• Korean Journal of Food Science and Technology
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• v.33 no.1
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• pp.50-54
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• 2001

The amylose content, based on iodine blue value, of eight rice cultivars decreased in order of Nampungbyeo>Whachungbyeo>Punchilmi>Nampung CB243>Whachung du-1>Nampung EM90>Whachungchalbyeo>shr. The amylopectin chain length distribution was obtained by enzyme treatments followed by high-performance size-exclusion chromatographic separation. Chain length distribution profiles of the isoamylase-debranched starches showed distinct patterns according to cultivars. Based on the sensory evaluation result of the bread prepared from gluten and rice flours of eight rice cultivars, chewiness of the product was related with the presence of amylose while the short-chain amylopectin fraction was contributed to the texture and overall quality.

• Korean Journal of Food Science and Technology
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• v.32 no.1
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• pp.82-89
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• 2000

Relationship among the properties of rice, such as amylose contents of endosperm starch, sugar content and amylogram characteristics, and processing properties for rice bread was studied. The amylose content of the rice cultivars decreased in order of Nampungbyeo, Whachungbyeo>Punchilmi(fl)>Nampung CB243> Whachung du-I, Nampung EM90>Whachung-chalbyeo>shr. Protein contents of rice tested in this study were almost same level, however, shr, the high sugar rice, showed the highest protein content scored as 8.2%. The study showed that the amylose contents of rice cultivars were negatively correlated with their protein contents. The starting temperatures for gelatinization of the flour of Punchilmi(fl) and Shurunken(shr) were low, however, in case of Whachungbyeo and Nampungbyeo plus their mutants derived from the both, the stickiness and the hardness of the flours were shown to be positively correlated with the amylose contents. In addition, loaf volume tested using sensory evaluation and overall quality showed the same tendency. Among the rice cultivars tested in this study, breads made from white rice had good qualities in bread making process than those made from brown rice. The bread made from Nampungbyeo was demonstrated to have highest score e in overall quality, as well as the lowest retrogradation index during storage at $4^{\circ}C$

• Proceedings of the Korean Journal of Food and Nutrition Conference
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• 2001.12a
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• pp.39-74
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• 2001

The endeavors enhancing the grain quality of high-yielding japonica rice were steadily continued during 1980s∼1990s along with the self-sufficiency of rice production and the increasing demands of high-quality rices. During this time, considerably great, progress and success was obtained in development of high-quality japonica cultivars and qualify evaluation techniques including the elucidation of interrelationship between the physicochemical properties of rice grain and the physical or palatability components of cooked rice. In 1990s, some high-quality japonica rice caltivars and special rices adaptable for food processing such as large kernel, chalky endosperm aromatic and colored rices were developed and its objective preference and utility was also examined by a palatability meter, rapid-visco analyzer and texture analyzer. The water uptake rate and the maximum water absorption ratio showed significantly negative correlations with the K/Mg ratio and alkali digestion value(ADV) of milled rice. The rice materials showing the higher amount of hot water absorption exhibited the larger volume expansion of cooked rice. The harder rices with lower moisture content revealed the higher rate of water uptake at twenty minutes after soaking and the higher ratio of maximum water uptake under the room temperature condition. These water uptake characteristics were not associated with the protein and amylose contents of milled rice and the palatability of cooked rice. The water/rice ratio (in w/w basis) for optimum cooking was averaged to 1.52 in dry milled rices (12% wet basis) with varietal range from 1.45 to 1.61 and the expansion ratio of milled rice after proper boiling was average to 2.63(in v/v basis). The major physicochemical components of rice grain associated with the palatability of cooked rice were examined using japonica rice materials showing narrow varietal variation in grain size and shape, alkali digestibility, gel consistency, amylose and protein contents, but considerable difference in appearance and torture of cooked rice. The glossiness or gross palatability score of cooked rice were closely associated with the peak. hot paste and consistency viscosities of viscogram with year difference. The high-quality rice variety “Ilpumbyeo” showed less portion of amylose on the outer layer of milled rice grain and less and slower change in iodine blue value of extracted paste during twenty minutes of boiling. This highly palatable rice also exhibited very fine net structure in outer layer and fine-spongy and well-swollen shape of gelatinized starch granules in inner layer and core of cooked rice kernel compared with the poor palatable rice through image of scanning electronic mcroscope. Gross sensory score of cooked rice could be estimated by multiple linear regression formula, deduced from relationship between rice quality components mentioned above and eating quality of cooked rice, with high Probability of determination. The ${\alpha}$ -amylose-iodine method was adopted for checking the varietal difference in retrogradation of cooked rice. The rice cultivars revealing the relatively slow retrogradation in aged cooked rice were Ilpumbyeo, Chucheongbyeo, Sasanishiki, Jinbubyeo and Koshihikari. A Tongil-type rice, Taebaegbyeo, and a japonica cultivar, Seomjinbyeo, shelved the relatively fast deterioration of cooked rice. Generally, the better rice cultivars in eating quality of cooked rice showed less retrogiadation and much sponginess in cooled cooked rice. Also, the rice varieties exhibiting less retrogradation in cooled cooked rice revealed higher hot viscosity and lower cool viscosity of rice flour in amylogram. The sponginess of cooled cooked rice was closely associated with magnesium content and volume expansion of cooked rice. The hardness-changed ratio of cooked rice by cooling was negatively correlated with solids amount extracted during boiling and volume expansion of cooked rice. The major physicochemical properties of rice grain closely related to the palatability of cooked rice may be directly or indirectly associated with the retrogradation characteristics of cooked rice. The softer gel consistency and lower amylose content in milled rice revealed the higher ratio of popped rice and larger bulk density of popping. The stronger hardness of rice grain showed relatively higher ratio of popping and the more chalky or less translucent rice exhibited the lower ratio of intact popped brown rice. The potassium and magnesium contents of milled rice were negatively associated with gross score of noodle making mixed with wheat flour in half and the better rice for noodle making revealed relatively less amount of solid extraction during boiling. The more volume expansion of batters for making brown rice bread resulted the better loaf formation and more springiness in rice bread. The higher protein rices produced relatively the more moist white rice bread. The springiness of rice bread was also significantly correlated with high amylose content and hard gel consistency. The completely chalky and large gram rices showed better suitability for fermentation and brewing. Our breeding efforts on rice quality improvement for the future should focus on enhancement of palatability of cooked rice and marketing qualify as well as the diversification in morphological and physicochemical characteristics of rice grain for various value-added rice food processings.

