• Journal of Fashion Business
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• v.18 no.4
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• pp.114-124
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• 2014

This research was carried out to find the mordant effects by Tara and Myrobalan as natural tannins on the cow leather dyed with Lac powder. The cow leathers were treated with Tara, Myrobalan, Al, Cu, and Fe mordants by changing treatment orders. It was examined for K/S value, surface color changes, and color difference. The K/S value generally has higher Myrobalan than Tara, and pre-mordant than post-mordanted condition. Cu is the strongest among the three mordants. As a results of the treatment order, the K/S value is higer in pre-tannin-mordant agent than in pre-mordant agent-tannin. In the post mordant, K/S value is higher in mordant agent-tannin than in tannin-mordant agent. The color difference and color factors such as H, V and C were various according to the mordant agents, treatment orders and mordant methods; and surface colors of dyed cow leathers were R and RP. It was difficult to find some significant means of mordant orders.

• Korean journal of food and cookery science
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• v.8 no.1
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• pp.15-20
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• 1992

The changes in color of spinach leaves upon blanching in boiling water and by microwave oven were investigated. The noticible changes in color of leaves were observed above $70^{\circ}C$. The values of L (lightness), a (redness) and b (yellowness) were decreased upon blanching. The value of the under surface of leaves was decreased by 2~3 times compared to that of the upper surface. The noticible color changes occured from 15 sec and the absorbance at 432 nm of water increased rapidly from 2 min of blanching in boiling water. Salt (0.5 and 0.9%) decreased the absorbance at 432 nm of water. The changes of L and b of the under surface of leaves upon heating with a microwave oven were less compared with those in boiling water. Based on the color differences of leaves upon blanching in boiling water, the optimum ratio of spinach to water was 1:4 or 1:5.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.5
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• pp.831-837
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• 1997

Response surface methodology(RSM) was applied in roasting processes of Polygonatum odoratum roots in order to monitor Hunter color parameters and to optimize organoleptic properties of the tea. In roasting processing based on the central composite design with variations in roasting temperature (110~19$0^{\circ}C$) and roasting time(15~75min), coefficients of determinations($R^{2}$) of the models were above 0.9827(p<0.01) in Hunter color parameters and above 0.7748 in organoleptic properties. Hunter color L and $\Delta$E values of the powdered samples decreased with the roasting processes, whereas Hunter color a and b values increased up to around 59 min at 136$^{\circ}C$ and thereafter showed a decreased tendency. Organoleptic qualities on color, taste and aroma of Polygonatum odoratum tea were improved along with roasting processes, thereby estimating the optimum roasting conditions by RSM for the maximized qualities of organoleptic properties as a range from 127$^{\circ}C$ to 135$^{\circ}C$ and from 60min to 66 min. Hunter color a value(redness) was found to generate a similar response surface to that of organoleptic properties, showing the possibility of quality index in roasting processes of Polygonatum odoratum roots.

• The Journal of Advanced Prosthodontics
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• v.5 no.2
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• pp.75-83
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• 2013

PURPOSE. Maxillofacial silicone elastomer is usually colored intrinsically with color pigments to match skin colors. The purpose of this study was to investigate the color stability of a maxillofacial silicone elastomer, colored with a thermochromic, color changing pigment. MATERIALS AND METHODS. Disc-shaped maxillofacial silicone specimens were prepared and divided into 3 groups: a conventionally colored control group, one group additionally colored with 0.2 wt% thermochromic pigment, and one group with 0.6 wt% thermochromic pigment. Half of the surface of each specimen was covered with an aluminium foil. All of the specimens were exposed to UV radiation in 6 hour cycles over 46 days. In between the UV exposures, half of the specimens were stored in darkness, at room temperature, and the other half was stored in an incubator, at a humidity of 97% and a temperature of $+37^{\circ}C$. Color measurements were made with a spectrophotometer and registered according to the CIELAB $L^*a^*b^*$ color model system. The changes in $L^*$, $a^*$ and $b^*$ values during artificial aging were statistically analyzed by using paired samples t-test and repeated measures ANOVA. P-values <.05 were considered as statistically significant. RESULTS. The UV exposure resulted in visually noticeable and statistically significant color changes in the $L^*$, $a^*$ and $b^*$ values in both of the test groups containing thermochromic pigment. Storage in the incubator lead to statistically significant color changes in the $a^*$ and $b^*$ values of the specimens containing thermochromic pigment, compared to those stored at room temperature. CONCLUSION. The specimens containing thermochromic pigment were very sensitive to UV radiation, and the thermochromic pigment is not suitable, as such, to be used in maxillofacial prostheses.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.9
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• pp.1477-1484
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• 2005

