• 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 and cookery science
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• v.18 no.6
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• pp.586-592
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• 2002

The purpose of this study was to investigate the quality characteristics of Jeung-Pyhn by the addition of chitosan-oligosaccharide (COS, Chitoligo-L). Jeung-Pyun is a traditional Korean fermented rice cake leavened by yeast. To develop a functional Jeung-Pyun, COS was added to the rice at the levels of 0, 2, 4 and 6% of the 2-hour-soaked rice. Physicochemical, sensory, rheological and inner structure characteristics of Jeung-Pyun were examined. The pH values of COS Jeung-Pyun batters were decreased with fermentation time. In sensory evaluation, the uniformity of the grain and overall quality of Jeung-Pyun added with 2% COS had the highest score among the samples. In He rheological properties measured with rheometer, the hardness of Jeung-Pyun with COS was higher than control. Cohesiveness of Jeung-Pyun added with 4% COS and gumminess, brittleness and springiness of Jeung-Pyun added with 2% COS were the highest among the samples. The inner structure observed by scanning electron microscope showed that Jeung-Pyun added with 2% COS had the largest and the most uniform air cells. In conclusion, Jeung-Pyun with 2% COS had positive effects on the qualify of Jeung-Pyun.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.1
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• pp.15-26
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• 1994

To understand the relative contribution of varietal and environmental variation on various grain quality components in rice, grain appearance, milling recovery, several physicochemical properties of rice grain and texture or palatability of cooked rice for milled rice materials of seven cultivars(five japonica & two Tongil-type), produced at six locations of the middle and southern plain area of Korea in 1989, were evaluated and analyzed the obtained data. Highly significant varietal variations were detected in all grain quality components of the rice materials and marked locational variations with about 14-54% portion of total variation were recognized in grain appearance, milling recovery, alkali digestibility, protein content, K /Mg ratio, gelatinization temperature, breakdown and setback viscosities. Variations of variety x location interaction were especially large in overall palatability score of cooked rice and consistency or set- back viscosities of amylograph. Tongil-type cultivars showed poor marketing quality, lower milling recovery, slightly lower alkali digestibility and amylose content, a little higher protein content and K /Mg ratio, relatively higher peak, breakdown and consistency viscosities, significantly lower setback viscosity, and more undesirable palatability of cooked rice compared with japonica rices. The japonica rice varieties possessing good palatability of cooked rice were slightly low in protein content and a little high in K /Mg ratio and stickiness /hardness ratio of cooked rice. Rice 1000-kernel weight was significantly heavier in rice materials produced in Iri lowland compared with other locations. Milling recovery from rough to brown rice and ripening quality were lowest in Milyang late-planted rice while highest in Iri lowland and Gyehwa reclaimed-land rice. Amylose content of milled rice was about 1% lower in Gyehwa rice compared with other locations. Protein content of polished rice was about 1% lower in rice materials of middle plain area than those of southern plain regions. K/Mg ratio of milled rice was lowest in Iri rice while highest in Milyang rice. Alkali digestibility was highest in Milyang rice while lowest in Honam plain rice, but the temperature of gelatinization initiation of rice flour in amylograph was lowest in Suwon and Iri rices while highest in Milyang rice. Breakdown viscosity was lowest in Milyang rice and next lower in Ichon lowland rice while highest in Gyehwa and Iri rices, and setback viscosity was the contrary tendency. The stickiness/hardness ratio of cooked rice was slightly lower in southern-plain rices than in middle-plain ones, and the palatability of cooked rice was best in Namyang reclaimed-land rice and next better with the order of Suwon$\geq$Iri$\geq$Ichon$\geq$Gyehwa$\geq$Milyang rices. The rice materials can be classified genotypically into two ecotypes of japonica and Tongil-type rice groups, and environmentally into three regions of Milyang, middle and Honam lowland by the distribution on the plane of 1st and 2nd principal components contracted from eleven grain quality properties closely associated with palatability of cooked rice by principal component analysis.

