• Journal of Applied Biological Chemistry
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• v.42 no.3
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• pp.151-153
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• 1999

Gromwell (Lithospermum erythrorhizon) pigment solution and Jindo Hongju prepared in the laboratory showed characteristic pH-dependent color changes and a shift in absorption maxima. This phenomenon was not observed in the solution of the artificial food colorant Red No. 2 which was suspected to be used in the manufacture of fake Jindo Hongju. A few fake products could be detected by using the pH-dependent shift in absorption maxima among the Jindo Hongju on market.

• Journal of Korean society of Dental Hygiene
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• v.13 no.2
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• pp.351-360
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• 2013

Objectives : The purpose of this study was to evaluate the effects of tooth bleaching agent contained 15% carbamide peroxide on the color, microhardness and surface roughness of tooth-colored restorative materials by using pH cycling model. Methods : Four types of tooth-colored restorative materials, including a composite resin(Filtek Z350 ; Z350), a flowable composite resin(Filtek P60 : P60), a compomer(Dyract$^{(R)}$ AP ; DY), and a glass-ionomer cement(KetacTM Molar Easymix ; KM). were used in the study. Eighty-eight specimens of each material were fabricated, randomly divided into two groups(n=44): experimental group(15% carbamide peroxide) and control group(distilled water). These groups were then divided into four subgroups(n=11). All groups were bleached 4 hours per day for 14 days using pH cycling model. The authors measured the color, microhardness, and roughness of the specimens before and after bleaching. The data were analyzed with ANOVA and T-test. Results : Z350 and P60 showed a slight color change(${\Delta}E^*$), whereas DY and KM showed significantly color change(p<0.05). Among them, the greatest color change was observed in DY. Percentage microhardness loss(PML) of the distilled water group was 1.8 to 5.1%, and 15% peroxide peroxide group was 5.0 to 25.2%. Microhardness of DY and KM showed a statistically significant decrease(p<0.05). Roughness was increased in all groups after bleaching. Z350 and P60 does not have a significant difference(p>0.05), however DY and KM significantly increased more than the 0.2 ${\mu}m$(p<0.05). Conclusions : The effects of bleaching on restorative materials were material dependent. It is necessary to consider the type of the material before starting the treatment.

• Journal of Korea Foresty Energy
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• v.25 no.1
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• pp.18-23
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• 2006

pH dependent K/S values, Hue, Value, and Chroma change of the hot-water and alkali extract of Boehmeria tricuspis have investigated as a part of the studies on natural dye resources. Maximum optical absorption of the dyed cotton, Korean paper, and silk with the extract were observed at 400 nm. According to the result of pH dependent K/S values change, it tended to increase as pH decreased except for the silk and there was no change near pH 7. For Hue, the materials dyed with hot-water and alkali extract indicated YR and R color, respectively. The change in Value of the dyed materials tended to increase, whereas Chroma of them decreased as the pH moved to alkali conditions although there were no significant changes near pH 7. As a result, it is considered that the optimum pH would be 7 when the mentioned materials are dyed with Boehmeria tricuspis extract.

• Food Science of Animal Resources
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• v.34 no.2
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• pp.200-206
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• 2014

To determine the effects of grape skin and seed pomace (GSP) additions on the lipid oxidation susceptibility and the color change of cooked pork sausages, the chemical characteristics of GSP itself and the addition for two different levels of GSP (0.5 and 1.0% GSP, respectively) to sausages were examined. Both the redness and blueness of the GSP were significantly reduced as the pH level was increased from 5 to 7, but a reverse result was determined in the color tint and yellowness (p<0.05). The GSP polyphenol and flavonoid contents were influenced by the percentages of methanol solvents, and more flavonoids were established when 100% of methanol was applied as a solvent to the GSP. But, similar results were not observed in the polyphenol of GSP. In cooked pork sausages, significant decreases in the lightness and redness were found in both the 0.5% and 1.0% of GSP sausages during the storage period (p<0.05). However, an incompatible effect was observed in terms of yellowness, which increased as compared to the control sausage after 6 days of storage. The 0.5% addition of GSP decreased the levels of TBARS (p<0.05), but the ability of GSP to minimize lipid oxidation was not dose dependent. Therefore, the results indicated that the GSP is an efficient suppressor of lipid oxidation and has latent effects as a natural antioxidant when 0.5% of GSP is added to the cooked pork sausages.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.23 no.1
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• pp.37-45
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• 2017

