• Journal of Applied Biological Chemistry
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• 제50권4호
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• pp.234-238
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• 2007

The effects of ultra-fine pulverization on the physicochemical properties of rice starch (RS) were investigated using a high impact planetary mill. After pulverization, RVA characteristics, peak viscosity, break down, and set back values of RS decreased from 274.75 to 9.42 RVU, 214.46 to 6.17 RVU, and 87.80 to 17.00 RVU, respectively. The pasting properties also changed significantly. X-Ray diffractogram revealed RS had four A-type peaks, which disappeared after pulverization. The peak temperature and gelatinization enthalpy of RS using differential scanning calorimetry (DSC) were 13.99 J/g at $75.14^{\circ}C$, whereas the pulverized RS (PRS) had two peaks, 0.13 J/g at $63.88^{\circ}C$ and 1.23 J/g at $101.24^{\circ}C$. DSC measurement showed the retrogradation degree of PRS was lower than that of RS after storage at 4 and $25^{\circ}C$. The enzymatic (${\alpha}$-amylase) digestibilities of RS and PRS were 72.7 and 77.3%, respectively.

• Applied Biological Chemistry
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• 제50권3호
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• pp.160-166
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• 2007

본 연구는 초미세 분체기술을 이용하여 쌀 전분의 입자구조 파괴가 이루어졌을 때 분자구조적, 물리적 변화가 어떻게 이루어지는지를 구명하고자 하였다. 분쇄 후 쌀 전분의 평균직경은 약 20% 감소가 이루어졌으며 비표면적은 25% 증가하였다. 분쇄 전후의 쌀 전분에 대한 분자량분포를 GPC(gel permeation chromatography)로 측정한 결과 Peak II의 면적이 36.5%에서 59.5%로 상승하였다. 분쇄 전후 손상전분 정도는 각각 16.40%와 99.2%로 나타났다. 분쇄 전에 비하여 분쇄 후 쌀 전분의 물결합능력, 용해도와 광 투과도에서도 월등히 높았다. $30^{\circ}C$에서 20 rpm을 기준으로 분쇄후의 쌀 전분의 겉보기점도는 상대적으로 분쇄 전의 7% 수준에 불과하였으며 측정온도가 높아짐에 따라서 차이는 더욱 커졌다.

• 산업식품공학
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• 제13권4호
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• pp.335-340
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• 2009

본 연구는 초미세분쇄기술을 이용하여 옥수수전분의 입자구조파괴가 이루어졌을 때 분자구조적, 물리적 변화가 어떻게 이루어지는지를 구명하고자 하였다. 초미세 분쇄처리 후 옥수수전분의 평균직경은 약 50% 감소가 이루어졌으며 비표면적은 567% 증가하였다. 초미세분쇄처리 전 후의 옥수수전분에 대한 분자량분포를 GPC로 측정한 결과 분쇄 후 저분자량의 Peak II의 면적이 21.0%에서 86.5%로 상승하였다. 손상전분 함량은 각각 9.63%와 83.57%로 초미세분쇄처리에 의하여 크게 증가하였다. 옥수수전분의 경우는 겔(gel)을 형성하였으나 초미세분쇄처리 후에는 전분의 분쇄과정에서 전분입자파괴와 아울러 옥수수전분의 분자량이 저분자화 되면서 겔 형성능력이 크게 저하되었다.

• 한국정밀공학회지
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• 제21권10호
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• pp.34-41
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• 2004

A new method to fabricate the fine magnetic abrasives by using mechanical alloying is proposed. The mechanical alloying process is a solid powder process where the powder particles are subjected to high energetic impact by the balls in a vial. As the powder particles in the vial are continuously impacted by the balls, cold welding between particles and fracturing of the particles take place repeatedly during the ball milling process using a planetary mill. After the manufacturing process, fine magnetic abrasives which the guest abrasive particles c lung to the base metal matrix without bonding material can be obtained. The shape of the newly fabricated fine magnetic abrasives was investigated using SEM and its polishing performance was verified by experiment. It is very helpful to finishing the injection mold steel in final polishing stage. The areal ms surface roughness of the workpiece after several polishing processes has decreased to a few nanometer scales.

• 산업식품공학
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• 제15권2호
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• pp.169-174
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• 2011

This study was performed to analyze the effects of ultra fine pulverization (UFP) on the physicochemical properties of sweet potato starch (SPS). The average diameter and specific surface area of the SPS was decreased from 22.94 to 10.25 $\mu$m and from 0.879 to 1.909 $m^2$ /g throughout UFP, respectively, and the damaged starch content was increased from 13.7 to 99.2%. The pulverized sweet potato starch (PSPS) had higher swelling power, solubility, and transmittance values than the SPS. X-ray diffractograms revealed that the SPS had a C-type pattern, which disappeared in PSPS. The rapid visco analysis (RVA) characteristics, peak viscosity, break down, and set back of SPS ceased to exist in PSPS. According to differential scanning calorimetry (DSC) curves, the peak temperature ($T_p$) and gelatinization enthalpy ($\Delta$E) of SPS were $71.95^{\circ}C$ and 10.40 J/g, respectively, while these remained undetected in PSPS. The enzymatic digestibilities of SPS and PSPS were 61.7 and 84.7%, respectively.