• Asian-Australasian Journal of Animal Sciences
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• v.21 no.5
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• pp.663-670
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• 2008

The effect of supplementing the diet of grazing dairy cows with fish oil (FO) and linseed oil (LSO) on milk conjugated linoleic acid (CLA) was investigated. Sixteen Holstein cows (17019 DIM) were assigned into two groups and fed a grain supplement (8.0 kg/d; DM basis) containing 800 g of saturated animal fat (CONT) or 200 g FO and 600 g LSO (FOLSO). All cows grazed together on Sudan grass pasture ad libitum and were fed the treatment diets for 3 wks. Cows were milked twice a day and milk samples were collected during the last three days of the trial. Milk production (24.89 and 22.45 kg/d), milk protein percentage (2.76 and 2.82) and milk protein yield (0.68 and 0.64 kg/d) for the CONT and FOLSO diets, respectively, were not affected (p>0.05) by treatment diets. Milk fat percentage (3.90 and 2.86) and milk fat yield (0.97 and 0.64 kg/d) were lower (p<0.05) with the FOLSO diet compared with the CONT diet. The concentration and yield of milk cis-9 trans-11 CLA were higher (p<0.05) with the FOLSO diet (2.56% of total FA and 16.44 g/d, respectively) than the CONT diet (0.66% of total FA and 6.44 g/d, respectively). The concentrations of milk trans C18:1 and vaccenic acid (VA) were higher (p<0.05) with the FOLSO diet (13.53 and 7.48% of total FA, respectively) than the CONT diet (3.69 and 2.27% of total FA, respectively). In conclusion, supplementing the diet of grazing cows with FO and LSO increased milk cis-9 trans-11 CLA content but reduced milk fat content and yield.

• Korean Journal of Food Science and Technology
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• v.46 no.2
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• pp.127-134
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• 2014

This study was performed to evaluate the effects of sesame oil addition to a tuna oil-enriched emulsion during chlorophyll-photosensitized oxidation. The emulsion principally consisted of tocopherol-stripped canola and tuna oil with or without sesame oil, acetic acid, phospholipids, and xanthan gum. Chlorophyll b was added to promote the production of singlet oxygen upon exposure to light. The oxidation of oil in the emulsion was evaluated by determining the peroxide value (POV) and conjugated dienoic acid (CDA) contents. Concentrations of minor compounds in the emulsion were monitored. Increasing POV and CDA contents in the emulsion were paralleled with decreased docosahexaenoic acid during oxidation, and oxidation was inhibited by the addition of sesame oil. Chlorophyll, polyphenols, tocopherol, and phospholipids were degraded during oxidation of the emulsion; however, their degradation was slowed down by the addition of sesame oil. Lignans in the emulsions containing added sesame oil were barely changed, suggesting that they quenched singlet oxygen physically. Polyphenols were the most effective in improving the stability of tuna oil-enriched emulsions during chlorophyll-photosensitized oxidation.

• Environmental Analysis Health and Toxicology
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• v.21 no.2 s.53
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• pp.103-113
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• 2006

This study examined effects of crude oil on the phase II drug-metabolizing enzymes UDP-glucuronosyl transferase (UDPGT) and glutathione S-transferase (GST) in mussel Mytilus edulis and rockfish Sebastes schlegeli, a representative bivalve and a culture fish, respectively. This work also intended indirectly to evaluate the post impact recovery from the massive oil tanker spillage accidents occurred during the summer of 1995 in the sea area off Yosu City, Chonnam. For these, enzyme activities of UDPGT and GST were examined in the fish and mussel following laboratory exposure to fresh crude oil, weathered oil, field-obtained oil residues, or in the field biota samples. Decreased GST activity was observed in rock fish following exposure to oil-soluble fraction (OSF) of fresh oil. A similar diminished GST activity was also observed after OSF of artificially weathered oil. OSF of field oil residues retrieved from the spillage area approximately 1 year later also exerted a slight inhibition of GST to rockfish. There was neither a change in UDPGT in rockfish, nor were there changes in mussel in both enzymes to any oil fractions. We could not observe any difference in the two enzymes either in rockfish or mussel sampled from the field during $1.5{\sim}2.0$ years post spillage, indicating that their enzyme systems might had been recovered by the sampling time. In conclusion, it seems that the inhibition of GST activity in rockfish is a biomarker response to crude oil exposure. The results, however, must be interpreted with care, as the inhibition nay reflect various factors such as oil concentration, duration and water temperature.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.8
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• pp.1252-1257
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• 2007

This study was conducted to determine the effect of dietary soy isoflavone (ISF, 0 and 20 mg/kg) on performance, meat quality and antioxidative property in male broilers. Six replicates of 45 birds (42 d old) were used for each treatment. The birds were fed soybean meal-free diets containing 3% oxidized fish oil (acid value, 6.76 mg potassium hydroxide/g; and peroxide value, 6.18 meq/kg) for 3 wk. The results showed that average daily gain, feed intake, feed conversion and carcass traits were not affected by soy ISF. Compared with the control group, breast muscle color redness value and water holding capacity were increased (p<0.05) by ISF supplementation. The activity of plasma catalase was increased by supplementing with 20 mg ISF/kg diet. In breast muscle, Broilers fed 20 mg ISF/kg had decreased production of malondialdehyde and lactic acid. The ISF supplementation elevated total antioxidative capacity and activities of total superoxide dismutase and glutathione peroxidase. The results indicated that dietary ISF could increase redness and water holding capacity of meat, and antioxidative property of meat in male broilers fed oxidized fish oil diet.

