storage period (p<0.05), and those of RW10 and RW15 were lower than those of the control and RW5 after 10 days of storage (p<0.05). The TBARS values increased with longer storage period (p<0.05), and those of the control, RW5, RW10, and RW15 were 0.61, 0.45, 0.35 and 0.33 mg MA/kg, respectively, after 10 days of the storage. The total bacterial numbers increased with longer storage period, and those of RW5, RW10 and RW15 were lower compared to the control (p<0.05). Taste, tenderness, juiciness, and palatability were not significantly different among the samples, but the flavor of RW5 had the highest value after 10 days of storage (p<0.05). These results suggest that red wine can inhibit protein degradation, lipid oxidation, and bacterial growth when used as an additive of seasoned pork meat.

• Journal of Life Science
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• v.28 no.2
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• pp.229-239
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• 2018

As customers pay more attention to choosing food that will support their health, many people in the academic and industrial world have focused on developing foods made with bioactive components. Thus, the use of bioactive components rather than synthetic materials has increased. Because there are no limits to how bioactive components can be used, customers assume they are highly reliable and healthy to consume. In the present study, imitation crab stick samples were made from Alaska Pollack with breast recovered protein from spent laying hens and silkworm cocoon powder (10 g) (T1), Alaska Pollack with breast recovered protein from spent laying hens and silkworm cocoon powder (5 g) + cordyceps powder (5 g) (T2), and Alaska Pollack with breast recovered protein from spent laying hens and cordyceps powder (5 g) + conjugated linoleic acid (CLA) (5 g) (T3). The pH and shear force increased after 2 weeks of storage in all three samples. Shear force was significantly higher in the T3 sample in comparison to the T1 and T2 samples. In meat color, redness ($a^{\ast}$) and whiteness (W) increased as the storage periods increased in all three samples, whereas yellowness ($b^{\ast}$) decreased during storage. The T2 sample was significantly higher in redness ($a^{\ast}$), yellowness ($b^{\ast}$), and deformation than the other two samples. The addition of bioactive components did not influence the texture properties in any of the samples. Lipid oxidation (thiobarbituric acid reactive substances [TBARS]) and microorganism count (total plate count [TPC]) were significantly higher in the T1 sample than the two other samples, whereas protein degradation (volatile basic nitrogen [VBN]) was higher in the T2 sample than the other samples. Total amino acid content decreased in the T1 and T3 samples as the storage period increased. Consequently, the T3 sample of Alaska Pollack with breast recovered protein from spent laying hens and cordyceps powder (5 g) + conjugated linoleic acid (CLA) was found to have the necessary functionality to be considered for use in making imitation crab sticks.

• Journal of the korean academy of Pediatric Dentistry
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• v.30 no.3
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• pp.423-430
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• 2003

The teeth bleaching with bleaching agent is widely used at recent times. Until yet the exact mechanism of the bleaching agent isn't known but it is thought that is by the complex reduction-oxidation reaction of the decomposed free radical from bleaching agent through various ways. In other words, it is supposed that the teeth are whitened by agent's changing chemical structures of stain-causing materials. The purpose of this study is to exam the change of the dentinal character by bleaching agent and to evaluate the safety of this agent. For this study, after applying 10% carbamide peroxide to enamel of human premolar for 6 hours a day for 2 weeks we examined changes of surface morphology, microhardness, composition and contents of minirals in human dentin using SEM, microhardness tester, FT-Raman spectrometer and EPMA and got following results. There was no significant difference in surface morphologic change when we examined the effect of 10% carbamide peroxide which penetrated into dentin after applied on enamel surface comparing with result from specimen in distilled water No change was shown on the surface of peritubular and intertubular dentin within the nanometeric range. The microhardness between bleached teeth and teeth stored in distilled water showed no statistically significant difference FT-Raman spectra of dentin exhibited no change of the component in human dentin. Only the least change in peaks of organic and inorganic materials were detected in Raman intencity. The total content of mineral elements in dentin with no treatment, stored only in distilled water and stored in distilled water after bleaching were $98.73{\pm}1.89,\;98.56{\pm}2.11\;and\;97.47{\pm}2.51$ respectively. Also they showed no statistically significant difference. From above results, the effect of 10% carbamide peroxide bleaching on structure of dentin is very low and the results may confirm the safety of this bleaching agent.

• Resources Recycling
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• v.16 no.3 s.77
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• pp.19-26
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• 2007

The bottom ash of municipal solid waste incineration generated during incineration of municipal solid waste in metropolitan area consists of ceramics, glasses, ferrous materials, combustible materials and food waste and so on. Although the ferrous material was separated by the magnetic separation before the incineration process, of which content accounts for about $3{\sim}11%$ in bottom ash. The formation of a $Fe_3O_4-Fe_2O_3$ double layer(similar to pure Fe) on the iron surface was found during air-annealing in the incinerator at $1000^{\circ}C$. A strong thermal shock, such as that takes place during water-cooling of bottom ash, leads to the breakdown of this oxidation layer, facilitating the degradation of ferrous metals and the formation of corrosion products and it existed as $Fe_2O_3,\;Fe_3O_4\;and\;FeS_2$. So, many problems could occur in the use of bottom ash as an aggregate substitutes in construction field. Therefore, in this study, the separation of ferrous materials from municipal solid waste incineration bottom ash was investigated. In the result, the ferrous product(such as $Fe_2O_3,\;Fe_3O_4,\;FeS_2$ and iron) by magnetic separator at 3800 gauss per total bottom ash(w/w.%) accounted for about 18.7%, and 87.7% of the ferrous product was in the size over 1.18 mm. Also the iron per total bottom ash accounted for about 3.8% and the majority of it was in the size over 1.18 mm.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.11
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• pp.1409-1416
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• 2007

Seven selected commercial pure or refined olive oils were obtained from the market, and their physicochemical properties and volatile characterizations were investigated. Fatty acid profiles of the analyzed olive oils showed oleic $(61.2{\sim}74.7mole%)$, palmitic $(10.2{\sim}16.8mole%)$, linoleic $(9.4{\sim}18.0mole%)$, stearic $(1.9{\sim}3.0mole%)$, palmitoleic $(0.7{\sim}2.4mole%)$ and linolenic acid $(0.5{\sim}0.9mole%)$. According to Hunter#s color measurement, pure or refined olive oils showed $L^*$ value of $92.2{\sim}99.0$, $a^*$ value of $-22.2{\sim}-3.2$, and $b^*$ value of $18.5{\sim}55.0$. Their total phenol contents ranged from 1.9 to $13.3mg/100g$ while ${\alpha}-tocopherol$ content showed $7.91{\sim}13.88mg/100g$. Oxidation stability of the pure or refined olive oils were observed by Rancimat. The induction period ranged from 17.37 to 34.72 hr while their POV were $6.83{\sim}20.31meq/kg$ oil. Electronic nose and gas chromatograph-mass spectrometry with head-space solid phase microextraction were applied to identify and discriminate the volatile compounds and flavors in pure or refined olive oils, respectively.