To visually identify the spoilage of chicken breasts, a three layered freshness indicator consisting of PET/bromocresol green (BCG)-ethylene vinyl acetate (EVA)-acetic acid (AA) composite layer/porous substrates was successfully prepared and their performance were simulated at 20% of $CO_2$ and 4 different trimethylamine (TMA) concentrations to evaluate color change at minimal spoilage level. The visibility and range of color changes of the as-prepared indicators responding to TMA concentration as a simulant were strongly dependent on the concentrations of BCG and AA. As the BCG content increased, the visibility of color change in the freshness indicators was apparently improved and the range of color change could be controlled by contents of AA. Among the as-prepared freshness indicators, 'G0.12_A0.5' which consisting 0.12g of BCG and 0.5g of AA was selected as an optimum composition due to the highest visibility at TMA 20 mg% corresponding to the minimal spoilage level. The color of the indicator changed from yellow to green for spoilage indication of chicken breast, which could be easily seen with the naked eyes and well consistent with the simulation results. It is expected that our developed freshness indicator can be useful in monitoring various food freshness and quality.

• The Korean Journal of Food And Nutrition
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• v.26 no.3
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• pp.453-458
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• 2013

This study was conducted to investigate the quality change of pork rectum by addition of maesil. pH of the pork rectum was decreased by the addition of maesil in a dose dependent manner. The changes in the L and a color values of both raw pork rectum and cooked pork rectum by storage were negligable. The b color value of raw pork rectum was certainly increased in the early stage of storage. The b value of cooked pork rectum, which was slightly dropped by addition of maesil, was decreased as storage progressed. In both raw and cooked pork rectum, thiobarbituric acid value (TBA) was significantly decreased in a dose dependent manner up to 5% addition of maesil. The volatile basic nitrogen (VBN) content in the ground pork rectum was conspicuously decreased by the addition of maesil. Consequently, the storage time of both raw and cooked pork rectum was extended more than 4 days by the 5% addition of maesil.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.6
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• pp.511-517
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• 2002

The complex 1 $([Cp*Fe(CO)_2]_2-(\mu-CH=CH-CH=CH))$ which have butadiene as a bridge were synthesized from $Cp*(CO)_2FeK$ and cis-3,4-dichlorocyclobutene. The derivatives of complex 1 where one or two carbonyl groups are replaced by phosphine ligands have been prepared by photochemical substitution. The new derivatives $([Cp*Fe(L)_2]_2-(\mu-CH=CH-CH=CH))$ where L = $(Ph_2PCH_2CH_2PPh_2)$ and $([Cp*Fe(CO)(L)]_2-(\mu-CH=CH-CH=CH))$ where L : $PPh_3$ have been characterized from $^^1H-$, $^^13C-$,$^^31P-NMR$ and elemental analysis. Obtained complexes have been studied in electrochemical experiment and UV/VIS-near-IR. The mixed-valence radical cation forms of complex 2, 3 species were found to be delocalized as the Class III. Based on the separation of the waves ($\triangle E$ : 0.470 ~ 0.605 V), the efficiency of electronic communication between two metal centers of cation species leading to stabilization relative to neutral species. The phosphine-substitute complexes (2, 3) displays two reversible oxidation waves and oxidation state of metal centers-dependent color change, electrochromism, was observed from yellow to orange and deep blue in methylene chloride.

• The Korean Journal of Food And Nutrition
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• v.33 no.5
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• pp.473-482
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• 2020

The purpose of this study was to prepare bread added with sea buckthorn (Hippophae rhamnoides L.) berry powder (SBBP) (1, 3, and 5%) using a straight dough method. The quality and antioxidant characteristics of the bread were analyzed. The results indicated that the pH value and dough raising power of the dough decreased and the moisture content of the bread added with SBBP increased compared to that without the SBBP. The crust color of the bread did not change significantly. However, the crumb lightness value decreased and the redness and yellowness value increased respectively to the concentration of the SBBP. The texture measurement indicated that the hardness, gumminess, and chewiness of the bread increased with the addition of the SBBP. The total polyphenol content of the bread supplemented with the SBBP was increased (4.60~16.14 mg GAE/g) compare to the control (1.67 mg GAE/g). Dose-dependent, significant-high DPPH (26.86%) and ABTS (42.52%) radical scavenging activities were observed in the bread with the addition of the SBBP up to 5%. Based on these results, the optimum amount of the SBBP to add for baking bread would be 3% and the SBBP could be considered a functional agent.

