• Korean Journal of Food Science and Technology
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• v.23 no.1
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• pp.57-61
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• 1991

Rheological properties of Tongjinbyeo(Japonica) and Samgangbyeo($J{\times}Indica$) rice starches gelatinized with thermal or alkali solutions were investigated with rotational viscometer(Brabender Viscotron). The two starches showed Bingham pseudoplastics behavior in $4{\sim}8%$ thermal or alkali gelatinized starch solutions. Rheological properties of thermal gelatinized starch solutions were similar between the two varieties. However, alkali gelatinized Samgangbyeo starch solutions showed higher values of yield stress and consistency index than that of Tongjinbyeo starch. The values of pseudoplasticity, yield stress and consistency index were higher in the thermal gelatinized samples than those of in the alkali gelatinized ones.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.44 no.3
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• pp.277-281
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• 1999

Dull grains segregated from F$_3$ and F$_4$ of the crosses between two dull mutants and a glutinous cultivar were compared with non-glutinous and glutinous segregants for their physicochemical properties. Amylose content of dull rice grain segregated from the dull/glutinous cross showed the intermediate value between glutinous and non-glutinous rice grain, whether it is controlled by the recessive or dominant gene. Alkali digestibility value (ADV) of dull rice grain was lower than that of glutinous or non-glutinous rice. A positive correlation was found between ADV and amylose content of homozygous non-glutinous or dull F$_4$ grains, but a negative relationship was observed in glutinous grains. Protein content of dull grain was significantly higher than that of glutinous or non-glutinous grain segregated from the same cross, while those of glutinous and non-glutinous grains were not different. Among gelatinization characteristics, initial pasting temperature and peak viscosity of dull grains were higher than glutinous rice, and were not different with non-glutinous grain. Hot, cool and consistency viscosities of dull grain were intermediate between glutinous and non-glutinous rices. Dull grains showed the highest breakdown viscosity and the lowest setback viscosity among the three endosperm types.

• Korean Journal of Food Science and Technology
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• v.18 no.3
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• pp.192-196
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• 1986

Cold gelatinization of two naked burley (Songhak and Youngsan) starches in NaOH (0.14-0.21N) and KSC N (1.5-4.5M) was compared. Light transmittance of starch suspension in aqueous NaOH solution was higher in Youngsan starch than in Songhak starch. Viscosity of Youngsan starch was also higher at various starch concentrations (5-12.5%), however the critical concentration of NaOH for the gelatinization of Youngsan starch was lower by 0.1meq NaOH/g starch compared to Songhak starch. Two starches held a linear relationship between viscosity development rate and alkali concentration at a fixed starch concentration. The viscosity development rate of the starch was linearly decreased as starch concentration increased at a fixed alkali concentration. Gel volume of the starches was attained maximum at 2.5M KSCN, however Youngsan starch showed a higher volume and a less stability in KSCN than Songhak starch.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.46 no.1
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• pp.12-16
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• 2001

In order to develop near isogenic lines (NILs) the heterozygous rice plants for alkali digestibility value(ADV) were selected and tested in every generation from $F_5$to $F_9$ of a cross, Seratus malam/Suwon 345. Finally several sets of NILs, which were six low ADV lines and four medium-high ADV lines, were selected among $F_{10}$ lines. No differences of the plant growth characteristics, amylose content and protein content of rice grain were found between low and medium-high ADV lines. Rice flour of low ADV lines showed longer gel length in gel consistency test than medium-high ADV lines, and also showed different gelatinization characteristics measured by rapid visco analyzer compared with medium-high ADV lines. The result of genetic analysis indicated that ADV-NILs developed were differed in a pair of major gene controlling ADV, and low ADV was dominant over medium-high ADV.

