• Applied Biological Chemistry
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• v.47 no.2
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• pp.216-221
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• 2004

Changes in physiological functionality of giant embryonic rice by germination process were investigated using 70% ethanolic extract of the rices. Physiological functionality was evaluated by determining the reducing power, phenolic compound content, GABA content, and antimutagenicity. The results showed that the order of reducing power of the non-germinated rices was Nampung giant embryonic rice>normal rice> Whachung giant embryonic rice, however, the activity was high as the order of Whachung giant embryonic rice> Nampung giant embryonic rice> normal rice by germination process. About 3-fold activity increase was observed for Whachung giant embryonic rice, while, the activity of Nampung giant embryonic rice and normal rice decreased by the same treatment. The phenolic compound content of three rice cultivars were found to be almost same levels. Germination of rice increased the content of phenolic compounds by 2.6-fo1d without any considerable changes for both Nampung giant embryonic rice and normal rice. The GABA contents was highest in Whachung giant embryonic rice, followed by Nampung giant embryonic rice, normal rice in either germination or non-germination condition. The germination increased the GABA contents by more than 2.4-fold for all rice cultivars tested. We also found an increase in the antimutagenic activity by germination process for all cultivars, where the activity was the greatest for Whachung cultivar.

• Applied Biological Chemistry
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• v.46 no.2
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• pp.117-122
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• 2003

Starches from 4 rice cultivars, including Whachungchalbyeo and Whachungbyeo, together with two correspondiug conversion mutants with giant embryonic phenotype, Whachungchal-giant embryonic rice and Whachung-giant embryonic rice, were isolated to compare its physico-chemical properties. The amylose content and the length of glucose chains in the fractionated amylose was reduced in response to conversion of the rice cultivars for developing giant embryonic phenotype. For the fine structure of amylopectin, conversion to giant embyonic rice cultivars accompanied with slight increase in the length of B chain plus decrease in the amount of A chain, and also a slight increase in average glucose chains length of amylopectin fractions could be observed. X-ray diffractogram revealed 4 cultivars to be the representative A types. We could also obtain the results that the hydrolysis rate by glucoamylase in the waxy rice cultivars decreased in response to conversion to the giant embryonic rice cultivars, while the rate increased in the non-waxy rice cultivas. Termination temperature for gelatinization was observed to decrease in response to conversion into the giant embryonic rice cultivars, however, the enthalpy for gelatinization was found to increase with the same conversion process.

• Applied Biological Chemistry
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• v.46 no.3
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• pp.189-194
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• 2003

Rice seeds of 4 cultivars including Whachung-giant embryonic rice and Nampung-giant embryonic rice, as a group of the non-waxy rice cultivars, and Shinsunchal-giant embryonic rice and Whachungchal-giant embryonic rice, as that of the waxy rice cultivars, were germinated at $27^{\circ}C$ for 3 days to compare the changes in some physicochemical properties of the starch granules and the starch-hydrolysing enzyme activities during germination, respectively. ${\alpha}-Amylase$ activity of rices germinated for 3 days found to be higher than that of malt. Especially, Whachung-giant embryonic rice and Shinsunchal-giant embryonic rice were greater in activity than other rice cultivars and possessed the activities double that of malt. In contrast, ${\beta}-amylase$ of germinated rice found to be considerably less active than malt, although the giant embryonic rice group showed prevalent activity as compared o the normal rice group. With the starch granules, the amount of long glucose chains from amylose molecules were reduced in the non-waxy type giant embryonic rices, while the chain length increase was found in the waxy type giant embryonic rices. For the distribution profile of the glucose chain length from amylopectin molecules, we could observed that the chain length with DP (degree of polymerization) ranged 33 to 66 and 14 to 32 increased with the decreasing rate of that above 67 and below 13 regardless of starch waxiness. With non-waxy type of giant embryonic rices, susceptibility for glucoamylase were found to reduce along with germination, however, increase in susceptibility was observed with waxy rice types. In addition, we found the reduction in both initiation and termination temperature, and enthalpy for gelatinization.