The effects of various seasoning components, pH of seasoning solution, heating time and storage temperature were investigated on the color and textural properties of the salted radish root (nanmooji) The effects of individual seasoning components in the salted radish root, additives of polyphosphate (AD3), citric acid (AD5), malic acid (AD2) delayed the color changes and softening more, compared to control soaked in water. On the other hand, additives of potassium sorbate (AD1), succinic acid (AD7), MSG (AD8), saccharin (AD6) accelerated the color changes and softening of the salted radish roots. The effects of pH of seasoning solution($X_1$), and heating time ($X_2$) were central composite design and response surface analysis. R- square represented dependent variables correlated independent variables ($X_1,\;X_2$), showed over 0.8 in the color and area value calculated thickness and firmness of salted radish root. Especially, R- square of 'b' represented 'yellow-green' was 0.899. And the result of crossing analysis of individual independent variables ($X_1,\;X_2$), showed that both independent variables had significant effects on the color and textural changes of the salted radish root. The salted radish root increased its color changes and softening, rapidly at $40^{\circ}C$, compared to the other storage temperatures at most storage periods.

• Journal of dental hygiene science
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• v.22 no.1
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• pp.57-66
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• 2022

Background: This study aimed to investigate the effect of selecting commercially available blending teas and applying them to bovine teeth on color change over time. Methods: After selecting healthy bovine teeth, using a cutting-disc, 105 specimens with a dimension of 5×5×3 mm were prepared, and 15 specimens were distributed to each group. Black tea was used as a positive control, water was used as a negative control, and blended tea of five types was used as an experimental group. First, pH and buffering capacity were measured with a pH meter, and tooth color was determined using a spectrophotometer before immersion in the blending tea solution and 1, 5, 7, 14, and 21 days after immersion. Thereafter, the shape change of the enamel surface was observed using a scanning electron microscope, and SPSS ver.26 was used to analyze the color change. Results: The average pH of the five blending teas in the experimental group was 3.78, and the pH of group 3 (strawberry rhubarb) was the lowest at 3.22. The pH levels of black tea and water were 5.19 and 7.30, respectively. The buffering capacity was the highest in group 3 at both pH levels of 5.5 and 7.0. The L^*a^*b^* color change according to immersion time was the largest in group 4 (rooibos yellow flower), and the amount of color change was large in black tea and group 4. As a result of observing the enamel surface of bovine teeth, changes in the surface shape were noted in all groups immersed in the experimental solution for 21 days, except for water. Conclusion: There was a significant difference between the experimental groups in terms of color change according to the immersion time, and color and enamel surface changes were observed in black tea and all experimental groups, except for water.