• Korean Journal of Food Science and Technology
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• v.50 no.6
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• pp.614-620
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• 2018

A rice bran physically treated to increase the residual gamma amino butyric acid (GABA) content (200 mg/100 g) or its hot-water extract (200 mg/100 g) was added into a white pan bread, and changes in the physical properties including color, and volume and texture changes during storage at room temperature were examined. The addition of bran powders had negative effects on bread quality and storage stability whereas that of rice bran extract (RBE) improved the storage stability of bread. The lightness of bread crumbs decreased but the volume of bread slightly increased after addition of the RBE. The increase in crumb hardness during storage was retarded by the RBE addition. The residual concentration of GABA in bread was increased 38-fold when 20% of RBE was added. The addition of RBE to white pan bread improved the resistance to staling and health-promoting function because of GABA.

• Korean Journal of Food Science and Technology
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• v.32 no.1
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• pp.75-81
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• 2000

The processing properties for rice bread were examined using eight kinds of endosperm mutant rice. The varietal differences among eight kinds of endosperm mutant rice having the respective sugar contents and amylose contents were studied. The water absorptions of these eight cultivars were observed to have significant differences among the cultivars, revealing the water absorption ability of Shrunken(shr.) was 61.5%, and that of Punchilmi(fl) was 48.4%. In addition, the experiments using Whachungbyeo, Nampungbyeo and their mutant cultivars showed that the maximum water absorption was tend to be negatively correlated with the amylose content of each rice cultivars. This study also showed that the rice breads made by dry-milling was better in shape, mechanical properties(hardness, springiness, adhesiveness, chewiness) and texture tested using sensory evaluation than that made by wet-milling.

• Korean Journal of Food Science and Technology
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• v.27 no.6
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• pp.944-949
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• 1995

To investigate the effect of processing on the antimutagenicity of rice, antimutagenic effect of rice products including cooked rice, plain steamed rice bread(baikseolgi) and parched rice powder were observed. They showed inhibitory effects of $46%{\sim}100%$ on the frameshift mutation, whereas they showed little inhibitory effect on the base substitution mutation in the Salmonella typhimurium reversion assay. No inhibitory effect was found in the SOS chromotest. Inhibitory effect was more clearly observed on the indirect-acting mutagen than on the direct-acting mutagen. In case of the S. typhimurium reversion assay, the range of inhibition rate against the frameshift and base substitution mutation was $75%{\sim}100%$ and $66%{\sim}87%$, respectively, and was $19%{\sim}67%$ in the SOS chromotest. Antimutagenic activity of raw rice was supposed to be maintained in processed rice products.

