• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.10-10
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• 2017

Rice consumption has been continuously decreasing as the eating habits of Koreans have become westernized and diversified. The per capita annual rice consumption in Korea has dropped sharply from 136.4 kg in 1970 to 61.9 kg in 2016. The Korean government, therefore, has been trying to promote rice consumption by invigorating the processed food industry using rice flour. To facilitate the market for processed rice foods, it is essential to develop proper milling technology in terms of flour particle size and damaged starch content to produce high quality rice flour at competitive cost. Dry milling and wet milling are the two major processes used to produce rice flour. Although the dry milling process is relatively simple with a lower production cost, damaged starch content increases because of the high grain hardness of rice. In wet milling, the quality of rice flour is improved by reducing flour particle size as well as damaged starch content through soaking procedures. However, the production costs are high because of the additional expenses associated with the disposal of waste water, sterilization and drying of the wet flour. Recently developed technologies such as jet milling and cryogenic milling also require expensive investment and production. Therefore, developing new rice cultivars with dry milling adaptability as well as good processing properties is an important goal of rice breeding in Korea. 'Suweon 542' is a floury endosperm mutant line derived from sodium azide treatment on a high-yield, early maturing, and non-glutinous japonica rice cultivar, 'Namil'. Compared with the wild type, after dry milling process, the grain hardness of 'Suweon 542' was significantly lower because of its round and loosely packed starch granules. Also, the flour of 'Suweon 542' had significantly smaller particles and less damaged starch than 'Namil' and other rice cultivars and its particle size distribution was similar to a commercial wheat cultivar. Recently, through collaborations with nine universities and food companies, a total of 21 kinds of processed prototypes, using the dry milling flour of 'Suweon 542', were evaluated. In the production of major rice processing products, there was no significant quality difference between the flours prepared by wet milling and dry milling. Although the amount of water added to the dough was slightly increased, it was confirmed that the recipe applying the wet flour could be used without significant change. To efficiently transfer the floury endosperm characteristics of 'Suweon 542' to other commercial rice cultivars, it is essential to develop DNA marker tightly linked to the target gene. Association analysis using 70 genome-wide SSR markers and 94 F2 plants derived from 'Suweon 542'/'Milyang 23' showed that markers on chromosome 5 explained a large portion of the variation in floury grains percentage (FGP). Further analysis with an increased number of SSR markers revealed that the floury endosperm of 'Suweon 542' was directed by a major recessive locus, flo7(t), located in the 19.33-19.86 Mbp region of chromosome 5, with RM18639 explaining 92.2% of FGP variation in the F2 population. Through further physical mapping, a co-segregate and co-dominant DNA marker with the locus, flo7(t) was successfully developed, by which, thereby, breeding efficiency of rice cultivars having proper dry milling adaptability with high yield potential or useful functional materials would be improved. 'Suweon 542' maintained the early maturity of the wild type, Namil, which can be used in rice-wheat double cropping systems in Korea not only for improved arable land but also for sharing flour production facilities. In addition to the high susceptibility against major rice diseases, nevertheless, another possible drawback of 'Suweon 542' is the high rate of viviparous under prolonged rainfall during the harvesting season. To overcome susceptibility and vivipary of 'Suweon 542', the progeny lines, derived from the crosses 'Suweon 542' and 'Jopyeong', an early maturing rice cultivar with multiple resistance against rice blast, bacterial blight, and rice strip virus, and 'Heugjinju', a anthocyanin pigment containing black rice cultivar, were intensively evaluated. As the outputs, three dry milling suitable rice elite lines, 'Jeonju614', 'Jeonju615', and 'Jeonju616' were developed.

• Journal of the East Asian Society of Dietary Life
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• v.17 no.6
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• pp.883-893
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• 2007

To optimize the preparation process for oven-roasted glutinous rice cake, an experiment was derived using a central mixing composite design to determine the optimal conditions. The addition of flour by soaking time as well as sucrose and water, were the independent variables, with the moisture content, color, sensory, and texture properties of the ovenroasted glutinous rice cakes selected as response variables. For the moisture content, color, sensory, and textural properties, we found significant effects for moisture, lightness, redness, hardness, and cohesiveness in the oven-roasted glutinous rice cakes, and water was one of the most influential factors. The optimal mixing conditions for the highest quality oven-roasted glutinous rice cake, in terms of sensory and textural properties, were 266.0 g of water, 25.4 g of sucrose, and 61.5 minutes of soaking time for the glutinous rice flour. The soaking time was in close to the median, whereas the water and sucrose values were slightly above the median.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.4
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• pp.499-506
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• 2006

Response surface methodology was used to investigate the cookie manufacturing process with black rice flour. A three- variable, three-level central composite design was employed where the independent variables were the amount of black rice flour ($0{\sim}20%$), baking time ($10{\sim}14 min$), and sugar type (sucrose, aspartame and oligosaccarides). pHs of dough and cookie tended to increase with the addition of black rice flour. Moisture content of dough slightly increased with tile addition of black rice flour but nearly affected by baking time. Spread factor increased with the addition of black rice flour and it was more evident in the samples prepared with sucrose. L*-value decreased but a*-value increased significantly with the addition of black rice flour. Generally the amount of black rice flour in the sample did not affect the textural characteristics of cookie. As the amount of black rice and baking time increased, sensory flavor became stronger. Sensory sweetness as well as hardness increased but sensory color became darker with the addition of black rice flour. In addition, the response surface models developed in this study for most of physicochemical and sensory characteristics of black rice cookie were adequate.

