• Journal of Environmental Science International
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• v.13 no.12
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• pp.1131-1138
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• 2004

The starch-filled waterborne acrylate (SWAC) films were prepared. The structures and properties of SWAC films were investigated by infrared spectroscopy, thermogravimetric analysis, and strength test. The biode­gradability of SWAC film was also studied by determination of reduced sugar products after enzymatic hydrolysis. The surface morphology of the SWAC film was investigated by scanning electron microscopy (SEM). The results showed that the tensile strength and elongation of SWAC film decreased with the increase of starch content. The SWAC film showed significantly higher water absorbed content than waterbonre acrylate film. The biodegradability of SWAC film increased as the content of starch increased. The biodegradation of starch in SWAC film by ${\alpha}-amylase\;was\;about\;77{\%}$ of that of pure starch.

• The Korean Journal of Food And Nutrition
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• v.13 no.4
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• pp.342-347
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• 2000

The stabilization of barley $\beta$-amylase(Biozyme ML, Amano) was attained by modification with periodate-oxidized soluble starch. The specific activities of modified enzyme at pH 9.7 and pH 8.0 were 42% and 92%, respectively, compared with that of native enzyme. The pH stability of modified enzyme was increased at pH 2~5 and 7~12 in the presence of $\alpha$-cyclodextrin( $\alpha$ -CD) compared wish that of native enzyme. Thermal stability of the modified enzyme was increased. After treatment at 6$0^{\circ}C$ for 10min. the activity remained 8% for the enzyme modified at pH 8.0 in the presence of $\alpha$-CD, 4.5% for the native enzyme. The native enzyme and modified enzyme showed two peak in HPLC. The molecular weight of the modified enzyme was slightly increased in HPLC analysis.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.5
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• pp.878-885
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• 1997

Effect of various ingredients and cooling methods on the quality of modified Jeung-pyun(traditional Korean steamed rice cake) were studied. Three different kinds of wheat flours(strong, medium, and weak) were studied to evaluate the volume and firmness of Jeung-pyun. Weak flour showed the maximum volume and good sensory results. The optimum ratio of ingredients was flour : water ; sugar ; Tak-Ju=100 : 20 : 20 : 50 for steaned Jeung-pyun. When three different cooking methods were compared, the maximum volume showed from convection oven method, but the crust color of Jeung-pyun was like bread. Steaming method showed higher volume than that of product heated by microwave method. The optimum formula ratio for the microwave method was flour ; water ; sugar ; Tak-Ju = 100 : 30 : 20 : 50, which required 10% higher added water content than that of steaming. When wheat flour was used instead of rice flour, the addition of 5% normal corn starch increased volume of both steamed and microwave cooked products. In the case of added modified starches to Jeung-pyn, 5% $\alpha$-waxy corn starch showed the highest volume in steaming method. When rice flour was used, the addition of 5%$\alpha$-waxy corn starch also showed highest volume f both steamed and microwave cooked products. The firmness of steamed wheat flour Jeung-pyun, containing 5%$\alpha$-corn starch was higher firmness than that of control and other added samples. Microwave cooked products showed two or three times higher firmness of steaming products. The use of wrap(uni-wrap) and stabilizer(METHOCEL) decreased the firmness of microwave cooked wheat flour Jeung-pyun to 200~300g compared with that of untreated Jeung-pyun.

• Food Science and Biotechnology
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• v.18 no.2
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• pp.570-573
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• 2009

The debranching enzyme of Nostoc punctiforme (NPDE) is a novel enzyme that catalyzes the hydrolysis of $\alpha$-1,6-glycosidic linkages in starch, followed by the sequential hydrolysis of $\alpha$-1,4-glycosidic linkages. The debranching activity of NPDE is highly specific for branched chains with a degree of polymerization (DP)>8. Moreover, the rate of hydrolysis of $\alpha$-1,4-linkages by NPDE is greatly enhanced for maltooligosaccharides (MOs) with a DP>8. An analysis of reaction mixtures containing various starches revealed the accumulation of maltooctaose (G8) with glucose and maltose. Based on the novel enzymatic properties of NPDE, an MO mixture containing more than 60% G8 with yield of 18 g G8 for 100 g starch was prepared by the reaction of NPDE with soluble starch, followed by ethanol precipitation and gel permeation chromatography (GPC). The yield of the G8-rich mixture was significantly improved by the addition of isoamylase. In summary, a 4-step process for the production of a G8-rich mixture was developed involving the enzymatic hydrolysis of starch by NPDE.

• BMB Reports
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• v.37 no.4
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• pp.429-438
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• 2004

Complementary DNAs encoding $\alpha$-amylases (Amyl I, Amyl III) and glucoamylase (GA I) were cloned from Aspergillus awamori KT-11 and their nucleotide sequences were determined. The sequence of Amyl III that was a raw starch digesting $\alpha$-amylase was found to consist of a 1,902 bp open reading frame encoding 634 amino acids. The signal peptide of the enzyme was composed of 21 amino acids. On the other hand, the sequence of Amyl I, which cannot act on raw starch, consisted of a 1,500 bp ORF encoding 499 amino acids. The signal peptide of the enzyme was composed of 21 amino acids. The sequence of GA I consisted of a 1,920 bp ORF that encoded 639 amino acids. The signal peptide was composed of 24 amino acids. The amino acid sequence of Amyl III from the N-terminus to the amino acid number 499 showed 63.3% homology with Amyl I. However, the amino acid sequence from the amino acid number 501 to C-terminus, including the raw-starch-affinity site and the TS region rich in threonine and serine, showed 66.9% homology with GA I.