• Proceedings of the Korean Environmental Health Society Conference
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• 2002.04a
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• pp.55-56
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• 2002

Aflatoxin is a secondary fungal metabolite and is a public health hazard because it is a human carcinogenic and has many deleterious effects in men and animals. Rice is one of the better substrates for the fungus which can produce aflatoxins. This study was performed to investigate aflatoxin reduction during the cooking and processing of rice. Aflatoxin was produced by Aspergillus parasiticus ATCC 15517 on well-milled rice(Japonica type) at the level of 13.2 ppb. Cooked rice, rice cakes (baek-sol-gi, plain steamed rice bread), fermented rice (sik-hye, sweet rice beverage), and popped rice were prepared from the aflatoxin-contaminated rice. Aflatoxin content in the samples was determined by high performance liquid chromatography. The total aflatoxin level was decreased to 46.9％ in the cooked rice, 85.6％ in the rice cakes, 11.4％ in the fermented rice, and 7.6％ in the popped rice, respectively (p＜0.05). This reduction brought the level of aflatoxins down to below the Standard and Specification of Korea (10 ppb), except for the rice cakes. These results indicate that washing, steaming, fermentation, and popping of rice was helpful in reducing the aflatoxin level in the rice and the most helpful factors were high temperature & high pressure. More research is needed to understand why the preparation of rice cakes did not reduce the level of aflatoxin as much as the other cooking methods.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.11
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• pp.1571-1576
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• 2012

The purpose of this study was to investigate the physicochemical and pasting properties of long-term stored domestic and imported rice supplied for food processing from government-controlled public rice stocks. Goamibyeo, which was bred for processing and harvested in 2011, was selected as the control rice for comparison. Rice was dry-milled, and the amylose contents of stored rice were 12~13%. Stored rice kernels were significantly harder than those of control, whereas damaged starch content and water absorption of flour were not significantly different from those of control. Overall, long-term stored domestic and imported rice showed high peak viscosities along with high viscosities of both hot and cold pastes. Both imported and domestic rice demonstrated insufficient properties for making 100% flat rice noodles or bread. They showed the greatest shrinkage during cooling after baking. Although their levels of cooking loss were less than that of control, stored rice showed a less elastic and softer cooked noodle texture compared to control flour.

• Korean Journal of Agricultural Science
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• v.48 no.3
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• pp.535-544
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• 2021

When baking, the proper blending or mixing of materials will affect the quality of the product. The mixing strength is important when establishing the optimal conditions for batter, and control of the mixing condition is accordingly an important factor. This study investigated the effects of the mixing speed and time on the quality characteristics of a gluten-free type of rice batter. The batter samples manufactured for this purpose are as follows: control (+) (wheat flour), control (-) (rice flour), T1 (1,800 rpm, 1 min), T2 (1,800 rpm, 2 min), T3 (1,800 rpm, 3 min), T4 (3,600 rpm, 1 min), T5 (3,600 rpm, 2 min), T6 (3,600 rpm, 3 min). In this study, rice flour was used in the T1 to T6 samples. The pH of the batter tended to be higher when the mixing speed was slower and the time was shorter depending on the ultra-high mixing conditions. The moisture content of T3 was highest, and there was no difference according to the ultra-high speed conditions. The specific volumes of the ultra-high mixing treatments were higher than those of the control samples. The relationship between the specific volume, hardness and springiness of rice bread according to the mixing speed and time was weak. Therefore, it is considered that the application of ultra-high speeds when manufacturing gluten-free batter can have a positive effect on improving the production efficiency by reducing the processing time.

• Korean Journal of Food Science and Technology
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• v.18 no.4
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• pp.264-269
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• 1986

This study was undertaken to investigate the removal efficiency of heavy metals (Cd, Pb) in rice and wheat flour by cooking and processing. After four times washing of rice grains with water, the removal ratios of cadmium and lead from artificially-contaminated samples were 39.271 and 34.9%, respectively. In cookingof rice grains washed three-times with water, the residue levels of cadmium and lead decreased to 85.7%, 83.0% in electric rice cooker and 74.51%, 72.6% in pressure rice cooker, respectively. No significant difference was observed in the removal of the metals between naturally-contaminated and artificially contaminated rice samples, and between the electric and pressure rice cookers. In baking of artificially-contaminated wheat flour into cookie and loaf bread, the removal ratios of cadmium and lead were negligible as expected. When knife-cut noodle was made from artificially-contaminated wheat flour and boiled in water, 75% of the metals were found in the noodle solids and only 25% of them were removed into the broth.