• 한국식품과학회지
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• 제38권4호
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• pp.495-500
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• 2006

본 연구에서는 제분기, 건조방법별 등 다양한 조건별로 현미쌀가루 제조하여 각 쌀가루별 품질특성을 조사하였다. 건조조건에 따른 roll mill 제분한 현미쌀가루의 수분함량은 열풍건조 10.7% 마이크로파건조 13.7%로 측정되었다. 대조구인 백미쌀가루의 수분함량은 10.0%였다. Zet mill 분쇄 후 쌀가루의 수분함량은 8.0-8.6%로 측정되었다. WAI는 전분손상도가 높을수록 흡수되는 수분의 양이 증가하여 전분손상도가 가장 높은 Zet mill로 분쇄한 현미쌀가루가 0.58-0.79g/g으로 높았고, 전분손상도가 낮은 roll mill 분쇄한 대조구와 BrWRH 쌀가루가 각각 0.45, 0.40g/g으로 낮은 값을 나타내었다. WSI 역시 WAI와 같이 전분손상도가 증가할수록 증가하는 경향을 나타내었고 입자크기가 감소함에 따라 증가하였다. 대조구 백미 쌀가루 L, a, b는 97.1, -0.4, 4.2로 측정되었고, 현미쌀가루는 분쇄과정에서 생성된 미강층 때문에 L값은 대조구보다 낮고 반면에 b값은 높은 결과를 나타내었다. 제분방법에 따른 L값, b값은 roll mill로 분쇄한 현미쌀가루의 L, b값은 각각 91.3-91.9, 9.2-10.1이었고, zet mill로 제분한 현미쌀가루의 L, b값은 각각 94.1-96.8, 5.8-6.8로 측정되어 입자크기가 작을수록 L값은 증가하였고, b값은 감소하였다. 전분손상도는 대조구가 8.2%로 가장 낮았고, 마이크로파 건조 시 열품건조보다 4-10%정도 높은 전분손상도 값을 보였다. 제분기 종류에 따른 전분손상도는 roll mill 15.5%, zet mill 28.2% 그리고 micro mill 51.9%로 입자크기가 작을수록 전분손상도는 증가하였다. RVA 측정결과 대조구 호화개시온도는 $65.4^{\circ}C$로 가장 낮은 값을 나타내었다. 제분방법에 따른 대조구, BrWRH, BrWZH, HBrZMU 쌀가루의 호화특성 측정결과 최고점도(peak), 최저점도(trough)는 각각 321, 255, 221, 162 RVU와 217, 185, 175, 113 RVU로 측정되어 입자크기가 작아질수록 감소하였다 또한 호화액의 안전성을 나타내는 breakdown 값은 대조구가 105 RVU, 현미 쌀가루가 37-96 RVU로 측정되어다 DSC 분석결과 호화엔탈피$({\Delta}H)$는 대조구가 10.4 J/g으로 가장 높은 값이었고, 가장 작은 입도분포를 나타낸 HBrZMU가 6.1 J/g으로 가장 낮은 값을 보였다. 본 연구결과 가공제품으로 현미쌀가루 이용 시 침지, 건조방법 보다는 제분방법 즉 입도분포가 현미쌀가루의 품질특성에 않은 영향을 미치는 것을 알 수 있었다.

• Restorative Dentistry and Endodontics
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• 제22권1호
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• pp.1-33
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• 1997

The objective of this study was to analyze the in vitro and in vivo corrosion products of low and high copper amalgams. The four different types of amalgam alloy used in this study were Fine cut, Caulk spherical, Dispersalloy, and Tytin. After each amalgam alloy and Hg were triturated according to the directions of the manufacturer by means of the mechanical amalgamator(Amalgam mixer. Shinhung Co. Korea), the triturated mass was inserted into a cylindrical metal mold which was 12mm in diameter and 10mm in height. The mass was condensed by 150Kg/cm compressive force. The specimen was removed from the mold and aged at room temperature for about seven days. The standard surface preparation was routinely carried out by emery paper polishing under running water. In vitro amalgam specimens were potentiostatically polarized ten times in a normal saline solution at $37^{\circ}C$(potentiostat : HA-301. Hukuto Denko Corp. Japan). Each specimen was subjected to anodic polarization scan within the potential range -1700mV to+400mV(SCE). After corrosion tests, anodic polarization curves and corrosion potentials were obtained. The amount of component elements dissolved from amalgams into solution was measured three times by ICP AES(Inductive Coupled Plasma Atomic Emission Spectrometry: Plasma 40. Perkim Elmer Co. U.S.A.). The four different types of amalgam were filled in occlusal and buccal class I cavities of four human 3rd molars. After about five years the restorations were carefully removed after tooth extraction to preserve the structural details including the deteriorated margins. The occlusal surface, amalgam-tooth interface and the fractured surface of in vivo amalgam corrosion products were analyzed. In vivo and in vitro amalgam specimens were examined and analyzed metallographically by SEM(Scanning Electron Microscope: JSM 840. Jeol Co. Japan) and EDAX(Energy Dispersive Micro X-ray Analyser: JSM 840. Jeol Co. Japan). 1. The following results are obtained from in vitro corrosion tests. 1) Corrosion potentials of all amalgams became more noble after ten times passing through the in vitro corrosion test compared to first time. 2) After times through the test, released Cu concentration in saline solution was almost equal but highest in Fine cut. Ag and Hg ion concentration was highest in Caulk spherical and Sn was highest in Dispersalloy. 3) Analyses of surface corrosion products in vitro reveal the following results. a)The corroded surface of Caulk spherical has Na-Sn-Cl containing clusters of $5{\mu}m$ needle-like crystals and oval shapes of Sn-Cl phase, polyhedral Sn oxide phase. b)In Fine cut, there appeared to be a large Sn containing phase, surrounded by many Cu-Sn phases of $1{\mu}m$ granular shapes. c)Dispersalloy was covered by a thick reticular layer which contained Zn-Cl phase. d)In Tytin, a very thin, corroded layer had formed with irregularly growing Sn-Cl phases that looked like a stack of plates. 2. The following results are obtained by an analysis of in vivo amalgam corrosion products. 1) Occlusal surfaces of all amalgams were covered by thick amorphous layers containing Ca-P elements which were abraded by occlusal force. 2) In tooth-amalgam interface, Ca-P containing products were examined in all amalgams but were most clearly seen in low copper amalgams. 3) Sn oxide appeared as a polyhedral shape in internal space in Caulk spherical and Fine cut. 4) Apical pyramidal shaped Sn oxide and curved plate-like Sn-Cl phases resulted in Dispersalloy. 5) In Tytin, Sn oxide and Sn hydroxide were not seen but polyhedral Ag-Hg phase crystal appeared in internal space which assumed a ${\beta}_l$ phase.