• The Korean Journal of Food And Nutrition
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• v.30 no.5
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• pp.860-866
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• 2017

This study was conducted to assess effects of addition of walnuts on soy sauce quality. The pH was significantly increased by adding more than 4 percent of walnuts. As the addition of walnuts increased, Hunter's color values and brown color increased. Total solid of soy sauce did not change significantly with the addition of walnuts. Crude fat content increased by two times in the 2 percent added walnuts group compared to the control group, but it was not dependent on the addition of walnuts. DPPH radical scavenging activity was significantly increased with the addition of walnuts. The addition of walnuts decrease saturated fatty acids and increased unsaturated fatty acids. Composition ratio of linoleic acid was highest in the control group and all the additions. These results revealed that soy sauce made with walnuts have a positive effect on functionality and preference.

• Journal of the Korean Society of Groundwater Environment
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• v.7 no.3
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• pp.103-115
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• 2000

The formation of brown-colored precipitates is one of the serious problems frequently encountered in the development and supply of groundwater in Korea, because by it the water exceeds the drinking water standard in terms of color. taste. turbidity and dissolved iron concentration and of often results in scaling problem within the water supplying system. In groundwaters from the Pajoo area, brown precipitates are typically formed in a few hours after pumping-out. In this paper we examine the process of the brown precipitates' formation using the equilibrium thermodynamic and kinetic approaches, in order to understand the origin and geochemical pathway of the generation of turbidity in groundwater. The results of this study are used to suggest not only the proper pumping technique to minimize the formation of precipitates but also the optimal design of water treatment methods to improve the water quality. The bed-rock groundwater in the Pajoo area belongs to the Ca-$HCO_3$type that was evolved through water/rock (gneiss) interaction. Based on SEM-EDS and XRD analyses, the precipitates are identified as an amorphous, Fe-bearing oxides or hydroxides. By the use of multi-step filtration with pore sizes of 6, 4, 1, 0.45 and 0.2 $\mu\textrm{m}$, the precipitates mostly fall in the colloidal size (1 to 0.45 $\mu\textrm{m}$) but are concentrated (about 81%) in the range of 1 to 6 $\mu\textrm{m}$in teams of mass (weight) distribution. Large amounts of dissolved iron were possibly originated from dissolution of clinochlore in cataclasite which contains high amounts of Fe (up to 3 wt.%). The calculation of saturation index (using a computer code PHREEQC), as well as the examination of pH-Eh stability relations, also indicate that the final precipitates are Fe-oxy-hydroxide that is formed by the change of water chemistry (mainly, oxidation) due to the exposure to oxygen during the pumping-out of Fe(II)-bearing, reduced groundwater. After pumping-out, the groundwater shows the progressive decreases of pH, DO and alkalinity with elapsed time. However, turbidity increases and then decreases with time. The decrease of dissolved Fe concentration as a function of elapsed time after pumping-out is expressed as a regression equation Fe(II)=10.l exp(-0.0009t). The oxidation reaction due to the influx of free oxygen during the pumping and storage of groundwater results in the formation of brown precipitates, which is dependent on time, $Po_2$and pH. In order to obtain drinkable water quality, therefore, the precipitates should be removed by filtering after the stepwise storage and aeration in tanks with sufficient volume for sufficient time. Particle size distribution data also suggest that step-wise filtration would be cost-effective. To minimize the scaling within wells, the continued (if possible) pumping within the optimum pumping rate is recommended because this technique will be most effective for minimizing the mixing between deep Fe(II)-rich water and shallow $O_2$-rich water. The simultaneous pumping of shallow $O_2$-rich water in different wells is also recommended.