• Korean Journal of Food Science and Technology
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• v.35 no.3
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• pp.359-365
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• 2003

Headspace solid-phase microextraction(HS-SPME) was used to isolate the off-flavor volatile compounds, which are formed during the oxidation of porcine liver and unsaturated fatty acids in porcine liver induced by iron. Three fibers for HS-SPME method development were tested, and the polydimethylsiloxane/divinylbenzene(PDMS/DVB) fiber was selected as providing the best detection of analyzed compounds. In the oxidized arachidonic acid, the major compounds identified were hexanal, 1-octen-3-one(metallic), (Z)-4-heptenal, (E)-2-octenal, 1-octen-3-ol(mushroom), (Z)-2-nonenal (cardboard-like), and (E,E)-2,4-decadienal(fatty, oily). In the oxidized linolenic acid, the major ones were (E,E)-2,4-heptadienal(fishy), (E,E)-3,5-octadien-2-one and (E,Z)-2,6-nonadienal. Moreover, those of th oxidized porcine liver with iron were hexanal, 1-octen-3-one, (Z)-4-heptenal, (E,Z)-2,4-decadienal and (E,E)-2,4-decadienal. These results showed that the fishy and metallic off-flavor in porcine liver were due to the oxidation of unsaturated fatty acids in porcine liver.

• Food Science and Preservation
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• v.5 no.1
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• pp.35-39
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• 1998

The cell membrane properties in relation to flesh browning of Fuyu persimmon fruits during CA storage were studied. Compared to intact fruits, the flesh tissue of browned fruits showed higher rate of electrolyte leakage, indicating incresed membrane permeability. It could be assumed that the increased membrane permeability results in 1eakage of phenolic compounds from vacuole and their oxidation by contacting with PPO, inducing finally the development of flesh browning. In addition, lower content of fatty acids and higher saturation rate of them were found in browned fruits. In conculusion, it was suggested that the inhibited fatty acid metabolism and fatty acid saturation during CA storage cause membrane Permeability to increase.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.12
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• pp.1764-1769
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• 2000

The purpose of this experiment was to investigate the antioxidant effect of nitrite on total, neutral, and polar lipids and fatty acid composition in laboratory-cooked ground pork. Muscle samples (Biceps femoris) were analyzed using Iatroscan, gas chromatography, phosphorus content, and TBARS value. The total and neutral lipid contents of muscle were higher in nitrite-untreated meat (0 ppm) than in nitrite-treated meat (100 ppm) but the reverse was observed for polar lipid contents. The results for neutral lipids showed a similar trend when compared with total lipids. Polyunsaturated fatty acids contents of total, neutral and polar lipid in 100 ppm treated meat were higher than that of 0 ppm. The phosphorus content was higher in 100 ppm meat than in 0 ppm but the reverse was observed for TBARS value. These results showed that the addition of 100 ppm nitrite to ground pork resulted in a remarkable antioxidant effect during refrigeration storage.

• Journal of Microbiology and Biotechnology
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• v.14 no.6
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• pp.1256-1266
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• 2004

