• Korean Journal of Food Science and Technology
• /
• v.28 no.6
• /
• pp.1126-1134
• /
• 1996

The physical characteristics changes of carrots during drying were studied to minimize the quality degradation by applying improved drying process and pretreatment method. Physico-chemical properties of the product were analyzed, and then, drying mechanisms were explained by diffusion coefficients and drying models. In hot air drying process, the drying and rehydration efficiencies were high at low relative humidity and high temperature. Browning degree and specific volume also showed similar trend to drying efficiency. Diffusion coefficient, which describes moisture transfer, was also high at low relative humidity and at high temperature. It was verified using. Arrhenius equation that drying process was influenced by temperature. It was also observed during experiment that temperature changes were more effective in drying than relative humidity changes. Quadratic model was the most fittable in explaining the process. As a result of analyzing the experimental data with respect to the drying time, the contents of carotene and moisture could be modeled as a polynomial. As the air velocity increased, drying performance and rehydration efficiency increased.

• Journal of Conservation Science
• /
• v.25 no.4
• /
• pp.451-464
• /
• 2009

To do conservation for ceramics, sometimes it needs to clean the ceramics chemically to remove stains on the ceramics, which should be performed with caution. This study will provide quantitative data about the extraction characteristics of major elements from ceramics through the soaking test to evaluate the stability of ceramic cleaning agents. As soft textured pottery(fired at $700^{\circ}C$) had high absorption, it showed higher extraction characteristics in short soaking time. Especially the strong acid among chemical cleaning agents caused the expoliation and the color change on the surface of soft textured pottery. But these color change had no effect on the physical characteristics of soft textured pottery. The hard textured pottery(fired at $1,000^{\circ}C$) is relatively stable in the cleaning agent because it is ascertained the extraction of that was not enough and also it had little chromatic and physical change by strong acid. Porcelains(Celadon, Whiteware and Puncheong ware) was safer than the soft textured pottery due to their low extraction. But it should take precautions to clean the porcelains with lots of cracklewares such like Puncheong ware chemically in connection with the extraction characteristics and their cracklewares.

• Journal of Conservation Science
• /
• v.28 no.4
• /
• pp.321-328
• /
• 2012

A $SO_2$ gas acceleration test was carried out on four textile groups (silk, cotton, ramie cloth, hemp cloth) which were categoried in five categories by the dyeing materials (undyed, red, yellow, blue, black) and the relation between the concentration of $SO_2$ and deterioration rate was evaluated. The textiles were exposed to 0.01, 0.12, 1, 10, 100, 1000, and 5000 ppm of $SO_2$ for 24 hours and the optical, physical, and chemical deterioration rates were studied. An optical change was identified as the color difference and grey scale rating (colorfastness) enhanced with the increase of gas concentration while there was little physical change. Chemical damage was caused by the acidification of the textile material due to the trapped sulfate ion concentration. The result of optical, physical, and chemical deterioration rates shows that 1 ppm/day $SO_2$ is a critical level of deterioration of traditional textiles.

• Food Science and Preservation
• /
• v.13 no.3
• /
• pp.316-321
• /
• 2006

Disinfection of electrolyzed water (EW) on strawberry by immersion washing and quality changes during storage at $5^{\circ}\C$ was compared with one immersed in chlorine water and not treated. Total count of strawberry washed with EW by immersion in 10 volumes of EW for 20 min was decreased to about 2 log cycle compared to the untreated And rate of microbial growth during storage was lower than ethers. Decaying ratio in strawberry treated with electrolyzed low-alkalinewater (EW-2) showed lower as of 10% level after 5 days of storage compared) to the untreated and the treated with chlorine water (CW). Hardness in the treatment of EW was not changed significantly until 3 days of storage, after then rather increased. Change in surface color of strawberries was observed; L value in the CW treated and the untreated increased whereas it decreased in the treatment of EW. And color difference(${\Delta}E$) during storage was observed the lowest in the untreated until 3 days of storage. The initial value of residual chlorine in the treatment of EW was at the level of $0.04{\sim}0.06ppm$, and $1{\sim}3$ days later showed almost the equal value to level of $0.02{\sim}0.03ppm$ in all treatments. Sensory characteristic during storage was preferable on strawberry washed with EW (EW-1 and EW-2) to the other treatments.

• Journal of the Korean Applied Science and Technology
• /
• v.38 no.1
• /
• pp.9-18
• /
• 2021

This study was aimed to investigate the effects of hair dyeing and changes of hair quality by the application of indigo dye. Methods: Indigo dye was used after water bath. After application of the dye to healthy and bleached hair samples, they were treated with heat and remained naturally by different times. Each sample was measured before and after the application and compared for the analysis. To investigate the effects of dyeing, L⁎, a⁎, and b⁎ values and bleaching degree were measured using by color-difference meter. To understand the changes of hair quality, absorbance and gloss were measured using by tensile strength and methylene blue. Results: Upon the results of dyeing, all the samples showed the significant dyeing effects before and after the application in terms of L⁎, a⁎, and b⁎ values. With respect to the bleaching effects, it showed the greatest change on Day 1 and did not show any changes from Day 3. For the measurement of tensile strength, mean values of all the samples were increased. However, the results were not significant, statistically, demonstrating no change of hair quality. No statistically significant results were found in the samples except healthy 7L(3) sample upon the absorbance results using methylene blue. Gloss of samples was changed upon the statistical analysis results. Conclusion: Indigo dye showed the hair dyeing effects, significantly, while gloss was changed and tensile strength and absorbance were not changed in terms of hair quality. Further studies are required on the processing with a variety of dyes and on the measurements for reliability and objectivity.