• Applied Biological Chemistry
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• v.27 no.2
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• pp.107-111
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• 1984

Changes of starch, soluble sugar and activities of amylase in germinating maize seeds were studied with comparison of germinating barley seeds. The starch in the endosperm was degraded slowly during the course of germination, and starch degradation of maize seeds compared with barley seed was found after 2 or 4 days of seed germination. There was a transient decline of soluble sugar come-its in ungerminated seed at early stages, followed by the rapid increase which concided with the degradation of starch. Activities of amylases were increased with the progress of germination, and maximum activities were founded after 8 days of seed germination. The higher activities of ${\alpha}$- and ${\beta}$-amylase were found at Hwang-ok maize and barley, respectively.

• BMB Reports
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• v.35 no.6
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• pp.568-575
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• 2002

An $\alpha$-amylase (EC 3.2.1.1) was purified that catalyses the production of a high level of maltose from starch without the attendant production of glucose. The enzyme was produced extracellularly by thermophilic Streptomyces sp. that was isolated from Thailand's soil. Purification was achieved by alcohol precipiation, DEAE-Cellulose, and Gel filtration chromatographies. The purified enzyme exhibited maximum activity at pH 6-7 and $60^{\circ}C$. It had a relative molecular mass of 45 kDa, as determined by SDS-PAGE. The hydrolysis products from starch had $\alpha$-anomeric forms, as determined by $^1H$-NMR. This maltose-forming $\alpha$-amylase completely hydrolyzed the soluble starch to produce a high level of maltose, representing up to 90%. It hydrolyzed maltotetrose and maltotriose to primarily produce maltose (82% and 62%, repectively) without the attendant production of glucose. The high maltose level as a final end-product from starch and maltooligosaccharides, and the unique action pattern of this enzyme, indicate an unusual maltose-forming system. After the addition of the enzyme in the bread-baking process, the bread's volume increased and kept its softness longer than when the bread had no enzyme.

• Journal of the Korean Professional Engineers Association
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• v.17 no.1
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• pp.27-35
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• 1984

When starch is hydrolyzed either by acid or by the enzymes maltase or diastase, contained in germinating barley, a yield of 80% of maltose is obtained. Maltose is built of two molecules of ${\alpha}$-glucose, bound in the position 1:4 i.e., carbon atom 1 of one glucose molecule is bound in a glucosidic bond to carbon atom 4 of the second molecule. Until around 1960, dextrose and glucose syrups were prepared from starch exclusively by acid hydrolysis. The process was corrosive, and the dextrose yield low. It was, therefore, a great step forward when pure glucoamylase in combination with bacterial ${\alpha}$-amylase made possible a complete enzymatic hydrolysis of starch to dextrose. Today several enzymatic processes are used in the industry.

• KSBB Journal
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• v.9 no.5
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• pp.499-505
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• 1994

Bacillus macerans cyclodextrin glucanotransferase(EC 2.4.1.19: 1, 4-${\alpha}$-D(1, 4-${\alpha}$-glucano)-transferase, CGTase) was purified by the technique of starch adsorption and DEAE-cellulose column chromatography. The molecular weight of the enzyme was 67,000, consisting of a subunit. The enzyme converted starch into ${\alpha}$-, ${\beta}$-, and ${\gamma}$-CD in the relative amounts of 1:1.68:0.32, respectively. In the early reaction period, maltohexose was formed mainly by the coupling reaction of ${\alpha}$-CD with D-glucose and then other oligosaccharides. Maltotetrose was formed mainly from ${\alpha}$-CD in the initial stage of hydrolysis of the enzyme and then small amount of other oligosaccharides. Maltotriose was a good substrate for the enzyme and maltosyl or D-glucopyranosyl group can be transfered from this sugar. In this work, D-glutosyl transfer was premiered.

• Korean Journal of Human Ecology
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• v.14 no.6
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• pp.1037-1046
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• 2005

Using three consecutive years' harvested rices and their starches isolated from rice flours by alkaline method, it was found that no significant aging effect on rice flour and starch was observed based on following results. Proximate data of flours or starches showed in similarity, except high level of crude fat in rice flour and rice starch harvested in 2002. In SEM, the surface of aged rice flour had slightly layered shape due to possible abrasion during storage, and that of aged starch showed more smooth and less rigid polygonal shape. X-ray diffraction patterns of flours and starches were all A type, and crystallinity of rice starch harvested in 2000 had the smallest. From tristimulus colorimetry (Hunterlab Color), total color difference ($\Delta$E) calculated from L, a, and b gave less color difference with the darkest in 2002 harvested one among flours and the lightest in 2001 one among starches. WBCs of both 2002 rice flour and starch were the lowest among samples studied. At 80$^{\circ}C$, swelling power and solubility of rice starches harvested in 2000, 2001 and 2002 were 14.35, 9.75; 14.04, 9.6; and 12.49, 8.82, respectively. The highest peak viscosities measured by RVA were shown both in 2001 rice flour and in its starch. Starch and milled rice flour harvested in 2000 had higher hydrolytic $\alpha$-amylase, compared to other flour and starch samples.