• 제목/요약/키워드: rice drying

검색결과 259건 처리시간 0.025초

곡물건조저장법 개선을 위한 농가용 Grain Bin에 관한 연구 (Study on the Small Grain Bin for the Improvement of Grain Drying and Storage)

  • 김성래
    • 한국농공학회지
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    • 제16권1호
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    • pp.3263-3291
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    • 1974
  • Experimental work of grain bin was carried out to develop the methods of natural air in-bin drying and storage. The method is considered to be more economical, labour saving, and an effective countermeasure to grain loss. To examine the possibility of farm use of the grain bin and to analyze the related factors concerned with in-bin grain drying and storage, ambient air conditions (especially the change of air temperature and relative humidity) and grain quality during drying and storage periods were investigated. A laboratory model bin was constructed to investigate the effect of different forced air conditions on the drying characteristics of rice. In addition, a grain bin with 2.2m diameter and 1.8m height, considered to be the optimum size for the average Korean farm, was constructed and tested to examine the drying and storing characteristics of rice. The weather data analyzed in this study was the nine-year (from 1964 to 1972) record of air temperature and relative humidity in the Suweon area, and the thirty-year (from 1931 to 1960) record of pentad normal relative humidity and air temperature in the Seoul area. From the results of the weather data analyses, the adequate air delivery hours (which was arbitrary defined as the condition to give less than 75% relative humidity) to dry the rice during October were about nine hours (from approximately 10 A.M. to 7 P.M, ) a day, in which the average air temperature was about 15.9$^{\circ}C$ and average relative humidity was 66%. The occurence of days having three hours of such conditions was 1, 2, and 1-day within the 1st, 2nd add last 10-day periods for the month of October, respectively. Therefore, it may be considered that the weather condition in October was satisfactory for the forced natural air drying. The results of the laboratory model bin test were analyzed to obtain the drying curve and drying rate for different drying stages and grain layers in the bin corresponding to various conditions of forced natural air. A drying experiment with a prototype grain bin showed that an approximate 5 percent grain moisture gradient through a 1.6 meter grain deposit was observed after 80 hours of intermittent drying, giving an over dried zone in the lower grain layers and an extremely high grain moisture zone in the upper layers. This indicates that an effective measure should be taken to reduce this high moisture gradient. In order to investigate the drying characteristics of bulk grain in a layerturning operation a grain bin test was performed. This showed a significant improvement of uniform drying. In this test, approximate 107 hours were required to dry a depth of 1.6 meter of grain from an initial moisture content of 22.2 percent to a moisture content of 16.7 percent using an air delivery rate of 2.8 cubic meter per a minute per every cubic meter of grain. This resulted in a 2 percent moisture gradient from the top to the bottom of the bin. During storage period, till the end of June the average temperature of grain was 2~3$^{\circ}C$ higher than ambient air temperature. But during July when the grain moisture content went up slightly (less than 1 percent), the average temperature of the grain also increased to 3~5$^{\circ}C$ higher than ambient air temperature. It is therefore recommended that for safe grain storage, grain should not be stored in sheet metal bins after mid May. From the above results, in-bin rice drying and storage can be used effectively on Korean farms. It is strongly recommended that the use of grain-bin system should be implemented for farm use to improve farm drying and storage of rice.

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벼의 물리적(物理的) 및 열적(熱的) 특성(特性)에 관(関)한 연구(硏究) -열적(熱的) 특성(特性)에 관(関)하여- (Study on the Physical and Thermal Properties of Rice Kernels - Thermal Properties -)

  • 고학균;노상하;정종훈
    • Journal of Biosystems Engineering
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    • 제9권2호
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    • pp.89-96
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    • 1984
  • This study was intended to search the thermal properties of rice which are necessary in preventing qualitative and quantitative losses in the drying and milling processes. First, the coefficient of cubical thermal expansion of brown rice was measured, which is required for analyzing the internal stress of rice, and then theoretical thermal and moisture stresses were calculated. The results are summarized as follows: 1. The coefficient of cubical thermal expansion of brown rice was about $2.81{\times}10^{-4}/^{\circ}C$ in the temperature range of $10^{\circ}C-60^{\circ}C$. 2. When the shape of brown rice was assumed to be a sphere or a cylinder, maximum thermal stress due to temperature change of $20^{\circ}C-60^{\circ}C$ was in the range of $25-100kg/cm^2$. And maximum moisture stress was in the range of $450-650kg/cm^2$ when the drying temperature was $35^{\circ}C$, initial and final moisture contents of brown rice were 20% and 14% (w.b.), and the moisture diffusion coefficient was assumed to be $6.79{\times}10^{-4}cm^2/hr$. 3. Consequently, it was concluded that crack formation in a rice kernel is mainly caused by moisture stress.

