• Bulletin of the Korean Chemical Society
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• 제35권6호
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• pp.1809-1816
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• 2014

This study demonstrates gel-to-fluid transition temperatures of polydiacetylene bilayer vesicles could play important roles in their colorimetric transition temperatures. We prepared five types of polydiaceylene vesicles with 10,12-pentacosadiynoic acid (PCDA) and cholesterol (0-40 mol % of total content). From temperature-dependent observations of the optical signals (colors and UV-vis spectra), the blue-to-red colorimetric transition temperatures of polydiacetylene vesicles were decreased with the cholesterol contents. A further study with microcalorimetry and dynamic light scattering revealed that the polydiacetylene vesicles first underwent gel-to-fluid transitions, which were followed by event(s) responsible for the colorimetric transitions. Energies required for each event were quantified from analysis of the peaks in the microcalorimetry thermograms. The inclusion of cholesterol in the vesicles decreased both the gel-to-fluid and the colorimetric transition temperatures, suggesting that the colorimetric transition of the polydiacetylene vesicles was mediated by the former event although the event was not the direct reason for the color change.

• Korean Chemical Engineering Research
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• 제46권2호
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• pp.310-315
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• 2008

실란커플링제인 glycidoxypropyl trimethoxysilane(GPTMS)과 vinyltriethoxysilane(VTES)을 출발물질로 하여 sol-gel 법에 의해 유-무기 혼성 용액을 제조하였다. 이 용액에 spiropyran계 광 변색 염료를 ethylacetate에 용해시킨 용액을 혼합하여 광 변색 코팅 용액을 제조하였다. 그 후 기재인 polycarbonate 시트에 스핀 코팅 시키고 $100^{\circ}C$에서 2 h 동안 열 경화시켜 광 변색성을 갖는 하드 코팅 막을 제조하였다. 코팅 막은 UV 광을 조사함에 의해 투명색으로부터 푸른색으로 변했다가 다시 투명색으로 변하는 가역적인 색변화를 보여주었다. 이때 코팅 막의 소색속도 및 연필경도는 코팅 용액 중의 GPTMS의 mol비가 증가됨에 따라 증가하였다.

• 한국세라믹학회지
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• 제52권6호
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• pp.449-454
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• 2015

The fabrication process of zirconia gel-casting was studied to obtain dense zirconia on a large scale or with complicated shapes. As an experimental parameter, two different particle sizes ($0.1{\mu}m$ and $0.7{\mu}m$) of zirconia powder were applied to the gel-casting process. The viscosity behavior of slurries incorporating 40 vol% of zirconia powder was examined as a function of the dispersant content and the solid load to determine the optimum dispersion conditions. In addition, the gelation time with an initiator, the de-binding behavior, and the main factors affecting densification were examined. The densification of the gel-casted zirconia green body depended on the mixing ratio between the monomer and the dimer and on the zirconia particle size. A green body with a small particle size of $0.1{\mu}m$ showed less densification, with a relative density of 93%. This may be due to the excess number of bubbles created through interactions between the larger particle surface and polymer additives during the ball-milling process.

• Korean Chemical Engineering Research
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• 제46권1호
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• pp.112-117
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• 2008

1:1로 몰 비가 조절된 glycidoxypropyl trimethoxysilane(GPTMS)과 methyl triethoxysilane(MTES)을 출발물질로 하여 sol-gel법에 의해 유-무기 혼성 용액을 제조하였다. 이 용액에 spiropyran계 광 변색 염료를 ethylacetate(EA)에 용해시킨 용액을 혼합하여 광 변색 코팅 용액을 제조하였다. 그 후 기재인 polycarbonate 시트에 스핀 코팅 시키고 $100^{\circ}C$에서 2 h 동안 열 경화 시켜 광 변색 코팅 막을 제조하였다. 코팅 막은 UV 광을 조사함에 의해 가역적인 색변화를 보여주었다. 이때 코팅 막의 소색속도는 코팅 용액 중의 EA의 첨가량이 증가됨에 따라 증가하였다.

