• Journal of Biosystems Engineering
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• 제5권2호
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• pp.1-14
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• 1980

This study was carried out to investigate the effects of the counter-pressure setting and the roller speed of a rice whitening machine on the head rice recovery. milling capacity and milling efficiency, and also to find out the optimum operational conditions of the machine. The radial pressure inside the whitening chamber and the outlet axial pressure were measured to study their relationships with the head rice recovery, milling capacity and milling efficiency. The results of the study are summarized as follows. (1) The most important factor in rice whitening was the counter-pressure setting. It significantly affected the head rice recovery. (2) The roller speed significant affected the milling capacity and milling efficiency , but it did not affected the head rice recovery. (3) Both the radial pressure and the outlet axial pressure were affected by the counter-pressure setting but not by the roller speed. Both of them increased almost linearly with the counter-pressure setting. There was a significant correlation between the radial pressure and the outlet axial pressure. (4) The flow rate through the whitening chamber when the feed gate was fully opened increased with the roller speed, but it was not affected by the counter-pressure setting. (5) The head rice recovery decreased as the counter-pressure setting increased , but it was not affected by the roller speed. The reason could be explained by the fact that the radical pressure increased only with the counter-pressure setting. (6) The milling capacity increased with the counter-pressure setting and linearly with the roller speed. The milling efficiency generally increased with both the counter-pressure setting and the roller speed. However, the effect of roller speed was negligible at the higher counter-pressure setting. The temperature rise inside the whitening chamber was moderate with the mean of 11.3℃ (range 5.6-18.3℃) even though it increased slightly with the roller speed. Considering the head rice recovery and milling efficiency, the optimum operational conditions of the machine appeared to be the counter-pressure setting of 67g/㎠ and the roller speed of 1,050rpm. Neglecting the small difference in the head rice recovery , the greater milling capacity could be obtained at the counter-pressure setting of 85g/㎠ with the roller speed of 850-1050rpm.

• Journal of Biosystems Engineering
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• 제4권2호
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• pp.1-8
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• 1979

This study was carried out to investigated the actual state of rice milling at local milling plants and to find out sources for elevating their milling recoveries in both quantity and quality. At 36 local milling plants located in Gyeongnam and Jeonnam , milling recoveries and head rice recoveries were measured with respect to their different milling systems and rice varieties. Then, the same samples of rice were milled by experimental milling equipments at laboratory, and the two experimental results were compared in order to determine the amount of milling recovery possibly to be increased. The results of this study are as follows ; 1. Milling recoveries of rice at local milling plants were proved to have no relationship with milling systems, and were 68.1% per ent and 72.6percent on an average with new variety and native variety, respectively. 2. The milling recoveries above stated can be elevated 4.5 percent and 2.9percent with new variety and native variety, respectively, by developing and extending technologies of manufacturing and handling rice milling machinery. 3. The head rice recovery of new variety at local milling plants has insignificant differences among milling systems, and was 54.8 percent on the average. With native variety, the recovery by friction type rice polisher was 0.9percent higher than that of friction-abrasive type polisher, and was 64.9 percent on the average. 4. The head rice recoveries of new variety and native can be elevated 5.1percent and 3.9percent, respectively, by the same stimulation above mentioned.

• 한국작물학회지
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• 제57권3호
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• pp.280-285
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• 2012

본 연구는 국내에서 재배되고 있는 조 품종의 도정수율 증진을 위한 도정방법 및 적정 수확시기를 검토한 결과를 요약하면 다음과 같다. 제현횟수와 도정시간에 따라 제현율과 완전미도정수율의 차이가 인정되었고, 이들의 상호작용에 있어서도 유의성이 인정되었다. 조의 완전미도정수율은 제현횟수를 2회, 도정시간을 1분 30초로 하였을 때 높았다. 출수 후 수확일수에 따른 현곡천립중, 제현율, 현곡의 경도, 도정율과 완전미도정수율의 차이가 인정되었고, 이들 요인간 상호작용에 있어서도 유의적인 상관이 인정되었다. 등숙율과 완전미도정수율 향상을 위해 조생종인 황금조는 출수 후 45일(적산온도 $1,148^{\circ}C$), 중생종인 삼다메와 경관1호는 출수 후 50일(적산온도 $1,150^{\circ}C$), 만생종인 삼다찰은 출수 후 55일(적산온도 $1,168^{\circ}C$)에 수확하는 것이 가장 적당하였다.