• Korean Journal of Food Science and Technology
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• v.28 no.4
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• pp.714-719
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• 1996

Changes in physicochemical properties of brown rice (Chu-chunk byeo, Japonica type) kept at $4^{\circ}C,\;20^{\circ}C,\;30^{\circ}C\;and\;40^{\circ}C$ in laminated film (4 layer) pouches were analyzed. Hardness of brown rice grain increased during storage periods. In case of color changes, 'L' value increased during storage below $30^{\circ}C$, and decreased after three months at $40^{\circ}C$. The 'a' value did not change below $30^{\circ}C$, but increased at $40^{\circ}C$. The 'b' value increased under all storage conditions. Percent germination was above 97% below $20^{\circ}C$ regardlesss of storage period and was inhibited by heat above $30^{\circ}C$. The rice did not germinate after one month storage at $40^{\circ}C$ Gelatinization enthalpy and gelatinization peak temperature by DSC of brown rice powder decreased during storage. As a result, storage below $20^{\circ}C$ in laminated film pouch is recommended far brown rice.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.49 no.3
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• pp.160-166
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• 2004

This study was carried out to get the basic informations regarding the varietal variations for the physicochemical properties such as protein content, amylose content, fatty acid content, grain quality values and color properties such as lightness value, chroma and hue for the 164 recombinant inbred lines(RILs) of Milyang 23 and Gihobyeo(M/G) at the experimental farm in the Sangji University. The principal component analysis and heritability study were conducted for this experiments. The rapidity of grain filling(RCF) for the 164 M/G RILs could be classified into four groups such as slow maturing group less than 41％, mid-slow maturing group 41∼60％, fast maturing group 61∼80％ and very fast maturing group more than 81％ based on the rapidity of grain filling rate. The slow maturing group of RGF showed a little bit higher protein content 9.1％, compared to the other RGF groups. However, the amylose content of all the RGF groups revealed the same content by the groups. The very fast maturing group of RGF showed longer grain length in brown rice compared to other RGF varietal groups, in case of grain width in brown rice showed shorter than any other groups. The alkali digestive value which was so much related to gelatinization temperature showed 3.40 degree at fast maturing group of RGF in M/G RILs. However, the very fast maturing group of RGF revealed 4.31 degree of alkali digestive value. The principal component analysis was performed by the chemical and color properties such as quality value, protein content, amylose content, alkali digestive value, fatty acid content, lightness value, chroma and hue for M/G RILs. The first principal component was able to explained upto 36％ to total informations. It was corresponded to quality value, protein content, amylose content, fatty acid content, lightness value and a-value(green -1 red). The characters regarding grain quality showed high heritable properties more than 75％ of heritability, but color characters appeared relatively lower heritability compared to grain quality.

• Korean Journal of Food Science and Technology
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• v.4 no.3
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• pp.179-181
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• 1972

The physicochemical properties of Korean glutinous rice was compared with those of foreign one in order to investigate their appropriateness as raw materials for making rice-cake. The results are summarized as follows: 1) It was found that the Korean ed more crude protein and less total sugar than the foreign one. Therefore, the Korean variety appears to have a higher value of protein. 2) The Korean glutinous rice appeared more plentiful in crude fat and crude fibre content than those of the foreign one. Judging from this fact, it was found out that the Korean glutinous rice had a lower rate of husking and cleaning. 3) The purity of grain in Japanese glutinous rice was highest with 90.2% and the Kyungki glutinous rice was lowest with 47.4%. 4) While showing a low viscosity, the Honam glutinous rice, strange enough, also showed a low dextrinizing temperature.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.9
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• pp.1313-1319
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• 2010

