• The Korean Journal of Food And Nutrition
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• v.35 no.5
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• pp.302-312
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• 2022

The purpose of this study was to investigate the Maillard reaction-related physicochemical properties of three maize varieties (Kwangpyeongok, Sinhwangok2ho and Gangdaok) after roasting them for different times (0, 15, 25, 40, and 55 minutes). The Maillard reaction is a non-enzymatic browning reaction involving reducing sugars and amino compounds. The content of reducing sugar, the causative agent of the Maillard reaction, decreased as roasting time increased. Gangdaok showed the lowest reducing sugar content of 1.04 mg/g after 55 minutes of roasting. In the elapsed roasting time, chromaticity 'L' and 'b' values decreased. At 55 minutes of roasting, wherein the Maillard reaction occurred most actively, Gangdaok showed the lowest 'L' value of 56.37 and the highest 'a' value of 7.60. Gangdaok had superior conditions for inducing the Maillard reaction compared to other varieties, and it is consider that 'flint-type', an endosperm characteristic, may have been the influencing agent. This study detected a total of 52 types of volatile aroma compounds (VACs), of which 28 were produced after roasting. Of the total VACs detected, 2-Formyl-5-methylfuran and 2-Furancarboxaldehyde accounted for 43.8~45.5% and have been confirmed to be the major VACs present in roasted maize. Most of the correlations between the Maillard reaction-related characteristics showed high correlation coefficients.

• The Journal of Engineering Geology
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• v.33 no.1
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• pp.61-68
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• 2023

This study analyzed and compared the physicochemical characteristics of topsoil and subsoil of Grade 1 soil from an igneous rock area on the ecological and nature map. The water content and pH of the collected soil samples were measured, and X-ray fluorescence and X-ray diffraction analyses were performed. The results showed that the water content of the topsoil was higher than that of the subsoil, and its pH was more acidic than that of the subsoil. According to the X-ray fluorescence analysis results, sample I9 was closest to kaolinite, while sample I7 was most distant from kaolinite. All other samples were located between samples I7 and I9. The X-ray diffraction analysis showed that the average content of clay minerals was higher in the topsoil than in the subsoil. The most notable clay minerals produced included illite, vermiculite, kaolinite, chlorite, and gibbsite. The results of this study will be used as a basic data for topsoil restoration to convert subsoil into topsoil.

• Journal of Korean Society of Water and Wastewater
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• v.36 no.5
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• pp.261-273
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• 2022

In this study, we collect water control valves that have had accidents due to existing cracks, etc. are collected, and propose investigation items for strengthening the valve structural safety evaluation through a series of analyzes from valve specifications to physicochemical properties are proposed. The results of this study are as follows. First, there was a large variation in the thickness of the body or flange of the valves to be investigated, which is considered to be very important factor, because it may affect the safety of the valve body against internal pressure and the flange connected with the bolt nut. Second, 60% of the valves under investigation had many voids in the valve body and flange, etc. and the decrease in thickness due to corrosion was relatively large on the inner surface in contact with water rather than the outer surface. It is judged that the investigation of depth included voids is very important factor. Third, all valves to be investigated are made of gray cast iron foam, and therefore it is judged that there is no major problem in chemical composition. It is judged that the chemical composition should be investigated. Fourth, as a physical investigation item, the analysis of metal morphology structure seems to be a very important factor for nodular cast iron from rather than a gray cast iron foam water valve with a flake structure. As it was found to be 46.7~68.8% of the standard recommended by KS, it could have a direct effect on damage such as cracks, and therefore it is judged that the evaluation of tensile strength is very important in evaluating the safety of the valve.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.16 no.2
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• pp.109-115
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• 2023

In this paper, we demonstrated the orientation characteristics of liquid crystals using UV-treated FSAM as alignment layer. Moreover we confirmed the FSAM properties before and after UV treatment on indium tin oxide (ITO) glass substrates using physicochemical analysis. The hydrophobic property of the FSAM surface is change to hydrophilic through UV treatment. After UV treatment the LC molecules also were uniformly and horizontally aligned on the FSAM surfaces and the pretilt angle was obviously changed 90° degrees to 0° degrees. EO characteristic of TN cell which was fabricated with UV-treated FSAM was faster response time compare to conventional PI layer. The FSAM before and after UV treatment has a superior application potential as the LC alignment layer for LCD, potentially replacing the conventional polyimide layer.

• Journal of Environmental Health Sciences
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• v.27 no.1
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• pp.36-43
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• 2001

Chitosans were prepared from red crab chitin under various alkali treatment conditions(different alkali concentrations, reaction times and temperatures) and theirphysicochemical properties were investigated. The nitrogen content and deacetylation degree of red crab chitin were 6.15% and 22.17A%, respectively. By the IR spectra, red crab and reference chitin showed the sharp bands at 1650 $cm^{-1}$ / and 1550 $cm^{-1}$ /, which are characteristic of chitin. The nitrogen contents of prepared chitosans ranged from 6.19~7.48%. Thedeacetylation degree was increased from 63~76% and 48~78% with increasing reaction time and temperature, whereas viscosity was decreased. The nitrogen content and yield of red crab chitosan perpared from chitin with 50% NaOH, 1:25(w/v) for 3.0 hr at 120$cm^{-1}$ / were 7.26% and 85.0%, respectively. and viscosity, deacetylation degree and molecular weight, 67.0 mPa.s, 75.0% and 6.5$\times$10$^{5}$ Dalton, respectively. From the IR spectra, the amide absorption bands of red crab and reference chitosan became very weak, similarly. And at solid state $^{13}$ C-NMR spectra, C=O(carbonyl carbon) signals absent, whereas $CH_3$(methyl carbon) was residues. Chemical shift of $^{13}$ C-NMR spectra of red crab and reference chitosans were in good agreement with slight experimental deviation.