• Journal of Biosystems Engineering
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• 제27권2호
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• pp.125-132
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• 2002

In order to investigate the optimum moisture content of paddy for milling process, a series of tests were conducted by examining the recovery rate and whiteness of milled rice in relation with the various moisture content. Hwabong-byeo and Dongjin-byeo varieties which were major paddies cultivated in Korea were used for the experiment. The test was performed with small experimental milling machines. In order to minimize the unexpected factors, environment conditions were kept in constant during the experiment. As a result, the recovery rate of milled rice were varied as the changes in milling time and degree of whiteness. However, the recovery rate of milled rice increases as its moisture content increases untill a certain point of moisture content and decreases slowly afterward. This certain point can be called optimum moisture content for rice milling. Also, it has a different value depending on the variety. In this experiment, optimum moisture content of Hwabong-byeo and Dongjin-byeo were considered around 14.8% and 15.3%, respectively. It is not sure that these optimum moisture contents for the two varieties would assume the same values irrespective of harvest year and place. However, it could be concluded that the optimum moisture content for rice milling is around 15%(w.b.) for Hwabong-byeo and 15.5%(w.b.) for Dongjin-byeo, respectively.

• 한국식품저장유통학회지
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• 제23권4호
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• pp.530-537
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• 2016

본 연구에서는 보리 품종 및 도정률이 막걸리 품질특성에 미치는 영향을 살펴보기 위해 도정률(95, 85, 75%)을 달리한 새쌀보리, 새찰쌀보리, 흰찰쌀보리 원료의 특성을 살펴보고 이를 이용하여 제조한 막걸리의 품질특성을 살펴보았다. 원료곡의 품질 특성은 도정률이 감소할수록 단백질, 지방 및 회분 함량이 감소하는 경향을 나타내었으며 호화특성 또한 도정률이 감소할수록 유의적(p<0.05)으로 높은 경향을 나타내었다. 일반적으로 호화 특성 측정 결과 최고점도 및 강하점도가 높고 치반점도가 낮으면 식미가 양호하게 되는데 본 연구에서는 새쌀보리 및 흰찰쌀보리가 새찰쌀보리에 비해 식미특성이 양호할 것으로 판단된다. 보리의 품종 및 도정률에 따라 제조한 막걸리의 알코올 함량과 총산도의 유의한 차이는 없었으나, 도정률이 감소할수록 고형분 함량과 환원당함량이 유의적(p<0.05)으로 증가하였으며, 관능 특성을 살펴본 결과 보리의 품종과 도정률이 낮을수록 막걸리의 향기, 맛, 색의 점수가 증가하는 것으로 나타났다. 또한 고형분 함량, 환원당함량 그리고 관능적 특성에서 새쌀보리로 제조된 막걸리에서 다른 품종에 비해 높은 수치를 확인할 수 있었다. 따라서 본 연구결과, 도정률이 75%인 새쌀보리로 막걸리를 제조하였을 때 우수한 품질특성을 갖는 막걸리를 기대할 수 있을 것으로 판단된다.

• Journal of Biosystems Engineering
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• 제3권1호
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• pp.47-63
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• 1978

