• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.47
• /
• pp.15-32
• /
• 2002

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 quality 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 cultivars 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, Recently, new special rices such as extremely low-amylose dull or opaque non-glutinous endosperm mutants were developed. Also, a high-lysine rice variety was developed for higher nutritional utility. 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 texture of cooked rice. The glossiness or gross palatability score of cooked rice were closely associated with the peak, hot paste and consistency viscosities of viscosities with year difference. The high-quality rice variety "IIpumbyeo" 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 microscope. 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 IIpumbyeo, Chucheongyeo, Sasanishiki, Jinbubyeo and Koshihikari. A Tonsil-type rice, Taebaegbyeo, and a japonica cultivar, Seomjinbyeo, showed the relatively fast deterioration of cooked rice. Generally, the better rice cultivars in eating quality of cooked rice showed less retrogradation 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 breed. 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 grain rices showed better suitability far fermentation and brewing. The glutinous rice were classified into nine different varietal groups based on various physicochemical and structural characteristics of endosperm. There was some close associations among these grain properties and large varietal difference in suitability to various traditional food processing. Our breeding efforts on improvement of rice quality for high palatability and processing utility or value-adding products in the future should focus on not only continuous enhancement of marketing and eating qualities but also the diversification in morphological, physicochemical and nutritional characteristics of rice grain suitable for processing various value-added rice foods.ice foods.

• Korean Journal of Agricultural Science
• /
• v.16 no.2
• /
• pp.179-200
• /
• 1989

Mucor miehei rennet(MR) was added as calf rennet(CR) substitutes in the fixed amounts of mixed rennets in making Camembert cheese. The conditions in the variations of chemical composition: water-soluble nitrogen, non-caseinic nitrogen, non-proteinic nitrogen, amino nitrogen, ammoniacal nitorgen, electrophoresis, molecular fractionation, mineral distribution, texture characterisitics, free amino acids and free fatty acids, were checked up with the sensory test and the chesse yields at each ripening period. The results obtained by investigating the utility of Mucor rennet were summarized as follows: 1. CR chesse, MR cheese and the mixed-rennet chesse failed to show any significant difference in their yields of 15%. 2. The contents of protein, fat and ash in MR cheese gave lower value than CR cheese did and with progress of ripening lactose decreased rapidly after 14 days of ripening. The difference among the rate of addition of mucor rennet was not recognized. 3. The WSN contents of 5 fresh sample chesse were from 14.7% to 17.3% and WSN increased from 39.7% to 41.0% with progress of ripening. After 21 days of ripening MR chesse had more WSN than CR cheese did. In NCN and ammoniacal nitrogen MR cheese showed higher value. 4. As the ripening progressed, MR chesse showed more cystein, phenylalanine and proline than CR chesse did but it failed to show any increase in aspartic acid, threonine and glutamic acid etc. 5. In the content of free fatty acid MR chesse showed higher value than CR cheese did and with the progress of ripening fatty acids increased from 8.36 mEq to 26.36 mEq but did not show any significant difference in the cheese types by the coagulant ratio. 6. Ca contents in the sample chesse were 0.238-0.27%, Mg 0.019-0.022%, Na 0.910-1.047%, and K 0.175-0.200%. The important non-sedimentable Ca in casein remained from 61 % to 77% without regard the ripening periods and added-rennets and Mg remained from 59.1% to 92.5% in non-sedimentable and water-soluble conditions. 7. In the fractionation of protein by ultrafilteration, MW> $5{\times}10^4$ decresed from 95% at the beginning period of ripening to 45% and MW< $10^4$ increased from 0.2% to 38% and definite caseinolysis was shown in all samples. 8. All the cheese showed to different electrophoretic patterns for the added-amounts of mucor rennet in the 14 days of ripenig. In the 28 days or ripening, MR cheese kept some bands on the patterns compared with CR cheese. 9. In vitro digestibility increased from 81.48-94.81 % to 94.47-98.61% but failed to show any significant difference in the cheese types by the coagulant ratio. 10. In hardness, MR cheese showed lower value compared with CR cheese as the ripening progressed. 11. The results of the sensory test failed to show any difference in flora rind, feelings in mouth and hands, deep structure, flavor and bitterness between CR Camembert cheese and MR Camembert chesse.