• 한국수산과학회지
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• 제41권6호
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• pp.419-426
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• 2008

Physicochemical characteristics of gelatin extracted from abdominal skin of yellowfin tuna (Thunnus albacares), were investigated by comparing its proximate composition, pH, amino acid composition, viscoelastic properties, gel strength and SDS-PAGE patterns, with those of bovine and porcine gelatins. The effects of gelatin concentration, maturation time, heat and freeze treatments on the gel strength of yellowfin tuna abdominal skin gelatin were studied. Amounts of $\alpha$-chains, $\beta$- and $\gamma$-components of yellowfin tuna abdominal skin gelatin were higher than those of the two mammailan gelatins. Yellowfin tuna abdominal skin gelatin had the lowest imino acids (proline and hydroxyproline) content, which was consistent with that of other fishes. However, yellowfin tuna abdominal skin gelatin was highest in glycine, alanine, and lysine. The gel strengths of all gelatins were proportional to the concentration of gelatin, but yellowfin tuna abdominal skin gelatin exhibited the greatest gel strength at each concentration. Yellowfin tuna abdominal skin gelatin required a longer maturation time than the two mammalian gelatins to form a firm gel. Higher heating temperature decreased the gel strength of yellow fin tuna abdominal skin gelatin more than in the two mammalian gelatins. Freezing decreased the gel strength of bovine gelatin only slightly, but longer freezing times resulted in greater reductions in gel strength in the yellowfin tuna abdominal skin and porcine gelatins.

• 농업과학연구
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• 제10권1호
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• pp.156-165
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• 1983

태양열(太陽熱)을 이용(利用)한 silica gel의 활용(活用)에 대(對)한 기초자료(基礎資料)를 얻고자, silica gel을 이용(利用)한 양파의 건조특성(乾燥特性)과, 공기(空氣)의 제습효과(除濕效果)를 구명(究明)하고, 건조제(乾燥劑)로서의 재사용(再使用)을 위(爲)하여 실험(實驗)한바, 그 결과(結果)를 요약(要約)하면 다음과 같다. 1. 외기온도(外氣溫度) $30^{\circ}C$, 상대습도(相對濕度) 55% 내외(內外)에서 포화(飽和)silica gel을 수분함량(水分含量) 8%까지 재생(再生)시키는데 14시간(時間) 소요(所要)되었다. 2. 집열기(集熱器)를 재순환(再循環)시켜 건조(乾燥)한 결과(結果), 노천건조(露天乾燥)보다 1/2정도(程度) 시간(時間)이 단축(短縮)되었다. 3. 실험기간중(實驗期間中) 집열기(集熱器)의 평균효율(平均效率)은 25%였다. 4. 건조실(乾燥室)을 이용(利用)한 송풍건조시(送風乾燥時), 갈변도(褐變度)가 1/2로 감소(減少)되었다.

• 산업식품공학
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• 제13권3호
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• pp.216-220
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• 2009

Aloe gel의 동결건조에 농축도가 서로 다른 액상 시료를 사용하였을 때 건조분말의 기능성 변화를 비교분석하였다. Aloe의 많은 기능성 중에서 유효 다당류의 농도, 기능성 작용기에 대한 FT-IR 특성, Jack bean urease 저해 효과, FAC(fat adsorption capacity)를 대상으로 하였다. 농축도가 높은 경우에 유효 다당류의 농도, urease 저해 효과, FAC 모두 상대적으로 크게 나타났다. FT-IR의 분석에서는 농축도가 높은 경우에 glucomannan의 acetyl 기에 대한 spectrum 영역인 1600-1550 $cm^{-1}$와 1450-1400 $cm^{-1}$에서 흡광도가 크게 관찰되었다. 결과적으로 Aloe gel의 동결건조시 전처리과정인 농축 공정에서는 농축도가 높을수록 유효다당류의 양과 acetyl기 함량의 수준이 크며, 간접적으로 urease 저해 효과에 따른 Helicobacter pylori의 억제 및 FAC의 증가 효과를 보였다.

