• KOREAN JOURNAL OF CROP SCIENCE
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• v.38 no.6
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• pp.524-530
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• 1993

The experiment was carried out to investigate the changes in physicochemical properties of milled rice harvested in different year and stored for four to sixty four months. The fat acidity of milled rice increased sharply from four to sixteen months storage, and after then it was increased slowly to sixty four months. Amylose, magnesium, potassium content, and K/Mg ratio of milled rice were not changed by storage duration. Water absorption rates of milled rice at 21$^{\circ}C$ and 77$^{\circ}C$, and alkali digestion value were increased by longer storage duration. Difference of water absorption rate between rice samples was greater during initial forty minutes after soaking at 21$^{\circ}C$ and with longer the soaking time at 77$^{\circ}C$. Shorter gel length of rice flour was found with prolonged storage duration, while peak, minimum, cool, breakdown and setback viscosity of gelatinized rice flour on amylograph were increased along with increasing the storage duration. The volume expansion rate during cooking and degree of iodine coloration of cooking water were higher in the longer stored rice compared with shorter one, and the amount of soluble solid in cooking water was significantly decreased in rice stored longer period.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.6
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• pp.805-809
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• 1997

The influence of cool temperature occurred during the booting stage in 1993 on quality of rice grain was compared with that in favorable weather of 1994. The mean and minimum air temperatures during the reproductive growth stage at the paddy field of Jinbu Substation, National Crop Experiment Station were 2.2~7.4$^{\circ}C$ and 2.0~8.9$^{\circ}C$ lower respectively in 1993 compared to those of 1994. Grain fertility and brown rice yield were 11.8％ and 0.4t /ha, and 84.3％ and 5.5t /ha in 1993 and 1994, respectively. There was no difference in amylose content between two years. However, protein content of brown rice in 1994 were 1.6％ lower than that of 1993. There was no difference in alkali digestion value of milled rice between two years. Gel consistency of rice flour was 45mm in 1993 and 59mm in 1994. Amylogram characteristics of rice flour produced in 1993 showed lower peak hot, cool, and breakdown viscosities, and higher consistency and setback viscosities. The palatability of cooked rice by sensory panel test was considerably better in 1994 rice than in the rice of cool year.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.30 no.4
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• pp.431-435
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• 1985

Nine hybrid rices crossed between Korean cytoplasmic-genetic male sterile rices having the WA cytoplasm and the Korean restorer lines or varieties, HR1619A/Nampungbyeo, HR1619A/Gayabyeo, HR1619A/Line234, TongilA/Nampungbyeo, TongilA/Cheongcheongbyeo, Suwon 296A/Line 209, Suwon 296A/Line 237, Suwon 296A/Line 252 and Line 201A/Line 234, and their parents were grown at Yeungnam University in 1984. The rough rice yield of the hybrids Line 201A/Line 234, TongilA/Nampungbyeo and HR1619A/Nampungbyeo were 939, 927 and 900 Kg/10a respectively. The heterosis(F$_1$/Midparent) of the above three hybrids was 40%, 20% and 19%, the heterobeltiosis(F$_1$/Better parent) was 36%, 17% and 10%, and the standard heterosis (F$_1$/Standard variety, Cheongcheongbyeo) was 19%, 17% and 14% respectively. The hybrids HR1619A/ Gayabyeo and Suwon 296A/Line 237 showed negative heterosis in grain yield. Significant heterobeltiosis for grain number per panicle was found while less or no heterobeltiosis was observed in panicle number per hill, 1000-grain weight and grain fertility. The bacterial leaf blight disease reaction of the hybrids tested was almost the same as that of one parent at least. The amylose content of the hybrids was medium to low the same as their parents. The protein content and alkali digestion value of the hybrids were almost the same as their parents.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.59 no.4
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• pp.413-426
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• 2014

