• Biomolecules & Therapeutics
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• v.20 no.2
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• pp.152-157
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• 2012

Docosahexaenoic acid (DHA) is the major polyunsaturated fatty acid (PUFA) in the brain and a structural component of neuronal membranes. Changes in DHA content of neuronal membranes lead to functional changes in the activity of receptors and other proteins which might be associated with synaptic function. Accumulating evidence suggests the beneficial effects of dietary DHA supplementation on neurotransmission. This article reviews the beneficial effects of DHA on the brain; uptake, incorporation and release of DHA at synapses, effects of DHA on synapses, effects of DHA on neurotransmitters, DHA metabolites, and changes in DHA with age. Further studies to better understand the metabolome of DHA could result in more effective use of this molecule for treatment of neurodegenerative or neuropsychiatric diseases.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.1
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• pp.31-38
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• 2014

Docosahexaenoic acid (DHA, 22:6n-3) and ecosapentaenoic acid (20:5n-3) have attracted increasing attention since the first epidemiological report on the importance of n-3 essential fatty acids. It is thought that DHA has important functions in brain and retinal tissues. Thraustochytrids, a group of marine protists, are capable of heterotrophic growth, and are potential omega-3 producers for industrial use, especially the members of the Schizochytrium and Thraustochytrium genera. The aims of this work were to isolate, identify and screen thraustochytrids from 17 different locations. Twenty-three isolates were screened for biomass, total fatty acid (TFA) and DHA content. Analysis of the fatty acid methyl esters revealed four distinct clusters biomass ranged from $8.68-9.36gL^{-1}$, and lipid and DHA contents ranged from $3.11-4.10gL^{-1}$ and $1.05-1.93gL^{-1}$ biomass, respectively. B-12 isolates were screened for biomass ($9.36gL^{-1}$), TFA ($4.10gL^{-1}$) and DHA (47.01%, w/w) content. C-6 isolates were also screened for biomass ($8.92gL^{-1}$), TFA ($3.30gL^{-1}$) and DHA (49.41%, w/w) content. The 18S rRNA gene sequencing results identified Schizochytrium mangrovei as B-12 and Crypthecodium cohnii as C-6.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.43 no.4
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• pp.285-292
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• 2010

To prepare high-quality fast foods using salmon, this study developed a docosahexaenoic acid (DHA)-enriched salmon patty, and compared its quality with soybean oil-added patty and commercial patty. The moisture and lipid contents of the DHA-enriched patty were 61.9% and 7.7%, respectively. The moisture content was lower than in the commercial patty, while the lipid content was higher. The lipophilic and hydrophilic browning indices of the DHA-enriched patty were 0.10 and 0.05, respectively, which were lower than those of the commercial patty. The DHA-enriched patty had 5% less trichloroacetic acid (TCA)-soluble nitrogen than the commercial patty, and it was firmer. There were no differences in the proximate composition, browning indices, TCA-soluble nitrogen content, and hardness between the soybean-added and DHA-enriched patties prepared in this experiment. Examining the fatty acid compositions of the patties, the saturated acid and monoenoic acid compositions decreased in the following order: DHA-enriched patty > soybean oil-added patty > commercial patty, while the polyenoic acid composition increased in that order. The total amino acid content of the DHA-enriched patty was 19.13 g/100 g, which was 32% higher than that of the commercial patty (14.47 g/100 g). No enriching effect of minerals would be expected on eating a 100 g DHA-enriched patty, except for phosphorus. The sensory evaluation indicated that the DHA-enriched patty was superior in color and taste to the commercial patty, while there was no difference in flavor between the patties.

• Journal of Food Hygiene and Safety
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• v.2 no.4
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• pp.197-200
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• 1987

Nutritive value of lipids was associated with composition of fatty acid. Unvalance diet may increase the incidence of diseases. Abundant of EPA and DHA, polyunsaturated fatty acid, were contained in fishes. Studies on 10 kinds of fishes, lipid components were determined. The results were as follows; 1. The content of crude fat 18.1% were high in eels, on the contrary the content of EPA 0.1% and DHA 0.1% were low. The content of crude fat were low in mackeral and sadrine, but the content of poly unsaturated fatty acid were high. 2. Iodine value 189 was high in sadrine, consequently, this results showed the interrelation between Iodine value and the content of polyunsaturated number. 3. The content of crude fat 1.3% in flounder(sole) were low and the content of cholesterol 20 mg% were lowest in present studies.

• KSBB Journal
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• v.18 no.3
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• pp.229-233
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• 2003

Antioxidant effect of reconstituted liposome was studied for application to food and cosmetic industry. Vitamin-C/alginate alginate gel-entrapped DHA-PC liposome (AVDL) was prepared and studied with respect to morphology (TEM), loading efficiency (TLC) and antioxidant effect (TBARS assay). AVDL has spherical structure and 80 ∼ 250 ㎚ size. As DHA content increased, DHA and PC loading efficiency and antioxidant effect was increased. At addition of 0.2 % vitamin C in AVDL, DHA auto-oxidation was minimized and sustained about 3 days.