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산업용지 현장테스트를 통한 왕겨 유기충전제 최적 사양 탐색 (Development of New Organic Filler Made from Rice Husk by Paperboard Mill Trials)

  • 이지영;김영훈;김철환;성용주;위상욱;박종혜;김은혜
    • 펄프종이기술
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    • 제47권4호
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    • pp.96-101
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    • 2015
  • In the previous study, we investigated the physical properties of new organic fillers made from major agricultural byproducts, including rice husks, peanut husks and garlic stems, and we estimated that rice husk was the best candidate for use as new organic fillers in paperboard. In this study, an organic filler prototype was produced with rice husk and the mill trials were carried out in a white liner chipboard (duplexboard) mill. The rice husk organic filler was added to the middle ply of SC $350g/m^2$ to determine the optimal conditions for the manufacture of rice husk organic fillers. The mill trials were performed three times and the bulk improvement and drying energy reduction were measured to identify the functionality of the rice husk organic filler compared to that of the commercial wood powder. In the first mill trial, the test failed because the surface roughness of the duplexboard had deteriorated after the rice husk organic filler was added to the OCC stock. As all of the particles remaining on the 60 mesh sieves were removed and the particle size was decreased by increasing the length of the grinding process, the surface roughness of the duplexboard did not be deteriorated in the second mill trial. However, the bulk improvement and drying energy reduction were not observed. In the final mill trial, as the particle size of the rice husk organic filler was controlled by increasing the portion of particles passing through the 60 mesh sieves and remaining 100 mesh sieves, higher bulk improvement and drying energy reduction were acquired compared to the commercial wood powder.

AN ENERGY ANALYSIS ON GRAIN DRYING SYSTEMS IN CHINA

  • Shao, Y.J.
    • 한국농업기계학회:학술대회논문집
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    • 한국농업기계학회 1993년도 Proceedings of International Conference for Agricultural Machinery and Process Engineering
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    • pp.906-911
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    • 1993
  • There will be about 0.25 to 0.3billion tons of grain product including rice, wheat and corn etc. each year in China. An energy analysis on grain drying system on which electricity , oil , coal or sun power and batch, tower with thick or thin layer of grain, infra red radiation. fluidized flowing types grain drying systems were made and compared for the sake of energy saving is shown in this paper.

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건식과 습식 제분조건에 따른 멥쌀가루의 특성 (The Properties of Rice Flours Prepared by Dry and Wet Milling Method)

  • 김은미
    • 한국식품조리과학회지
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    • 제26권6호
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    • pp.727-736
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    • 2010
  • The purpose of this research was to compare the physicochemical compositions and morphological properties of five varieties of rice flours (RR, RGD, RSGD, RWDG, RWGD). RR was raw milled rice without washing, RGD was raw rice flour without soaking, RSGD was raw milled rice flour with 0 hr of soaking, RWDG was raw rice flour with 8 hr of soaking and grinding after drying, and RWGD was raw rice flour with 8hr of soaking and drying after grinding. The protein and lipid contents of wet milling rice flour (RSGD, RWDG, RWGD) were significantly lower than those of dry milling rice flour (RR, RGD). L and a values were significantly increased in wet milling rice flour, and b value was significantly increased in dry milling rice flour. Scanning electron microscopy (SEM) showed that RWDG and RWGD were distributed as separated fine particles in rice flours. The WBC of RWDG and RWGD were higher than those of other rice flours. Solubility was significantly increased according to the temperature, and swelling power of RWDG was higher than that of other rice flours at 50 and $60^{\circ}C$. Using RVA, the initial pasting temperature and setback of RWDG were lower and the peak viscosities of RSGD and RWDG were higher than those of other rice flours. Using a mixograph, peak times were not significantly different among the groups, wheras peak heights were significantly decreased in RSGD, RWDG, and RWGD. The peak width of RWGD was lower than those of other rice flours. Based on these findings, RWDG flour was less damaged, and had a lower setback and pasting temperature, which makes it an appropriate rice flour for commercial mass production.

