• Food Science and Biotechnology
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• 제17권4호
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• pp.814-818
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• 2008

Com and rice starches were physically modified by planetary mill. While native starches showed high peak viscosities (1,001 and 563 cp), it decreased largely (42 and 20 cp for rice and com starch, respectively) after 2 hr of physical modification. When two starches were co-ground, peak viscosities decreased more largely than single ground one only in 30 min, indicating the pasting properties could be easily changed by co-grinding. Especially, the higher the amount of com starch, the viscosity decreased more largely, which means that paste stability could be controlled also by changing the ratio of com and rice starch. Mean particle size increased with physical modification time since particles became spread because of shear force. There were also changes in surface morphology after physical modification. Fluid property, such as mean time to avalanche (MTA), was improved (from $6.16{\pm}0.47$ and $8.37{\pm}1.23\;sec$ to $5.47{\pm}0.78$ and $5.26{\pm}1.37\;sec$ for rice and com starch, respectively) by physical modification. Pasting property, such as swelling power, was also improved by physical modification. These mean that native starches can be applied to both conventional powder and new paste-food industry more efficiently by physical modification.

• 펄프종이기술
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• 제37권5호통권113호
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• pp.70-77
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• 2005

The development of printable Hanji is regarded as an important work to create a new demand of Hanji in information-oriented era. Hanji has rougher surface, huger absorption of ink and lower optical properties and printabilities than common printing papers. Improving those shortcomings of Hanji is required to be printable Hanji. Sizing and calendering have known as a way to make properties of paper good. Accordingly, this research was performed to find out useful sizing agents for reforming its drawbacks. Four sizing agents (CMC, com starch, PVA, AKD) were used in this research. The optical properties and the printabilities of sized Hanji were tested. The obtained results were as follows. Based on concentration, each sizing agent was prepared. These were CMC(0.5, 1, $1.5\%$), corn starch(1, 2, $3\%$), PVA(1, 5, $10\%$), AKD(0.5, 0.1, $0.15\%$) respectively. After sizing, we performed calendering treatment with pressure of 0.5, $1\;kgf/cm^2$. All the sizing agents and calendering treatment improved the properties of Hanji to some extent. Particularly, com starch was good for gloss. In case of printability, $1\%$ AKD with $1\;kgf/cm^2$ was recommendable for typography ink density, $3\%$ com starch with $0.5\;kgf/cm^2$, inkjet ink density, $2\%$ com starch with $0.5\;kgf/cm^2$, inkjet ink girth. PVA and AKD without calendering were counter-effective agents for inkjet ink density. Printable Hanji is required to have not only better surface strength enough to appear non-picking, higher ink density and lower show-through than base paper but also the lowest ink girth in comparison with base paper. When referring to them, efficient sizing agents were regarded as $0.1\%$ AKD with $1\;kgf/cm^2$, calender pressure, for typography printing and $2\%$ com starch with $0.5\;kgf/cm^2$, calender pressure, for inkjet printing.

• Food Science and Biotechnology
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• 제17권1호
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• pp.176-179
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• 2008

Amylose contents and amylopectin chain architecture of sorghmn and waxy sorghum starches were determined and compared with those of other common cereal and tuber starches. Also, in vitro digestibility of sorghum starch was estimated using a novel methodology. The absolute amylose content of sorghum starch was similar to that of com and wheat starches. The side chain length distribution patterns for sorghum and waxy sorghum amylopectin were very similar to those of com and waxy com, respectively. The $k_{cat}/K_m$ values for sorghum and potato amylopectin did not show a significant difference. The kinetic parameters could be used as novel indicators for starch digestibility.

• Food Science and Biotechnology
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• 제16권5호
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• pp.832-835
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• 2007

Moisture content of normal, waxy, and high amylose com starches was adjusted to 10-35%, and irradiated in a microwave oven. The effect of microwave irradiation on the crystalline structure of starch was measured by using a differential scanning calorimetry (DSC), and X-ray diffractometry. Pasting viscosity profile was also determined by using a rapid viscoanalyzer (RVA). For all the 3 types of starches tested, the rate of temperature increase by the microwave irradiation was faster and more rapidly reached the maximum temperature of the pressure bomb ($120^{\circ}C$) when the moisture content was higher. X-ray diffraction and DSC data revealed that the microwave irradiated starch underwent partial disruption of crystalline structure. RVA studies showed that the irradiation caused significant reductions in maximal viscosity and breakdown, whereas pasting temperature was increased. Overall trends revealed that the microwave irradiation on the starch containing limited moisture content (less than 35%) provided the effects similar to the heat moisture treatment. These effects became more significant when the moisture content was higher. Compared to waxy com starch, normal, and high amylose com starches appeared to be more susceptible to the microwave irradiation.