• Journal of Nutrition and Health
• /
• v.9 no.2
• /
• pp.59-67
• /
• 1976

A series of experiment was carried out to study the effect of commonly used dietary fat or oils on the growth, feed efficiency, nutrient utilizability, nitrogen retention and serum cholesterol of rats and chicks fed various fat or oils at the level of 10% during 12 weeks of experimentation. Fat and oils used in this experiment were also analyzed for the composition of some fatty acids. The main observations made are as follows: 1. All groups received fat or oils gained more body weight than unsupplemented control group except chicks fed fish oil and rapeseed oil although no statistical significance was found between treatments. It was found that body weight gain achieved by the rats fed soybean oil, rapeseed oil, animal fat or corn oil was much greater than other group and that achieved by the chicks fed corn oil and animal fat was greater than other vegetable oil groups, although no statistical significance was found among treatments. 2. Feed intake data indicated that corn oil group of both rats and chicks consumed considerably more feed than other groups. Whereas feed intake of fish oil groups was the lowest among the experimental animals indicating that fish oil might contain unfavorable compound that depresses the palatability. In feed efficiency, soybean oil group of rats and corn oil group of chicks were significantly better than other experimental groups. In general, addition of fat or oils in the diet improved feed effeciency of diet. 3. Nutrient utiIizabiIity and nitrogen retention data showed that fat in the experimental diet containing 10% fat or oils was absorbed better than crude fat in control diet. It was also found that there was no significant difference in nitrogen retention among treatment. 4. Liver fat content of rapeseed oil group was much higher than that of control group and other group. It was also noticed that feeding more polyunsaturated fatty acids resulted in higher content of Iiver fat. 5. Present data indicated that serum cholesterol content of rapeseed oil and sesame oil group of rat was the higher than that of control group. Serum cholesterol content of animal fat group of chicks was higher than other group. It was interesting to note that serum cholesterol content of chicken was higher than that of rats?regardless of the kind of oils received. 6. Analytical data revealed that fatty acid composition of vegetable oil was composed mainly of oleic acid and linoleic acid, whereas animal fat and fish oil were composed of saturated fatty acid such as, myristic and palmitic acid. It should be mentionted that the perilla oil contained a very large amount of linolenic acid (58.4%) comparing with that in order vegetable oils. Little arachidonic acid was detected in vegetable oil, whereas none in animal fat and. fish oil.

