• 한국식품조리과학회지
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• 제12권1호
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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.

• 대한영양사협회학술지
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• 제21권3호
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• pp.194-202
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• 2015

The study examined dietary intake, satiety rate, and eating rate using rice bowls with an elevated bottom (diet rice bowl) and rice bowls with an elevated bottom and monitoring line (monitoring rice bowl). The monitoring rice bowl was used to help subjects monitor amounts they had eaten as they ate. Eighteen normal weight college female students participated in this study once a week for 2 weeks. Three hundred grams of fried rice in a diet rice bowl (1st week), and 300 g of fried rice in a monitoring rice bowl were served to the participants over 2 consecutive weeks. After each lunch, dietary intake, satiety rate, and eating rate were measured. The consumption amount of fried rice was 261.6 g in the diet rice bowl group, and 264.8 g in the monitoring rice bowl group. There was no significant difference in fried rice intake between the two groups. The satiety rate of fried rice in the monitoring rice bowl group was significantly higher than that of the diet rice bowl group after 1 hour and 2 hours (P<0.05). The eating rate of the diet rice bowl group (21.3 g/min) was significantly faster than that of the monitoring rice bowl group (18.7 g/min) (P<0.05). This result shows that food consumption monitoring can affect not only eating rate but also the subjective feelings of satiety after meal eating. Although more study is needed, these data suggest consumption monitoring in a rice bowl may help to control obesity and weight.

• Journal of Biosystems Engineering
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• 제29권2호
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• pp.121-130
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• 2004

This study was carried out to develop a miller to produce white embryo rice with functional nutrients by improving the conventional vertical miller. The effects of rice moisture content and the shaft revolution speed of the miller on germ(embryo) adherence rate, whiteness, broken rice rate, and cracked rice rate were investigated. Also, the effect of the mesh size of emery stones on the germ adherence rate was investigated. The vertical prototype miller was improved with the increasement of about 42% in producing white embryo rice at proper conditions(shaft revolution speed of 900 rpm, emery stones of mesh ＃50, processing capacity of 2.3t/h, zero outlet resistance, rice moisture content of 16.2%). The results were as follows: 1. The germ adherence rate of white rice was significantly influenced by the moisture content of brown rice. The germ adherence rate of white rice decreased rapidly with the increase of the moisture content of brown rice. When brown rice with moisture content of 13.2%, 14.5%, 15.2%, 15.4% was milled by the prototype with emery stones of mesh ＃35 and shaft speed of 900(1,100) rpm, rpm adherence rate of milled rice was 76.2%(70%), 69.2%(66%), 45.9(38%), 13.0(9%), respectively. 2. The whiteness of white rice milled by the prototype with emery stones of mesh ＃35 and shaft speed of 1,100(900)rpm increased from 27(23) to about 40, respectively, as the moisture content of brown rice increased from 13.2% to 17.2%. 3. The rate of broken rice of white rice milled at 900rpm decreased by 0.6∼1.0% compared with that at 1,100rpm when the moisture content of brown rice was less than 15.2%. 4. The germ adherence rate was increased by 10.3% and 11.0%, respectively when brown rice with moisture content of 16.2% and 15.5% was milled by the prototype miller with shaft speed of 900rpm and emery stones of mesh ＃50 instead of mesh ＃35. 5. Considering the germ adherence rate, broken rice rate, and whiteness of milled rice, the proper milling conditions of the prototype miller for producing embryo rice were the moisture content of about 15%, the processing capacity of 2.3t/h and minimum outlet resistance of 0Nㆍm with shaft speed of 900rpm and emery stones of mesh ＃50.

• Journal of Biosystems Engineering
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• 제24권1호
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• pp.31-40
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• 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.