This study was conducted to obtain a basic information necessary to assess present rice milling technology in Korea The profiles for milling plants was analyzed by survey work.For the private custom-work mills, which process about 80 percent of domestic rice consumption ,their actual milling test for the identical samples as used for filed mills was conducted. Two rice varieties Japonica and Tongil-type were associated with the experiments. The results are summarized as follows: 1. Analyses for private custom-work mills showed their general aspects as; about 91 percent of the mills belonged to an individual owner ship ; more than 93 percent of the mills was established earlier than 1950 ; about 80 percent of the mills was powered with electric motor; mills having less than two employees were about 75 percent; about 45 percent of the mills provided for warehouse in storing customers cereal grains. 2. The polishers installed in 1,255mills within the surveyed area (7 counties) have been supplied by 44 different domestic manufacturers ;in but about 60 percent of which was supplied by 6major manufacturers. The polishers could be classified into two categories in terms of principles of their polishing actions ;jet-pearler and friction types. About 51 percent of the mills was equipped with the former which has been recognized as giving greater milling recovery than the friction types. 3. Reason for owners of private mills to supplement new machines was due mainly to pgrading their mills to meet the requirements that established by the Government. However, about 60 percent of the mill owners intended to replace with new pearler by their own needs to meet with new high yielding varieties. 4. Processing systems of each previate rice mills surveyed could be classified into three categories, depending upon whether the systems posessed such components as precleaner and paddy separator or not. Only 36.7 percent of mills was installed with both precleanr ad paddy seperrator, 5.0 percent of mills did have neither percleaner nor paddy seperator, and rest of them equipped only one of the two. Hence,it is needed for about 63% of rice miils to be supplemented with these basic facilities to meet with the requirements for the standaized system. 5. Actual milling capacity measured at each field rice mills was shown a wide variation, having range from about 190 to 1,210 kg/hr. The percentages of mills classified according to daily milling capacity based on this hourly capacity were 24.3% for the capacity less than 3 M/T a day; 20.0% for 3-4 M/T; 15.6% for 4-5 M/T; 6.7% for 5-6 M/T; 22.3% for 6-7 M/T; and 11.0% for more than 7 M/T a day. 6. Actual amount of rice processed was about 310 M/T a year in average. About 42% of total milled rice was processed during October to Decembear, which formed a peak demand period for rice mills. The amount of rice milled during January to May was relatively small, but it had still a large amount compared to that during June to September. 7. Utilization rate of milling facility, i. e., percentage of the actual amount of milled rice to the capacity of rice mills, was about 18% on the year round average, about 41% in the peak demand season, and about 10% during June to September. Average number of operating days for mills surveyed was about 250 days a year, and about 21 days a month. 8. Moisture contents of paddy at the time of field mill tests were ranged 14.5% to 19.5% for both Japonica and Tong-i] varieties, majority of paddy grains having moisture level much higher than 1530. To aviod potential reduction of milling recovery while milling and deterioration of milled rice while storage due to these high grain mJisture contents, it may be very important for farmers holding rice to dry by an artificial drying method. 9. Milling recovery of JapJnica varieties in rice mills was 75.0% in average and it was widely ranged from 69.0% to 78.0 % according to mills. Potential increase in milJing recovery of Japonica variety with improvement of mill facilities was estimated to about 1.9%. On the other hand, milling recovery of Tong-il varieties in the field mill tests was 69.8% in average and it ranged from 62% to 77 %, which is much wider than that of Japonica varieties. It is noticed that the average milling recovery of Tong-il variety of 69.8% was much less than that of the Japonica-type. It was estimated th3.t up to about 5.0% of milling recovery for Tong-il variety could be improved by improving the present lo'.ver graded milling technology. 10. Head rice recoveries, as a factor of representing the quality of commercial goods, of Japonica and Tong-il varieties were 65.9% and 53.8% in average, and they were widely ranged from 52% to 73% and from 44% to 65% , respectively. It was assessed that head rice recovery of Japonica varieties can be improved up 3.3% and that of Tong-il varieties by 7.0% by improving mill components and systems.

• Journal of Biosystems Engineering
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• 제4권1호
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• pp.76-86
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• 1979

