• Title, Summary, Keyword: 가교화

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Physicochemical Properties of Cross-linked Rice Starches (가교화 쌀 전분의 이화학적 특성)

  • Choi, Hyun-Wook;Chung, Koo-Min;Kim, Chung-Ho;Moon, Tae-Hwa;Park, Cheon-Seok;Baik, Moo-Yeol
    • Applied Biological Chemistry
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    • v.49 no.1
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    • pp.49-54
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    • 2006
  • Physicochemical properties of cross-linked rice starches were investigated. Swelling power of cross-linked rice starch increased at relatively lower temperature $(60^{\circ}C)$ than native rice starch $(70^{\circ}C)$. Cross-linked rice starch showed lower solubility $(1.7{\sim}6.1%)$ than native rice starch $(2.2{\sim}13.8%)$ and solubility is not significantly different with the amount of phosphorus oxychloride. Pasting temperature $(69.2{\sim}70.6^{\circ}C)$ and peak viscosity $(2,874{\sim}3,175\;cp)$ of cross-linked rice starch were lower than native starch $(71.6^{\circ}C,\;3,976\;cp)$, but holding strength $(2,177{\sim}2,708\;cp)$ and final viscosity $(3,424{\sim}3,826 \;cp)$ of cross-linked rice starch were higher than native starch (1,000 cp, 2,312 cp). DSC thermal transitions of cross-linked rice starches were shifted to a lower temperature than native rice starch but there was no significant difference in gelatinization enthalpy between native and cross-linked rice starches. X-ray diffraction pattern of both native and cross-linked rice starches showed typical A-type crystal indicating that cross-linking had not affected the crystalline region of starch.

Immobilization of Thermolysin for Synthesis of Aspartame Precursor (아스파탐 전구체의 합성을 위한 Thermolysin의 고정화)

  • Han, Min-Su;Kim, Woo-Jung
    • Korean Journal of Food Science and Technology
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    • v.27 no.5
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    • pp.753-756
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    • 1995
  • Optimum conditions for immobilization of thermolysin, a metalloendopeptidase catalyzing synthesis of aspartame precursors, were investigated with using Amberlie XAD-7 as carrier and glutaraldehyde as cross-linking agent. Adsorption of thermolysin onto the carrier was rapid at the initial stage and 96% of the enzyme was adsorbed after 24 hours at $5^{\circ}C$. There was a linear relationship between amount of thermolysin adsorbed and thermolysin loaded upto 300g per liter of carrier. The effective range of cross-linking time, concentration of glutaraldehyde and pH for immobilization of the enzyme were $3{\sim}7\;hours,\;6{\sim}12.5%\;and\;pH\;6.0{\sim}7.0$, respectively. Degree of cross-linking and residual enzyme activity were high when cross-linked for 7 hours with 6% glutaraldehyde or for 3 hours with 12.5% glutaraldehyde. The residual enzyme activity was over 30% under these conditions.

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Physicochemical Properties of Crosslinked Potato Starch (가교결합 감자 전분의 이화학적 특성)

  • Kim, Hyang-Sook;Lee, Young-Eun
    • Korean Journal of Food Science and Technology
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    • v.28 no.3
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    • pp.573-579
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    • 1996
  • Crosslinked potato starches (XP), from 2,400 to 1,900 anhydroglucose units per crosslinked (AGU/CL), were prepared by reacting with epichlorohydrin. Some of the physicochemical properties of the XPs were then compared with those of native potato and cowpea starches. Crosslinking decreased moisture, protein and ash contents but had no effect on phosphorus content. Water binding capacities of the XPs increased as the degree of crosslinking increased, and that of the XP with 2,100 AGU/CL approached the value of cowpea starch. The absorption maxima of the starch-iodine complex shifted from 594 to 580 nm. Granule size increased slightly and surface appearance of the granule became rough when crosslinked. Both native and crosslinked potato starches showed B type X-ray diffraction pattern, and the relative crystallinity was not affected by crosslinking. Gelatinization temperature and the heat of gelatinization, measured by differential scanning calorimeter (DSC), did not change within the range of crosslinking tested. From X-ray and DSC data, it was concluded that the crosslinking ocurred in the amorphous region of the starch granule.

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가교화 ${\beta}-CD$를 이용한 콜레스테롤 제거와 달맞이꽃 종자유와 phytosterol를 이용한 혈중 콜레스테롤 저하에 관한 연구

