• Journal of Biosystems Engineering
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• 제39권4호
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• pp.336-344
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• 2014

Purpose: In this study, the effect of milling on paddy rice stored at low temperature, the changes in grain temperature of bulk storage bags exposed at room temperature, the post-milling water content of paddy rice, the whiteness of rice, and the rate of pest incidence were investigated and data were analyzed. Methods: Changes in temperature inside the bulk storage bags kept at low temperature and grain temperature after exposure to room temperature were measured. Experiments were conducted for identifying the reasons of post-milling quality changes in paddy rice stored at low temperature. Results: It was determined that a short-term increase of water content in paddy rice was directly related to surface condensation, and that rice should be milled at least 72 h after removal from low-temperature storage, in order to completely eliminate surface condensation of paddy rice kept in bulk storage bags. It was observed that post-milling quality of rice changed, but water content was maintained at high levels for more than 18 d in rice that was milled when condensation occurred, regardless of paper or vinyl packaging. Rice whiteness rapidly decreased in rice that was milled when condensation occurred, regardless of packaging, while rice that was milled 72 h or more after removal from low temperature storage did not show any significant changes in whiteness. No pest incidence was observed up to 12 d after removal from low temperature storage, regardless of packaging. Starting at 18 d, after removal from low temperature storage, rice that was milled when condensation occurred, was affected by pests, while 24 d after removal from low temperature storage, all portions of rice were affected by pests. Conclusions: Our results suggest that changes in post-milling quality of rice could be significantly reduced by exposing paddy rice to room temperature for at least 72 h before milling, in order to allow the increase of grain temperature and prevent surface condensation.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 1993년도 Proceedings of International Conference for Agricultural Machinery and Process Engineering
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• pp.922-931
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• 1993

Boundary element method was used to solve heat conduction problem for predicting temperature distribution in grain storage bin. Temperature of grain in storage is one of the three main abiotic factors, besides the intergranular gas composition and the grain moisture content, that determine the keeping quality and control measures used to protect grain from insects and damaging microflora. Collecting the temperature data at various points in the storage bins at different time of the day over a period of time is one way of finding the temperature distribution, this method requires a lot of time, cost and labour and less efficient. However data so collected serve useful purpose of being used to validate predicted temperature distribution using mathematical models. Mathematical models based on physical principles can potentially predict with accuracy the temperature distribution in a grain storage bin. Using the boundary element model the effect of bin wall material, ambient emperature, bin size etc. on temperature distribution can be studied. A knowledge of temperature distribution in stored grain not only helps in identifying active deterioration , but also gives an indication of potential for detection.

• Journal of Biosystems Engineering
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• 제3권1호
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• pp.33-46
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• 1978

To get the goal of self-supply of food grain, improvement of post-harvest grain operations in rural area is under consideration as an important task of agriculture in Korea. This is study is focused on elimination of losses and deteriorations of grain and reduction of labour requirements and funds for post-harvest grain operations. The purpose of this study are presentation of basic data referring to conventional post-harvest grain operations in rural area and suggestion of improving methods for the operations, and also finding out reasonable operating processes of the operations. The result of this study are follows; 1. Grain drying in-the-filed which is performed before threshing has major factors of grain loss during drying, and so should be restrained as possible. Combine harvesting system is recommended among other king of mechanized harvesting systems for restraining in-the-field drying and securing available labors for drying. 2. It is predicted that mechanical grain drying could be prevalent when combine harvesting is taken place. Recommended grain drier for pre-combine harvesting system and for combine harvesting system is batch-type drier and circulating -type drier, respectively. 3. As existing farm storages for grain have insufficient spaces and offer poor conditions for grain storing , it is greatly needed to build up new storage which store only grains. And it is concluded that storing grain in community common storages in desirable. 4. Power supplying system for milling machinery in local milling plants, that a large capacity prime mover supplies power to 4 to 6 kinds of milling machinery simultaeously, should be converted to a system of several small capacity prime movers supplying power to each machiner y for the purpose of reducing extra consumption of energy. 5. Governmental grain, of which Korean farms produced, should be milled and stored in the local milling plant successively for the purpose of reducing transportation fee and stroing facilities. 6. Furture post-havest grain operations-drying, storing and milling should be periormed successively in he community common plant. And average optimum processing capacity of the plant is estimated about 300 metric ton of grain every year.

