• Korean Journal of Food Science and Technology
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• v.27 no.4
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• pp.516-519
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• 1995

Seven Korean milled rice samples (5 Japonica, 1 Indica, 1 Commercial) were used to compare the quality of brewing adjunct with that of U.S. IR36(Indica) sample was classified as having higher amylose and protein content and lower starch content than Japonica samples. IR36 sample did not differ from Japonica samples in wort color, wort viscosity, soluble protein, percent extract and sugar composition when it was used as brewing adjunct. Korean milled rice samples did not differ from U.S. sample in soluble protein, wort pH, wort viscosity, but lower in percent extract.

• Korean Journal of Food Science and Technology
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• v.30 no.3
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• pp.502-508
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• 1998

The characteristics of hydration and hot-water solublilization of milled rice during cooking were investigated using Korean rice [3 varieties of Japonica type and 3 varieties of Tongil type (Japonica-Indica breeding type)]. The water uptake rate constants of Japonica type varieties during cooking were later than those of Tongil type varieties. The contents of solubles and soluble amylose among Japonica type varieties during cooking were similar, but those among Tongil type varieties were different. At the same cooking conditions, Japonica type varieties showed higher contents and leaching rate constants of solubles as well as soluble amylose than Tongil type varieties.

• Korean Journal of Food Science and Technology
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• v.24 no.2
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• pp.187-192
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• 1992

Some structural characteristics of Japonica and Tongil type rice starches and their fractions were investigated to elucidate the differences between the two rice types. Japonica rice starches showed broader gelatinization temperature ranges and had higher ${\lambda}_{max}$ than those of Tongil ones. Intrinsic viscosity of starch, amylose and amylopectin for Japonica type were lower compared with those of Tongil type. ${\beta}-amylolysis$ limit of rice starch were not different between two rice types, but those of amy_lose and amylopectin of Japonica ty_p_e were lower than Tongil type. The average unit chain length(${\overline}CL$) and average outer chain length(${\overlne}OCL$) of Japonica type amylopectin were shorter than those of Tongil one. Sepharose CL-2B chromatography of hot water soluble starch revealed that each starch had unique elution profile.

• Korean Journal of Agricultural Science
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• v.45 no.4
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• pp.779-787
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• 2018

The objective of this study was to investigate the structural and physicochemical properties of starch by barely cultivars. Hwanggeumchal had a moisture content and ${\beta}$-glucan content of 12.02 and 6.23%, respectively. Hyegang had higher protein contents than those of the other cultivars. As a result of observing the particle size of starch, Hwanggeumchal and Hyegang had smaller particles of starch compared with the other cultivars at 15.7 and $15.9{\mu}m$, respectively. The analysis results on the content of damaged starch showed that Dahan and Hyegang had a damaged starch content of 1.14 and 1.20%, whereas Boseokchal and Hwanggeumchal were 0.76 and 0.49% respectively, showing low waxy cultivars. As for the content of amylose, the results show that Dahan and Hyegang had an amylose content of 37.07 and 37.75%, and Boseokchal and Hwanggeumchal were at 11.22 and 37.75%, respectively. As for the degree of amylopectin polymerization, all four cultivars had the highest degree of polymerization (DP) content of 13 - 24 at more than 54%, whereas the DP content ${\geq}37$ was the lowest at less than 5.35%. The results for the soluble and resistant starch content show that the content of soluble starch ranged from 93.90 to 95.76%, and resistant starch was 0.17 - 0.40%. After analyzing the gelatinization properties of barley starch, the value of the setback was low in Hwanggeumchal and Hyegang; thus, it is considered that the aging process of those cultivars will be slower than that of the others.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.2
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• pp.189-195
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• 2002

Corn starch was modified by oxidation with sodium hypochlorite (NaOCl) as an attempt to expand the application of starches in food industry. Corn starch was oxidized with 0.25, 0.5, 0.75, 1.0 and 1.5% active Cl/g starch at pH 7.0 and $25^{\circ}C$ for 10 minutes. The size, shape and amylose content of oxidized starches were similar to those of native corn starch. As the extent of oxidation increased, solubility, swelling power and the amount of soluble amylose increased, X-ray diffraction patterns changed, and relative crystallinity decreased. In Brabender amylogram, oxidation did not chance the gelatinization temperature, but oxidized starches had a lower peak in viscosity and their cooled pastes gave less setback, compared with native corn starch.

