• Fisheries and Aquatic Sciences
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• v.3 no.2
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• pp.118-125
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• 2000

Lipid classes and fatty acid compositions of eight species of wild and cultured seawater fish in Korea were investigated. Total lipid (TL) contents of wild and cultured fish were $2.64\pm1.88\%$ and $5.42\pm1.76\%$, respectively, except for rockfish and striped beakperch. Non-polar lipids (NL) in all fish samples comprised approximately $84\%$ of the TL content. The proportion equation of NL content to TL content was y=0.9296x-0.4468 $(R^2=0.98l2, p<0.001)$. The most abundant NL class was triglyceride. The prominent fatty acids in all fish samples were 16: 0, 18: 1(n-9), 22 : 6(n-3) (docosahexaenoic acid, DHA), 16: 1(n-7), 20 : 5 (n-3) (eicosapentaenoic acid, EPA), 18 : 0 and 18 : 1(n-7). The polyunsaturated fatty acid (PUFA) group was the richest among the total fatty acids (TFA). DHA and EPA were comprised of approximately $85\%$ of n-3 PUFA. There was a positive correlation between TFA content and n-3 PUFA content; y=0.292x-0.0055 $(R^2=0.9349, p<0.001)$. The n-3 PUFA content of the cultured fish was approximately twice as much as that of the wild fish. Therefore, cultured fish were proven to provide better sources of n-3 PUFA if compared to wild fish.

• Journal of Nutrition and Health
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• v.27 no.10
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• pp.967-978
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• 1994

This study was done to investigate the effect of age and dietary linolenic acid content and the linolenic acid/linoleic acid(LNA/LA) ratio on the lipid metabolism and formation of PGI2 and TXA2. The male Sprague-Dawley rats were fed 6 different with 0.2, 0.4, 0.6 of LNA/LA ratio within either 8% LNA(high LNA) or 4% LNA(low LNA) of fatty acid content for different feeding period(1, 4, 12 month). The dietary fat used were sesame oil, perilla oil, soybean oil and beef tallow. The concentration of serum total lipid, total cholesterol and HDL-C were increased with aging. Triglyceride concentration was decreased in 0.2 ratio of LNA/LA. The lipid content of liver showed similar tendency to that of serum. The ratio of PGI2/TXA2 was increased in 1 month rats and antithrombotic effect was reduced significantly with increasing age. The PGI2/TXA2 ratio was tended to be higher in diet of 0.2 and 0.4 LNA/LA ratio at high LNA level and in diet of 0.6 LNA/LA ratio at low LNA level. Especially PGI2/TXA2 ratio was increased linearly with rising LNA/LA ratio at low LNA level. It seemed that the LNA content and LNA/LA ratio had interaction to increase the antithrombotic effect bychanging TXA2 synthesis. And the dietary fatty acid related effect lowering the serum and liver lipid content, excepting triglyceride, was increased when dietary n3/n6 ratio was high(0.6) at both high and low n3 level. Therefore, it could not be recommended to consume large amount of n3 fatty acid or high ratio of n3/n6 to prevent cardiovascular diseases. These results suggested that the dietary fatty acid ratio of n3/n6 could be determined based on the n-3 content of dietary fat to reduce the risk of cardiovascular disease.

• Journal of the Korean Society of Tobacco Science
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• v.18 no.1
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• pp.49-53
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• 1996

This experiment was carried out to study the effect of oxygen on chemical composition and physical properties of tobacco leaves during flue-curing. The results obtained were as follows: Starch content decreased and sucrose content increased with increasing oxygen supply during curing. Glucose and fructose of the cured leaves showed high content at the 5-10% oxygen supply. Amino-N and nitrate-N increased with increasing oxygen supply. Total nitrogen and NH4-N showed the lowest value at the 5-10% and 10-15% oxygen supply in the cutters and leaf, respectively. Chlorophyll and chlorogenic acid increased, and total volatile base decreased with increasing oxygen supply. The activity of α-amylase increased at the latter period of flue-curing, and the maximum activity point were delayed 12 hours with increasing oxygen supply. Shatter index of cured leaves decreased with increasing oxygen supply. It was desirable to supply oxygen during flue-curing for the improvement of chemical and physical properties such as starch, total sugar, chlorogenic acid, and shatter index of cured leaves.

