• Korean journal of food and cookery science
• /
• v.23 no.5
• /
• pp.777-784
• /
• 2007

The purpose of this study was to provide the descriptive sensory profiles for cooked rice by various rice cookers, losing descriptive analysis. The rice samples cooked in an electric pressure cooker, and in pressure cooker B, were separated by roasted flavor, sweetness, burnt flavor, cooked rice flavor, moistness, cohesiveness, and chewiness using PCA. The rice cooked in pressure cooker A was harder and rougher, and showed grain wholesomeness, but it still had a cooked and burnt flavor. The rice cooked in a stone cooker and an electric rice cooker was less hard, and showed less grain wholesomeness, but it had a burnt, cooked rice, and less raw rice type of flavor. Finally, the RTE (ready-to-eat) rice showed more grain wholesomeness, and had more raw rice and sour flavor.

• Proceedings of the Korean Society of Crop Science Conference
• /
• 2017.06a
• /
• pp.67-67
• /
• 2017

We developed the breeding materials with diverse grain size and shape in japonica rice. Grain size and shape are important factors affecting consumer preference and choice. However, most of Korean japonica rice cultivars have small, short, and round grain. To diversify the grain size and shape of japonica rice, we conducted the breeding program using donor parents, Jizi1560 and Jizi1581. Jizi1560 and Jizi1581 are japonica germplasm with extremely large grain. Four crosses between the each donor parents and high yielding japonica rice cultivars, Deuraechan and Boramchan, were constructed and then anther culture method was applied. We obtained 290 doubled-haploid (DH) lines with appropriated morphological traits and selected 91 DH lines with diverse grain size and shape. The grain related-traits of the selected DH lines showed a higher diversity when compared with 319 cultivars developed by NICS (264 japonica, 13 black, and 32 Tongil type cultivars). We designated the selected DH lines, four parents, and Daeripbyeo 1, large grain japonica cultivar, as the breeding materials for further analysis. The breeding materials were classified into five groups, A to E, based on the grain-related traits. Group A (including Jizi1581) and Group B (including Daeripbyeo 1) showed similar grain width, whereas Group A exhibited longer grain length and heavier grain weight. Group C (including Deuraechan and Boramchan) showed shorter and rounder grain shape and smaller grain size than any other groups. Group D including solely Jizi1560 had extremely large grain, such as the longest grain length, width, and thickness and heaviest grain weight. Group E including only two DH lines had long and slender grain shape, so that showed the highest ratio of length to width. The grain size and shape of the breeding materials exhibited beyond the characteristics of previously developed Korean japonica cultivars. The breeding materials will be applied in the breeding programs to diversify the grain size and shape of japonica rice.

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

• Journal of the Korean Society of Food Culture
• /
• v.16 no.4
• /
• pp.323-329
• /
• 2001

This study was carried out to observe the character change of expanded rice grain for Salyeotgangjung at various gelatinization methods. The expansion and structure change of rice grain was different at conditions of heating methods and gelatinization, respectively. The boiling showed good expansion compared to other heating methods by electric rice-cooker, pressure cooker, and steam cooker. There was not difference in expansion of rice grain between the boiling and the boiling after soaking. Rice grain did greatly expand as the boiling time was extended. But the quality for Salyeotgangjung would be not good because of crack of expanded rice grain surface when the boiling time was too long.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.42 no.3
• /
• pp.357-366
• /
• 1997

Rice quality is considered to have two general meanings; 1) milling, cooking, and processing quality, which refer to suitability of the grain for a particular end-use; and 2) physical quality, which means cleanliness, soundness, and freedom from foreign materials. Grain type is associated with specific milling, cooking, and processing characteristics. Thus, this experiment was conducted to classify the grain type categories and marketing grades for Korean leading rice varieties. Length: width ratio of brown rice kernel ranged from 1.57 to 2.25 and most of varieties belonged to short grain except Tongil type rice varieties. Mean of length: width ratio of brown rice kernel was 1.77 and coefficient of variance was 4.79％ in short grain type varieties. Grain shape could be further classified into 5 types by length:width ratio of brown rice kernel; 1 type(less than 1.75), 2 type(1.76∼1.80), 3 type(1.81∼1.90), 4 type(1.91∼2.00), and 5 type (greater than 2.00). For 1 and 2 type of varieties, woven wire sieve having 1.7mm openings showed better whole-kernel yields for special marketing grade, and sieve having 2.0mm openings for 3 and 4 type of varieties. Grain type which classified into 5 categories was not associated with physicochemical and cooking characteristics of rice grain, but sensory evaluation of cooked rice showed better score for 1 type varieties in terms of appearance, gloss, flavor, texture, stickiness, and taste.