• 한국식품저장유통학회지
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• 제10권4호
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• pp.506-511
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• 2003

DSC를 이용하여 acom starch와 com starch 및 starch-saccharide-water system 의 겔화와 노화에 관한 열적 메카니즘을 알아보았다. 전분에 fructose와 maltose를 첨가한 starch-saccharide-water 계의 엔탈피를 측정한 결과, 당을 첨가하지 않은 경우의 엔탈피 값보다 컸으며 겔화 온도 역시 증가하였는데 이는 당이 물과 상호 작용하여 비결정성 영역에 흡수된 자유수가 감소하고 결정부분이 안정화되어 겔화가 일어나는 것을 지연시키기 때문이라고 생각되었다. 노화 엔탈피는 acorn starch 와 com starch에 대해 1일 ∼ 14일까지 저장시간에 따르는 변화를 관찰한 결과, 저장시간이 길어짐에 따라 엔탈피 값이 유의성 있게 증가하는 경향을 나타내었으며 이는 amylopectin 의 재결정화가 서서히 일어나기 때문으로 보였다. 또한 s-s-w system의 노화과정을 관찰한 결과, 저장시간이 길어짐에 따라 엔탈피 값이 증가하다가 7일이 지나면서부터는 일정해졌다. 이는 당이 amylopectin의 재결정화를 정지시켜서 노화를 지연시키기 때문으로 판단되었다. 당의 첨가가 노화에 미치는 영향은 fructose와 maltose 중에서 maltose의 노화지연 효과가 더 컸는데 이는 전분 겔 계를 안정시키는 junction zone의 수와 equatorial OH 수 및 활동적인 수화상태가 증가되는 요인을 maltose가 fructose보다 더 많이 갖고 있기 때문인 것으로 설명할 수 있었다.

• 한국식품조리과학회지
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• 제12권2호
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• pp.207-213
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• 1996

옥수수빵(CON)과 그 구성 성분중 옥수수 전분을 Amylomaize Vll starch로 대체한 제품(AMZ)을 제조하였다 또한 AMZ의 구성 성분중 지방의 일부를 RS 로 대체한 제품(지방의 15%대체시 RSl5, 30%대체 RS30)을 제조하여 총 네 가지 제품에 있어서 품질 특성을 살펴본 결과는 다음과 같다. 1. Sievert and Pomeranz의 방법에 따라 열처리-냉각 과정을 3번 반복하여 제조한 시료에서 분리된 RS의 수율은 28.96%였다. 2.옥수수빵의 텍스쳐 특성 표현어를 Szczesniak의 방법에 따라 분류한 결과 가장 많이 언급된 항목은 시료의 수분 함량에 관련된 촉촉하다였으며 깨짐성 및 검성에 관련된 표현어로서 푸석푸석하다, 부슬부슬하다 및 입자 크기와 관련된 용어로서 부드럽다, 꺼끌꺼 끌하다, 모래같다 등이었다 3. 관능검사 결과 기공의 크기는 지방을 RS로 대체 한 경우 유의적으로 증가하였고 CON에 비해 AMZ, RSl5및 RS30의 견고성이 유의적으로 증가하고 탄성은 유의적으로 감소되는 것을 알 수 있었다. 4. Texture analyser를 이용하여 deformation 30％로 기계적 texture를 관찰한 결과 견고성은 시간이 경과함에 따라 유의적으로 차이가 없거나 증가하는 경향을 보였으며 응집성은 변화가 없거나 감소하였고 탄성은 CON이 AMZ, RSl5 및 RS3O과 비교하여 항상유의적으로 높은 값을 보여 관능검사 결과와 일치하였다. 5. 50% 변형시킨 경우에도 30% 변형시킨 경우와 비슷한 경향을 보였으며 특히 지방의 30%를 RS로 치환했을 경우 물성에 유의적인 변화를 가져온다는 것을 알 수 있었다.

