• Journal of Animal Science and Technology
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• v.44 no.4
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• pp.427-442
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• 2002

Conjugated linoleic acid(CLA) is a collective term for a group of positional (c8, c10; c9, c11; c10, c12, and c11, c13) and geometric(cis,cis; cis,trans; trans,cis; and trans,trans) isomers of octadecadienoic acid (linoleic acid) with conjugated double bond system. CLA has been shown to have a variety of biological effects. Major effects of CLA on health, such as anti-cancer, anti-oxidation, anti-atherosclerosis and improving immuno-responses, might be derived or partially derived from the alternated lipid metabolism after CLA feeding. Most of studies on the effect of CLA on fat metabolism are concentrated on rats, mice, pigs and other mammals. The CLA inhibited carcinogen-induced neoplasia in several animal models and inhibited the proliferation of human malignant melanoma, colorectal and breast cancer cells and CLA reduced the atherosclerosis. Several studies have determined the antioxidant property of CLA; however, the property still remains controversial. Some of the studies have shown that CLA acted as an antioxidant, whereas some other studies have demonstrated that CLA might be a prooxidant. Several studies suggested that CLA could reduce fat accumulation in mammals. CLA was suggested to promote muscle growth and reduce fat deposition in mouse, and improve feed efficiency in rats. CLA has been shown to inhibit the activity of stearoyl-CoA reductase. CLA also reduced the content of arachidonic acid. Since arachidonic acid, and eicosapentaenoic acid (EPA) and docosahexenoic acid (DHA) are synthesized by different pathways, reducing the synthesis of arachidonic acid may not mean reducing that of EPA and DHA. Many sutdies have been shown biological effects of CLA. Therefore, further research is needed to answer the following questions: 1) how to synthesize the new CLA by new methods, 2) why CLA has shown biological effects, 3) how to increase CLA effects in animal products.

• Korean Journal of Food Science and Technology
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• v.27 no.2
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• pp.185-192
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• 1995

Microbial and chemical changes of salt-fermented youbsak which is a traditional processed fish product only manufactured in Hampyung bay region were investigated in this study. Total microbial cells of salt-fermented youbsak was gradually increased up to 30 days fermentation and then it was decreased. The pH and total acidities of fermented youbsak were not greatly changed, except for a rapid decrease in pH and acidity after 15 days fermentation. Volatile basic nitrogen and amino-type nitrogen were rapidly increased until 30 days fermentation and then slightly decreased by adding the extracted soup of pig bones. Palmitic acid was the most abundant fatty acid, and the major free amino acids in salt-fermented youbsak were composed of leucine, tyrosine, glutamic acid, valine, isoleucine, alanine and methionine.

• Korean Journal of Food Science and Technology
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• v.19 no.3
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• pp.181-187
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• 1987

The lipids of ten major fishes caught in Korean seas were analyzed for fatty acid composition and for the content of $\omega-3$ polyunsaturated fatty acids. The major fatty acids present were hexadecanoic acid $(14{\sim}24%)$, hexadecenoic acid $(4{\sim}13%)$, octadecenoic acid $(8{\sim}29%)$, eicospentaenoic acid $(4{\sim}18%)$ and docosahexenoic acid $(6{\sim}33%)$. The ${\omega}-3$ polyunsturated fatty acids ranged from 18% to 48% of the total fatty acids depending on the species. The content of eicosapentaenoic acid was relatively high in sardine, gizzard shad and atka fish on the basic of fresh body weight, while that of docosahexaenoic acid was highest in hair tail and followed by atka fish and sardine.

• Toxicological Research
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• v.26 no.3
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• pp.185-192
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• 2010

Isaria sinclairii (Cicada Dongchunghacho) was studied as a potential crude natural food in powdered form. The role of tissue fatty acids in relation to the anti-obesity effects of I. sinclairii (IS) was examined by feeding the powder to SD rats ad libitum at 0, 1.25, 2.5, 5 and 10% (calculated about 8 g/kg) of the feed for a period of 3 months and 6 months. The fatty acid composition profile as indicated GC-MS, showed significantly slight dose-dependent increases in the levels of unsaturated fatty acids, particularly, arachidonic acid (C20: 4n6), oleic acid, linoleic acid, eicosadienoic acid, eicosapentaenoic acid (EPA) (C20: 5) concentration in the the ad libitum IS-fed groups compared to the control group in SD abdominal fat over 6 month period. Over viewing of the SD and Ob mice treated Isaria sinclairii powder; there were increases in the single (mono) unsaturated fatty acids ratio but decreases in polyunsaturated fatty acid. In IS-fed groups in proportion to the treatment period, this Dongchunghacho also induced an increase in the level of same result of unsaturated fatty acid in C57BL/6 obese (ob/ob) mice over a 6-month period treatment compared to those given 10% dry mulberry leaf powder (ML) or silkworm powder mixed with the standard diet.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.4
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• pp.539-549
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• 2012