2-Bromooctanoic acid (2-BrOA) is known to block the formation of polyhydroxyalkanoic acid (PHA) in Pseudomonasfluorescens BM07 without any influence on the cell growth when grown on fructose, but it inhibits the cell growth when grown on octanoate (OA) (Lee et al., Appl. Environ. Microbiol. 67: 4963- 4974, 2001). We investigated the role of 2-BrOA in the PHA synthesis of the bacterium grown with mixtures of fructose and fatty acids. OA, 11­phenoxyundecanoic acid (1 1-POU), and 5-phenylvaleric acid (5-PV) were selected as model substrates. When supplemented with 50 mM fructose, all these carboxylic acids suppressed the formation of PHA from fructose, however, the ~-oxidation coenzyme A monomers derived from the carboxylic acids were efficiently polymerized, but the conversion yield [(mol of carboxylate substrate converted into PHA)/(mol of carboxylate substrate in the feed)] was low (e.g., maximally $\~53\%$ for 5 mM 11-POU). Addition of 2-BrOA (up to 5 mM) to the mixed carbon sources raised the conversion yield sensitively and effectively only at low levels of the acid substrates (e.g., 2 mM 1 1-POU or 5 mM OA): For instance, $100\%$ of 2 mM ll-POU were converted into PHA in the presence of 5 mM 2-BrOA, whereas only $\~10\%$ of the 1 1-POU were converted in the absence of 2-BrOA. However, at highly saturated suppressing levels (e.g., 5 mM ll-POU), 2-BrOA inhibitor showed no significant additional effect on the conversion ($60- 70\%$ conversion irrespective of 2-BrOA level). The existence of competitive and compensative relationship between 2­BrOA and all the carboxylic acid substrates used may indicate 'Present address: Section on Brain Physiology and Metabolism, Bldg. 10, Rm. 6N202, National Institute on Agmg, National Institute of Health, Bethesda, MD 20892, U.S.A. that all the acid substrate-derived inhibiting species bind to the same site as the 2-BrOA inhibiting species does. We, therefore, suggest that 2-BrOA can be used for efficiently increasing the yield of conversion of expensive substituted fatty acids into PHA and then substituted 3-hydroxyacids by hydrolyzing it.

• Journal of Microbiology and Biotechnology
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• v.28 no.4
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• pp.597-605
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• 2018

Acyl-CoA oxidases (ACOXs) play important roles in lipid metabolism, including peroxisomal fatty acid ${\beta}$-oxidation by the conversion of acyl-CoAs to 2-trans-enoyl-CoAs. The yeast Yarrowia lipolytica can utilize fatty acids as a carbon source and thus has extensive biotechnological applications. The crystal structure of ACOX3 from Y. lipolytica (YlACOX3) was determined at a resolution of $2.5{\AA}$. It contained two molecules per asymmetric unit, and the monomeric structure was folded into four domains; $N{\alpha}$, $N{\beta}$, $C{\alpha}1$, and $C{\alpha}2$ domains. The cofactor flavin adenine dinucleotide was bound in the dimer interface. The substrate-binding pocket was located near the cofactor, and formed at the interface between the $N{\alpha}$, $N{\beta}$, and $C{\alpha}1$ domains. Comparisons with other ACOX structures provided structural insights into how YlACOX has a substrate preference for short-chain acyl-CoA. In addition, the structure of YlACOX3 was compared with those of medium- and long-chain ACOXs, and the structural basis for their differences in substrate specificity was discussed.

• Journal of Nutrition and Health
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• v.29 no.9
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• pp.925-933
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• 1996

This study intended to compare the hypolipidemic effects among six experimental groups fed by three different dietary carbohydrates on hyperlipodemic rats. Sixty experimental animals were divided into 6 groups, SB, ST, SP and CB, CT, CP after production of hyperlipidemia fed by SB diet on Sprague-Dawley rats for 4 weeks. Rats were fed by six experimental diets for eight weeks. Hyjperlipidemic rats showed three times higher in plasma TG level not in cholesterol content compare to control group fed by stock diet. Two different dietary carbohydrates seem to be effective in body weight gain and fat cumulation as weight of epididymal fat pad. In comparison of S and C groups, C fed groups showed lowering effect in plasma TG and total lipid contents, but among S fed groups, ST and SP group showed lower than SB in this respects. Dietary carbohydrates seem to be more effective than fat in plasma lipid contents. When we compare among three different fat groups, only T groups with different carbohydrates increased in peroxisomal lipid oxidation and decreased in lipogenic enzyme activites. As same token, sucrose fed group with three fat sources seem to increase activiteies enzyme activities. In epididymal fat pad and Heart, SP and CP effect more in LPL activites than other groups. In conclusion, we can recommed to consume polysaccharides rather than disaccharide and n-3 fatty acids such as perilla and tuna oils to alleviate hypertringlycemic condition.