  • Kim, Jae-Jun;Jeong, Tae-Hui;An, Jeong-Jwa;Gwak, Hae-Su
    • Proceedings of the Korean Society for Food Science of Animal Resources Conference
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    • pp.312-316
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    • 2005
  • 본 연구는 크림에 가교화 ${\beta}-CD$ 처리로 콜레스테롤을 제거 시킨 후 phytosterol 과 EPO 8%를 첨가하여 제조한 버터의 저장 기간 중의 이화학적 특성, 물성, 관능적 특성과 혈중 콜레스테롤 저하 기능을 관찰하기 위하여 수행되었다. 가교화 ${\beta}-CD$를 이용하여 평균90%의 콜레스테롤을 제거한 후 phytosterol 과 EPO 8%을 첨가한 버터의 저장기간이 경과할수록 지방산화도는 증가하였으나, 색도, 물성의 조직 부분이나 관능평가 시 texture, color 부분에서는 유의적 차이를 나타내지 않았다. 그러나 이미 이취를 발생시켜서 바람직하지 않은 결과를 보였으나, 동물 실험 결과 phytosterol 과 EPO 8%를 첨가한 버터 섭취 후 혈중 콜레스테롤을 저하 기능이 있는 HDL-콜레스테롤이 증가하고, 반면에 혈중 콜레스테롤을 증가시키는 기능이 있는 LDL-콜레스테롤과 중성 지방이 감소를 관찰할 수 있었으므로 혈중 콜레스테롤 저하 기능을 가진 버터의 개발이 가능 할 것으로 사료된다.

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Synthesis of Nanoporous NiO-SiO2 Pillared Clays and Surface Modification of the Pillaring Species (나노다공성 NiO-SiO2 가교화 점토의 합성 및 가교물질의 표면개질 연구)

  • Yoon, Joo-Young;Shim, Kwang-Bo;Moon, Ji-Woong;Oh, You-Keun
    • Journal of the Korean Ceramic Society
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    • v.41 no.1
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    • pp.81-85
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    • 2004
  • Nanoporous materials with nanometer-sized pores, are of great interest in the various applications such as selective adsorbents, heterogeneous catalysts and catalyst supports because of their high porosity, surface area, and size selective adsorption properties. This study is aimed to prepare nanoporous catalytic materials on the basis of two-dimersional clay by pillaring of $SiO_2$ sol particles. $SiO_2$ Pillared Montmorillonite (Si-PILM) was prepared by ion exchanging the interlayer $Ni^{2+}$ ions of clay with $SiO_2$ nano-sized particles of which the surface was modified with nicked polyhydroxy cations sach as $Ni_4(OH)_4^{4+}$. Nano-sized $SiO_2$ particles were formed by the controlled hydrolysis of tetraethyl orthosilicate (TEOS). Upon pillaring of $Ni^+$-modified $SiO_2$ nano particles between the clay layers, the basal spacing was expanded largely to $45{\AA}$ and the extremely large specific surface area ($S_{BET}$) of $760m^2/g$ was obtained.

Dehydration of Alcohol Solutions Through Crosslinked Chitosan Composite Membranes II. Dehydration of Ethanol Solution Through Modified Chitosan Composite Membranes (가교키토산 복합막을 통한 알콜수용액의 탈수 II. 변성 키토산 복합막을 통한 에탄올의 탈수)

  • 이영무;남상용;유제강;류경옥
    • Membrane Journal
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    • v.6 no.4
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    • pp.242-249
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    • 1996
  • To improve pervaporation performance of water/ethanol mixtures, chitosan/poly(vinyl alcohol) blended and phosphorylated chitosan composite membranes were prepared. Chitosan/poly(vinyl alcohol) blends were prepared with various blend ratios and then crosslinked with glutaraldehyde by two methods. With increasing crosslinking agent content and crosslinking times separation factor increased and permeate flux decreased. Separation factor of the membrane which contains glutaraldehyde as a crosslinking agent was higher than that of the membrane surface crosslinked. Phosphorylated chitosan was prepared with various reaction times and composite membrane was prepared. As reaction times increased, the separation factor increased with high affinity for water.

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Physicochemical Properties of Cross-linked Waxy Rice Starches and Its Application to Yukwa (가교화 찹쌀전분의 물리화학적 성질 및 유과제조 특성)

  • Yu, Chul;Choi, Hyun-Wook;Kim, Chong-Tai;Ahn, Soon-Cheol;Choi, Sung-Won;Kim, Byung-Yong;Baik, Moo-Yeol
    • Korean Journal of Food Science and Technology
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    • v.39 no.5
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    • pp.534-540
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    • 2007
  • In this study, waxy rice starch was chemically modified using phosphorous oxychloride ($POCl_3$, 0.002-0.008%). Then the physicochemical properties of resulting cross-linked waxy rice starches were investigated in order to reduce the steeping time of Yukwa (a Korean oil-puffed rice snack) processing. The swelling powers of the cross-linked waxy rice starch samples were higher than the native waxy rice starch at temperatures above $60^{\circ}C$, and their increases were proportional to the $POCl_3$, concentration. The solubility of the cross-linked waxy rice starch was lower (1.6-3.4%) than the native waxy rice starch (2.7-6.1%). However, the moisture sorption isotherm of the cross-linked waxy rice starch was not significantly different from the native waxy rice starch. The rapid visco analyze. (RVA) pasting temperatures $(65.4-67^{\circ}C)$ of the cross-linked waxy rice starch were lower than those of the native starch $(67^{\circ}C)$. The RVA peak viscosities (287-337 RVU) of the cross-linked waxy rice starch were higher than that of native starch (179 rapid visco units (RVU)), and increased with increasing $POCl_3$ concentration. For the differential scornning calorimeter thermal characteristics, although Tc shifted toward higher temperatures with cross-linking, the To, Tp, and amylopectiin melting enthalpy of the cross-linked waxy rice starch showed no differences compared to the native waxy rice starch. The X-ray diffraction patterns of both the native and cross-linked waxy rice starches showed typical A-type crystal patterns, suggesting that cross-linking mainly occurs in the amorphous regions of starch granules. Therefore, the cross-linking reaction did not change the crystalline region, but altered the amorphous region of the waxy rice starch molecules, resulting in changes of solubility and RVA pasting properties in the cross-linked waxy rice starch. In summary, since cross-linked waxy rice starch has a high puffing efficiency and no browning reaction, it may be applicable for Yukwa processing without a long steeping process.