• Applied Biological Chemistry
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• v.47 no.3
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• pp.293-299
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• 2004

Antioxidant activity of ethanolic extract of two giant embryonic rices, Nampung giant embryonic rice and Hwachung giant embryonic rice, were investigated mainly focusing on their ability to inhibit lipid peroxidation and scavenge reactive oxygen species in comparison with those of general rice. The results showed that germination process increased reducing power, inhibitory activity on lipid peroxidation and scavenging ability either on superoxide or hydroxyl radicals. Among the cultivars tested, increase in antioxidative action was found to be most prominent for Hwachung giant embryonic rice cultivar. For scavenging of superoxide radicals, the extract from Nampung giant embryonic rice has the most potent activity, however, increasing rate of scavenging activity by germination process was also found to be the greatest for Hwachung giant embryonic rice. We found that the scavenging mechanism for superoxide radicals was attributed to the direct scavenging of the radicals. The scavenging of hydroxyl radicals, the most toxic oxygen radical to biological system, by the rice extracts were also examined, and the results showed that either overall activity or the increasing rate of the activity to scavenge hydroxyl radicals by germination process was the greatest for Hwachung giant embryonic rice. Moreover, the results suggested that the scavenging action to hydroxyl radicals might be mediated by direct quenching of the radicals, not by chelating $Fe^{2+}$. Further studies showed that the antioxidant action of the rice extracts tested in vitro was also operative for suppressing ROS production induced in TPA-stimulated HL-60 cells.

• Korean Journal of Food Science and Technology
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• v.33 no.5
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• pp.540-544
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• 2001

The quality characteristics for brown rice flake were examined using eight kinds of brown rice cultivars such as Shinsunchalbyeo, Shinsunchal giant embryonic rice, Whachungchalbyeo, Whachungchal giant embryonic rice, Whachungbyeo, Whachung giant embryonic rice, Nampungbyeo, and Nampung giant embryonic rice. The qualities of grain such as the released reducing sugar, water absorption rate and hardness of grain are examined with different temperature and time at sedimentation in water and pressed grain-brown rice flake are prepared after sedimentation in $60^{\circ}C$ water for 5 hours. The brown rice flakes prepared from the giant embryonic type rice cultivars showed higher expansion volume, lower hardness, more crispness, longer bowl life time and better taste than that prepare from normal type rice cultivars, which showed the giant embryonic type rice cultivars were appropriate for brown rice flakes. Among the giant embryonic type rice cultivars, the glutinous rice varieties were better to prepared the brown rice flakes than its normal rice cultivars. The water absorption index of flakes tested were positively correlated with expansion volume and bowl life hardness. From tested sensory evaluation were shown to be negatively correlated with water absorption index. Among the tested cultivars, Shinsunchal giant embryonic and Wachungchal giant embryonic rice were most appropriate for brown rice flakes preparation.

• Applied Biological Chemistry
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• v.47 no.1
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• pp.61-66
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• 2004

70% ethanolic extracts were prepared from the three mutant rice cultivars with giant embryo termed Shinsunchal-giant embryonic rice, Whachung-giant embryonic rice and Nampung-giant embryonic rice, and its antioxidative and antimutagenic properties were evaluated and compared. For analysing antioxidativity, various antioxidative indices, such as electron donating ability to DPPH radical, scavenging capacity to hydroxyl radicals generated by Fenton reaction, scavenging capacity to superoxide radicals generated by HPX/XOD system, inhibitory effect on autoxidation of linoleic acid and inhibitory effect on membrane lipid peroxidation derived from rabbit erythrocyte ghost, were determined. For analysing antimutagenicity, suppressive effects on mutagenesis induced by the chemical mutagen, mitomycin C, were measured using E. coli PQ 37 as a indicator cell. The results showed that for both antioxidativity and antimutagenicity the giant embryonic rices were more effective compared to the general cooking rice, Among the giant embryonic rice cultivars, Nampung-giant embryonic rice tended to be most effective, showing its scavenging activity to DPPH radical, superoxide radical and hydroxyl radical, and inhibitory activity to lipid peroxidation was 2,3-, 3,3-, 1.7-, and 2.5-fold greater than those of normal rice, respectively.