In order to acquire basic data on the development of squid processing food, we investigated changes in the composition of boiled squid upon heat treatment ($100^{\circ}C$), acid treatment (acetic acid, 0~5%), and pre-boiling ($55^{\circ}C$, $80^{\circ}C$). The proximate composition of squid was 73~78% moisture and 19~24% crude protein, treatment with acid solution had a significant effect on the proximate composition of boiled squid (p<0.05). The major free sugars were ribose and glucose in all treatment samples. The $55^{\circ}C$ pre-boiled sample had lower levels of glucose than the other samples. The total free sugar content of the non-peeled sample was the highest, followed by the $80^{\circ}C$ pre-boiled sample, whereas the sugar content in the $55^{\circ}C$ pre-boiled sample was very low. With regards to amino acid content, proline was the highest in all samples, followed by taurine and histidine. Treatment with acid solution had a significant effect on the total free amino content of boiled squid (p<0.05). The total free amino acid content of the $55^{\circ}C$ pre-boiled sample was the highest, followed by the $80^{\circ}C$ pre-boiled sample and non-peeled sample. Inosine and related compounds were not detected in any of the samples, and the adenosine triphosphate (ATP) content was low. The hypoxanthine contents of the $55^{\circ}C$ and $80^{\circ}C$ pre-boiled samples were the highest, the adenosine monophosphate (AMP) and inosine monophosphate (IMP) contents were similar, and the IMP content of the non-peeled sample was higher than those of the peeled samples. The palmitic acid content was very high and constituted 40% of total saturated fatty acids. eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) contents were also high and constituted 60% of total unsaturated fatty acids. Of these, DHA content was the highest, followed by palmitic acid and EPA, which accounted for about 85% of total fatty acids. No difference in fatty acid content was observed between acid treatment and pre-boiling. The mineral P content was the highest on average in all boiled squid samples, followed by K, Na, Mg, and Ca contents. In addition, the pre-boiling temperature and acid solution concentration had significant effects on the mineral content. Further, heavy metal, Cd, Pb, and As contents were detected only at trace amounts, and their levels were lower than standard and permissible amounts for food.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.49 no.6
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• pp.779-784
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• 2016

We evaluated seasonal variations in the proximate, fatty acid and total amino acid compositions and mineral content of the muscles of wild and cultured Korean bullhead Pseudobagrus fulvidraco. The wild and cultured samples showed a significantly higher proportion of crude lipids than other components. Crude lipid content was highest in May in wild fish but lowest in May in cultured fish. We found no significant difference between wild and cultured samples in terms of fatty acid and total amino acid compositions and mineral content. The levels of saturated fatty acids (SFA) and polyunsaturated fatty acids (PUFA) as well as n-6/n-3, were higher in the muscles of wild fish compared with those of cultured fish. However, monounsaturated fatty acids (MUFA) levels were higher in cultured fish. Both wild and cultured fish were good sources of eicosapentaenoic acid (EPA) and docosa hexaenoic acid (DHA). In wild fish, the Mg and Zn contents were highest in August, while the Ca, P, Na, K, Fe, and Cu contents were highest in May. However, the mineral content of the cultured fish did not exhibit significant seasonal variation.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.9
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• pp.1182-1187
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• 2007

Changes in composition of fatty acids and free amino acids in three differently dried Alaska pollack (sun dried, naturally cyclic freeze-thaw dried, and 1-year-aged cyclic freeze-thaw dried Alaska pollack (Hwangtae)) were investigated to correlate them with browning reactions in drying and aging Alaska pollack. Major fatty acids of the sun dried Alaska pollack were palmitic acid, oleic acid, and eicosapentaenoic acid (EPA), and those in the Hwangtae were palmitic acid, oleic acid, and gondoic acid. Hwangtae showed the lowest amount of polyunsaturated fatty acids among the three types of dried Alaska pollack. Free amino acids content of sun dried Alaska pollack was higher than that of the cyclic freeze-thaw dried Alaska pollack and Hwangtae. Lesser amount of histidine in Hwangtae (0.02%) than that in the cyclic freeze-thaw dried Alaska pollack (0.087%) may indicate the degradation of histidine due to the browning reaction in aging the cyclic freeze-thaw dried Alaska pollack. Significant changes in compositions of fatty acids and free amino acids among the dried products revealed the browning reaction resulted from carbonyl compounds produced by decomposition of lipid hydroperoxides and free amino acids. Aging the cyclic freeze-thaw dried Alaska pollack for a year contributed to the development of browning.