• 한국식품조리과학회지
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• 제12권2호
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• pp.193-199
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• 1996

첨가물질이 무처리 그리고 탈지옥수수와 녹두전분겔의 텍스쳐 특성에 미치는 영향을 알아 보기 위하여 실온에서 24시간과 72시간 저장하면서 관능적 기계적 특성을 조사하였다. 슈크로오스 지방산 에스테르, 셀룰로오스 유도체와 식용유를 전분량에 대해 0.5%첨가한 전분겔의 종합적인 맛은 24시간 저장한 전분겔의 경우에 응집성, 휘어짐성에서 높은 정의 상관관계를 보였고 72시간 저장한 전분겔에서는 탄성 , 응집성 ,색깔, 부드러움성 , 휘어짐성 , 견고성 , 투명도에서 정의상관관계를 보였다. 첨가물질의 유무에 관계없이 탈지에 의한 옥수수전분 겔의 물성적 특성이 크게 증가되었으며 첨가물질의 물성적 특성에 대한 영향은 모든 전분겔에서 낮게 나타났다. 종합적인 맛은 첨가물질을 넣은 전분겔이 다소 낮았고 24시간 저장한 전분겔은 응집성에서 72시간 저장한 전분겔은 탄성에서 가장 높은 상관관계를 보였다. 기계적 검사에 의한 텍스쳐 특성치도 관능검사 결과와 비슷한 경향을 보여 첨가물질의 종류에 따른 유의적인 차이는 보이지 않았다.

• Food Science and Biotechnology
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• 제17권2호
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• pp.234-240
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• 2008

The optimal conditions for the production of branched dextrin from com starch (CSBD) using branching enzyme (BE) were established by investigating the degree of retrogradation of the gelatinized starch. The physicochemical properties of CSBD prepared using the established process were evaluated. It was found that physicochemical properties of com starch were greatly modified by BE treatment. CSBD had a higher dextrose-equivalent value and water solubility than the corresponding control. On the other hand, the viscosities in gelatinized solution and amylose contents of CSBD were lower than those of the control. A high-performance size-exclusion chromatography/multiangle laser light scattering/retractive index (HPSEC/MALLS/RI) system showed that the average molecular weight of CSBD was lower than that of the control. The pasting viscosities of CSBD were stable during the entire temperature cycle. In general, the BE treatment resulted in the retrogradation during storage being lower for CSBD than for the control.

• Food Science and Biotechnology
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• 제17권4호
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• pp.755-760
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• 2008

The aim of this study was to produce resistant starch preparations from acid-modified com starches prepared at various hydrolysis levels (0.5-4.0 hr). Effect of autoclaving cycles on resistant starch (RS) formation was investigated. Molecular weight distribution, pasting and functional properties of acid-modified com starches were determined. For RS formation native and acid-modified starch samples were gelatinized and autoclaved (1 or 2 cycles). While native and acid-modified starches did not contain any RS, the levels increased to 9.0-13.5% as a result of storage at $95^{\circ}C$ after first autoclaving cycle. Second autoclaving cycle together with storage at $95^{\circ}C$ brought final RS contents of the samples incubated at 4 and $95^{\circ}C$ after the first cycle to comparable level. As acid modification level increased, the amount of high molecular weight fractions decreased, resulting in significant decreases in viscosities (p<0.05). The samples produced in this study had low emulsion stability and capacity values.

• 한국환경과학회지
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• 제13권9호
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• pp.827-833
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• 2004

The biodegradability of vinyl acetate acrylate resin and com starch blend was studied by determination of the reduced sugars produced after enzymatic hydrolysis. The starch hydrolysis reaction by $\alpha-amylase$ was achieved within 5 minutes. Optimal ranges of temperature and pH for the starch hydrolysis by $\alpha-amylase$ were around $80^{\circ}C$ and 6.5-7.2, respectively. The biodegradability of the starch-filled acrylate films increased as the content of starch increased. The biodegradation of starch in the starch-filled acrylate film by $\alpha-amylase$ was about 48.6% of that of pure starch. This value of biodegradable starch-filled acrylate film gave a good result with enzymatic shortcut test. The surface morphologies of the starch-filled acrylate film after enzymatic hydrolysis were investigated by scanning electron microscopy (SEM).