• KOREAN JOURNAL OF CROP SCIENCE
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• v.60 no.3
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• pp.308-317
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• 2015

The aim of the present study was to investigate the ear and kernel characteristics of colored waxy corn hybrids during ripening according to different sowing dates. Heukjinjuchal and Eolrukchal 1 were sown at April 20 (first cropping) and July 20 (second cropping) in 2011~2012. The accumulated temperature from silking to harvesting was about $590{\sim}610^{\circ}C$. It takes 23~24 days when Heukjinjuchal and Eolrukchal 1 were sown in April 20, but July 20 sowing takes 32~35 days. Ear weight, ear diameter, 100-kernel weight and starch content of colored waxy corn were increased as ears matured (p<0.05). Growth temperature was getting decreased during the ripening stage of second cropping, the rate of ear and kernel development had slowed. Starch granules started to accumulate in the cells around the pericarp, then developed in the cells around the embryo. In the second cropping, starch granules in the kernel of colored waxy corn were less compact than the first cropping. The contents of total anthocyanins, cyanidin-3-glucoside and pelargonidin-3-glucoside were increased according to ripening (p<0.05). These results will be helpful to farmers for double cropping of colored waxy corn cultivation and management.

• Korean Journal of Food Science and Technology
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• v.37 no.1
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• pp.44-49
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• 2005

Physicochemical properties of hydroxypropylated rice starches were investigated. Swelling power of hydroxypropylated rice starch increased at relatively lower temperature than native rice starch. Solubility of hydroxypropylated rice starch was lower (1.9-13.4%) than that of native rice starch (2.2-13.8%), and increased with increasing amount of propylene oxide. Pasting temperature ($66.2-70.8^{\circ}C$) and peak viscosity (2,843-3,395cp) of hydroxypropylated rice starch were lower than those of native starch ($71.6^{\circ}C,\;3,976\;cp$) and decreased with increasing amount of propylene oxide, regardless of reaction time. DSC thermal transitions of hydroxypropylated rice starches shifted toward lower temperature. Amylopectin-melting enthalpy of hydroxypropylated rice starch decreased (11.8-9.8J/g) with increasing amount of propylene oxide and was lower than that of native starch (11.9 J/g). These results indicate hydroxypropylation lowered swelling power and gelatinization temperatures of rice starch, because internal bonds of rice starch molecules were sterically weaken by substituted hydroxypropyl groups.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.5
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• pp.569-577
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• 1996

This experiment was conducted to investigate the effects of water potential by PEG treatment on germination and quantitative changes of seed storage reserves of soybean [Glycine max (L.) Merr.], peanut(Arachjs hypogaea L.) and corn(Zea may L.). Water potential of PEG(M.W. 10, 000) solution as germination media was 0.0, -0.2, and -0.5MPa. The highest moisture uptake rate was found in soybean seedlings among three crops. Moisture content of seedlings of three crops was decreased at -0.5MPa treatment and seedling length was delayed with water potential decrement. As water potential decreased, decreasing rate of protein content of the seedlings compared to seeds was declined in soybean and peanut. Decreasing rate of starch content of the seedlings was decreased in corn at -0.5MPa treatment. Increasing rate of sugar content of the seedlings was markedly decreased at -0.5MPa treatment in all crops. The results of this experiment showed that availability of moisture and synthesis of sugar for seed germination were influenced below -0.5MPa water potential in three crops.

• Korean Journal of Food Science and Technology
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• v.22 no.6
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• pp.659-667
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• 1990

Starch acetates were prepared by conventional method, preheat treatment, and extrusion process through acetylation of corn starch with acetic anhydride and their physicochemical properties were investigated. The optimal conditions of the acetylation of starch by conventional method(CSA) was found that starch concentration was 30%, reaction temperature $35^{\circ}C$ and pH 8.5. With increasing the molar ratio of acetic anhydride to anhydrous glucose unit from 0.03 to 0.20, DS(Degree of substitution) value of corn starch acetate prepared at the optimum condition was increased from 0.019 to 0.080, while the acetylation efficiency was decreased from 31.6% to 20.5%. In the case of the preheated (gelatinized), then acetylated starch(PSA), DS value was increased from 0.027 to 0.04 at the fixed molar ratio of the acetic anhydride with increasing preheating temperature from $60^{\circ}C\;to\;90^{\circ}C$. The DS was low as 0.02 in the case of starch acetate prepared by extrusion process(WESA). The CSA and PSA showed lowering gelatinization temperature and enthalpy than raw corn starch with increasing DS. All of starch acetates showed the increased degree of transparency, the decreased lightness and the increased yellowness as compared to the raw corn starch. WESA showed lower apparent viscosity and more close to the characteristic of the Newtonian fluid than CSA and PSA. Intrinsic viscosity was reduced in CSA and WESA, although PSA has a slightly higher one than raw corn starch. The rate of retrogradation of the gels was retarded in all starch acetates.