• Korean Journal of Food Science and Technology
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• v.23 no.5
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• pp.578-581
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• 1991

The antioxidative effects of three kinds of commercial lecithin in fish oil(EPA 25%, DHA 10%) were investigated through active oxygen method (AOM, hrs. at $97.8^{\circ}C$), Oven test, polymer test by gel chromatography and coloring test. Although there were difference of antioxidative effect among commercial lecithins, antioxidative effects of the lecithins added to the fish oil increased with increasing the concentration of lecithin. Lecithin III(acetone insoluble content 65%) had the greatest antioxidative effect and the addition of 1%, 5 and 10% enhanced the oxidative stability to 310%, 620% and 840%, respectively. The results also showed that the polymerization in presence of 10% lecithin III did not occur up to 10 hours at the AOM condition, and the degree of color(Gardner number) increased as storage time went by and was accerated at high temperature.

• Food Science and Preservation
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• v.24 no.4
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• pp.529-535
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• 2017

Rapeseed cake was extracted with 80% ethanol and then fractionated with $H_2O$ (fraction I) as well as with 30% (II), 50% (III), 70% (IV), and 100% ethanol (V). Total phenolic content (TPC), 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, ferric-reducing antioxidant potential, and Trolox equivalent antioxidant capacity were in the order of fractions II > III > I > IV > V. The three fractions with high antioxidant activities and TPC (I, II, and III) were pooled and hydrolyzed by NaOH solution, resulting in 18.97 mg sinapic acid/g hydrolyzed extract and 21- and 2.2-fold increases in TPC and DPPH radical scavenging activity, respectively. Hydrolyzed rapeseed cake extracts (200, 500, and 1,000 ppm) and catechin (200 ppm) as a comparison were added to 10% fish oil-in-water emulsion, and their effects on oxidative stability were investigated by measuring hydroperoxide values (PV) during refrigerated storage. PVs were significantly lower in the emulsions with added hydrolyzed extract as compared to the control (p<0.05) and significantly decreased with increasing extract concentration (p<0.05) over a period of 29 days. The emulsion added with hydrolyzed extract showed higher PV than that added catechin at the same concentration (200 ppm) during 13-22 days (p<0.05), but after then, the PV was not significantly different (p>0.05). This study indicates that hydrolyzed rapeseed cake extract rich in sinapic acid may inhibit oxidation in a fish oil-in-water emulsion in a concentration-dependent manner.

• Journal of the Korean Society of Food Science and Nutrition
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• v.24 no.3
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• pp.384-388
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• 1995

High content of polyunsaturated fatty acid in fish oil makes it very susceptible to oxidation, which prevent fish oil from successful application to food processing or functional foods. To resolve this problem, oxidation stability model of fish oil was developed using the following differential equation : $dp/dt=k{\cdot}p(t){\cdot}[P_{max}\;-\;p(t)]$. This differential equation can be intergrated using analytical techniques to give : $p(t)=P_{max}/[1\;+\;[(P_{max}/P_{(0)})\;-\;-1]{\cdot}EXP(-K_p{\cdot}t)]$. At 50, 60, 70 and $80^{\circ}C,\;K_p$ were 0.00535, 0.01345, 0.02516 and 0.04675, respectively. The proposed model was well agreed with the measured data except for some minor deviations. In addition, $K_p$ was expressed as a function of temperature : $K_p=(1/P_{max})EXP\;[1\;-\;(8148/T)+20.1]$. Where T is absolute temperature($^{o}K$).

• Korean Journal of Food Science and Technology
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• v.23 no.4
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• pp.433-436
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• 1991

Natural compounds which could improve the oxidative stability of fish oil was screened from spices, herbs and naturally occurring antioxidants. Induction period of fish oil determined from oxidation curve by Rancimat ($80^{\circ}C$) was hardly affected with the addition of water-soluble and lipid-soluble fractions of garlic, leek, sesame leave and orange peel, and of organic acids such as citric acid, EDTA and selenium. Caffeic acid, catechin, quercetin and gallic acid laurylester, however, could extend the induction periods by $2.2{\sim}3.8$ times with the addition level of 0.1%(w/w). Rosemary extract and sesamol have a marked effect in retarding oxidation of fish oil. For example, induction periods of the oil samples stabilized with 0.1 rosemary extract and 0.1 sesamol were 16.4 hr and 11.6 hr, respectively, as compared to 4.0 hr of a control. When rosemary extract was used in combination with ascorbic acid (0.02%) or 8-tocopherol (0.2%), induction period could be extended to ca. 28 hr due to the synergism.

• 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.

• KSBB Journal
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• v.20 no.1 s.90
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• pp.12-17
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• 2005

Despite a wide range of fatty acids in fish oil, its the usage are very limited owing to off-flavors and volatile compounds in the oil. A way to extract and remove volatile compounds was performed at a semi-flow extractor by using supercritical carbon dioxide $(SC-CO_2)$. Samples of the oil were treated at the conditions which ranged from $30\;to\;80^{\circ}C$ and from 80 to 200 bar with 10 mL/min flow rate of carbon dioxide. In the oil the volatile compounds were analyzed by gas chromatography. Before extraction with $SC-CO_2$ the oil sample was detected over 129 peaks but 99 compounds were identified. The results demonstrated that at $40^{\circ}C$ and 200 bar extraction condition the volatile compounds in the tuna fish oil were removed, except for 14 compounds identified after extraction and other $SC-CO_2$ extraction conditions reached to high reduction of the volatile compounds.