• Journal of Conservation Science
• /
• v.33 no.6
• /
• pp.467-483
• /
• 2017

In this study, the degradation properties by temperature stress of $Araldite^{(R)}$ rapid-curing epoxy resin used for inorganic cultural heritages, was identified. The tensile and tensile shear strength of durability decreased for 12,624 hours at temperatures of $40{\sim}60^{\circ}C$. In terms of stability of external stress and temperature, the slow-curing epoxy was superior to the rapid-curing epoxy, and cultural heritage conservation plans should therefore consider the strength and stress properties of restoration materials. Color differences increased for 12,624 hours at temperatures of $40{\sim}60^{\circ}C$, and glossiness decreased. Both color and gloss stability were weak, which necessitates the improvement of optical properties. Thermal properties (weight loss, decomposition temperature, and glass transition temperature) of adhesives are linked to mechanical properties. Interfacial properties of the adherend and water vapor transmission rates of adhesives are linked to performance variation. For porous media (ceramics, brick, and stone), isothermal and isohumid environments are important. For outdoor artifacts on display in museums, changes in physical properties by exposure to varying environmental conditions need to be minimized. These results can be used as baseline data in the study of the degradation velocity and lifetime prediction of rapid-curing epoxy resin for the restoration of cultural heritages.

• Korean Journal of Food Science and Technology
• /
• v.33 no.2
• /
• pp.184-189
• /
• 2001

Comparative effects of gamma irradiation and methyl bromide (MeBr) fumigation on water-soluble components of small red bean and mung bean were investigated. The levels of soluble solid and reducing sugar of soaked water at $20^{\circ}C$ for 16 h definitely increased as irradiation dose increased, which was more apparent in small red bean than in mung bean. But, their levels of MeBr-fumigated sample showed a similar result to those of the control, except for soluble solid of small red bean. The pH of soaked water was insignificantly different among treatments. The decrease in lightness (L value) and the increases of redness (a value) and yellowness (b value) were remarkable as irradiation dose increased, which was more significant in fumigated samples. The ${\Delta}E$ values of fumigated sample showed almost equaled to those of 10 kGy in red bean and 30 kGy in mung bean, respectively. Gamma irradiation caused the increase in free amino acids of soaked water, that mainly consisted of asparagine, glutamic acid, and valine, while fumigation reduced their contents. The extractables in soaked water, such as soluble solid and reducing sugar, showed a highly positive correlation with irradiation dose applied.

• Korean Journal of Food Science and Technology
• /
• v.41 no.1
• /
• pp.21-26
• /
• 2009

Polycyclic aromatic hydrocarbon(PAH) contents were evaluated in sesame oils from sesame seeds of different origins and in commercial samples using HPLC with fluorescence detection. The sesame seeds, which had been harvested from India, China, and Korea, were roasted at $250^{\circ}C$ for 25 min, and the commercial sesame oils were purchased from a local market. The recoveries for eight PAHs spiked into the sesame oils ranged from 80.2 to 99.2%. The mean levels of total PAHs in the sesame oils harvested from China, Korea, and India were 3.97, 1.57, and 1.20 ${\mu}g$/kg, respectively. The PAH contents in the commercial sesame oils ranged from 0.79 to 2.15 ${\mu}g$/kg.

• Journal of dental hygiene science
• /
• v.13 no.1
• /
• pp.13-19
• /
• 2013

This study evaluated the change of color and the microhardness according to time-out using the office bleaching with in vitro test after bleaching one time 1 day per week, total three times, for the control group and three times per 1day for the experimental group. $L^*$ was increased in both groups. Group 1 showed a significant increase statistically between before and after tooth whitening (p<0.05). Group 2 showed a significant increase statistically between before and after tooth whitening (p<0.05). ${\Delta}E^*$ was huge in both groups. In group 1, it was great in terms of statistical significance between 1 day and 7 days after tooth whitening (p<0.05). In group 2, it was the greatest between before and 1 day after tooth whitening and was significant statistically as well (p<0.05). Vickers hardness number (VHN) decreased in both groups. In group 1, VHN decreased over time and the difference was significant statistically (p<0.05). In group 2, VHN decreased over time and the difference was significant statistically (p<0.05). Percentage microhardness loss was great in both groups. In group 1, it was the greatest between 1 day and 7 days after the treatment, and it was significant statistically (p<0.05). In group 2, it was the greatest between before and 1 day after the treatment, and it was significant statistically (p<0.05). Put together, the more frequent tooth whitening a day is, the longer the period of tooth whitening when applying the same frequency, the greater color change was, however the microhardness decreased, in regard to the results over time using 15% hydrogen peroxide tooth whitening product for professionals.

• Journal of Digital Convergence
• /
• v.16 no.12
• /
• pp.593-602
• /
• 2018

The purpose of this study was to investigate the coloring properties of non-mordant dyes by examining local literature on silk fabric dyeing using red-colored natural dyes. Natural dyes can be prepared from the following 8 materials: purple-fleshed sweet potato, Impatiens balsamina, mulberry, fruits of Ligustrum japonicum Thunb, guava leaves, dansam, hibiscus flowers, and pruned branches of Prunus persica. To examine the surface color calculated $L^*$, $a^*$, $b^*$, ${\Delta}E^*$, and K/S value and H V/C. The variables considered in the dyeing experiment were dye concentration, dyeing temperature, dyeing time, and number of dyeing iterations, which were varied to evaluate the dyeing properties and color characteristics. As a result, the abovementioned variables, dye affinity, and red color expression were directly proportional to one another. In this study, it was found that red coloring can be obtained with natural dyes; moreover, excellent dyeing was achieved without the need for repeated dyeing or mordanting processes, which cause environmental pollution.