• Korean Journal of Food Science and Technology
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• v.27 no.4
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• pp.625-630
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• 1995

In order to know the effects of hot-water extracts of starches on gel formation and gel properties, some physicochemical properties and molecular distribution of the extracts were measured. Also, after acid-hydrolysis of starch gels and extract gels, extent of hydrolysis and $\overline{D.P}._n$, and molecular distribution of hydrolysis-residue were measured. Extraction ratio of grain starches (buckwheat, corn, rice, and wheat) were $4.0{\sim}6.6%$. The ratio of acorn and mungbean starches were 11.7 and 13.5%, respectively. Iodine affinity of the extracts was $17.2{\sim}17.7%$ in starches using for Mook, SM(acorn, buckwheat, and mungbean), $13.7{\sim}14.9%$ in starches not using for Mook, SNM(corn, rice, and wheat). Blue value was also higher in SM than in SNM. $\overline{D.P}._n$. of extracts of SM were bigger than those of SNM. In molecular distribution experiment, amylopectin fraction was not found from the extracts except rice starch extract. The extent of acid hydrolysis of the starch gels were $70{\sim}84%$ after 60 days, and the extent of the extract gels were $22{\sim}35%$. The extent of hydrolysis of starch gels and extract gels made with SM were lower than those of SNM.

• Journal of the Korean Society of Food Science and Nutrition
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• v.17 no.2
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• pp.144-148
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• 1988

Differential scanning calorimerty(DSC) was used to study gelatinization phenomena of defatted rice, corn, wheat, potato starch and nondefatted rice and wheat starch at heating rate $5{\sim}15^{\circ}C/min$. Gelatinization temperature of defatted rice and wheat starch indicated $4{\sim}5^{\circ}C$ lower temperature than nondefatted starch. More rapid heating rate resulted in a increasing of the gelatinization enthalpy for various starches. A linear relation was observed between water content, heating rate and gelatinization temperature. From the linear relationship existing between water content and gelatinization enthalpy, minimum water content for the gelatinization were 41, 38, 33 and 30% of rice, potato, wheat and corn starch, respectively.

• Korean Chemical Engineering Research
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• v.46 no.1
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• pp.106-111
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• 2008

Polypropylene (PP)/corn starch master batch (starch-MB)/silicate composites with different corn starch compositions of 10, 20, 30, 40 and 50 were prepared by melt compounding at $200^{\circ}C$, using lab scale Brabender mixer. The content of silicate was fixed at 5 wt%. The composition of starch-MB in composites was confirmed by the existence of hydroxy group and peak intensity in fourier-transform-infrared (FT-IR) spectrum. The thermal properties of the PP/starch-MB/silicate composites were investigated by differential scanning calorimetry (DSC), and thermogravimetric analyzer (TGA). There was no district change in melting temperature, and TGA curve indicates a decrease in degradation temperature with the increase of starch-MB content. The silicate dispersion of the composites was measured by X-ray diffraction (XRD) and transmission electron microscope (TEM). The degree of silicate dispersion in PP/starch-MB/silicate composites depended on the content of starch-MB. There was detectable change in d-spacing and peak intensity of the composite when the content of starch-MB was higher than 20 wt%. The rheological behavior of the composites was explained by both shear thinning effect and elastic property with the starch-MB amount. These effects were remarkable when the content of starch-MB was higher than 20 wt%. These were confirmed by an oscillatory viscometer at $200^{\circ}C$.