• Economic and Environmental Geology
• /
• v.20 no.4
• /
• pp.289-303
• /
• 1987

당(當) 광산(鑛山)은 1936년(年) 금(金), 은(銀) 광종(鑛種)으로 출원(出願)하였다가 1940년(年) 망간을 추가(追加)하여 망간 광산(鑛山)으로 1975년(年)까지 Mn(30~35%) 110,000여(餘)톤을 생산(生産), 국내생산량(國內生産量)의 70%를 점(占)하였고 1976년(年) Mn광상(鑛床) 하부(下部)에 연(鉛), 아연(亞鉛) 유화광(硫化鑛)을 발견(發見), 현재(現在)까지 Pb十Zn=10% 이상(以上) 원광석(原鑛石) 500,000여(餘)톤을 처리(處理), 연정광(鉛精鑛)(Pb : 62%) 37,000여(餘)톤, 아연정광(亞鉛精鑛)(Zn : 46.5%) 37,000여(餘)톤, 유비광정광(硫砒鑛精鑛)(As : 30%) 5,000여(餘)톤을 생산(生産)하였다. 현재(現在) 일처리(日處理) 220톤 선광장(選鑛場)을 일처리(日處理) 400톤 규모(規模)로 증설계획중(增設計劃中)이다. 당(當) 광산(鑛山)에서 현재(現在)까지 시행(施行)한 갱외시추(坑外試錐)는 75개공(個孔) 18,500여(餘)m, 갱내시추(坑內試錐) 750개공(個孔) 40,000여(餘)m 갱도(坑道) 총연장(總延長) 13,000m에 달(達)하며 지표(地表)(623ML)로 부터 수직(垂直) 300m 하부(下部)까지 갱도(坑道)가 개착(開鑿)되어 있다. 당(當) 광산(鑛山)의 지질(地質)은 여러 조사서(調査書)에 의(依)하여 견해(見解) 차이(差異)를 보여주고 있으나 대체(大體)로 다음과 같은 쪽으로 인정되고 있다. 즉(卽) 본지역(本地域) 루층군(累層群)의 층순(層順)을 하위(下位)로 부터 상위(上位)로 향(向)하여 원남층(遠南層)${\rightarrow}$율리통(栗里統)${\rightarrow}$장산규암층(壯山珪岩層)${\rightarrow}$두음리층(斗音里層)${\rightarrow}$장군석회암층(將軍石灰岩層)${\rightarrow}$동수곡층(東水谷層)${\rightarrow}$재산층(才山層)의 순위(順位)로 보며 장산규암층(壯山珪岩層)과 두음리층(斗音里層)을 조선계(朝鮮系)의 양덕통(陽德統)으로, 장군석회암층(將軍石灰岩層)을 대석회암통(大石灰岩統)으로, 동수곡층(東水谷層)과 함탄층(含炭層)인 재산층(才山層)을 평안계(平安系) 지층(地層)으로 대비(對比)한다. 이들은 본지역(本地域) 북(北)쪽에서는 선(先)캠브리아기(紀)의 원남층(遠南層)과 율리통(栗里統)을 불정합(不整合)으로 덮고 남측(南側)에서는 재산층(才山層)과 원남층(遠南層)이 단층접촉(斷層接觸)하고 있다. 이들 지층(地層)의 주향(走向)은 $N60^{\circ}{\sim}80^{\circ}W$, $N60^{\circ}{\sim}80^{\circ}E$이며 경사(傾斜)는 대체(大體)로 $50^{\circ}{\sim}80^{\circ}N$이며 전체적(全體的)으로 역전(逆轉)된 층서(層序)를 보여주는 바 지질구조(地質構造)에 있어서 단사구조(單斜構造)인지 등사(等斜)습곡의 향사(向斜), 또는 등사(等斜)습곡이 배사구조(背斜構造)인지 아직 밝혀지지 않고 있다. 화성암체(火成岩體)는 본지역(本地域) 서측(西側)에 쥬라기(紀) 춘양화강암(春陽花崗岩)이 불규칙(不規則)한 실입(實入) 접촉면(接觸面)을 보여주며 시대미상(時代未詳)(백악기(白堊紀)?)의 거정화강암(巨晶花崗岩), 반화강암(半花崗岩)이 소암주상(小岩株狀)으로 몇 곳 실입(實入)하고 산성(酸性)~중성(中性)의 맥암(脈岩)과 염기성(鹽基性) 안산암질암(安山岩質岩)이 실입(實入)해 있다. 광상(鑛床)은 장군석회암층(將軍石灰岩層)에 배태(胚胎)되어 있는 열수교대(熱水交代) 연(鉛), 아연(亞鉛), 은등(銀等)의 혼합(混合) 유화광상(硫化鑛床)으로 다량(多量)의 Mn분(分)을 수반(隨伴)하며 지표부(地表部)에 Mn광상(鑛床)을 형성(形成)하고 있다. 광상(鑛床)의 형태(形態)는 괴상(塊狀), 각력(角礫)pipe상(狀), 맥상(脈狀)으로 나타난다. 광상(鑛床)의 성인(成因)과 생성시기(生成時期)에 대(對)하여 많은 논란(論難)이 있다. 즉(卽) 열수교대(熱水交代)냐, 접촉교대(接觸交代)냐, 동시퇴적기원(同時堆積起源)이냐, 또는 생성시기(生成時期)가 쥬라기(紀)인지 백악기(白堊紀)인지에 대해 이론(異論)이 있다. 본지역(本地域) 광상(鑛床)은 남본(南本), 100우(右), 북(北), 유비철(硫砒鐵), 동(東), 서(西), 재남(才南), 재동(才東), 110호(號) 등(等)이 지표(地表) Mn로두광화대(露頭鑛化帶)와 관련(關聯) 명명(命名)된 바 전(前)4자(者)는 하부(下部)에서 유화광상(硫化鑛床)이 확인(確認)되었으나 나머지 후자(後者)에서는 아직 하부(下部)에 유화광상(硫化鑛床)이 확인(確認)되지 않고 있으며 남본광상(南本鑛床)으로 부터 남동(南東) 300여(餘)m 지점에 장군석회암층(將軍石灰岩層)과 동수곡층(東水谷層) 경계부(境界部)에 Fe 55~60% 자철광상(磁鐵鑛床)이 확인(確認)된 바 신례미(新禮美) 자철광상(磁鐵鑛床)과 유사성(類似性)이 있는 것 같아 흥미(興味)롭다. 당(當) 광산(鑛山)의 현재(現在)까지의 탐광(探鑛)은 남본광상(南本鑛床) 지표로두(地表露頭)(Mn) 하부(下部)에서 확인(確認)된 연(鉛), 아연(亞鉛), 은(銀) 유화광체(硫化鑛體) 하부(下部)와 전탐(電探)에 의(依)해 확인(確認)된 북광체(北鑛體), 갱도접근중(坑道接近中)에 확인(確認)된 100우광체(右鑛體), 유비철광체(硫砒鐵鑛體) 등(等)의 하부(下部) 탐광(探鑛)을 주(主)로 하고 지표(地表) Mn로두(露頭) 하부(下部)에 대(對)한 시추탐광(試錐探鑛0을 병행(竝行)하고 있으며 시추(試錐)에 의(依)해서 지표(地表)로 부터 790m 하부(下部)(해발(海拔) 200ML)까지 광화대(鑛化帶)가 확인(確認)되었다. 향후(向後) 탐광방침(探鑛方針)을 확고(確固)히 수립(樹立)하기 위(爲)하여는 광상(鑛床)의 성인구명(成因究明)은 물론(勿論) 광상(鑛床)의 배태조건(胚胎條件)에 있어 지질구조규제(地質構造規制)와 화강암(花崗岩)의 실입상(實入狀)과의 관계(關係), 광액(鑛液)의 통로(通路)에 대(對)한 지질구조(地質構造), 모암(母岩)의 화학(化學) 물리적(物理的) 특성(特性)에 대(對)한 연구(硏究) 검토(檢討)가 었어야 하겠다.