This study was conducted to investigate changes of physicochemical properties and fatty acid compositions of rough rice stored at different storage temperatures and periods. So we analyzed texture, alkali digestion value (ADV), toyo glossiness value, pasting properties, fat acidity and fatty acid compositions of five rice varieties every 4 month on the condition of which rough rice had been stored at different temperatures (ambient and low temperature condition at $15^{\circ}C$) for 2 years. Hardness of cooked rice was increased by storage periods and cohesiveness of cooked rice was not considerably different among varieties according to storage temperatures and periods. ADV was significantly different among varieties and storage periods but not different with storage temperatures. Toyo glossiness value of cooked rice was continuously decreased from 4 months after storage regardless to storage temperature. The pasting properties were considerably affected by storage temperatures and periods of rough rice. Increase in peak viscosity, final viscosity and breakdown was observed but setback was decreased by storage periods. Fat acidity of brown rice was much higher than that of milled rice during storage of rough rice and tend to increase by storage period. Oleic acid among fatty acids of brown rice except Sindongin and Hitomebore tended to be decreased by storage periods and linoleic acid among fatty acids of brown rice of Hopum was decreased by storage periods. The contents of linoleinic acid and stearic acid among fatty acids of milled rice were comparatively decreased from 4 months after storage, whereas the content of palmitic acid tended to be increased by storage periods.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.1
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• pp.27-37
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• 1994

To catch the relative importance of varietal and environmental variation in various grain quality components associated with palatability of cooked rice, grain appearance, milling recovery, several physicochemical properties of milled rice and texture or eating quality of cooked rice for rice materials of five japonica cultivars, produced at four locations of the mid-mountainous and alpine area of Korea in 1989, were evaluated and analyzed the obtained data. Highly significant varietal and locational variations were detected in 1000-grain weight, amylose content, K/Mg ratio, gelatinization temperature, peak viscosity, breakdown and setback viscosities as compared with variety x location interaction variation. Also, marked locational variations were recongnized in milling recovery from rough to brwon rice, alkali digestibility and protein content, and significant varietal variation was caught in stickiness /hardness ratio of cooked rice. The variety x location interaction variation was especially large in quality components of grain appearance and ripening, palatability of cooked rice and consistency viscosity. One thousand kernel weight was heaviest in Jinbuolbyeo and Odaebyeo, and the unfilled grain ratio was lowest in Jinbuolbyeo. Odaebyeo showed slightly' lower ratio of intact and clear milled rice because of more chalky rice kernels compared with other cultivars. Amylose content of Jinbuolbyeo and Sobaegbyeo was about 1% lower than that of others and K/Mg ratio of Odaebyeo was the lowest one among rice materials. Odaebyeo, Sobaegbyeo and Jinbuolbyeo revealed significantly low gelatinization temperature and setback viscosity while high peak and breakdown viscosities. Cholwon rice showed the greatest kernel weight, good grain filling but lowest ratio of intact and clear milled rice while Jinbu rices exhibited the highest milling recovery from rough to brown rice and ratio of sound milled rice. Amylose content of milled rice in Jinbu rices was about 2-3% lower than those in other locations. Protein content of polished rice was about 1% lower in rice materials of middle zone than those of southern part of Korea. K/Mg ratio of milled rice was highest in Jinbu rice and potassium content was slightly higher in the rice materials of middle region than in those of southern region. Alkali digestion value and gelatinization temperature of polished rice was markedly high in Jinbu rices as compared with other locations. Breakdown viscosity was hightest in Chlown rices and next higher with the order of Hwaso>Unbong>Jinbu rices, and setback viscosity was the quite contrary tendency with breakdown. The stickiness /hardness ratio of cooked rice was relatively higher value in Cholwon rices than in the others and the palatability of cooked rice was a little better in Unbong and Cholwon rices than in Jinbu and Hwaso rices, although variety x location interaction variation was large. The rice materials can be classified largely into two groups of Jinbu and the others by the distribution on the plane of 1st and 2nd principal components (about 60% of total informations) contracted from twelve grain quality properties closely associated with eating quality of cooked rice. Also, Jinbu and the other rices were divided into two and three rice groups respectively. Varietal variation of overall rice quality was smallest in Hwaso. The most superior rice group in overall quality evaluation included Odaebyeo produced at Cholwon, Unbong and Hwaso, and Sobaegbyeo grown at Unbong

• Korean Journal of Food Science and Technology
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• v.43 no.2
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• pp.142-148
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• 2011