복원용 밥의 미생물 안전성 및 식감 향상을 위한 저온 숙성 및 건조 처리 (Low-temperature aging and drying treatments of restorative rice to improve its microbial safety and texture)

  • 천희순;조원일;정명수;최준봉
    • 한국식품과학회지
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    • 제51권1호
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    • pp.29-34
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    • 2019
  • 본 연구의 침지쌀을 $90-100^{\circ}C$의 온도에서 1, 2차 증숙한 다음 $0-10^{\circ}C$의 냉장저온에서 숙성하는 1단계 처리와 이어 상대습도 85%, $-20^{\circ}C$에서 냉동하는 2단계 그리고 $1-20^{\circ}C$의 상압에서 5 m/s 풍속으로 저온 건조하는 3단계로 구성된 최종 수분함량 30% 인복원용 밥의 제조방법은 기존 열풍건조 대비 관능품질을 향상시키고 상온 3개월 내외의 보관을 가능하게 하였다. 구체적인 효과는 2단계 증숙 및 저온 장시간 건조 과정을 통해 개선된 복원용 밥의 수분함량이 기존 건조밥의 7% 대비 4.3배 높고 쌀알의 고유 형태가 잘 유지되어 있어 취식을 위한 열수 복원시 전반맛, 식감과 외관이 관능평가에서 통계적 유의 있게 향상되었다(p<0.05). 또한 수분 30% 수준은 최적의 관능품질을 나타내면서 미생물 생육을 저해하여 저장성을 향상시키는 조건으로 파악되었다. 이러한 품질 및 저장성 향상 효과가 있는 처리 방법을 멥쌀, 찹쌀, 밀, 콩, 메밀 및 보리 등의 다양한 곡물을 이용한 복원용 밥 제품의 제조에 적용할 수 있어 상업적 활용성이 매우 높다고 할 수 있다.

보리 산물처리에 의한 품질변화와 생력효과 (Effects of Post-Harvest Bulk Management System Using Rice Processing Complex on Labor Saving and Quality of Barley)

  • 이춘우;윤의병;구본철;백성범;손영구;서세정;남중현;김완석
    • 한국작물학회지
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    • 제47권6호
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    • pp.475-478
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    • 2002
  • 보리의 산물처리 확대를 위한 기초자료를 제공하고자 미곡종합처리장을 이용한 보리 산물처리시 품질변화와 생력효과를 조사 분석한 결과는 다음과 같았다. 1. 정립율은 2.5-2.2mm의 비율이 가장 많았으며, 건조방식에 따른 차이는 없었다. 2. 경도는 건조방식에 따른 차이는 없었고, 색도는 산물건조와 관행인 천일건조와 차이는 없었다. 3. 흡수율은, 고형용출물, 퍼짐성 등의 취반특성은 건조방식에 따른 차이는 없었다. 4. 산물처리에 의하여 관행의 ha당 46시간에 비하여 21시간으로 54.3%의 생력효과가 있었고, 수확 후 관리는 54.3% 생력화되었다. 5. 산물처리로 수확 후 관리노력이 관행에 비하여 ha당 25시간이 절감되어 101,83원의 경영비 절감효과가 있었다.

쌀가루의 건조방법에 따른 Bacillus cereus와 Enterobacter sakazakii 생육 억제 특성 (Effect of Drying Methods of Rice Flour on Growth Properties of Bacillus cereus and Enterobacter sakazakii)