• Journal of Aquaculture
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• v.17 no.4
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• pp.275-281
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• 2004

The present study was conducted to evaluate dietary requirements for essential fatty acids (EFAs) such as linoleic acid (LA, l8:2n-6), -lenolenic acid (LNA, 18:3n-3), or docosahexaenoic acid (DHA, 22:6n-3), eicosapentaenoic acid (EPA, 20:5n-3) and arachidonic acid (ARA, 20:4n-6) in juvenile eel Anguilla japonica cultured in a recirculating system for 16 weeks. The experimental diets contained 50% crude protein, 10% crude lipid and 3800 kcal/kg energy.Brown fish meal and blood meal were used as the main protein sources, while coconut oil, com oil and linseed oil were used as the lipid source to yield target fatty acids ratios. At the end of the trial, the effects of essential fatty acids supplementation on weight gain (WG), specific growth rate (SGR), feeding efficiency (FE), proximate composition andwhole body fatty acids contents were examined. WG, SGR, and FEof eels fed diet D2, D3, was significantly higher (P<0.05) than those of fish fed the other diets. Whole body HUFA concentration of eels fed D 1 was significantly lower (P<0.05) than those fed the other diets. HUFA/SFA (saturated fatty acids) ratio of whole body in eels fed diets D2, D3 and D6 were significantly higher than that of eels fed diet D1 (P<0.05).DHA/EPA ratio of whole body in eels fed diet D7was significantly higher than those fed the other diets; and eels fed diet D5 showed the lowest DHA/EPA ratio among all the dietary treatments (P<0.05).Based on the experimental results, we concluded that LNA (n-3) and LA (n-6) were necessary for optimum growth of juvenile eel, and the dietary requirement of LNA and LA were 0.35∼0.5% and 0.5∼0.65%, respectively.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.7
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• pp.1052-1058
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• 2005

Structured lipid (SL) was synthesized by enzymatic interesterification with algae oil containing docosahexaenoic acid (DHA) and soybean oil in the stirred-batch type reactor. The reaction was performed for 15hr at $65^{\circ}C$ with 300 rpm catalyzed by sn-1,3 specific Lipozyme RM 1M lipase from Rhizomucor miehei ($11\%$ by weight of total substrates) in the absent organic solvent. SL contained $87.1\;area\%$ triacylglycerol (TAG), $12.1\;area\%$ diacylglycerol (DAG), $0.6\;area\%$ monoacylglycerol (MAG), and $0.2\;area\%$ free fatty acid (FFA). Major fatty acid profiles of SL were DHA $(15.7\;mol\%)$, linoleic $(31.1\;mol\%)$, palmitic $(20.2\;mol\%)$, oleic $(13.5\;mol\%)$ and eicosapentaenoic acid $(EPA,\;6.6 mol\%)$. SL contained the newly synthesized several peaks. Iodine and saponification of SL were 206.7 and 183.8. SL color showed darker and redder than soybean oil, and appeared the most yellowish color among SL, soybean, and algae oil.

• Journal of Food Hygiene and Safety
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• v.34 no.5
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• pp.480-488
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• 2019

To ensure the safety of products containing omega-3 fatty acids, twenty fish and algae oil omega-3 products available in a Gyeonggi Province, South Korea market were analyzed for eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) content, as well as for oxidative status. Of the tested products, 90% complied with the CODEX/FAO fish oil standards on a p-anisidine value (p-AV) limit of 20, and 80% complied with the CODEX/FAO fish oil standards on the TOTOX limit of 26, respectively. Fully 100% of the products complied with EPA/DHA content levels. In addition, 90% of the tested products met with a peroxide value (PV) limit of 10 meq/kg while 95% of products were within the a p-AV limit of 30. Also, 95% of the products had a calculated TOTOX value of 50, which is lower than the stringent limits used by the European and British Pharmacopeia and Australian authorities.