• Applied Biological Chemistry
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• v.38 no.5
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• pp.403-407
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• 1995

For the use of starch gel like Mook(a Korean traditional gel food), the physicochemical properties and gelatinization patterns of defatted high amylose corn starch were investigated. The crude and total lipid contents of starch decreased by defatting from 0.07%, 0.92% to 0.03%, 0.19%, respectively. But iodine affinity increased from 51.6% to 71.3%. Water binding capacity of starches increased from 104.6% to 117.3% after defatting. Soluble carbohydrate and leached amylose of untreated and defatted starches were increased rapidly above $110^{\circ}C$. The apparent viscosity of starch dispersion using alkali solution increased above 0.3N NaOH solution but the transmittance increased above 0.4 N NaOH. The DSC thermograms of both starches showed broad and double endotherm with relatively low enthalpy, but the second peak of endotherm was larger in defatted starch than in untreated starch.

• Applied Biological Chemistry
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• v.38 no.6
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• pp.554-562
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• 1995

Effect of the modification of rice protein by protease and 2-mercaptoethanol on physicochemical and gelatinization properties was investigated for the three cultuvars of rice. Total amylose contents of Chucheongbyeo(japonica type), Chosengtongilbyeo(tongil type, indica x japonica) and IR 36 (indica type) were in the range of $20{\sim}25%$. Total amylose and insoluble amylose content of IR 36 were higher than the others. The differential scanning calorimetric and X-ray diffraction results revealed higher relative crystallinity of IR 36 than the others. Water uptake was increased and amylographic viscosity was significantly decreased by 2-mercaptoethanol treatment. Amylographic viscosity was significantly decreased and hot water-soluble carbohydrate content was increased by protease treatment. The proportions of high molecular weight of soluble carbohydrate fractionated by gel filtration chromatography were increased by protease treatment. These effects were most significant in IR 36. This results suggested that starch gelatinization be accelerated by alteration of the protein with protease and reducing agent.

• Korean journal of food and cookery science
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• v.16 no.5
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• pp.431-436
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• 2000

Gelatinization properties of potato starches which were prepared by steeping at 10 ${\pm}$ 1$^{\circ}C$ or 25 ${\pm}$ 1$^{\circ}C$ for 11 days were investigated. The pasting and initial gelatinization temperatures measured by rapid visco-analyzer (RVA) were increased, but the peak and trough viscosities of potato starch were decreased by steeping. The onset temperature, peak temperature, conclusion temperature, and enthalpy of gelatinization were increased by steeping as measured by DSC. The contents of hot-water-soluble carbohydrate and amylose in potato starch were decreased by steeping.

• The Korean Journal of Food And Nutrition
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• v.7 no.4
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• pp.259-266
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• 1994

The hyperthermophilic archaebacterium Thermococcus profundus Isolated from a deep-sea hydrothermal vent system, produced several amylolytic enzymes such as extracellular amylase and pullulanase, intracellular a-1,4-91ucosidase in respone to the presence of complex carbohydrates In the growth medium. This strain showed high activities on 0.5% maltose than on complex carbohydrates One of the amylases was partially purified by ammonium sulfate precipitation, DEAE-Toyopearl chromatography. The amylase exhibited maximal activity at pH 5.5 and 80$^{\circ}C$, and was stable in the range of pH 5.5 to 9.5 and up to 80$^{\circ}C$ for 30 min. The enzyme activity was no dependence on Ca2+ and not inhibited by detergents. The amylase hydrolyzed soluble starch, amylose, amylopectin and glycogen to produce maltose and maltotriose with trace amounts of glucose, but not pullulan and ${\alpha}$-, ${\beta}$-, ${\gamma}$-cyclodextrin. Malto-oligosaccharides ranging from maltotetraose to maltoheptaose were hydrolyzed in an endo fashion.

• Korean Journal of Food Science and Technology
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• v.30 no.1
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• pp.97-102
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• 1998

Arrowroot starches, harvested in March, June, September and December, indicated that the December starch had the lower values of amylose content, ${\beta}-amylolysis$ limit and intrinsic viscosity, but the highest value of water-binding capacity. The swelling power were similar among different starches. The gelatinization by KSCN revealed that the December starch was the most resistant to alkali gelatinization. Gelatinization temperature, determined by differential scanning calorimetry, of the December sample was shifted to higher temperture by $1^{\circ}C$ compared with the others. When the December starch was heated at $98^{\circ}C$ for 8min, 93.8% of total amylose and 7.2% of total amylopectin were solubilized, which was the highest and the lowest, respectively.