• 한국식품영양과학회지
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• 제32권8호
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• pp.1385-1389
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• 2003

본 연구는 표준 경작법으로 재배한 육성 품종 5종(광안, 대안, 대진, 수라, 화성)의 현미와 백미의 품종간 단백질과 아미노산 함량을 분석하고, 단백질의 화학적 질적 가치를 알아보고자 하였다. 단백질 함량은 현미에서는 대진벼(7.98%)>대안벼ㆍ화성벼(7.46%)>수라벼 (7.03%)>광안벼(6.70%) 순이었고, 백미에서는 대진벼(7.52%)>대안벼(6.90%)>화성벼(6.78%)>수라벼(6.64%)>광안벼(6.08%) 순으로 대진벼가 단백질 함량이 다른 품종에 비하여 가장 높았다. 총 아미노산에 대한 총 필수아미노산의 비율을 보면, 현미는 36.8∼38.3%이었으며, 백미는 35.8∼37.7%으로 화성벼가 가장 높았고, 대안벼가 가장 낮았다. 쌀의 모든 품종에서 가장 많이 함유된 아미노산인 Glx(glutamate+glutamine)은 현미에서 900.5∼965.9 mg/g N, 백미에서 1003.3∼1058.5 mg/g N으로 분석되었다. 현미와 백미의 아미노산 함량은 Glx>Asx>arginine>leucine>valine순이었다. A/E비 화학가는 현미에서 수라벼>화성벼>대진벼>대안벼>광안벼 순이었고, 백미에서 수라벼>광안벼>대안벼>대진벼>화성벼 순이었다. A/T비 화학가는 현미에서는 화성벼>대진벼>수라벼ㆍ광안벼>대안벼 순이었고, 백미에서는 광안벼>대진벼>수라벼>화성벼>대안벼 순이었으며, 제 1제한 아미노산은 lysine으로 판정 되었다. Protein score와 amino acid score에서 제 1제 한 아미노산은 lysine이었고, 제 2제 한 아미노산은 threonine, 그리고 제 3제한 아미노산은 isoleucine이었다.

• 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.

• 한국작물학회지
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• 제50권6호
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• pp.447-452
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• 2005

전자코를 이용하여 한국에서 주로 재배되고 있는 자포니카 44품종의 쌀과 밥의 향 패턴을 분석하여 얻은 결과는 다음과 같다. 1. 백미 44품종의 향은 주성분분석과 군집분석결과 만금, 남평 ,신동진쌀이 한 그룹으로, 대진, 추청쌀이 또 다른 그룹 분류되어 나머지 39품종 쌀의 향과는 구분이 되는 것으로 나타났다. 2. 밥의 향은 분석결과 44품종들이 제1주성분 값 -8에서 +6사이에서 고른 분포를 보이며 품종간 구분은 되어지지 않았다. 3. 쌀과 밥의 향 측정에 사용된 12개의 MOS센서가 얻은 값을 상관관계 분석한 결과 쌀의 향과 밥의 향과는 서로 유의성이 없어 전자코를 이용하여 쌀시료로 취반 후 밥의 향을 예측하는 것은 어려운 것으로 나타났다.

• 한국작물학회지
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• 제51권1호
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• pp.1-13
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• 2006

Response of grain yield and milled-rice protein content to nitrogen topdress (N) timing at panicle initiation stage (PIS) is critical for quantifying real-time N requirement for target grain yield and milled-rice protein content. Two split-split-plot experiments with three replications, one in 2004 and the other in 2005, were conducted in Experimental Farm, Seoul National University, Suwon, Korea. The experiments included three N rates at tillering stage (TS), three N timing treatments at panicle initiation stage (PIS) and two rice cultivars. The N rates at TS, N timing at PIS, and rice cultivars were randomly assigned to main plot, sub plot, and sub-sub plot, respectively. Results showed that the delayed N application at PIS reduced grain yield in 2004 and increased milled-rice protein content in both years significantly at 0.05 probability level. The calculated optimum N timing at PIS from pooled data by N rates and rice cultivars in two years was at 28 days before heading (DBH). However, real-time of N timing at PIS was dependent on plant growth and N status around PIS that in turn was dependent on applied N rates at TS. The optimum N timing at PIS was at 30 DBH for no N treatments at TS while at 27 DBH for 3.6 and 7.2 kg N/10a treatments and at 27 and 29 DBH for Hwaseongbyeo and Daeanbyeo, respectively. In general, earlier applied N at PIS resulted in lower milled-rice protein content but the highest grain yield was expected to be obtained when N topdress at PIS was applied at the time when shoot N concentration started to drop below about 23 mg/g due to dilution effect after transplanting. In conclusion, the results of our experiments imply that the currently recommended N topdress time (24DBH) at PIS in Korea should be reconsidered for the higher grain yield and the better quality of rice.