• Applied Biological Chemistry
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• v.29 no.2
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• pp.148-158
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• 1986

The effects of sodium nitrite on weight loss, pH, color development, color and lipid oxidation for the cooking of longissimus pork muscle were studied. Higher cooking temperature and grinding of sample increased the extent of weight loss, but sodium nitrite lowered it. Cooking decreased pH and sodium nitrite lowered the level of decrease in pH. Sodium nitrite developed color and controlled discoloration with higher lightness. The content of malonaldehyde was generally accelerated by cooking, but was considerably reduced at higher cooking temperature and for longer cooking time. Sodium nitrite acted as an antioxidant but the antioxidant effect decreased with increasing cooking temperature and time. Cooking reduced the extent of each lipid on the whole. Phosphatidyl choline and phosphatidyl ethanolamine were the major phospholipids of pork, and their contents decreased during cooking. The major fatty acids in total lipids were oleic acid and palmitic acid. Those in phospholipids were linoleic acid ana palmitic acid. The high level of polyunsaturated fatty acids and essential fatty acids in phospholipids decreased during cooking. Sodium nitrite had an antioxidant effect on polyunsaturated fatty acids in both total lipids ana phospholipids.

• Journal of the Korean Society of Food Science and Nutrition
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• v.24 no.1
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• pp.60-66
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• 1995

The oxidation of purified pinenut oil containing various concentration of tocopherols and β-carotene were studied. α-tocopherol revealed an antioxidant activity at the concentration of lower than 0.05%, however, it showed a prooxidant activity when the concentration was higher than 0.05%. The antioxidant activity of γ-tocopherol was not affected by the concentraitons in the range of 0.01∼0.10% in pinenut oil. γ -Tocopherol resulted in higher antioxidant activity than that of α-tocopherol. β -carotene seemed to be a prooxidant when 0.01% of β-carotene was added. The fatty acids composition of purified pinenut oil have been changed during autoxidation. The concentration of linoleic acid decreased readly while oleic acid seemed to increase. And the concentration of saturated fatty acid has'nt been changed much during autoxidation.

• Korean Journal of Food Science and Technology
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• v.52 no.1
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• pp.46-53
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• 2020

Carrots were deep fat fried with sunflower oil (SO), palm oil (PO), and a blend of palm and sunflower oils (PSO with PO:SO as 2:8 or 4:6) at different temperatures (180 and 190℃) and lengths of time (0.5 to 2.5 min). The quality of deep fat fried carrots was determined by the moisture and fat content, color, conjugated dienoic acid (CDA), hydroperoxide, p-anisidine value, and fatty acid composition. The moisture content of fried carrots decreased with increasing frying time, while the fat content increased. The CDA and p-anisidine values of carrots fried with SO were higher than those fried with PO because of greater unsaturated fatty acids content in SO. PSO was a better choice than SO or PO for deep fat frying carrots in the aspects of oxidative stability and ratio of unsaturated to saturated fatty acids. These results indicate that the quality of deep fat fried carrots depends on the type of oil and frying temperature used, as well as the length of time.

• Asian-Australasian Journal of Animal Sciences
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• v.29 no.12
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• pp.1748-1755
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• 2016

An experiment was conducted to investigate the effect of niacin supplementation on hepatic lipid metabolism in rabbits. Rex Rabbits (90 d, n = 32) were allocated to two equal treatment groups: Fed basal diet (control) or fed basal diet with additional 200 mg/kg niacin supplementation (niacin). The results show that niacin significantly increased the levels of plasma adiponectin, hepatic apoprotein B and hepatic leptin receptors mRNA (p<0.05), but significantly decreased the hepatic fatty acid synthase activity and adiponectin receptor 2, insulin receptor and acetyl-CoA carboxylase mRNA levels (p<0.05). Plasma insulin had a decreasing tendency in the niacin treatment group compared with control (p = 0.067). Plasma very low density lipoproteins, leptin levels and the hepatic adiponectin receptor 1 and carnitine palmitoyl transferase 1 genes expression were not significantly altered with niacin addition to the diet (p>0.05). However, niacin treatment significantly inhibited the hepatocytes lipid accumulation compared with the control group (p<0.05). In conclusion, niacin treatment can decrease hepatic fatty acids synthesis, but does not alter fatty acids oxidation and triacylglycerol export. And this whole process attenuates lipid accumulation in liver. Besides, the hormones of insulin, leptin and adiponectin are associated with the regulation of niacin in hepatic lipid metabolism in rabbits.