• Journal of Animal Science and Technology
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• 제65권5호
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• pp.1065-1080
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• 2023

The solubility and structure of myosin and the properties of pork gel with NaCl, KCl, CaCl₂, and MgCl₂ were investigated. Myofibrillar proteins (MPs) with phosphate were more solubilized with NaCl than with KCl (p < 0.05). CaCl₂ and MgCl₂ showed lower MP solubilities than those of NaCl and KCl (p < 0.05). The α-helix content of myosin was lower in KCl, CaCl₂, and MgCl₂ than in NaCl (p < 0.05). The pH of pork batter decreased in the order of KCl, NaCl, MgCl₂, and CaCl₂ (p < 0.05). The cooking yield of the pork gel manufactured with monovalent salts was higher than that of the pork gel manufactured with divalent salts (p < 0.05). The pork gel manufactured with KCl and MgCl₂ showed lower hardness than that of the pork gel manufactured with NaCl. The solubility and structure of myosin were different with the different chloride salts and those led the different quality properties of pork gel. Therefore, the results of this study can be helpful for understanding the quality properties of low-slat meat products manufactured by replacing sodium chloride with different chloride salts.

• Asian-Australasian Journal of Animal Sciences
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• 제20권8호
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• pp.1285-1291
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• 2007

This research investigated variation in the improvement of the texture of chicken and pork sausages induced by microbial transglutaminase (MTG). The extractability of myofibrillar proteins from these sausages as well as the ${\varepsilon}-({\gamma}-glutamyl)$lysine (G-L)　content were also investigated. MTG treatment of sausages significantly increased the breaking strength values in both meat types, especially for samples incubated at $40^{\circ}C$. However, values of the breaking strength in both meat types were increased differently. The variation in protein extractability of samples incubated at $40^{\circ}C$ for both meat types could lead to some consideration of the mechanisms and the high accessions of myosin heavy chain (MHC) to MTG. SDS-PAGE analysis showed significant changes in the density of the bands after adding MTG, especially for the pork samples in which the bands disappeared totally. The G-L content in the presence of MTG was double that in control samples of both meat types. This study suggests that the binding ability of myofibrillar proteins with MTG is strong. This leads us to suggest that MTG functions positively with different improvements in the texture of chicken and pork products that are treated mechanically, such as sausages. Variability in gel improvement level between chicken and pork sausages was observed; this resulted from the variation in meat proteins in response to MTG, as well as to the original glutamyl and lysine content.

• 한국수산과학회지
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• 제33권1호
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• pp.70-74
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• 2000

우뭇가사리로부터 조한천을 조제하고, 이를 실제 산업에 적용할 목적으로 $0.4\;{\mu}m$ 기공을 가지는 여과 막을 microfiltration한 후, $50{\circ}C$의 온수로써 가용성 물질을 제거하고, 0.25 N NaOH로 $70{\circ}C$에서 2시간 처리하는 알칼리 처리를 거쳐 미생물 배지용 한천을 조제하였다. 이화학적 특성을 측정한 결과에 의하면, 겔강도는 $460g/cm^2$에서$738g/cm^2$으로 상승하였고, 점도는 12 cp에서 5.2 cp로, 황산기 함량은 $1.8{\%}$에서 $0.4{\%}$로, 그리고 이수율은 $10.3{\%}$에서 $5.4{\%}$로 저하하여 제품의 품질이 월등히 향상되었다. 상용되는 미생물 배지용 한천은 겔강도가 $358{\~}368g/cm^2$, 점도는 8 cp, 황산기 함량은 $2.18{\~}2.39{\%}$ 및 시너레시스율은 $11.3{\~}12.4{\%}$로 분석되어 본 실험법으로 정제한 한천이 물성 및 성분에 있어서 휠씬 우수 하였다.