• Journal of Food Hygiene and Safety
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• v.29 no.2
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• pp.117-122
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• 2014

Rice can be the contaminating with soil-borne bacteria. Furthermore, the contaminated bacteria can be grown during immersion process for produce wet-milled rice flour. Therefore, disinfectants can be added during the immersion process. Antibacterial activities of the natural disinfectant, fermented rice spent water (FRSW), and the chemical disinfectants, chlorine dioxide (CD) and sodium benzoate (SB), were respectively determined when added in pure cultures of target bacteria such as Salmonella typhimurium, Escherichia coli, and Bacillus cereus or when added to immersion water in the immersion process. In addition, rinsing effects for removing bacteria were determined when rice was rinsed with water before and after the immersion process. Antibacterial activities were rapidly increased as increasing amounts of the disinfectants are added to the pure cultures of the target bacteria. Antibacterial activity of CD was the most effective among the three tested disinfectants when added to the pure cultures of the target bacteria, respectively. Those of the same disinfectants were increased when they were increasingly added to the immersion water. However those of the disinfectants were less effective when added to the immersion water. On the other hand, rinsing effects for removing bacteria were the most effective when rice was rinsed only with water without the immersion process. Collectively, rinsing rice with water only was more effective than using disinfectants in the immersion water during rice flour production.

• Journal of the Korean Wood Science and Technology
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• v.33 no.1 s.129
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• pp.29-37
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• 2005

The main objective of this research was conducted to evaluate the impacts on the thermoplastic polymer which is a matrix polymer and the rice husk flour (RHF) which is a reinforcing filler relative to the manufacturing temperature and time when bio-composites were manufactured. In order to evaluate the impacts on the rice husk flour relative to the manufacturing temperature, the rice husk flour was persevered for 10 minutes to 2 hours period at $220^{\circ}C$ temperature which was then added with the polypropylene (PP) and low-density polyethylene (LDPE) to complete the manufacturing process of the bio-composites and measure the corresponding mechanical properties. As preserving time increased at $220^{\circ}C$, the tensile and impact strength were decreased due to the thermal degradation of the main components within the rice husk flour. The thermogravimetric analysis (TGA) was used to measure weight loss caused by the actual manufacturing temperature and the result was that the thermoplastic polymer had not scarcely occurred weight change, but there had been increasing rate of weight loss relative to time for the rice husk flour and the bio-composites under the consistent temperature of $220^{\circ}C$ for 2 hour time period. Therefore, the proper manufacturing temperature and time settings are significantly important features in order to prevent the reduction of mechanical properties which were induced throughout the manufacturing process under the high manufacturing temperature.

• Korean journal of food and cookery science
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• v.12 no.1
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• pp.46-53
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• 1996

To investigate physicochemical and cooking properties of parboiled rice, choochung paddy processed to parboiled rice by three methods (PL, PT, PA) milled and examined hydration, cooking qualities and firming rate of cooked parboiled rice. The results were obtained as follows. The longer the steaming time during parboiling the larger EMC of soaked parboiled rice. Water uptake rate constants (k) of all the parboiled rice during soaking except for PT rice were generally increased than those of raw rice. The longer the steaming time during parboiling the greater volume increase rate constants ( $k_{v}$) of parboiled rice samples. The glelatinization temperature of parboiled rice flour by DSC was more increased than that of raw rice flour. Gelatinized entalpy was decreased and gelatinization content (%SG: degree of starch gelatinization) was increased by parboiling process. In cooking tests, parboiled rices were harder than raw rice and softness (reciprocal of hardness) was greater PT30, PA, PL30 in turns the cooking time of the parboiled rice took longer 3-10 min than that of raw rice, PL30 took longer time than anyother rices. Cooking water of parboiled rices could be observed lighter turbidities than that of raw rice. Firming rate constants of cooked rice during storage 24 hours were generally decreased by parboiling-processing. The time constants, reciprocal of firming constants of cooked PL30 rice were 2 times slower than those of cooked raw rice.e.