The objective of this study was to analyze proximate composition and physicochemical properties according to different kinds of rice. In total, 20 varieties of rice were used (Domestic-19, Imported-1). The moisture contents ranged from $11.11{\pm}0.20$ to $3.28{\pm}0.03%$. The crude protein and crude lipid contents were ranged from $5.04{\pm}0.03$ to $7.02{\pm}0.10%$ and $0.18{\pm}0.01$ to $0.73{\pm}0.05%$, respectively. The mineral contents were Calcium, $3.56{\pm}0.11-6.69{\pm}0.08mg/100g$; Sodium, $3.39{\pm}0.01-17.43{\pm}0.04mg/100g$; Phosphorus, $64.12{\pm}0.88-102.0{\pm}0.36mg/100g$; Zinc, $0.95{\pm}0.01-1.75{\pm}0.0mg/100g$; Iron, $0.19{\pm}0.0-0.69{\pm}0.02g/100g$; Magnesium, $9.89{\pm}0.47-23.31{\pm}0.21mg/100g$; Potassium, $47.11{\pm}3.49-82.19{\pm}1.08mg/100g$;and Manganese, $0.47{\pm}0.0-1.14{\pm}0.01mg/100g$. Eighteen kinds of rice exhibited small kernels. Amylose contents ranged from $10.3{\pm}1.27$ to $19.4{\pm}0.15%$, while starch value ranged from $70.8{\pm}2.67$ to $80.1{\pm}5.09%$. Alkali digestion value was described as 5-6 grade and gel consistency was shown to be 'soft' regardless of the rice kinds.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.47
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• pp.15-32
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• 2002

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 quality 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 cultivars 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, Recently, new special rices such as extremely low-amylose dull or opaque non-glutinous endosperm mutants were developed. Also, a high-lysine rice variety was developed for higher nutritional utility. 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 texture of cooked rice. The glossiness or gross palatability score of cooked rice were closely associated with the peak, hot paste and consistency viscosities of viscosities with year difference. The high-quality rice variety "IIpumbyeo" 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 microscope. 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 IIpumbyeo, Chucheongyeo, Sasanishiki, Jinbubyeo and Koshihikari. A Tonsil-type rice, Taebaegbyeo, and a japonica cultivar, Seomjinbyeo, showed the relatively fast deterioration of cooked rice. Generally, the better rice cultivars in eating quality of cooked rice showed less retrogradation 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 breed. 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 grain rices showed better suitability far fermentation and brewing. The glutinous rice were classified into nine different varietal groups based on various physicochemical and structural characteristics of endosperm. There was some close associations among these grain properties and large varietal difference in suitability to various traditional food processing. Our breeding efforts on improvement of rice quality for high palatability and processing utility or value-adding products in the future should focus on not only continuous enhancement of marketing and eating qualities but also the diversification in morphological, physicochemical and nutritional characteristics of rice grain suitable for processing various value-added rice foods.ice foods.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.38 no.5
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• pp.418-424
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• 1993

In order to test combining ability of the cytoplasmic-genetic male sterile(CGMS) and restorer lines with backgrounds of Korean japonica rice varieties, diallel crosses were made among the early maturing CGMS lines Sobaegbyeo A, Odaebyeo A, Gwanagbyeo A and Daeseongbyeo A, and the restorer lines Sobaegbyeo R, Odaebyeo R, Gwanagbyeo Rand Daeseongbyeo R, and among the medium maturing CGMS lines Hwajinbyeo A, Paldal A, Suwon 224 A and Iri 386 A and the restorer lines Hwajinbyeo R, Paldal R, Suwon 224 Rand Iri 386 R, and among the late maturing CGMS lines Nagdongbyeo A, Palkweng A, Hwacheongbyeo A and Milyang 97 A and the restorer lines Nagdongbyeo R, Palkweng R, H wacheongbyeo Rand Milyang 97 R. The fourty eight combinations of the hybrids, their parents and the maintainers were grown in field condition in 1992. General combining ability, relative specific combining ability and relative combining ability for yield of the CGMS and restorer lines were tested. Combining ability of the CGMS lines Odaebyeo A, Iri 386 A, Nagdongbyeo A and Palkweng A, and of the restorer lines Odaebyeo R, Hwajinbyeo R, Hwacheongbyeo Rand Palkweng R was relatively high. Heterobeltiosis for grain yield over the better parent of the early maturing hybrids ranged from -17 % to 15%, and that of the medium maturing ones from -4% to 22%, and that of the late maturing ones from -46% to 30% respectively, Standard heterosis over the standard variety of the early maturing hybrids ranged from -13 % to 12 %, and that of the medium maturing ones from 0 % to 26%, and that of the late maturing ones from -38% to 26% respectively, Positive and negative heterosis for grain yield of the hybrid rices were observed depending on cross combinations, In the positive heterosis hybrids, number of panicles per hill and number of spikelets per panicle contributed mostly to grain yield, while in the negative heterosis hybrids, spikelet fertility and 1000 grain weight were closely correlated to grain yield. Amylose content of the hybrid rices, maintainer and restorer lines was mostly lower than 20 %, and alkali digestion value was higher than 6.0. Grain appearance of the hybrids tested was similar to the korean japonica rice varieties.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.7
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• pp.624-631
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• 2006