• Journal of the Korean Society of Tobacco Science
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• v.9 no.1
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• pp.27-33
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• 1987

This study was carried out to investigate the effect of cultural practices on the nicotine and sugar contents in flue-cured tobacco(NC82), and the relationship between them. Significant reduction I sugar content and ratio of total sugar to nicotine(ratio, S/N) were observed with increased fertilizer, lower topping height, late transplanting and decreased application of male hydrazide(MH). Significant increases were observed in nicotine content with increased fertilizer and lower topping height. A positive correlation was found between total sugar content and plant density. A negative correlation was found between nicotine and total sugar contents for 8-years. An increase of 1.0% nicotine in the cured leaf would result in a 4.8% reduction in total sugar. The most desirable contents were 2.7% for nicotine and 19.0% for total sugar(S/N=7).

• Korean Journal of Soil Science and Fertilizer
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• v.24 no.3
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• pp.171-176
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• 1991

Field experiment was conducted to investigate the seasonal change in inorganic nitrogen content in grassland soil profile after urea application. Urea was applied at the levels of 0 (0N), 14 (14N), and 28 (28N) Kg N per 10a. Soil samples were taken at every 20 cm interval upto 100 cm soil depth in spring (May 26), summer (July 27), and autumn (October 18) and analysed for total and inorganic nitrogen ($NH_4-N$ and $NO_3-N$). The results obtained are as follows ; 1. In spring, the $NH_4-N$ content of ON treatment was higher than $NO_3-N$ content both in surface and subsoil. The urea application increasing both $NH_4-N$ and $NO_3-N$ contents in the surface soils and these contents decreased with soil depth. 2. In summer, increase in urea application rate elevated the $NO_3-N$ content in soil profile of 0 to 100cm and the content reached upto 42 ppm in the 28N treatment. 3. The seasonal difference in $NH_4-N$ content between summer and autumn was insignificant throughout soil profile. Soil $NO_3-N$ content in autumn were 7 and 14 ppm for 14N and 28N respectively, showing very low values compared with that of summer. 4. The ratio of inorganic nitrogen to total nitrogen increased with soil depth and with urea application rates.

• Journal of The Korean Society of Agricultural Engineers
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• v.48 no.3
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• pp.3-8
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• 2006

The fractions of nitrogen were investigated in the soils of reclaimed and natural tidelands of southwest coastal area of Korea. The content of total-N varied to ranged form 619 to 5,534 mg/kg dry weight with a mean value of 1,857 mg/kg. The order of different fractions of nitrogen was as follows: Acid non-extractable-N > uncounted-N > acid extractable-N > ammonia-N > nitrate-N. The content of ammonia-N, acid extractable-N, and acid non-extractable-N showed highly negative correlations with pH. The content of acid extractable-N and ammonia-N showed highly positive correlation with clay content.

• Preventive Nutrition and Food Science
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• v.6 no.3
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• pp.197-199
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• 2001

The effects of cooking peanut kernels before grinding on the n-hexanal content of peanut milk was investigated. Analysis of headspace volatiles revealed that n-hexanal was greatly reduced by cooking peanut kernels before grinding. Total solids and protein content tended to decrease as cooking time was increased. The most satisfactory condition of cooking peanut kernels for preparing peanut milk was 10 min.