Rice cultivars of Goami2 (G2), Baegjinju (BJJ), and Sulgaeng (SG) with different amylose contents were developed by mutation breeding via N-methyl-N-nitrosourea (MNU) treatment to Ilpumbyeo (IP), high japonica rice. They were identified by different appearances such as grain size, color, and shape. In this experiment, the compositional and physical qualities of those cultivars were examined. The G2 rice classified as a high-amylose rice cultivar was significantly higher in its non-digestable carbohydrates contents. Linoleic and oleic acid were composed of 70~75% of all fatty acids composition regardless of milled and brown rice, except G2 rice in which palmitic acid was the major fatty acid followed by linoleic acid and oleic acid in order. Major amino acids were aspartic acid, glutamic acid, and hydroxy lysine. It was found that cysteine contents were higher in the cultivars of endosperm mutant rice. The DSC analysis revealed that enthalpy was the highest in BJJ followed by SG, IP, and G2 rice. The lowest enthalpy of G2 might be attributable to the higher amylose content. Ilpumbyeo in its cooked rice form showed the highest in Toyo value and less in hardness, but G2 was vise versa. Results of gelatinization and cooked rice properties suggest that G2 was less suitable for cooked rice, but has a potential for functional ingredients from nutritional point of view. The BJJ and SG could be used for traditional cooking as well as for processed foods.

• Applied Biological Chemistry
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• v.44 no.3
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• pp.179-184
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• 2001

To investigate the effects of harvesting times on physicochemical and milling properties of rice, milling tests were performed applying laboratory milling systems. Milling and head rice yields were highest in rice harvested at the 45 days after heading at 76.49 and 94.43%, respectively. Milled rice grain harvested 45 days after heading showed the highest minimum viscosity, as shown in the amylogram curves, as well as the lowest consistency viscosity. Protein and amylose contents were highest in rice harvested at 35 days after heading, whereas the instrumental taste score was highest 45 days after heading.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.65 no.4
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• pp.294-302
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• 2020

Studies on the occurrence of rice preharvest sprouting (PHS) have primarily focused on temperature and rainfall duration at the time of PHS induction, but average temperature during grain filling can have a great influence on PHS. This study analyzed the effect of average temperature during grain filling on PHS occurrence and subsequent changes in grain quality after PHS. For two consecutive years, average temperature differences during grain filling were produced by varying the transplanting date. Artificial rainfall was treated under identical accumulated temperatures of 1200℃ after heading. It was confirmed that the occurrence of PHS was higher under high average temperature conditions during grain filling. In addition, the degree of grain quality reduction caused by PHS occurred more severely under high temperature conditions during grain filling. In order to reduce the risk of PHS occurrence and subsequent quality damage, it is important to control the planting date to avoid high-temperature conditions during grain filling.

• Applied Biological Chemistry
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• v.36 no.3
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• pp.146-153
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• 1993

The changes in water uptake rate, cooking property, color of rice grain, gelatinization property of milled rice during storage were studied. The water uptake rate constant of milled rice during storage at $4{\sim}30^{\circ}C$ for 3 months decreased, which was more pronounced at elevated storage temperatures. The activation energy of water uptake was different below and above $25^{\circ}C$ of storage temperature. The activation energy after storage for 3 months below and above $25^{\circ}C$ was 608 and 1269 cal/mole, respectively. The rice grain became harder and the cooking time was prolonged by $3{\sim}8$ minutes upon storage. The cooking rate constant was linearly decreased as a function of storage time. The activation energy of cooking after 1 month of storage was 235 cal/mole, which was increased by 1.7 times after storage of 1.5 months and thereafter by 1.2 times with the increase of 0.5 month. There were no significant changes in color of milled rice grains during storage at $4^{\circ}C$, but the increase of b value was observed at higher temperatures. The Initial pasting temperature of rice flour remained essentially unchanged during storage, but the peak viscosity consistently increased with the increase of storage time and temperature. The gelatinization temperature of rice flour by differential scanning calorimetry was not changed but enthalpy of gelatinization was decreased during storage.