• Korean Journal of Food Science and Technology
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• v.8 no.3
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• pp.179-184
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• 1976

Properties of starch from three rice varieties in Korea, Indica types Tongil, Yusin and a Japonica type Jinheung were investigated. 1) Gelatinization temperatures of Tongil, Yushin and Jinheung rice were $72^{\circ}C,\;70^{\circ}C\;and\;68{\sim}69^{\circ}C$ respectively. Gelatinization temperature of Indica variety was higher than that of Japonica variety. 2) Blue values of Tongil, Yusin and Jinheung rice starch were 0.40, 0.39 and 0.35 respectively, in which differences among rice varieties were small. 3) Color intensity of three varieties of rice starch with iodine gave rise to absorption maxima at $610{\sim}625\;nm$. 4) Amylose contents of Tongil, Yusin and Jinheung rice starch were 23.2%, 21.3% and 20.6% respectively, which were lower than those of other cereals. Amylose content of Indica variety was higher than that of Japonica variety. 5) Alkali numbers of Tongil, Yusin and Jinheung rice starchs were 7.0, 7.0 and 6.8, respectively. The differences were negligible among rice varieties. Those values were higher than that of glutinous rice starch.

• 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.

• Korean Journal of Food Science and Technology
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• v.26 no.5
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• pp.638-643
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• 1994

Gelatinization and retrogradation properties of modified starches which were prepared by steeping sweet potato at $40^{\circ}C$ for 2, 4, 7 and 10 days were investigated. The peak temperature of gelatinization and enthalpy of untreated starch by DSC were $53.9^{\circ}C\;and\;1.32\;cal/g$, respectively, but those of modified starch were increased by steeping. In gelatinization by alkali, starches with 2, 4 and 7 day steeping showed higher viscosities than untreated starch, whereas the viscosities of starches with 10 day steeping decreased. The clarities in paste decreased during storage in all starches and decreased in starches with steeping. The degrees of retrogradation by ${\alpha}-amylase-iodine$ method were higher in starches with steeping than untreated starch. The enthalpy of retrograded starches by DSC increased by steeping except 4 day steeping starch. The sweet potato extract containing sugar inhibited the retrogradation of starch paste and the degree were higher in residual starches than in untreated starch.

• Korean Journal of Food Science and Technology
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• v.17 no.1
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• pp.33-36
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• 1985

Some properties of starches from three naked barley cultivars(Songhak, Youngsan and Jinan 56) were compared. No significant differences in water-binding capacity, amylose content, relative crystallinity, swelling power and gelatinization degree at various pasting temperatures among cultivars were observed. However, starches showed characteristic viscograph indices and viscosity development patterns in aqueous sodium hydroxide solution. Songhak starch exhibited the lowest pasting temperature and was the most resist to alkali gelatinization.

• Korean Journal of Plant Resources
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• v.11 no.2
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• pp.146-151
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• 1998

A study was carried our to investigate the characteristics of physico-chemical components palatability of cooked rice accoring to different transplanting time. The treatments were consisted of five transplanting time, from May 5 to July 5 at 15 -day intervals, and six cultivars ; two early-maturing, two mid-maturing and two late-maturing cultivars which are clearly identified by evaluation of cumulative temperature and growth duration from seeding to heading of rice plants. In gelatinization characteristics of rice grain, alkali digestion value was low in the earlier transplanting regardlessof maturing types. Initial pasting temeprature maximum viscosity and breakdown as amylogram charcteristics were high at the transplanting of June 5. The palatability of cookedrice was evaluated that early-maturing cultivars were much better in early transplanting than in late transplanting . The optimum transplanting time for palatibility was the periods from May 5 to 20 in early maturing varieties, May 20 to June 5 in mid-maturing and June 5 to June 20 in late-maturing ones at Honam district in Korea.

• Applied Biological Chemistry
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• v.28 no.2
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• pp.106-109
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• 1985

Gelatinization of Japonica(30 varieties) and J/Indica(22 varieties) rice flours in 0.2N NaOH was examined. J/Indica rice flours were easily gelatinized and showed higher viscosities at all reference points than Japonica counterparts. Viscosity development rate was not correlated with protein or amylose content. Only J/Indica rice varieties showed positive correlation between hydration rate and viscosity development rate.