• KSBB Journal
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• v.23 no.3
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• pp.276-280
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• 2008

In this study, the productivity of bioethanol obtained from various domestic raw materials (barley, brown rice, corn and sweet potato) by simultaneous saccharification and fermentation (SSF) process was estimated. Also, optimal conditions of temperature, time and enzyme concentration in gelatinization and liquefaction process were investigated. As a result, corn showed high ethanol yield of 90.45% and sweet potato had a rapid fermentation time. Productivity of bioethanol increases in accordance with the starch value of raw materials except brown rice. Therefore, it is very important to understand the structure of starch. Further studieson the characteristics of raw materials are necessary to enhance the productivity of bioethanol.

• Korean Journal of Food Science and Technology
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• v.37 no.3
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• pp.438-442
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• 2005

Granule swelling is essential phenomenon of starch gelatinization in excess water, and characteristic of heated starch dispersion depends largely on size and distribution of swelled starch granule. Although swelling characteristic of starch granules depends on type of starch, heating rate, and moisture content, influence of heating rate on swelling phenomenon of starch granule has not been fully discussed, because constant heating rate of starch dispersion cannot be obtained by conventional heating method. Ohmic heating, electric-resistant heat generation method, applies alternative current to food materials, through which heating rate can be easily controlled precisely and conveniently at wide range of constant heating rates. Starch dispersion heated at low heating rates below $7.5^{\circ}C/min$ showed Newtonian fluid behavior, whereas showed pseudoplastic behavior at heating rates above $16.4^{\circ}C/min$. Apparent viscosity of starch dispersion increased linearly with increasing heating rate, and yield stress was dramatically increased at heating rates above $16.4^{\circ}C/min$. Average diameter of corn starch granules during ohmic heating was dramatically increased from $30.97\;to\;37.88\;{\mu}m$ by increasing heating rate from $0.6\;to\;16.4^{\circ}C/min$ (raw corn starch: $13.7\;{\mu}m$). Hardness of starch gel prepared with 15% corn starch dispersion after heating to $90^{\circ}C$ at different heating rates decreased gradually with increasing heating rate, then showed nearly constant value from $9.4\;to\;23.2^{\circ}C/min$. Hardness increased with increase of heating rate higher than $23.2^{\circ}C/min$.

• Food Science and Preservation
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• v.9 no.2
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• pp.179-183
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• 2002

This study was carried out to set up alcohol fermentation condition for uncooked corn. Response surface methodology(RSM) was applied to optimize and monitor the alcohol fermentation condition with uncooked corn. The optimal yeast strain for fermentation of uncooked corn was Saccharomyces cerevisiae GRJ. The polynomial equation for alcohol contents, brix, pH and total acidity showed 0.8852, 0.9202, 0.8806 and 0.9940 of R$^2$, respectively. The optimal rendition for maximum alcohol contents were 0.18%(w/w) of enzyme concentration and 180%(v/w) of added water content. Predicted values at optimum alcohol fermentation condition agreed with experimental value.

• Korean Journal of Food Science and Technology
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• v.22 no.6
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• pp.651-658
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• 1990

Starch phosphates were prepared by dry heating, gelatinizing method and extrusion process using sodium tripolyphosphote (STPP) as a substitution reagent and their physicochemical properities were compared. In the preparation of starch phosphate by dry heating method(DSP), the effect of reaction temperature was the most significant to the DS(Degree of substitution). In the phosphorylation reaction with gelatinized starch(GSP), the substitution ratio was increased with increasing the reaction temperature, but the increase was insignificant above $85^{\circ}C$. By extrusion with the corn starch containing 2.0% STPP at various moisture contents of 20, 25 and 30%, the DS values of extrudate(WESP) were within the range of between 0.0066 and 0.0083. The starch phosphate(DSP) products showed lowering the gelatinization temperature, increasing the clarity of the starch paste. However, WESP showed higher gelatinization temperature than that of raw starch. The starch phosphate prepared by extrusion process showed lower apparent viscosity of paste than that of the DSP at same condition. All of starch phosphates showed reducing the tendency of the paste retrogradation.

• Microbiology and Biotechnology Letters
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• v.18 no.3
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• pp.244-250
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• 1990

A bacterium capable of hydrotyzing raw starch was isolated from soil, which was identified as a strain of Bacillue. The effects of culture conditions and medium compositions on the enzyme production were investigated. Among tested carbon sources, soluble starch and wheat starch were most effective for the production of the enzyme, and the level of concentration for the optimal enzyme production was 0.5%. For nitrogen sources, polypeptone was best for the enzyme production, with the level of 0.5%. The enzyme was maximally produced by cultivating the organism at medium of initial pH 6.5, and temperature of $35^{\circ}C$. The enzyme was partially purified by Sepharose CL-6B gel filtration and DEAESephacel ion-exchange chromatography. The optimal pH and temperature for the enzyme reaction were 6.5 and $70^{\circ}C$, respectively. The enzyme most stable at pH 8.0, and temperature up to $60^{\circ}C$. In kinetic studies, the k, values for corn, wheat, rice and potato starch were 1.7, 1.4,2.5 and 1.090, respectively.