• Journal of Biosystems Engineering
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• 제15권1호
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• pp.33-43
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• 1990

Spectral reflectance of paddy, brown rice, milled rice, greenish grain, yellow grain and denatured grain were measured over the range of 340 to 820 nm with "Double Beam Spectrophotometer(Model UV-180)". Variation in the reflectance depending on milling degree of milled rice appeared greatest over the range of 420 to 500 nm, and that between white rice and other rice samples appeared greatest near 500 nm. On the basis of the above results, a whiteness meter to measure milling degree of rice was manufactured using tungsten lamp, photodiodes and amplifier, and its performance was compared with the existing whiteness meters (KETT and Z-II optical sensor). There were very high correlations among those whiteness meters.

• Applied Biological Chemistry
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• 제29권1호
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• pp.29-35
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• 1986

수분흡수속도가 다른 쌀로부터 추출한 전분의 알카리 호화양상을 조사하였다. 일정할 알카리 농도에서 최고점도와 점도의 증가속도 및 알카리 농도를 증가시킬 때의 점도의 증가 속도는 다수계 쌀 전분이 일반계 쌀 전분보다 높았다. 쌀전분의 점도양상은 쌀가루의 점도양상 및 쌀의 수화속도와는 상관관계를 보이지 않았다.

• 한국작물학회지
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• 제35권5호
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• pp.379-386
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• 1990

우리나라 수도장려품종 1988년 및 '89년산 미와 중ㆍ남부평야지대 6개소(수원, 남양, 이천, 이리, 계화, 밀양)에서 생산된 7개 품종(자포니카 5, 통일형 2)과 중북부 및 남부중산간지와 고랭지 4개소(철원, 진부, 화서, 운봉)에서 생산된 6품종에 대하여 쌀 단백질 함량의 품종 및 환경변이를 분석ㆍ조사하고 단백질 함량에 차이를 보이는 화성벼, 농백 및 용주벼의 세 품종에 대한 아미노산조성을 조사하였던 시험결과를 요약하면 다음과 같다. 1. 우리나라 벼 장려품종의 백미 단백질 함량은 '88년산미는 평균 7.93%에서 5.5-10.2%의 변이, '89년산미는 평균 9.17%에서 6.3-12.0%의 변이로 현저한 년차간 변이를 나타내었고 자포니카 품종군의 평균 단백질 함량 8.22%에 비해 통일형 품종군이 9.3%로 약 1%정도 높았다. 백미 단백질 함량이 높았던 품종은 자포니카에서는 농백, 도봉벼, 치악벼 등이었고, 통일형 품종군에서는 용문벼, 용주벼, 칠성벼 등이었다. 2. 자포니카 저단백 품종인 화성벼는 자로니카 및 통일벼 고단백 품종인 농백 및 용주벼에 비해 필수아미노산 함량의 절대함량은 낮았으나 질소 16.8g당(단백질 100g에 해당) 필수아미노산 함량은 31.7%로 다른 두 고단백 품종과 비슷하였으며 아미노산중에서 화성벼는 arginine, 농백은 alanine과 lysine, 용주벼는 leucine이 가장 높았다. 아미노산중에서 세 품종 모두 글루타민산 함량이 가장 높았고 필수아미노산중에는 leucine이 가장 높았으며 methionine이 가장 낮았다. 3. 쌀 단백질 함량은 한생종일수록 약간 높은 경향을 보였고 백미투명도가 떨어지고 Mg함량이 높을수록 유의하게 높았으며, K/Mg율, 알칼리붕괴도 및 아밀로즈 함량이 낮을수록 높은 경향을 보였는데 이러한 경향은 자포니카 품종군에서 더욱 두드러졌다. 4. 쌀 단백질 함량은 중부평야지산미가 평균 6.74%로 남부평야지산미의 평균 7.54%에 비해 약 1%정도 낮았고 단백질 함량의 품종간 변이와 산지간 변이의 전분산에 대한 기여율이 각각 55.8%와 28.1%로 품종간 변이가 산지간 변이보다 두배정도 컸다. 5. 중북부 중산간지 및 고랭지산미의 쌀 단백질함량은 평균 5.95%로 남부 중산간지 및 고랭지산미의 6.8%보다 약 0.8% 정도 낮았고 단백질 함량의 품종간 변이와 산지간 변이의 전분산에 대한 기여율은 각각 16.7%와 56.4%로 산지간 변이가 품종간 변이보다 약 4배 가까이 컸다.