• Journal of Biosystems Engineering
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• 제23권5호
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• pp.445-456
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• 1998

This study was carried out to evaluate the performance of a medium scale rice polisher of 2.5 t/h and to improve its performance for producing the clean rice with high quality. The maximum internal pressure, broken rice ratio. whiteness in the rice polisher were investigated, and the effects of outlet resistance, water spraying rate, shaft revolution speed and rice moisture content on the polishing performance were analyzed to find out proper operating conditions. The conclusions of this study were as follows: 1. In the performance evaluation of the polisher, the broken rice ratio increment of 0.1%, the max. internal pressure of about 11 N/${cm}^2$, and whiteness increment of 2.2~3.7 resulted at the conditions of 20 PS driving power, 950 rpm, 150 cc/min water spraying rate, 44.1 Nㆍcm outlet resistance and about 15% rice moisture content. 2. Though max. internal pressure and whiteness at the 17% rice moisture content were higher than those at the 15% moisture content under the same operating conditions of the polisher, but the broken rice rate at the 17% moisture content was absolutely low compared with that at 15% moisture content. The water spraying effect to reduce broken rice and to increase whiteness was much significant at the 15% moisture content not significant at 17% moisture content. 3. The main parameter of the performance was outlet resistance, and low resistance of about 44.1 Nㆍcm was recommended at the polisher. 4. The proper water spraying rate in the polisher was about 150 cc/min. 5. As the shaft revolution speed decreased from 950 rpm and 800 rpm to 650 rpm, the broken rice ratio increased and whiteness decreased. 6. As the driving power of the polisher increased from 20 PS to 30 PS, the max. internal pressure decreased by about 1~2.5 N/${cm}^2$ and whiteness increased by about 1~2, but the broken rice rate was not changed. 7. The proper operating conditions of the polisher seemed to be the revolution speed of 800-950 rpm, the water spraying rate of about 150 cc/min, the oulet resistance of about 44.1 N.cm and 30 PS driving power.

• 농업과학연구
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• 제50권2호
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• pp.231-239
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• 2023

Ammonia (NH₃) emitted from the use of fertilizers during agricultural practice generates particulate matter and odors. The application of carbonized rice husk, an eco-friendly material, is one of the measures used to reduce NH₃. The objective of this study was to evaluate the effect of the application rate and pH of carbonized rice husk on NH₃ emissions and soil quality. An experiment to assess NH₃ emissions was performed in a glasshouse using a static chamber method. The pH of the carbonized rice husk was divided into acidic, neutral, and basic groups, and the carbonized rice husk application rates were 1, 3, and 5% of the soil weight. NH₃ emissions showed a sharp increase within three days after the inorganic fertilizer was applied. Subsequently, NH₃ emissions decreased rapidly after basal fertilization compared to primary and secondary top-dressing. When carbonized rice husks were applied to soil, NH₃ emissions decreased in all treatments, and neutral carbonized rice husk was the most effective in comparison with acidic and basic carbonized rice husk. The application rate of carbonized rice husk and NH₃ emissions showed a negative correlation, and the lowest emissions were found in units with a 5% application rate. Also, there was no statistically significant difference between NH₃ emissions according to the application rate of carbonized rice husk, and when carbonized rice husks were applied at a 5% rate, soil OM increased excessively. Therefore, it is recommended to apply only 1% neutral carbonized rice husk to most effectively reduce NH₃ emissions in the soil.

• 농업과학연구
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• 제8권1호
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• pp.3-10
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• 1981

수도개체군(手稻個體群)의 생장(生長)과 수량(收量)을 생산생태자적관점(生産生態字的觀点)에서 해석(解析)하고저 그 생산구조(生産構造)와 평균생장속도(平均生長速度) 및 관련요인(關聯要因)의 영향(影響)을 구명(究明)하여 다음과 같은 결과(結果)를 얻었다. 1. 개체군하(個體群下)에서는 개체상태(個體狀態)보다 전생육기간(全生育期間)에 걸쳐 높은 평균생장속도(平均生長速度)를 지속(持續)하였으며 등숙기간(登熟期間)의 생장속도(生長速度)가 비교적(比較的) 높아 수량(收量)이 증가(增加) 하였다. 2. 벼의 개체군(個體群)이 평균생장속도(平均生長速度)를 높게 유지(維持)하였음은 순동화율(純同化率)보다 엽면적증대(葉面積增大)의 영향(影響)이 더 컸었다. 3. 개체군(個體群)서 품종(品種)에 따라서는 상위엽층(上位葉層)의 과번무(過繁茂)로 하위층엽(下位層葉)에 대(對)한 투광(透光)를 저해(沮害)하여 그 고사(枯死)를 많게 하였다. 4. 개체군(個體群)에서는 생육후기(生育後期)에 갈수록 동화기관(同化器官) 대(對) 비동화기관(非同化器官)의 비율(比率), 투광율(透光率) 및 엽신(葉身)의 질소함량(窒素含量)이 상대적(相對的)으로 저하(低下)하였다.