This study was conducted to find out the effects of rainfall occurring during the paddy sun-during process of traditional paddy harvesting operations on the quality of milld rice. Rice varieties used for the experiment were MINEHIJARI variety a japonica and SUWEON 264 vareity , a sister-line of TONG-IL . Sun-drying days after the paddy cutting, times of storm occurrance during sun-drying period, and storm duration were treated as variables. The results is summarised as follows : 1. Brown rice recovery exposed to rainfall during the sun-druing period were ranged 81.6-82.1% and 79.4-80.2% for MINEHIKARI and SUWEON 264 varieties, respectively. which showed negligible effect by rainfall. 2. Milling recovery of MINEHIKARI variety was not affected by storm duration but by the by the sun-drying days after cutting as the sun-drying days increased to eight and four days when the variety met the rainfall one and two times, respectively. The range of milling recoveries of MINEHIKARI variety were 75.18-74.07% and 75.24-73.46% as the variety met the rainfall one and two times, respectively, and it were estimated that up to 0.9% and 1.5% of milling recovery would be reduced by one and two times of rainfall during sun-drying period. 3. The milling recovery of SUWEON 264 variety was affected only by the increase of drying days after cutting when it met one time of rainfall during the sun-drying period, while it was begun to reduce by the storm duration more than 11hours as the drying paddy met two times of rainfall. The milling reveries of the paddy met one and two times of rainfall were ranged 74.24-73.21% and 74.02-72.36% which were estimated to be reduced up to 0.9 % and 1.8% by the increase of the drying days after cutting and storm duration , respectively. 4. The head rice recovery of MINEHIKARI rice variety showed notable decrease as the drying days after cutting increased, and also it was greatly reduced even by the five hours of storm duration when one time of rainfall occurred but it was not affected by storm duration when the rainfall occurred two times. Head rice recoveries of MINEHIKARI met one and two times of rainfall during the sun-drying period were 65. 15 -40.85% and 61.86 - 30.03 %, which showed terrible reduction as much as up to 25% and 35% compared to that which did not met rainfall during the sun-drying process. 5. Head rice recovery or SUWEON 264 variety was very much reduced as the sum-drying days after cutting increased. Storm duration less than five hours during the sun-drying process did not affect on the decrease of head rice recovery when the variety was exposed to one time of rainfall, while storm duration affected considerably on the reduction of head rice recovery of SUWEON 264 variety exposed to two times of rainfall. The range of head rice recovery, 56.43 - 33.94% and 51.28 - 21.03% , for the paddy exposed to rainfall one and two times were evaluated that up to 24% and 37% of reduction in head rice recovery would be brought about compared to the head rice recovery of the sundriedpaddy that did not met the rainfall.

• Journal of Biosystems Engineering
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• 제4권1호
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• pp.75-75
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• 1979

This study was conducted to find out the effects of rainfall occurring during the paddy sun-during process of traditional paddy harvesting operations on the quality of milld rice. Rice varieties used for the experiment were MINEHIJARI variety a japonica and SUWEON 264 vareity , a sister-line of TONG-IL . Sun-drying days after the paddy cutting, times of storm occurrance during sun-drying period, and storm duration were treated as variables. The results is summarised as follows : 1. Brown rice recovery exposed to rainfall during the sun-druing period were ranged 81.6-82.1% and 79.4-80.2% for MINEHIKARI and SUWEON 264 varieties, respectively. which showed negligible effect by rainfall. 2. Milling recovery of MINEHIKARI variety was not affected by storm duration but by the by the sun-drying days after cutting as the sun-drying days increased to eight and four days when the variety met the rainfall one and two times, respectively. The range of milling recoveries of MINEHIKARI variety were 75.18-74.07% and 75.24-73.46% as the variety met the rainfall one and two times, respectively, and it were estimated that up to 0.9% and 1.5% of milling recovery would be reduced by one and two times of rainfall during sun-drying period. 3. The milling recovery of SUWEON 264 variety was affected only by the increase of drying days after cutting when it met one time of rainfall during the sun-drying period, while it was begun to reduce by the storm duration more than 11hours as the drying paddy met two times of rainfall. The milling reveries of the paddy met one and two times of rainfall were ranged 74.24-73.21% and 74.02-72.36% which were estimated to be reduced up to 0.9 % and 1.8% by the increase of the drying days after cutting and storm duration , respectively. 4. The head rice recovery of MINEHIKARI rice variety showed notable decrease as the drying days after cutting increased, and also it was greatly reduced even by the five hours of storm duration when one time of rainfall occurred but it was not affected by storm duration when the rainfall occurred two times. Head rice recoveries of MINEHIKARI met one and two times of rainfall during the sun-drying period were 65. 15 -40.85% and 61.86 - 30.03 %, which showed terrible reduction as much as up to 25% and 35% compared to that which did not met rainfall during the sun-drying process. 5. Head rice recovery or SUWEON 264 variety was very much reduced as the sum-drying days after cutting increased. Storm duration less than five hours during the sun-drying process did not affect on the decrease of head rice recovery when the variety was exposed to one time of rainfall, while storm duration affected considerably on the reduction of head rice recovery of SUWEON 264 variety exposed to two times of rainfall. The range of head rice recovery, 56.43 - 33.94% and 51.28 - 21.03% , for the paddy exposed to rainfall one and two times were evaluated that up to 24% and 37% of reduction in head rice recovery would be brought about compared to the head rice recovery of the sundriedpaddy that did not met the rainfall.