• Applied Biological Chemistry
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• v.19 no.4
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• pp.219-226
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• 1976

To meet the need of protein feed and fine more efficient ways of returning waste to resources, we have carried out the study of the production of yeast for foods and feeds from the corn starch cake. The present study includes the method for acid-hydrolysis, the selection of yeast capable of utilizing hydrolyzate of the corn starch cake, and culture condition of Candida tropicalis under the liquid culture and the semisolid culture. Obtained results were as follows. 1. Hydrochloric acid was more excellent on the hydrolysis of the corn starch cake than sulfuric acid, and the yield of sugar was maximum, 57.2%, when the corn starch cake was hydrolyzed with 1.0% of hydrochloric acid at 2.0kg/cm for 30 minutes. 2. As the acid solution content was increased, more sugar was liberatedfrom the mixture, until the acid solution-substrate ratio reached 10:1. Beyond this point, no further increase was observed. To prepare the cultural medium of semisolid fermentation, a acid solution to substrate ratio of 3:1 appeared to be optimum. 3. Out of 6 yeast strains, Candida tropicalis had excellent growth on the hydrolyzate of the corn starch cake, and optimum temperature and initial pH were $30^{\circ}C$ and 6.0 respectively. 4. Optimum liquid medium of Candida tropicalis is ures 0.3%, potassium phosphate monobasic 0.15g and magnesium sulfate 0.04g in 100ml of the hydrolyzate of the corn starch cake, while optimum semisolid medium is ammonium chloride 0.4g, potassium phosphate monobasic 0.1%, magnesium sulfate 0.04%. 5. Candida tropicalis could assimilate the sugar in the hydrolyzate up to more than 88.75%, and a yield of dry yeast reached 19.13% to the corn starch cake under the liquid culture. 6. Compared to the that of the untreated corn starch cake, the cellulose content of the semisolid fermented cake decreased by 3.76% to 14.7%, whereas dry yeast contents increased by 13.89%.

• The Safety technology
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• no.189
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• pp.19-21
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• 2013

우리네 현대 생활에서 벽지가 주는 의미는 남다르다. 집안 들어섰을 때 첫 인상을 심어주는 것이 바로 벽지라는 것을 떠올리면 쉽게 이해가 갈 것이다. 이와 관련해 업계의 주목을 받고 있는 기업이 오늘의 주인공인 (주)서울벽지다. 1968년 창립된 이곳은 현재까지 벽지 소재 개발은 물론 디자인과 품질 향상 등에 꾸준히 노력해온 것으로 명성이 자자하다. 실제로 현재 (주)서울벽지는 국내에서 벽지산업을 이끌어 온 굴지의 벽지 전문회사다. 이곳이 단순히 벽지 생산에만 주력해 왔다고 생각하면 큰 오산이다. (주)서울벽지는 지난 2001년 업계 최초로 KS마크를 획득한 것을 시작으로 2007년에는 7년간의 연구개발 끝에 옥수수 전분을 활용한 '옥수수 벽지'를 국내 최초로 출시했다. 이 벽지는 LH공사 등 공기업에서 친환경 벽지로 인정받으면서 (주)서울벽지의 기술력을 널리 알렸다. 여기에 더해 이곳은 2008년부터는 디자인연구소를 설립해 신성장 동력을 발굴하고 있기도 하다. 실로 벽지업계를 선도하는 기업이라고 할 수 있다. (주)서울벽지 관계자들은 이처럼 회사가 끊임없이 성장 발전할 수 있었던 원동력을 빈틈없는 안전관리에서 찾고 있다. 감성안전을 필두로 하는 이곳의 자율안전관리가 어떻게 전개되고 있는지 찾아가 봤다.

• Journal of Nutrition and Health
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• v.42 no.8
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• pp.740-749
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• 2009

The objectives of this study was to determine whether a new physically modified cornstarch by ultra-fine- or nanoscale pulverizer to reduce particle size offers better bioactive function than native cornstarch in weanling Sprague-Dawley rats. Male weaning Sprague-Dawley rats were fed diets containing native cornstarch (NAC), ultra fine pulverized cornstarch (UFC) or nano-scale pulverized cornstarch (NSC) for 4 weeks. In vitro rate of starch hydrolysis, growth performance, organ weight, intestine length intestinal proliferation and the fermentation by Bifidobacterium of rat cecum were evaluated. The diet with reduced particle size (UFC or NSC) significantly increased body weight gain and organ weight. Feed efficiency was increased in NSC fed rats and was not affected in UFC fed rats. Intestinal proliferation was decreased in NSC group. Reduction of particle size also increased cecal short chain fatty acid concentration and the growth and acidifying activity of Bifidobacterium. It is concluded that a reduction of particle size of starch granules by physically modification may increase growing performance and gut function.