  • 최봉규;박신영;하상도;금준석;이현유;박종대
    • 한국식품과학회지
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    • 제39권3호
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    • pp.295-298
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    • 2007
  • 본 연구는 쌀가루의 저장온도 및 저장기간에 따른 병원성 미생물 생육특성을 조사하고 안전성과 유효성을 고려한 상업적 열풍 및 마이크로파 처리방법을 사용하여 쌀가루의 미생물학적 안전성, 저장성 및 품질유지를 최적화하고자 하였다. 마이크로파 처리(700 watt/30 sec, MT)와 열풍 처리($65^{\circ}C$/15 min, HT) 후 쌀가루의 처리전과 대비한 색차변화값(${\Delta}E$)은 각각 0.15와 0.27로 측정되어 마이크로파 건조가 열풍 건조보다 색깔의 변화가 적은 것으로 나타났다. B. cereus와 E. sakazakii의 살균력은 MT 처리 후 각각 0.54 log CFU/g, 1.45 log CFU/g으로 감소하여 HT 처리 보다 살균효과가 강하였다. 대조구(NT) 쌀가루의 B. cereus는 4, 10, $20^{\circ}C$ 모든 온도에서 빠른 성장을 보였으나, MT 처리시 성장이 최소화 되었다. E. sakazakii는 4, 10, $20^{\circ}C$ 모든 온도에서 그리고 HT, MT 모든 처리구에서 성장하지 못하였는데, MT 처리시 생존균수가 가장 적었다. 결론적으로 쌀가루의 품질면에서나 미생물학적 안전성 측면에서 마이크로파 처리는 열풍건조 처리를 대체할 수 있는 건조방법으로 평가되었다.

쌀의 품질평가 현황과 금후 연구방향 (Trend and Further Research of Rice Quality Evaluation)

  • 손종록;김재현;이정일;윤영환;김제규;황흥구;문헌팔
    • 한국작물학회지
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    • 제47권
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    • pp.33-54
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    • 2002
  • Rice quality is much dependent on the pre-and post harvest management. There are many parameters which influence rice or cooked rice qualitys such as cultivars, climate, soil, harvest time, drying, milling, storage, safety, nutritive value, taste, marketing, eating, cooking conditions, and each nations' food culture. Thus, vice evaluation might not be carried out by only some parameters. Physicochemical evaluation of rice deals with amy-lose content, gelatinizing property, and its relation with taste. The amylose content of good vice in Korea is defined at 17 to 20%. Other parameters considered are as follows; ratio of protein body-1 per total protein amount in relation to taste, and oleic/linoleic acid ratio in relation to storage safety. The rice higher Mg/K ratio is considered as high quality. The optimum value is over 1.5 to 1.6. It was reported that the contents of oligosaccharide, glutamic acid or its derivatives and its proportionalities have high corelation with the taste of rice. Major aromatic compounds in rice have been known as hexanal, acetone, pentanal, butanal, octanal, and heptanal. Recently, it was found that muco-polysaccharides are solubilized during cooking. Cooked rice surface is coated by the muco-polysaccharide. The muco-polysaccharide aye contributing to the consistency and collecting free amino acids and vitamins. Thus, these parameters might be regarded as important items for quality and taste evaluation of rice. Ingredients of rice related with the taste are not confined to the total rice grain. In the internal kernel, starch is main component but nitrogen and mineral compounds are localized at the external kernel. The ingredients related with taste are contained in 91 to 86% part of the outside kernel. For safety that is considered an important evaluation item of rice quality, each residual tolerance limit for agricultural chemicals must be adopted in our country. During drying, rice quality can decline by the reasons of high drying temperature, overdrying, and rapid drying. These result in cracked grain or decolored kernel. Intrinsic enzymes react partially during the rice storage. Because of these enzymes, starch, lipid, or protein can be slowly degraded, resulting in the decline of appearance quality, occurrence of aging aroma, and increased hardness of cooked rice. Milling conditions concerned with quality are paddy quality, milling method, and milling machines. To produce high quality rice, head rice must contain over three fourths of the normal rice kernels, and broken, damaged, colored, and immature kernels must be eliminated. In addition to milling equipment, color sorter and length grader must be installed for the production of such rice. Head rice was examined using the 45 brand rices circulating in Korea, Japan, America, Australia, and China. It was found that the head rice rate of brand rice in our country was approximately 57.4% and 80-86% in foreign countries. In order to develop a rice quality evaluation system, evaluation of technics must be further developed : more detailed measure of qualities, search for taste-related components, creation and grade classification of quality evaluation factors at each management stage of treatment after harvest, evaluation of rice as food material as well as for rice cooking, and method development for simple evaluation and establishment of equation for palatability. On policy concerns, the following must be conducted : development of price discrimination in conformity to rice cultivar and grade under the basis of quality evaluation method, fixation of head rice branding, and introduction of low temperature circulation.