• Journal of Biosystems Engineering
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• 제8권2호
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• pp.62-68
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• 1983

This study was to examine the drying characteristics of barley and the effect of moisture content of barley on milling performance. A barley variety, Jogang, having 35.0% of initial moisture content was used for this experiment. Thermo-hydrostatic dryer which consists of blower, condensor, heater, humidifier, drying chamber and control box, etc., was used for the drying experiment. The change in the weight of a barley sample was continuously measured by means of the ring type load cell installed inside the drying chamber. Milling test runs the samples having the predetermined moisture content were taken from each drying test run. A laboratory type barley miller was used for the milling test. The results of the study are summarized as follows: 1. The drying constants (k) applied for the thin layer drying model, (M-Me)/(Mo-Me) = $Ae^{-kt}$ were 0.155, 0.259 and 0.548, respectively, at the three levels of drying temperatures, $40^{\circ}C$, $50^{\circ}C$ and $60^{\circ}C$. The drying constants complied with the Arrhenius Equation, K = Ko exp (-C/T), were determined as $Ko=1.901455{\times}10^8$ and C = 6563. 2. The laboratory milling test indicated that the highest milled and head barley recovery was resulted from the sample which was dryed at $40^{\circ}C$. In general, the increase in the drying temperature from $40^{\circ}C$ to $60^{\circ}C$ indicated a negative effect on milling yields. 3. Also, the sample having 15% M.C. presented the highest milled and head barley recovery among the five moisture content levels (12, 15, 18,21 and 24%).

• Journal of Biosystems Engineering
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• 제2권1호
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• pp.56-80
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• 1977

This experimental work was conducted in order to find out the optimum time of harvest of Japonica-type (Akibare) and Indica-type(Tong-il) rice variety for three harvesting systems by investigating the harvesting losses and milling quality. The study was also concerned about the nature and amount of grain losses incurred during the each sequence of post-harvest technologies, and based on these result, a modification of existing systems giving a minimum grain loss was attempted. Binder, combine, and traditional systems were tested in this study and five grain moisture levels were disposed according to the decrease of grain moisture . The results are summarized as follows ; 1. The total losses of Akibare variety were ranged from 1.1 to 1.5 per cent for the traditional harvesting system , 2.1 to 4.8 per cent for the harvesting system by use of binder, and 2.8 to 4.3 per cent for the harvesting system by use of combine as the grain moisture content was reduced from 24 to 15 percent. Milling recovery of the harvesting system by use of binder, 74.8 ∼75.7 percent, was a little higher as it was compared to that of traditional harvesting system, 74.3 ∼75.0per cent, and that of the harvesting system by use of combine, 73.8 ∼75.0 per cent. Head rice recovery of mechanically dried paddy samples was higher than that of sun-dried paddy samples. 2. The total losses of Tong-il variety were ranged from 3.8 to 5.0 per cent for the traditional harvesting system, 5.2 to 10.0 percent for the system by use of binder, and 3.0 to 5.0 per cent for the system by use of combine as the grain moisture was reduced from 28 to 16 per cent. 3. Milling recovery of Tong-il variety harvested by the traditional harvesting system was 72.3 ∼73.6 percent and it was lower when compared to that of 72.3∼75.0 per cent harvested by binder, and 73.0∼74.6 percent harvested by combine. 4. Head rice recovery of Tong-il variety harvested by the traditional harvesting system (58.