• Korean Journal of Human Ecology
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• v.5 no.2
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• pp.55-74
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• 2002

This study, observing each respectively packaged Kongdduk during 12-day storing period and comparing it with unpackaged Kongdduk, through a cross-sectional view of its fiber and temperament, through a sensory evaluation rheometer measurement of rheological change depending on storing period and packaging type and through the organic acid content, micro-organic change, and retrogressive process. The results are as follows: 1. Kongdduk made of bean oil shows better chewiness, cohesiveness, and moistness than Kongdduk made of bean flour while Kongdduk made of bean flour shows better rheological properties as to roasted nutty taste or roasted nutty order. 2. The test of the cutted loaves of Kongdduk shows that adding oil of proper proportion to the dough of steamed rice cake in accordance with the amount of rice flour has a good influence on rheological properties of softness. 3. Rice cakes were prepared by addition of yellow soybean flour or peanut flour and packaged with CMP or VP, and their physical characteristics were monitored by sensory evaluation and mechanical measurement while storing for 6 days. For VP samples, yellow soybean rice cake showed little changes in cohesiveness, moistness and chewiness for 6 days of storage, while pure rice cake and peanut rice cake showed an increase in strength and hardness from the 4th day of storage. In case of CMP, yellow soybean rice cake hardly showed a difference in cohesiveness, moistness and chewiness for 6 days, while pure rice cake and peanut rice cake showed a significant difference from the 4th day in sensory evaluation. 4. For rheometer measurement, yellow soybean rice cake with CMP or VP showed little changes in strength or hardness for 6 days, while peanut rice cake and pure rice cake showed a drastic decrease in cohesiveness, from the End day and adhesiveness from the 4th day of storage. As there was no remarkable difference or deterioration for 6 days of storage in yellow soybean rice cake between CMP and VP, the ingredients of rice cakeappeared to be more important than the type of packaging in terms of quality deterioration of rice cake. 5. As the storing period passed by, organic acid is detected less at CMP-packaged Knngdduk than at wrapped. and its increasing speed proves to be slower as well. 6. The one wrapped with plyethylene film began to get moldy from pure rice cake or Kongdduk (rice cake mixed with yellow soybean or peanut) after 6 days, and more and more modly after 9 daysor after 12 days, but the CMP-packaged ones didn't get modly until 12 days or more. 7. CMP-packaged Kongdduk showed higher enthalpy of retrogradation than PE-wrapped one. As storing Period Passed by, Kongdduk,s enthalpy grew high. That is to say, it shows that Kongdduk got retrograded.

• Microbiology and Biotechnology Letters
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• v.38 no.1
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• pp.46-52
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• 2010

Yakju, a Korean traditional alcoholic beverage, is made from glutinous-rice flour or rice starch with nuruk. In this study, we investigated that fermentation characteristics in yakju was made with glutinous rice and pretreatment. The yeast and nuruk were used Y90-9 and SP1800 (a kind of improved nuruk), respectively. pH and brix degree of yakju, brewed with glutinous rice flour by heating, were higher than the others during fermentation process. Total acid contents were 0.2~0.3 and the highest alcohol degree (15.75%(v/v)) was fermented glutinous rice flour by heating. Reducing sugar contents were 3.5-3.9 mg/mL. Yakju, which brewed with glutinous rice flour, of amino acid degree, UV absorbance and color degree was higher than yakju which brewed with glutinous rice starch. Succinic acid was the highest organic acid among 6 organic acids and free sugar contents described as glucose > maltose > fructose. Twenty one components were identified including 3 alcohols, 17 esters and one aldehyde. Of these, ethyl palmitate, which was described as mild flavor, was the highest %area except ethyl alcohol. Overall, the fermentation performed using glutinous rice flour by heating and improved-nuruk showed the best results for yakju production.

• Korean Journal of Food Science and Technology
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• v.20 no.4
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• pp.463-469
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• 1988

The effects of moisture content and particle size of rice flour on the physical properties of the extrudate were examined by using a autogeneous single screw extruder. The moisture contents tested were in the range of 17-28% and the particle sizes were 18-60mesh and 60-120mesh. Samples were taken at different temperatures from the start-up period to the steady state operation. The expansion ratio increased and bulk density decreased as the moisture content and particle size of the flour decreased. The cutting force decreased and the air cell size became uniform as the moisture content and particle size of the flour decreased. As the moisture content increased, the yellowness of the extrudate powder decreased, while the lightness increased, the apparent viscosity increased and the water soluble index decreased. Gelatinization and partial dextrinization were apparent during the extrusion process, and the degree of dextrinization was appeared to be influenced by the levels of moisture content and particle size of rice flour.

• Korean Journal of Food Science and Technology
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• v.20 no.3
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• pp.392-398
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• 1988

Gelatinized rice flours were prepared by drum drying at different moisture contents of slurry made from dry milled and wet milled rice flours. Milled rice samples were prepared from the Chuchung and the Samgang varieties. Degree of gelatinization of drum-dried rice flours revealed over 92% at 60% moisture content of wet milled rice flours and 80% moisture content of dry milled ones. With regards to amylogram and rheological properties, drum-dried rice flours prepared from wet milled raw materials showed higher viscosity than from dry milled ones. Increasing water contents in the slurry increased water absorption index(WAI) and decreased water solubility index(WSI). Hunter's color values of drum-dried rice flour at high moisture contents showed higher L values and lower b values. For the preparation of gelatinized rice flours by drum drying process, the higher water content caused more gelatinized network structure of rice starch in scanning electron micrographs. With regards to farinogram properties of dough with drum-dried rice flours and wheat flours in mixing ratio of 1 to 9 by weight, drum-dried rice flours made from wet milled raw rice flours revealed higher MTI than from dry milled ones.