• Journal of Nutrition and Health
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• 제38권8호
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• pp.613-625
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• 2005

This study was designed to evaluate impact of kinds of dietary grain and dietary lipid level on the glucose metabolism and antithrombogenic capacity in obesity induced rats. Total of 80 Sprague-Dawley male rats were raised for one month with control diet containing $50\%$ (w/w) well-milled rice powder and $20\%$(w/w) of dietary lipids. The rats were blocked into 8 groups and raised for two months with diets containing well-milled rice, brown rice, black rice, or glutinous barley powder and 8 or $20\%$(w/w) of dietary lipids. The contents of total dietary fiber in experimental grains were in following order; glutinous barley > black rice > brown rice > well-milled rice. Weekly food intake were lower in glutinous barley group among all experimental groups. Body weight gain was high in high level of fat groups ($50\%$w/w) than medium level of fat groups ($8\%$ w/w). Plasma glucose concentration was not different significantly in each groups. But brown rice group was a little lower than others. Plasma insulin concentration was lower in black rice and glutinous barley group than rice group. Plasma glucagon concentration did not differ significantly among all experimental groups. Hexokinase activities in skeletal muscle are different significantly according to level of dietary fat and grain variety factors. Brown rice group was significantly highest among all experimental groups in hexokinase activity. Plasma $TXB_2$ concentrations in black rice and glutinous barley groups were lower as compared to rice and brown rice groups. Plasma 6-keto-$PGF_{1\alpha}$ concentrations in glutinous barley group was higher as compared to others. In conclusion brown rice has a little lowering effect glucose concentration. Black rice and glutinous barley intakes enhance antithromboenic capacity. It is suggested that the intakes of mixed gains are recommend.

• 한국식품영양과학회지
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• 제34권7호
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• pp.1098-1102
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• 2005

일반 백미를 분무수세한 후 건조하여 제조한 무세미와 부산물로 생성된 무세미 쇄립의 이화학적 특성 및 오염미생물을 분석하였다. 무세미 쌀가루는 명도와 황색도가 원료쌀에 비해 다소 낮았고 수분흡수지 수(WAI)와 수분용해지수(WSI)는 원료쌀에 비해 높게 나타났으며 무세미 쇄립에서 gel consistency가 다소 높게 나타났다. 무세미 쌀가루는 amylo-graph 최고점도와 breakdown이 높았으며 setback은 가장 낮은 반면에 무세미 쇄립은 최고점도와 breakdown이 낮았으며 setback이 높은 것으로 나타났다. 무세미의 DSC 측정결과 호화개시온도와 호화최고온도가 원료쌀에 비해 약간 감소하는 경향이었으며 호화엔탈피는 다소 높게 나타났다. 무세미는 원료쌀에 비해 total bacteria, yeast-like strain의 수가 감소하여 쌀 표면 미생물의 세척 효과에 따른 미생물의 오염정도가 낮았다.