• Journal of Biosystems Engineering
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• 제25권6호
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• pp.503-510
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• 2000

To improve the milling condition of brown rice a continuous type conditioning equipment was developed. To validate the performance of this machine the experimental operation was done at Sa-cheon RPC(Rice Processing Complex) using short grain rough. The initial moisture contents of brown rice were 15.0∼16.5%(w.b) and the flow rate of brown rice passing through the conditioner were 4,370kg per hour. The moisture content differences of brown rice between conditioned and non-conditioned were showed within 0.5%(w.b) This results means that the water injected to brown rice were absorbed to the surface of brown rice evenly. The moisture contents of conditioned treated milled rice were showed slightly higher than that of non-conditioned ones but it was considered that the conditioning process did not affected the weight increasing of milled rice by water supply. For initial moisture contents of 15.0∼16.5%(wb) brown rice it was found that the proper water supply rate was 0.115(cc-water)/(kg·%-brown rice) and the increments of whole rice were 2.2% compared to the non-conditioned ones. it was considered that the conditioning process did not influenced the whiteness of milled rice because the whiteness differences between conditioned and non-conditioned milled rice were negligible. About 18% of electric power which drives the abrasive type rice milling machine was saved at 0.115(cc-water)/(kg·%-brown rice) of water supply rate.

• Applied Biological Chemistry
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• 제28권2호
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• pp.62-67
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• 1985

일반계(35 품종) 및 다수계(24 품종) 쌀의 수분 흡수 속도에 미치는 인자에 대하여 조사하였다. 각 품종마다 독특한 수분 흡수 속도를 보였으나, 대체로 다수계 품종이 일반계 품종에 비하여 수분 흡수 속도가 빨랐다. 쌀의 수분 흡수 속도는 단백질, 아밀로스, 쌀알의 표면적 및 부피와 상관 관계를 보이지 않았으나, 쌀알의 길이와 폭의 비와는 부의 상관을 보였다.

• Applied Biological Chemistry
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• 제33권1호
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• pp.24-33
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• 1990

현미와 백미의 조리특성, 색도와 호화특성의 변화를 비교조사하였다. 현미와 백미를 $4^{\circ}$ 와 $25^{\circ}C$에 각각 5개월과 3개월간 저장했을 때, 침지온도 $30^{\circ}$에서의 수분흡수속도 상수 값은 백미가 현미보다 약 2.5배 높았고, 저장시간에 따라 직선적으로 감소하였으며 그 정도는 현미 보다 백미가 컸다. 부피증가속도 상수 값도 수분흡수 속도 상수값과 같은 경향을 보였다. 백미의 취반속도는 현미보다 1.8배 빨랐으며, 취반속도상수 값은 저장중 직선적으로 감소하였다. 취반 완료점은 현미가 백미보다 2배 늦었고, 저장 완료후 취반시간은 현미는 8분, 백미는 7분 정도 늦어졌다. 현미립의 색도는 저장에 따라 L값(명도)이 증가하였으나, 백미립은 변화가 없었다. 아밀로그라피에 의한 현미와 백미가루의 초기 호화온도는 변화가 없었으나, 호화점도는 저장에 따라 증가하였으며 $4^{\circ}$의 경우에는 큰 변화가 없었다. 저장중 쌀가루의 시차 주사 열량 측정기에 의한 호화온도는 차이가 없었으나, 호화 엔탈피는 감소하는 경향이었고 현미와 백미의 차이는 크지 않았다.