• Journal of Biosystems Engineering
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• 제31권4호
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• pp.355-362
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• 2006

A one-dimensional heat conduction problem in cylindrical coordinate system was solved using Crank-Nicolson finite difference method to predicting the temperature distribution in rice storage bin with wall insulator. The model can simulate the grain temperatures in insulated round bins using the input data of initial grain temperature. ambient air temperature, wind velocity, solar radiation on a horizontal surface, and thermal properties of grain, bin wall, wall insulator, insulator cover, and air. Temperatures were collected at the bin center, 0.65m in radial direction from the center, and near the bin wall in 2.7m diameter bin filled with rough rice to depth of 3.0m were used to validate the simulation model. Grain temperatures predicted by the model were in very good agreement with the measured temperatures. The residual mean square error between measured and predicted grain temperatures at the bin center was $1.38^{\circ}C$.

• 한국식품과학회지
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• 제7권1호
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• pp.7-10
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• 1975

국내(國內)의 변질미(變質米)에서 분리된 A. flavus var. columnaris가 저장곡류(貯藏穀類)에 오염(汚染)되었을 때 aflatoxin 생성(生成)에 의한 위험가능성(危險可能性)을 추구(追究)하기 위하여 일련의 실험이 수행되었다. 그 결과 쌀 저장중 aflatoxin의 생성에는 80%이상의 상대습도(相對濕度)가 요구되었고 일단 축적된 aflatoxin은 다른 미생물의 번식에 의하여 분해되어 50% 수준을 유지하였으며 다른 미생물이 공존하지 않는 경우는 aflatoxin의 대량축적이 일어났다. 곡류(穀類)에서의 aflatoxin생성량은 대두(大豆), 땅콩, 옥수수, 밀, 보리, 조, 쌀, 밀쌀, 녹두, 수수의 순서로 증가하였으며 곡립(穀粒)의 크기와 유지(油脂)의 함량에 영향되는 경향을 보여 주었다.

• 한국작물학회지
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• 제36권3호
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• pp.271-279
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• 1991

정부의 미곡저장관리기술향상에 필요한 자료를 축적시키고자 벼의 저장기간이 미곡의 품질변화에 미치는 영향을 1987, 1988, 1989년산으로 2개 지역의 교탈 창고에 저장되었던 통일벼와 1989 및 1990년산 일반계로 2지역의 1급 창고에 저장되었던 벼에 대해 조사했고, 벼저장창고등급이 미곡의 품질변화에 미치는 영향을 1989년산 일반계로 3개지역의 특급, 1급 및 2급창고에 저장된 벼에 대해 조사하였으며, 1988년산 동진벼와 1989년산 동진벼를 각각 수확조제 1개월 후부터 4$^{\circ}C$, RH50%에 저온저장하고 이들을 1990년산 동진벼와 비교 조사하여 저온저장의 효과를 검토하는 한편 비교적 장기저장된 벼의 식미가 도정도를 달리하므로서 향상될 수 있는가를 알기 위해 1988년산 특급창고저장 일반계 벼, 1989년산 특급, 1급, 2급 창고저장 일반계벼에 대해 10분도와 12분도로 도정하여 비교하였다 공시곡들을 1991년 3월～4월간에 수집하여 서울대농대의 특급창고에 일시 보관 후 정보의 수분함량을 16%로 조절한 후 제현 및 도정하여 현미의 지방산도와 23인으로 구성된 전문식미검정반에 의한 밥맛평가를 하여 소비자수준에서의 저곡에 따른 품질변화에 대해 조사하였다. 그 결과는 다음과 같이 요약된다. 1. 통일계벼는 일반계벼보다 장기저장에 있어서도 현미의 지방산도가 현저히 낮았고 밥맛의 변화가 크지 않았다 2. 통일계와 일반계벼 모두 저장기간이 길어질수록 현미의 지방산도가 약간씩 높아지고 밥맛이 종합평점, 맛, 외관 및 냄새에서 조금씩 나빠지는 경향이었으며, 특히 일반벼에서 1990년산과 1989년산간에 평균평점차이가 뚜렷해졌으나 통일계벼는 1987, 1988, 1989년산간에, 일반계벼는 1989년산과 1990년산간에 밥맛평가에서 통계적 유의차를 보이지 않았다 3. 정부양곡보관창고들 중 특급창고와 1급창고에 보관했던 일반계 벼간에는 3개조사지역 모두 현미지방산도와 밥맛평가면에서 유의적 차이가 없었으나 2급창고는 3개지역 모두에서 지방산도가 약간 높고 밥맛평점이 약간씩 낮았다. 4. 저온저장(4$^{\circ}C$, RH 50%)한 벼는 2년반 저장한 벼도 밥맛의 변화가 거의 없었다. 5. 1988년산 및 1989년산 일반계를 10분도와 12분도로 도정하였을 때 도정도에 따른 밥맛의 차이는 없었다.