• Korean Journal of Agricultural Science
• /
• v.38 no.3
• /
• pp.485-491
• /
• 2011

Yogurt was prepared from skim milk added with 2, 4 or 6% of green whole grain of barley, wheat, glutinous rice and common rice, respectively. Changes in pH, titratable acidity, viable cell counts and viscosity during fermentation were monitored and its sensory evaluation was also performed. The optimum level of additives such as green whole grain of barley, wheat, glutinous rice and common rice for yogurt manufacture was selected to 2%. The samples added with green whole grain of barley and wheat powders reached pH 4.5 in 12 hours. After 4 hours of fermentation, pH, the viable cell counts and viscosity in samples added with 2% green whole grain of barley, wheat, glutinous rice and common rice powders were the highest. Especially, in overall sensory evaluation using 5 parameters, the sensory scores of glutinous rice and common rice 2% yogurts were significantly high. From this experiment, the additives optimum level of glutinous rice and common rice powders was selected to be 2%.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.25 no.3
• /
• pp.497-503
• /
• 1996

In order to obtain basic data for the preparation of rice flour, chemical properties of grain layers were compared using Chucheongbyeo and Samgangbyeo, which are Japonica and Tongil type rice, respectively. The amylose contents of L6(center) layer in two different type of rice were the highest among 6 layers of rice grain tested. Reduction in amylose content was observed as the layer reached the surface, resulting in the lowest amylose content in the L0 layer. Amylose contents of L6 layer of Chucheongbyeo and Sangangbyeo were 3 and 2.2 times higher than those of L1 layer, respectively. Crude protein content of the L2 layer was the highest among 6 layers of rice grain tested and 2.2~2.5 times higher than that of whole milled rice. Crude fat content of grain layer was reduced as reaching the center layer. The crude fat contents of L6 layer of grain were 0.21% and 0.25% in Chucheongbyeo and Samgangbyeo, respectively. Most of free and bound lipids in L0 layer of two different rices were 69 : 31 and 79.5 : 20.5, respectively. Bound lipid content of grain layers increased as reaching the center layer. Major fatty acids in free lipids of both cultivars were linoleic acid, oleic acid, and palmitic acid. Linoleic acid content was higher than oleic acid in Chucheongbyeo, but oleic acid content was higher in Samgangbyeo. Palmitic and myristic acid contents of Chucheongbyeo were higher than those of Samgangbyeo, but stearic and linolenic acid contents were lower than those of Samgangbyeo.

• Journal of Biosystems Engineering
• /
• v.24 no.1
• /
• pp.31-40
• /
• 1999

The objective of this study were to develop a cooling simulation model for fixed-bed of rough rice and to analyze the factors affecting cooling time of rough rice. A computer simulation model based on equilibrium conditions between grain and air was developed to predict temperature and moisture content changes during cooling of rough rice. the result of t-test showed that there were no significant differences between predicted and measured temperature changes on significance model agreed well with measured values. This cooling simulation model was applied to analyze the effect of some factors, such as air flow rate, cooling air temperature and humidity, initial grain temperature and moisture content, and bed depth, on cooling time of rough rice. Cooling rate increased with increase of air flow rate and bed depth whereas it decreased with increase of cooling air temperature and humidity and initial grain temperature. Among these factors, the most important factor was air flow rate. Specific air flow rate of 0.35㎥/min㎥ was required for cooling rough rice in 24 hours.

• Korean Journal of Soil Science and Fertilizer
• /
• v.26 no.2
• /
• pp.85-92
• /
• 1993

This study was investigated on the morphological characteristics of rice grain as affected by three fertilizer application treatments. Of no-nitrogen, optimum nitrogen, and heavy nitrogen without potassium in three regions of Suweon (Mid-West Plain Zone), Ichon(Mid-Inland Plain Zone), and Kyehwado(South-charyung Mts. Plain Zone) with four varieties, i.e., three Tonsil types(Geumgangbyeo, Milyang 23, and Chilseongbyeo) and one japonica type(Chucheongbyeo, Akibare in Japanese name). The results obtained were as follows: The increase of nitrogen application caused an increase of grain length in rough rice and grain width in milled rice, resulting in a decrease of the width/thickness ratio in milled rice. The width and thickness of rice grain produced in Kyehwado were smaller than those in the other regions. Therefore, the ratio of length/width and length/thickness in rice grain produced in Kyehwado was larger. The one thousand grain weight of rice was heavier at the optimum nitrogen level than at the no-nitrogen and heavy nitrogen without potassium treatment levels. The weight percentage of hull in rough rice grain decreased in accordance with the increase of nitrogen application, while the weight percentage of bran in brown rice was constant. This suggested that for the normal development of rice grain a constant ratio of bran is needed. The morphological change of rice grain by fertilizer treatments and the change of region cultivated could not be distinguished from the native characteristics of the variety. Other grain characteristics were discussed in view of treatment and regional effects.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.37 no.3
• /
• pp.244-249
• /
• 1992

To investigate the varietal variations in absolute density of milled rice grain and its relations with other grain characters, the 235 rice varieties which consist of 30 Tongil type rices, 72 Japonica rices and 133 Indica rices were tested on grain size, volume, hardness, chalkiness and 1000 grains weight of brown rice, ADV, amylose content, starch composition on SEM and absolute density of milled rice grain using completely ripened grains. Average absolute density of milled rice grain was 1.496g / cm$^3$ in Tongil type rices, 1.506g / em in Japonica rices, and 1.500g / cm$^3$ in Indica rices. It was correlated positively with days to heading and grain hardness, and negatively with chalkiness, volume, grain weight and grain length of brown rice. Regression analysis indicated that grain volume and weight were the major characters affecting the density. However, since the absolute density of milled rice grain did not show great varietal variations it might not seem important as one of the characters contributing to the grain yield, while it could be a factor affecting the grain quality because there were definite varietal differences even though small. The microscopic feature of starch composition on SEM revealed differences between clear and chalky parts of the grain in shape and compactness of starch composition but did not discriminate between high and low-density grains.