Physicochemical Properties of Cross-linked Apios Starch (가교결합 아피오스 전분의 이화학적 특성)

  • Park, Mi Hye;Kim, Meera
    • Journal of the East Asian Society of Dietary Life
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    • v.24 no.3
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    • pp.400-406
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    • 2014
  • Apios (Apios americana Medikus) belongs to Leguminosae and is called 'American groundnut', 'Potato bean', and 'wild bean'. Apios is native to the Northern United States but is not widely distributed in Korea. In this study, cross-linked apios starch was prepared by reaction with epichlorohydrin, followed by characterization. FT-IR spectroscopy confirmed the degree of cross-linking of apios starch. X-ray diffraction patterns of native apios showed typical 'A' type as peaks at 15.1, 17.1, 17.9 and $23.2^{\circ}$, and cross-linking did not affect relative crystallinity and X-ray diffraction patterns of the starch. Scanning electron micrographs showed that apios starch granules were smooth with a globular shape, and there was little damage to starch granules after cross-linking. The lightness value of cross-linked apios starch was lower than that of native apios starch, whereas the redness value was not significantly different between cross-linked apios starch and native apios starch. Blue value showed that cross-linking of starch did not affect the iodine reaction of starch.

Studios on the Thermal Properties of Silane Crosslinked Polyethylene Prepared by Various Crosslinking Conditions (Silane 가교 PE의 가교조건에 따른 열적특성 변화에 관한 연구)

  • Sohn, Ho-Soung;Suh, Kyung-Do
    • Applied Chemistry for Engineering
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    • v.5 no.6
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    • pp.1036-1043
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    • 1994
  • The silane crosslinking method was applied for the crosslinking of polyethylene (PE). Crosslinking of PE was performed by, first grafting vinyltrimethoxysilane(VTMOS) to the main chain of PE using an extruder at $200{\sim}210^{\circ}C$, followed by exposure to three different silane crosslinking conditions (1. immersed in $80^{\circ}C$ water, 2. at $80^{\circ}C$ air forced convection oven, 3. exposed to air at room temperature ). The thermal characteristic changes of PE resins with respect to the silane crosslinking conditions were studied by measuring the crystalline melting temperature, density and crosslinking reaction rate. Because silane crosslinking was carried out at solid state, crystalline melting temperature, crystallinity, crystal growth rate, crosslinking reaction rate and the change in the density of silane crosslinked PE were affected by crosslinking condition and the type of base resin. The properties of silane crosslinked PE were different from those of Peroxide crosslinked PE which was crosslinked at the molten state. It was found, from the result of DSC analysis, that silane crosslinked linear low density polyethylene(LLDPE) crosslinked at room temperature had no secondary melting peak because the crosslinking reaction proceeds slowly as the crystalline grows. After crystallization, the melting point of PE was lowered by crystalline interruption of crosslinked site.

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Development of Surface Modified Tencel Fabrics through the Control of Fibrillation(Part II) - Fibrillation control effect through reactive dye treatment - (피브릴화 조절을 통한 다양한 감성의 텐셀소재 개발(제2보) -반응성 염료에 의한 피브릴화 조절 효과-)

  • Shin, Younsook;Son, Kyonghee
    • Journal of the Korean Society of Clothing and Textiles
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    • v.25 no.10
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    • pp.1738-1744
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    • 2001
  • 본연구의 목적은 반응성 염료를 이용한 텐셀섬유의 피브릴화 조절 효과를 표면 형태, 감량율, 역학적 성질 및 태의 변화의 측면에서 고찰하는데 있다. 반응성 염료에 의한 가교는 섬유의 비결정 영역의 구조를 변화시켜 피브릴화를 억제하였으며 또한 효소의 작용에 영향을 주어 감량율을 감소시켰다. 반응성 염료에 의한 가교는 역학적 성질 중 특히 전단강성, 압축에너지, 압축레질리언스를 증가시켰다. 염색후 효소처리한 시료는 다른 시료보다 numeri와 fukurami 값이 높아 더 나은 종합태를 보였다. 공정순서에 따라 약간씩 차이가 있는 촉감을 나타냈다.

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