• Economic and Environmental Geology
• /
• v.25 no.4
• /
• pp.417-433
• /
• 1992

Lead-zinc-copper deposits of the Jeonheung and the Oksan mines around Euiseong area occur as hydrothermal quartz and calcite veins that crosscut Cretaceous sedimentary rocks of the Gyeongsang Basin. The mineralization occurred in three distinct stages (I, II, and III): (I) quartz-sulfides-sulfosalts-hematite mineralization stage; (II) barren quartz-fluorite stage; and (III) barren calcite stage. Stage I ore minerals comprise pyrite, chalcopyrite, sphalerite, galena and Pb-Ag-Bi-Sb sulfosalts. Mineralogies of the two mines are different, and arsenopyrite, pyrrhotite, tetrahedrite and iron-rich (up to 21 mole % FeS) sphalerite are restricted to the Oksan mine. A K-Ar radiometric dating for sericite indicates that the Pb-Zn-Cu deposits of the Euiseong area were formed during late Cretaceous age ($62.3{\pm}2.8Ma$), likely associated with a subvolcanic activity related to the volcanic complex in the nearby Geumseongsan Caldera and the ubiquitous felsite dykes. Stage I mineralization occurred at temperatures between > $380^{\circ}C$ and $240^{\circ}C$ from fluids with salinities between 6.3 and 0.7 equiv. wt. % NaCl. The chalcopyrite deposition occurred mostly at higher temperatures of > $300^{\circ}C$. Fluid inclusion data indicate that the Pb-Zn-Cu ore mineralization resulted from a complex history of boiling, cooling and dilution of ore fluids. The mineralization at Jeonheung resulted mainly from cooling and dilution by an influx of cooler meteoric waters, whereas the mineralization at Oksan was largely due to fluid boiling. Evidence of fluid boiling suggests that pressures decreased from about 210 bars to 80 bars. This corresponds to a depth of about 900 m in a hydrothermal system that changed from lithostatic (closed) toward hydrostatic (open) conditions. Sulfur isotope compositions of sulfide minerals (${\delta}^{34}S=2.9{\sim}9.6$ per mil) indicate that the ${\delta}^{34}S_{{\Sigma}S}$ value of ore fluids was ${\approx}8.6$ per mil. This ${\delta}^{34}S_{{\Sigma}S}$ value is likely consistent with an igneous sulfur mixed with sulfates (?) in surrounding sedimentary rocks. Measured and calculated hydrogen and oxygen isotope values of ore-forming fluids suggest meteoric water dominance, approaching unexchanged meteoric water values. Equilibrium thermodynamic interpretation indicates that the temperature versus $fs_2$ variation of stage I ore fluids differed between the two mines as follows: the $fs_2$ of ore fluids at Jeonheung changed with decreasing temperature constantly near the pyrite-hematite-magnetite sulfidation curve, whereas those at Oksan changed from the pyrite-pyrrhotite sulfidation state towards the pyrite-hematite-magnetite state. The shift in minerals precipitated during stage I also reflects a concomitant $fo_2$ increase, probably due to mixing of ore fluids with cooler, more oxidizing meteoric waters. Thermodynamic consideration of copper solubility suggests that the ore-forming fluids cooled through boiling at Oksan and mixing with less-evolved meteoric waters at Jeonheung, and that this cooling was the main cause of copper deposition through destabilization of copper chloride complexes.

• Korean Journal of Soil Science and Fertilizer
• /
• v.15 no.1
• /
• pp.49-50
• /
• 1982

The objective of this paper is to review the changes in fertilizer use pattern and to discuss some aspects of the fertilizer development in Korea. Fertilizer consumption in Korea have steadily increased to triple the application rates of N, P and K during the 15 years from 1965 to 1980, and Korea became one of the countries which apply fertilizers at the highest rate. The ratio of N: $P_2O_5$: $K_2O$ in fertilizer consumption changed from 55.4 : 31.4 : 13.1 in 1965 to 54.0 : 23.8 : 22.2 in 1980. It can be said that Korean farmers practise a balanced fertilization at least in view of fertilizer consumption as compared to other developing countries. However, differences in soil properties, crops, and climate varying as region were not reflected on fertilization. In the technological development of fertilizer, the chemical form and composition of the fertilizer as well as the suitability to the specific crops must be taken into consideration for the efficient use of fertilizers. Although organic fertilizers and manure are accepted as minor element suppliers, it is necessary to add minor elements into chemical fertilizers on the industrial process. Industrial waste may be used for the agricultural production as a measure of pollution control providing careful study on the waste.