• Journal of Mushroom
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• v.16 no.3
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• pp.225-230
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• 2018

This study was conducted to reuse spent mushroom substrates (SMS) of Pleurotus ostreatus and improve their nitrogen content by bacterial treatment. Two kinds of bacteria were used to investigate the increase in total nitrogen (T-N) content. Bacillus sp. (GM20-4) was isolated from SMS of oyster mushroom, and Rhodobacter sphaeroides (RS) was obtained from Gwangju Si Agricultural Technology Center. SMS samples were collected from three oyster mushroom cultivation farms located in Gyeonggi-do province, Korea. When dried SMS was inoculated with 30% culture broth of GM20-4 and RS and incubated at room temperature ($25{\pm}2^{\circ}C$) for 5 days, T-N content increased. To investigate the T-N content of other SMS, three dried SMS samples (A, B, and C) were treated by the same method using GM20-4 and RS. As a result, the T-N content of sample B was 20% higher than that of the control, whereas the T-N content of samples A and C increased to 17% and 12%, respectively. The change in T-N content by bacterial treatment of wet SMS was slightly higher than that of the control. The changes in amino acid content were also found to be higher than those in the control in all SMS samples by GM20-4 and RS treatment. Aspartic acid and glutamic acid contents were the highest among all amino acid compositions. Especially, the aspartic and glutamic acid contents of sample B increased by 2.9 folds higher than the control.

• Journal of Animal Environmental Science
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• v.3 no.1
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• pp.13-18
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• 1997

This study was conducted to investigate the physicochemical changes during the aerobic composting of swine manure mixed with bulking agent, sawdust(v/v, 1:1), in a full-scale composting plant using rectangular escalator-aginated bed composting system. Physical and chemical properties were analyzed on the samples which were collected at 5, 15, and 25 day of composting, curing and final step. The results of this study were summarized as follows; 1. Moisture and K2O content, and pH of final step were higher than those of 5th day of composting (p＜0.05). 2. Ammonium nitrogen, total organic corbon and organic matter content, and electrical conductivity(EC) were significantly decreased (p＜0.05) but nitrate nitrogen, ash and P2O5 content increased(p＜0.05) throughout the aerobic composting process. 3. Total organic carbon per total nitrogen(C/N) and total organic matter per total nitrogen(OM/N) ratio were significantly decreased throughout the aerobic composting process(p＜0.05). 4. Physical and chemical properties of swine manure were varied by aerobic fermentation using rectangular escalor-aginated bed composting system.

• Journal of The Korean Society of Grassland and Forage Science
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• v.11 no.3
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• pp.175-181
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• 1991

The purpose of this experiment was to evaluate the effects of shade and levels of N fertilization on the dry matter yield and chemical compositions of orchardgrass grown under floor of chestnut tree. Shading conditions consist of $S_0$, (full light), $S_1$, (about 6OC4 shade) and $S_2$, (about 70% shade). And, nitrogen fertilizer was applied at 3 levels, O($N_0$), 12($N_1$), and 30($N_2$) kg per 10a, respectively. The results are may be summarized as follows: 1. Maximum total dry matter yield of $S_0$, was obtained about 1.28 ton/lOa at $N_2$, level. But, total dry matter yields of N levels in $S_1$, and $S_2$, were decreased about 42-45% compared with $S_0$. 2. The response of the dry matter yield to N fertilization were differences between shading and levels of N. Thus, the dry matter yield of $S_1$, increased almost linear up to about 30 kg/l0a level, while the dry matter yield of S, was increased slightly up to 30 kgIl0a. But. $S_2$, was increased up to 12 kg/lOa and then decreased slightly with N fertilization over the 12 kg/l0a. 3. Average increase in total dry matter yield to N fertilization were 23.85 kg, 7.97 kg and 5.08 kg DM for $S_0$, $S_1$, and $S_2$, respectively. 4. The level of 12 kg N/lOa is the limiting N level to obtain dry matter production under 60-709 shading conditions. 5. The contents of crude protein arid nitrate nitrogen were increased with shading and incremental N fertilization up to 30 kg/l0a. But, water soluble carbohydrate content was decreased greatly with high shading and high levels of N. 6. Nitrate nitrogen content indicated highly significant positive correlation with crude protein, but significant negative correlation with water soluble carbohydrate content. 7. At 30 kg N level with $S_1$, was necessary to exceed the potentially toxic nitrate nitrogen level of 0.20%.