• Journal of dental hygiene science
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• v.9 no.5
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• pp.525-530
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• 2009

The purpose of this study was to evaluate color change and enamel surface changes using the plasma arc light source during tooth bleaching treatments. Twenty-four extracted bovine incisors were selected and embedded in the resin blocks. All the specimens were highly polished and discolored with commercial $COCK^{(R)}$. High concentration carbamide peroxide with and without plasma arc were used for bleaching. Specimens were bleached for 1 hour per week during 3 weeks. Color and enamel surface changes were determined with colorimeter (TC-8600A), microhardness tester(MXT-a7), scanning electron microscope(S-4200). All the collected data analyzed with paired t-test, t-test and one-way ANOVA. After the bleaching, both groups showed the color changes(${\Delta}E^*$). Microhardness of two group decreased after tooth bleaching. The SEM evaluation of enamel surface of both group showed a similar morphology of decalcification after tooth bleaching. Office bleaching using the plasma arc application with 35% carbamide peroxide can increase the color change. Office bleaching using the high concentration of carbamide peroxide and plasma arc also detract the outer surface of enamel. It is recommended that careful procedures are needed during office bleaching with high concentration of carbamide peroxide and light source.

• Food Science and Preservation
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• v.5 no.2
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• pp.167-171
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• 1998

Bulkogi(roast beef) seasoning stored without cap at 5$^{\circ}C$ and 23$^{\circ}C$ and within capped boule at 5$^{\circ}C$, 23$^{\circ}C$, 38$^{\circ}C$, 48$^{\circ}C$ and heat cycling(38$^{\circ}C$-1 week and 5$^{\circ}C$-1 week) and investigated sensory quality, pH, VBN, amino-N, surface color, and viable cell counts during 6 month storage. Nonpackaged Bulkogi seasoning was deteriorated by molds after 2 weeks at 23$^{\circ}C$ but did not showed any significant quality changes at 5$^{\circ}C$ for 1 month. Sensory scores of packaged sample rapidly declined with the temperature increase but chemical criteria was not significantly changed depending on temperature and storage time. Correlations between sensory scores and chemical parameters was not found, but sensory scores on color was correlated with lightness(L. value) of surface color(r=0.899). Heat cycle storage resulted in similar changes in quality to 38$^{\circ}C$ storage. Ql0 values calculated by sensory evaluation results as a quality index was 6, and the shelf-life of packaged Bulkogi seasoning was predicted 88 months at 23$^{\circ}C$.

• Food Science and Preservation
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• v.4 no.1
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• pp.33-38
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• 1997

In order to provide informations for designing packaging and storage condition of dry jujube (Zizyphus jujuba MILLER), moisture sorption isotherm was determined for temperatures of 20, 30 and 4$0^{\circ}C$, and quality changes were evaluated as function of temperature and water activity. Dry jujube at a given water activity showed higher equilibrium moisture content for lower temperature. Moisture isothem could be fitted by GAB model equation, giving higher C value, lower m0 and relatively constant k value with increase in temperature. Ascorbic acid was lost more highly at higher temperature and water activity, and showed negligible retention for whole range of water activity and temperature studied after 141 days. Browning increased with water activity up to 0.73 at 30 and 4$0^{\circ}C$. Dry jujube of high water activity had high L value in surface color, which represent brightness of surface color. Considering quality retention in the storage, dry jujube is desired to be dried to water activity of 0.42 and be stored at temperature below 3$0^{\circ}C$

• Corrosion Science and Technology
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• v.17 no.6
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• pp.301-309
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• 2018

If galvanized steel is exposed to an outdoor environment, atmospheric corrosion will occur with time and red rust will form when the sacrificial protection capacity of zinc reaches its limit. With corrosion, the surface appearance of steel changes, and the properties of the exterior materials degrade. In this study, two kinds of galvanized steel, (GA and GI specimens) were subjected to an outdoor exposure test for 36 months in six regions of Korea. Chrominance (color, chroma, and brightness) and glossiness surface analyses were performed. The color change was not significant, regardless of the exposed area or the specimens tested. With increasing exposure times, the GA specimen became blackened by the formation of zinc oxide, and red coloration was increased by the formation of red rust. As the exposure time of GI specimen increased, the surface proceeded to blacken, but no red rust was formed and the color did not change significantly. Regardless of the outdoor exposure area or the specimen, longer exposure times led to lower glossiness, and this behavior appears to be influenced by the formation of zinc oxide.