• Culinary science and hospitality research
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• v.15 no.2
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• pp.309-321
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• 2009

This study was conducted the physicochemical and sensory characteristics of cookies added with Angelica gigas Nakai powder(0~2.5%). The pH of the samples ranged from 6.13 to 6.27, and the density ranged from 0.99 to 1.15. Increasing the amount of Angelica gigas Nakai powder in the cookies decreased the spread factor of the cookies and tended to decrease lightness(L) and yellowness(b) in the Hunter color value with redness(a) increased. For the textural characteristics, the addition of Angelica gigas Nakai powder increased strength and hardness. The sensory evaluation showed that the cookies with Angelica gigas Nakai powder were preferred more than those without in color, odor, texture, taste and overall preference. Especially, cookies with 1.5% of Angelica gigas Nakai powder were valued as best.

• International Journal of Industrial Entomology and Biomaterials
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• v.6 no.2
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• pp.151-155
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• 2003

Using gel filtration chromatography, high molecular silk fibroin with high purity was obtained and silk flbroin microsphere particles (SFMP) could be simply made by spray dryer method. Also, some of the physicochemical properties of SFMP and morphology were investigated. The average molecular weight of pure silk fibroin protein dissolved in calcium chloride is about 61,500g/㏖ as measured by gel permeation chromatography. SFMP was spherical in shape, and particles, sized average of 2 ${\pm}$ 10 ${\mu}$, were observed by SEM and particle analyzer, respectively. Obtaining microspheres particles by spray dryer method accelerated the transition from the random coil to the $\beta$-sheet structure during spray dryer treatment. It was identified by the basic fourier transform infrared spectroscopy of SFMP. The swelling ratio of SFMP is majorly dependent on the pH of the solution, not on the occurred gelation. The characteristic structure, which might be applicable to immobilization of drugs is superior to other matrix materials for the use of biomaterials with skin affinity.

• The Korean Journal of Food And Nutrition
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• v.20 no.4
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• pp.369-377
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• 2007

An investigation evaluating the preparation and physicochemical properties of sauce with various herbs(sancho, sage, and rosemary) derived from soy sauce was performed. The effects of the different kinds of herbs added to sauce for roasted mackerel were assessed using physiochemical, sensory, flavor, and texture analysis properties. This fish was then compared to, fish with salt. The moisture, crude protein, crude fat, and crude ash content of the roasted mackerel were significantly higher than the control(p<0.05, p<0.001). The salinity content of the herb sauce added samples were significantly higher than the control(p<0.05). Conversely, the pH and peroxide value of the herb sauce added samples were significantly lower than the control(p<0.001). A positive trend was observed for color value with sancho added sauce(p<0.001). The another positive effects on the texture of fish was observed for texture analysis, adhesiveness, springiness, gumminess, and chewiness with herb sauce added samples(p<0.05). In the flavor profile, the fishy smell was disappeared and antifungal flavor was improved with herb added sauce. Flavor, taste, texture, and overall preference of herb sauce were significantly highest in sancho added sauce(p<0.05, p<0.001). Results suggest that the best herb sauce for roasted mackerel was sancho added sauce.

• Journal of the Korean Applied Science and Technology
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• v.32 no.4
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• pp.748-757
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• 2015

This experiment was carried out the quality of astringent and dried persimmon according to various cultivars and harvesting time. There were need for proper selecting cultivar of astringent persimmon and knowing proper mature degree of persimmon in order to enhance the quality of dried persimmons. Immature persimmons showed lower moisture content, color value and higher hardness than riped and over-riped persimmons. The total quality of riped and over-riped fruit were superior than un-riped fruit.

• Journal of the Korean Society of Food Culture
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• v.33 no.1
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• pp.55-61
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• 2018

This study examined the quality of bread made from a wheat flour, oat powder, and wild carrot powder mixture. The lightness and redness values decreased with increasing amount of wild carrot powder addition, while the yellowness was increased significantly. In a sample of wild carrot powder addition, the total volume was lower than the control. The texture profile analysis of oat bread, such as hardness, gumminess and cohesiveness decreased significantly with increasing amount of wild carrot powder addition. In the case of springiness, the value was not significant. The sensory evaluation of oat bread was significantly different in all analyses. Oat bread (BCB2.0) containing 2.0% (w/w) wild carrot powder showed the highest value in the four sensory evaluation items. Therefore, the 2.0% (w/w) addition of wild carrot powder addition was appropriate. An analysis of the physicochemical active component and DPPH scavenging activity of oat bread revealed a higher total flavonoid and total polyphenol content than normal bread. The DPPH scavenging activity was also 20.3% compared to the wild carrot powder. The availability of wild carrot powder in oat bread could be identified.