• 한국식품영양학회:학술대회논문집
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• 한국식품영양학회 2001년도 동계 학술심포지움
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• pp.39-74
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• 2001

The endeavors enhancing the grain quality of high-yielding japonica rice were steadily continued during 1980s∼1990s along with the self-sufficiency of rice production and the increasing demands of high-quality rices. During this time, considerably great, progress and success was obtained in development of high-quality japonica cultivars and qualify evaluation techniques including the elucidation of interrelationship between the physicochemical properties of rice grain and the physical or palatability components of cooked rice. In 1990s, some high-quality japonica rice caltivars and special rices adaptable for food processing such as large kernel, chalky endosperm aromatic and colored rices were developed and its objective preference and utility was also examined by a palatability meter, rapid-visco analyzer and texture analyzer. The water uptake rate and the maximum water absorption ratio showed significantly negative correlations with the K/Mg ratio and alkali digestion value(ADV) of milled rice. The rice materials showing the higher amount of hot water absorption exhibited the larger volume expansion of cooked rice. The harder rices with lower moisture content revealed the higher rate of water uptake at twenty minutes after soaking and the higher ratio of maximum water uptake under the room temperature condition. These water uptake characteristics were not associated with the protein and amylose contents of milled rice and the palatability of cooked rice. The water/rice ratio (in w/w basis) for optimum cooking was averaged to 1.52 in dry milled rices (12% wet basis) with varietal range from 1.45 to 1.61 and the expansion ratio of milled rice after proper boiling was average to 2.63(in v/v basis). The major physicochemical components of rice grain associated with the palatability of cooked rice were examined using japonica rice materials showing narrow varietal variation in grain size and shape, alkali digestibility, gel consistency, amylose and protein contents, but considerable difference in appearance and torture of cooked rice. The glossiness or gross palatability score of cooked rice were closely associated with the peak. hot paste and consistency viscosities of viscogram with year difference. The high-quality rice variety “Ilpumbyeo” showed less portion of amylose on the outer layer of milled rice grain and less and slower change in iodine blue value of extracted paste during twenty minutes of boiling. This highly palatable rice also exhibited very fine net structure in outer layer and fine-spongy and well-swollen shape of gelatinized starch granules in inner layer and core of cooked rice kernel compared with the poor palatable rice through image of scanning electronic mcroscope. Gross sensory score of cooked rice could be estimated by multiple linear regression formula, deduced from relationship between rice quality components mentioned above and eating quality of cooked rice, with high Probability of determination. The ${\alpha}$ -amylose-iodine method was adopted for checking the varietal difference in retrogradation of cooked rice. The rice cultivars revealing the relatively slow retrogradation in aged cooked rice were Ilpumbyeo, Chucheongbyeo, Sasanishiki, Jinbubyeo and Koshihikari. A Tongil-type rice, Taebaegbyeo, and a japonica cultivar, Seomjinbyeo, shelved the relatively fast deterioration of cooked rice. Generally, the better rice cultivars in eating quality of cooked rice showed less retrogiadation and much sponginess in cooled cooked rice. Also, the rice varieties exhibiting less retrogradation in cooled cooked rice revealed higher hot viscosity and lower cool viscosity of rice flour in amylogram. The sponginess of cooled cooked rice was closely associated with magnesium content and volume expansion of cooked rice. The hardness-changed ratio of cooked rice by cooling was negatively correlated with solids amount extracted during boiling and volume expansion of cooked rice. The major physicochemical properties of rice grain closely related to the palatability of cooked rice may be directly or indirectly associated with the retrogradation characteristics of cooked rice. The softer gel consistency and lower amylose content in milled rice revealed the higher ratio of popped rice and larger bulk density of popping. The stronger hardness of rice grain showed relatively higher ratio of popping and the more chalky or less translucent rice exhibited the lower ratio of intact popped brown rice. The potassium and magnesium contents of milled rice were negatively associated with gross score of noodle making mixed with wheat flour in half and the better rice for noodle making revealed relatively less amount of solid extraction during boiling. The more volume expansion of batters for making brown rice bread resulted the better loaf formation and more springiness in rice bread. The higher protein rices produced relatively the more moist white rice bread. The springiness of rice bread was also significantly correlated with high amylose content and hard gel consistency. The completely chalky and large gram rices showed better suitability for fermentation and brewing. Our breeding efforts on rice quality improvement for the future should focus on enhancement of palatability of cooked rice and marketing qualify as well as the diversification in morphological and physicochemical characteristics of rice grain for various value-added rice food processings.