This study was conducted to make clustering analysis based on major physicochemical characteristics related to palatability of cooked rice. 89 Korea-bred japonica rice cultivars could be largely classified into two groups, that is, Dongjinbyeo and Ilpumbyeo groups. The Ilpumbyeo group was divided into two subgroups; Ilpumbyeo and Chucheongbyeo groups. The two major rice groups showed significant difference in viscogram properties of rice flour. Ilpumbyeo group revealed slightly higher estimates of viscogram traits as compared with Dongiinbyeo group in average. Early-maturing rice group showed slighly lower estimates of taste meter and higher protein content compared with medium or medium late maturing ones. Also, early and medium-maturing groups exhibited slightly higher estimates of peak, hot and breakdown viscosities but lower estimates of consistenency and setback viscosities compared with medium-late-maturing one. The rice cultivars developed in 2000's revealed slightly higher estimates of peak, hot, cool and consistency viscosities compared with those in $1980's{\sim}1990's$. The grain quality properties significantly associated with the esimates of Toyo taste meter were protein and amylose contents and hot viscosity. The lower protein content and hot viscosity and the higher amylose content, the higher estimates of the taster meter. The protein content was highly negatively correlated with amylose content of milled rice. The important quality components contributed to multiple regression formula for estimating the Toyo taster meter values were protein content, alkali digestion value, and hot viscosity. The fittness of this formula was about 49% along with the coefficients of determination.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.35 no.5
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• pp.379-386
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• 1990

Varietal difference of protein content in forty eight Korean recommended rice cultivars and environmental Variation in protein content of milled rice harvested at six sites of the middle and/or southern plain and four locations of mid-mountainous and/or alpine area in 1989 were investigated. Also, the composition of amino acid in milled rice was compared among three rice varieties: a high-protein japonica rice, Nongbaek, a high-protein Tongil-type rice, Yongjubyeo, and a low-protein japonica rice, Hwaseongbyeo. Korean recommended rice varieties showed 7.93% of average protein content with varietal variation from 5.5% to 10.2% for milled rice harvested in 1988, and 9.17% of mean protein content with the variation from 6.3% to 12.0% for milled rice harvested in 1989. Tongil-type rice was about 1% higher in protein content of milled rice than japonica. The low-protein japonica rice, Hwaseongbyeo exhibited lower content of essential amino acids per g of rice flour sample than the high-protein japoinica, Nongbaek and/or Tongil-type rice, Yongjubyeo, but the relative content of essential amino acids per 16.8g of nitrogen in milled rice of the former was not so different with those of the latters. Among amino acids the content of glutamic acid was highest and among essential amino acids the content of leucine was highest while methionine was lowest. The protein content of milled rice was negatively correlated with days from seeding to heading, K/Mg ratio, alkali digestion value(l-7) and amylose content, but it was positively correlated with translucency and magnesium content of milled rice. The protein content of milled rice harvested in the southern plain paddy field was about 1% higher compared with those harvested in the Middle plain. Also, the protein content of milled rice harvested in the southern mid-mountainous and alpine area was about 0.8% higher compared with those harvested in the resemble altitude area of the middle-northern part of Korea. The contribution of environmental variation to total in plain area was about 28.1% while that in mid-mountainous and alpine area was about 56.4%.