• Plant Breeding and Biotechnology
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• v.6 no.4
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• pp.337-353
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• 2018

We used Illumina/HiSeq sequencing for analysis of gene expression profiling among four maize seed types (dent, CM3 and CM6; waxy, CM5 and CM19) at 10 DAP (days after pollination). A total of 88,993,000 (CM3), 103,817,340 (CM6), 103,139,640 (CM5), and 66,978,958 (CM19) sequence reads were generated with read lengths of about 0.9, 1.0, 1.0, and 0.7 billion bp, respectively. We obtained 69.1 (CM3), 71.0 (CM6), 71.2 (CM5), and 71.8% (CM19) high quality reads from the raw data and compared them with reference RNA sequences in a public DB (NCBI). It was revealed that mapped reads were 58%, 63%, 62%, and 62% of the EST reference in CM3, CM6, CM5 and CM19, respectively; and more than 51,000 genes were expressed based on RPKM criteria (over 0.25 value) in each CM3, CM6, CM5, and CM19 inbred line. In differentially expressed gene (DEG) analysis, we found that 3,527 genes were differentially expressed by at least two-fold with 1,709 upregulated in the two waxy inbred lines and 1,818 upregulated in the two dent inbred lines. We also detected genes for the sucrose and starch biosynthesis pathways based on BINs, and different expression patterns between waxy and dent inbred lines were shown for the gene set for starch synthesis, such as sh2, bt2, du1, wx1, and ae1. Although some genes were more expressed in dent lines, most genes for starch synthesis were much expressed in waxy lines. Especially, there was greater expression of the sus2 gene in both waxy lines compared with the dent lines.

• Applied Biological Chemistry
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• v.38 no.4
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• pp.353-358
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• 1995

The influence of dry-heat treatment($130{\sim}220^{\circ}C$) on the gelatinization and rheological properties of corn starch(11.4% moisture) was examined. The enthalpy of gelatinization measured by differential scanning calorimetry decreased above $190^{\circ}C$. The viscosity of starch by alkali gelatinization increased as the heating temperature rised. All the values including peak viscosity on amylograms and shear stress, apparent viscosity, consistency index and yield stress of thermal-gelatinized starch dispersion showed decreasing tendencies with increasing of heating temperature from above $170^{\circ}C$ compared with those of raw starch. The apparent viscosity and yield stress of all the samples thermal-gelatinized at $90^{\circ}C$ were increased considerably with process of gelatinization time and especially their rapid increase at the early stage was observed in the $190^{\circ}C$ sample. But all the rheological parameters of $220^{\circ}C$ sample recorded very low values compared with those of the others.

• Microbiology and Biotechnology Letters
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• v.18 no.3
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• pp.251-259
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• 1990

Asp. usumii IAM 2185 was selected as a strain producing the powerful raw starch digesting glucoamylase. The optimum initial pH, the optimum temperature and the optimum cultural time for the enzyme production on wheat bran medium were pH 6-8,25-$30^{\circ}C$ and 72 hrs, respectively. The addition of ammonium nitrate and albumin on wheat bran medium, respectively, increase slightly the enzyme production. The enzyme was purified by ammonium sulfate fractionation, CM-cellulose and DEAE-cellulose column chromatography. The specific activity of the purified enzyme was 34.3 U/mg protein and the yield of enzyme activity was 10.3%. The purified enzyme showed a single band on polyacrylamide disc gel electrophoresis and its molecular weight was estimated to be 67,000 by SDS polyacrylamide disc gel electrophoresis. The isoelectric point for the purified enzyme was pR 3.7. The optimum temperature and optimum pH were $60^{\circ}C$and pH 3.0 and the purified enzyme was stable in the pH range of 1.0-11.0. The purified enzyme was stable below $50^{\circ}C$ and its thermostability was greatly increased by the addition of $Ca^{2+}$. The purified enzyme showed a high hydrolysis rate on various raw starches such as corn, rice, yam, arrow root, sweet potato and glutinous rice.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.8
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• pp.1290-1295
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• 2013

The aim of this study was to evaluate the quality characteristics of bread supplemented with extruded corn fiber. The extrusion was conducted as the moisture content of the corn fiber reached 30% and 40% (at $140^{\circ}C$ and 200 rpm). The bread baked with 5% extruded corn fiber at a 40% feed moisture exhibited the highest specific volume. The hardness of the bread supplemented with 10% corn fiber was the highest during storage compared to bread supplemented with extruded corn fiber and the control (100% wheat flour). However, the hardness of bread with corn fiber or extruded corn fiber (5%) was lower than the control. In the sensory evaluation, preferences decreased with the increased addition of untreated and extruded corn fiber. Quality characteristics, such as specific volume and texture, of bread baked with extruded corn fiber were better than bread baked with corn fiber. This improvement in quality is likely due to modification of corn fibers and starch gelatinization from the extrusion process. Supplement of extruded corn fiber had the potential for bread making compared to raw corn fiber.

• Microbiology and Biotechnology Letters
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• v.13 no.4
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• pp.329-337
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• 1985

A potent mold strain was selected to digest raw starch, which was classified as a strain of Rhizopus of zoe. Its amylase production was maximized when grown on wheatbran media for 3 days at 3$0^{\circ}C$ and initial pH 4. The crude enzyme was tested for ethanol fermentation by yeast, Saccharomyces cerevisiae IFO 7026, on various starchymaterials and the ethanol production after 4 days was: 9.4％ from rice powder, 9％ from corn powder, 8.1％ from sweet potato powder, and 5.4％ from potato powder, respectively.