• 한국응용곤충학회지
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• 제56권2호
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• pp.223-227
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• 2017

북미지역에서 저장곡물해충으로 잘 알려진 거저리과의 북미쌀거저리[Cynaeus angustus (LeConte)]가 국내 여러 정미소에 발생하고 있음을 새롭게 보고하며, 이 미기록종에 대한 성충과 유충 사진 및 진단형질과 저장산물을 검역하는 과정에서 검출되는 거저리과 해충 17종에 대하여 도해 검색자료를 제공하였다.

• 한국응용곤충학회지
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• 제49권4호
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• pp.363-369
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• 2010

친환경 소독 기술인 환경조절열처리(CATTS: controlled atmosphere and temperature treatment system)는 메틸브로마이드 훈증제 처리의 대체 기술로 사용되어 왔다. 본 연구는 저장 곡물 해충인 거짓쌀도둑거저리(Tribolium castaneum)를 CATTS를 통해 저장 기간 중 방제가 가능한 지를 알아보기 위해 시도되었다. 거짓쌀도둑거저리의 성충은 $46^{\circ}C$에서 열충격 감수성을 보였으며 여기에 CA 조건(15% 이산화탄소, 1% 산소)은 감수성을 현격하게 증가시켰다. CATTS 조건($46^{\circ}C$, 15% 이산화탄소 1% 산소)에서 120 분간 노출시켰을 때 유충(초기, 중기, 말기)과 성충 모두 100% 살충율을 나타냈다. CATTS 처리에 대한 감수성이 거짓쌀도둑거저리 발육 시기에 띠라 상이했고 말기 유충에서 높은 내성을 보였다. 거젓쌀도둑거저리 열충격단백질의 발현이 CATTS에 대한 내생과 관련이 있는 것으로 나타났다.

• Mycobiology
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• 제46권1호
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• pp.52-63
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• 2018

In our previous studies, Bacillus megaterium KU143, Microbacterium testaceum KU313, and Pseudomonas protegens AS15 have been shown to be antagonistic to Aspergillus flavus in stored rice grains. In this study, the biocontrol activities of these strains were evaluated against Aspergillus candidus, Aspergillus fumigatus, Penicillium fellutanum, and Penicillium islandicum, which are predominant in stored rice grains. In vitro and in vivo antifungal activities of the bacterial strains were evaluated against the fungi on media and rice grains, respectively. The antifungal activities of the volatiles produced by the strains against fungal development and population were also tested using I-plates. In in vitro tests, the strains produced secondary metabolites capable of reducing conidial germination, germ-tube elongation, and mycelial growth of all the tested fungi. In in vivo tests, the strains significantly inhibited the fungal growth in rice grains. Additionally, in I-plate tests, strains KU143 and AS15 produced volatiles that significantly inhibited not only mycelial growth, sporulation, and conidial germination of the fungi on media but also fungal populations on rice grains. GC-MS analysis of the volatiles by strains KU143 and AS15 identified 12 and 17 compounds, respectively. Among these, the antifungal compound, 5-methyl-2-phenyl-1H-indole, was produced by strain KU143 and the antimicrobial compounds, 2-butyl 1-octanal, dimethyl disulfide, 2-isopropyl-5-methyl-1-heptanol, and 4-trifluoroacetoxyhexadecane, were produced by strain AS15. These results suggest that the tested strains producing extracellular metabolites and/or volatiles may have a broad spectrum of antifungal activities against the grain fungi. In particular, B. megaterium KU143 and P. protegens AS15 may be potential biocontrol agents against Aspergillus and Penicillium spp. during rice grain storage.

• Journal of Applied Biological Chemistry
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• 제66권
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• pp.289-298
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• 2023

보관된 벼는 시간이 지남에 따라 물리화학적인 변성이 일어난다. 쌀알의 변성에 영향을 주는 중요한 요인으로 온도와 함수율을 들 수 있다. 가급적 저온보관과 밀폐보관이 중요하다. 미시적인 관점에서, 쌀에 함유된 단백질과 지질의 변성은 이미 많은 연구들이 보고되었다. 한편, 실제 보관 현장에서 확인되는 벼의 중량 감소, 즉 감모현상은 현재 진행형이며 다양한 원인으로 발생될 수 있다. 본 논문에서는, 쌀의 주성분인 탄수화물의 분해과정이 감모현상에 중요한 역할을 한다고 가정하였으며, 효소에 의한 탄수화물 분해과정들을 살펴보았다. 관심의 대상이 되는 주요 탄수화물로는 전분과 세포벽에 포함된 탄수화물이 있다. 쌀의 보관 과정 중 중량 감소는 주로 전분의 주성분인 아밀로스와 아밀로펙틴의 분해가 원인일 것으로 보이지만, 단백질과 지질을 포함한 다른 성분들의 변성 또한 종합적으로 영향을 주고 있다고 유추된다.