• Asian Journal of Turfgrass Science
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• v.8 no.3
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• pp.167-177
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• 1994

The relationship between microbial activity and physico-chemical characteristics of golf course soils were investigated in Kyonggi Province with different open years. The increasing tendency of soil PH with depth seemed to the result of mineral leaching. Exchangeable $Ca^2$+ , $Mg^2$+ and K+ showed relatively higher concentration in lower horizon indicating the leaching of minerals. The minerals were heavily leached in older golf course. There was a significant positive correlation between pH and $Ca^2$+.The contents of organic matters, total nitrogen and phosphorus were high in higher horizon.Dehydrogenase activity(DHA) and the content of ATP were determined as an index of soil microbial activity. DHA value was significantly different with golf club as well as golf courses ac-cording todifferent open year. This indicates that DHA was affected by several fertilizertreatments rather than herbicide pesticide treatments. DHA was positively correlated with water holding capacity and total nitrogen. The content of ATP was high in fairway and in golf course with older open year, showing the similar tendency with the results of DHA.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.1
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• pp.14-19
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• 2001

This study was designed to compare content and composition of fatty acid in egg yolk oil among general eggs from chicken, quail, duck. We also compared those of general and functional chicken egg. Fatty acids were determined by GC method and the results were as follows: Palmitic acid, palmitoleic acid, stearic acid, oleic acid, linoleic acid, linolenic acid and timnodonic acid were identified in egg of chicken, quail and duck. The major fatty acid was oleic acid and palmitic acid in three kinds of eggs. Arachidonic acid and docosahexaenoic acid (DHA) were analyzed in egg of quail , but no in chicken. Monounsaturaterd fatty acid (MUFA) was higher in egg yolk oil of chicken and quail. Polyunsaturated fatty acid (PUFA) was higher in duck egg. Ginseng egg had significantly higher palmitic acid and oleic acid lower than general chicken egg. Gamgoal egg had lower palmitic acid and oleic acid, and higher palmitoleic acid and stearic acid than general chiekcn egg. The content of oleic acid was lower in DHA egg than in general chiecken egg, but arachidonic acid was detected only in DHA egg. Ginseng egg had the highest content of saturated fatty acid among chicken eggs. The content of MUFA acid was the highest in gamgoal egg and general chicken egg. DHA egg had the most amount of PUFA among all chicken egg.

• ALGAE
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• v.32 no.1
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• pp.67-74
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• 2017

The heterotrophic dinoflagellate Oxyrrhis marina is known to produce high levels of docosahexaenoic acid (DHA) when fed on diverse algal prey. However, large-scale culturing of algal prey species is not easy and requires a large amount of budget, and thus more easily cultivable and low-cost prey is required. Dried yeast was selected as a strong candidate for an alternative prey in our preliminary tests. Thus, we explored the fatty acid composition and DHA production of O. marina fed on dried yeast and compared these results to those of O. marina fed on two algal prey species: the phototrophic dinoflagellate Amphidinium carterae and chlorophyte Chlorella sp. powder. O. marina fed on dried yeast, which does not contain DHA, produced the same high level of DHA as those fed on DHA-containing A. carterae. This indicates that O. marina is likely to produce DHA by itself regardless of prey items. Furthermore, the DHA content (and portion of total fatty acid methyl esters) of O. marina satiated with dried yeast, 52.40 pg per cell(and 25.9%), was considerably greater than that of O. marina fed on A. carterae (26.91 pg per cell; 15.7%) or powder of Chlorella sp. powder (21.24 pg per cell; 16.7%). The cost of dried yeast (approximately 10 US dollars for 1 kg dried yeast) was much lower than that of obtaining the algal prey (approximately 160 US dollars for 1 kg A. carterae). Therefore, compared to conventional algal prey, dried yeast is a more easily obtainable and lower-cost prey for use in the production of DHA by O. marina.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.43 no.6
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• pp.589-597
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• 2010

Monthly changes in the proximate and fatty acid compositions of chub mackerel (Scomber japonicus) muscle during cultivation from October 2007 to September 2008 were investigated. The lipid content increased gradually from the first stage of cultivation until March 2008 and then dramatically until May, before decreasing. The highest lipid content during cultivation was 21.6% in May, just before the fish spawns. There was a negative correlation (y=-1.1585x+87.741, $R^2$=0.9495) between the lipid and moisture contents during cultivation of chub mackerel. By contrast, the protein ($18.6{\pm}1.05%$) and ash ($1.18{\pm}0.11%$) contents were essentially unchanged during cultivation. Prominent fatty acids in chub mackerel muscle were 16:0, 18:0, 14:0 saturates, 18:1n-9, 16:1n-7, 18:1n-7 monoenes, and 22:6n-3 (docosahexaenoic acid, DHA), 20:5n-3 (eicosapentaenoic acid, EPA), and 18:2n-6 polyenes. The percentages of n-3 polyunsaturated fatty acids (PUFA), such as DHA and EPA, were higher during three months in the early stage of cultivation than they were subsequently. However, the PUFA (DHA+EPA) content (in mg/100 g of muscle) was lower in the early stage (740-796 mg/100 g muscle) than in the other stages. The highest PUFA (DHA+EPA) content was from April to May (2,749-2751 mg/100 g muscle). The PUFA content was positively correlated with the total lipid content of chub mackerel muscle during cultivation. The results indicate that cultured chub mackerel is a very good source of n-3 PUFA, such as DHA and EPA.

• Food Science and Biotechnology
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• v.14 no.6
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• pp.788-792
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• 2005

The effect of docosahexaenoic acid (DHA) on maze-learning ability in aged mice was investigated. Aged mice fed a diet deficient in n-3 fatty acid received a semi-purified diet of 0.5, 1 and 2% DHA-ethyl ester (DHA-EE) for 4 months. Maze-learning ability was assessed at 3 months after the start of the experiment. The time required to reach the maze exit and the number of times that a mouse strayed into blind alleys in the maze were measured in 3 trials conducted at 4-day intervals. The time was significantly less in the DHA-EE 0.5% and DHA-EE 2% groups than in the control group (p<0.05). The number of times mice strayed into blind alleys in the maze was significantly lower in the DHA-EE 2% group than in the control group (p<0.05). Mice fed DHA showed increased DHA and decreased level of arachidonic acid (AA) in the brain. These results suggest that the intake of a 2% DHA diet improves learning ability in aged mice, which is associated with a higher DHA content in the brain.