• Korean Journal of Food Science and Technology
• /
• v.36 no.4
• /
• pp.537-541
• /
• 2004

Based on reaction time and substrate molar ratio, structured lipid (SL-corn) was produced at 1:2:2(corn oil/capric acid/CLA) and 4% immobilized lipase from Rhizomucor miehei (RM IM). Reaction was carried out for 24 hr at $55^{\circ}C$ in 1-L stirred-batch reactor. After reaction, 13.3 mol% capric acid and 8.9%, CLA were incorporated into corn oil. Iodine and saponification values of SL-corn were 68 and 202, respectively. Tocopherol content decreased after reaction (about 39%). SL-corn showed more yellowish color than corn oil (p<0.05). Reversed-phase HPLC indicated triacylglycerol species containing capric acid in SL-corn resulted in faster crystallization than that of corn oil.

• Korean Journal of Food Science and Technology
• /
• v.32 no.1
• /
• pp.62-68
• /
• 2000

Effects of conjugated linoleic acid (CLA) on physico-chemical properties of cooked ground pork patty were investigated for 11 days at $4^{\circ}C$. Pork patties containing 0, 1, 2, and 3% CLA were cooked at $90^{\circ}C$ for 30 min. The contents of crude protein and fat did not change whereas the content of ash and water decreased as the level of CLA enhanced. Lipid oxidation as measured by thiobarbituric reactive substances of patty was inhibited by addition of CLA. CLA treatment also reduced nitrite and cholesterol content and changed fatty acid composition. Consequently, given these positive effects of CLA, it may be assumed that CLA could be used as a fat additive for value-added pork patty.

• Journal of Microbiology and Biotechnology
• /
• v.28 no.5
• /
• pp.739-747
• /
• 2018

The low solubility and high-cost recovery of Propionibacterium acnes polyunsaturated fatty acid isomerase (PAI) are key problems in the bioproduction of high value-added conjugated linoleic acid (CLA). To improve the solubility of recombinant PAI, six chaperone proteins were coexpressed with PAI. Introduction of GroELS proteins dramatically improved the PAI solubility from 29% to 97%, with increased activity by 57.8%. Combined expression of DnaKJ-GrpE and GroELS proteins increased the activity by 11.9%. In contrast, coexpression of DnaKJ-GrpE proteins significantly reduced the activity by 57.4%. Plasmids pTf16 harboring the tig gene and pG-Tf2 containing the tig and groEL-groES genes had no visible impact on PAI expression. The lytic protein E was then introduced into the recombinant Escherichia coli to develop a cell autolysis system. A 35% activity of total intracellular PAI was released from the cytoplasm by suspending the lysed cells in distilled water. The PAI recovery was further improved to 81% by optimizing the release conditions. The lipase from Rhizopus oryzae was also expressed in E. coli, with an extracellular activity of 110.9 U/ml. By using the free PAI and lipase as catalysts, a joint system was established for producing CLA from sunflower oil. Under the optimized conditions, the maximum titer of t-10,c-12-CLA reached 9.4 g/l. This work provides an effective and low-cost strategy to improve the solubility and recovery of the recombinant intracellular PAI for further large-scale production of CLA.

• Journal of Dairy Science and Biotechnology
• /
• v.22 no.2
• /
• pp.119-130
• /
• 2004

Application of lactic acid bacteria in the markets are divided into four categories: dairy industry, health food industry, animal feed industry and pharmaceutical industries. Recently, Lactobacillus acidophilus have been used in the food industry and have obtained great attention as key cultures for health benefit. Since commercial application of L. acidophilus has become a common practice, characterization of these cultures were made. Futhermore, the strains selected should produce a final dairy product possessing good taste and acceptable body and texture, a selection step that cannot be achieved unless the product is actually manufactured. Conjugated linoleic acid (CLA) have been recognized as antioxidants, cancer inhibitors, cholesterol depressing agents, and growth promoting factors. Food products from ruminants, particularly dairy products, are the major dietary source of CLA f3r humans. The CLA content in yogurt or cheese can be increased by action of the starter cultures. The finding of the production of CLA by food starter culture opens interesting perspectives far the future in producing fermented products enriched in CLA.

• Journal of Nutrition and Health
• /
• v.34 no.8
• /
• pp.858-864
• /
• 2001

The study was designed to observe an antioxidant activities of conjugated linoleic acid(CLA) in rat liver by determining the activities of antioxidative enzymes(superoxide dismutase, glutathione peroxidase, catalase) and the levels of tocopherol and thiobarbituric acid reactive substance(TBARS). Male Sprague Dawley rats at weeks-old were divided into groups according to the types of dietary fat(beef tallow and fish oil) and then each group was subdivided into groups depending on CLA supplement. All rats were fed experimental diet containing 12% total fat including 1% CLA by weight for 30 weeks. CLA supplemented to beef tallow diet did not have significant effect on the level of TBARS and tocopherol. The level of TBARS was significantly increased in fish oil diet(highly unsaturated fat diet), but its level was significantly reduced by increasing SOD and GSH-Px activities when CLA was supplemented to fish oil diet so that CLA showed a sparing action of tocopherol in tissue. CLA did not have significant effect on peroxisomal catalase activities, but its activity was significantly increased when TBARS production was high in the fish oil diet. CLA could be incorporated into phospholipid of microsomal membrane, and interfered the conversions of C18 : 0 into C18 : 1 and C18 : 2 into C20 : 4 in liver. In conclusion, CLA had an antioxidant activities depending on the type of fat in diet. Therefore, it could be recommended to use CLA when highly unsaturated fat was used in meal preparation.

• Preventive Nutrition and Food Science
• /
• v.4 no.3
• /
• pp.203-208
• /
• 1999

The effect of the polyunsaterated fatty acids, linoleic acid(LA), arachidonic acid(AA) and conjugated dienoic linoleic acid(CLA) on IEC-6 cells (rat intestinal cell)proliferation and cell transduction have been determined in vitro. IEC-6 cells proliferation was assessed by cell growth and [3H]-thymidine incroporation analysis. At 10 μM concentration , the proliferationof cells supplemented with AA or LA was significantly higher than that of CLA. [3H]-thymidine uptake showed the same results. LA and AA increased [3H]-thymidine uptake more than CLA. The stimulatory effect of LA or AA was even more pronounced in the presence of IGF. Both cell number analysis and [3H]-thymidine incorporation revealed that IEC-6 cell proliferation was influenced differently by exogenous free fatty acids, in which AA or LA stimulated IEC-6 cell proliferation and CLA inhibited it. Tyorosine phosphorylation provides a key switch to regulate celluar acitivity in response to extracellular stimuli. At 20 μM and 10μM, AA with IGF-1 stimulated protein tyrosine phophorylation in IEC-6 cells, but LA's impact was less than that of AA. CLA and CLA with IGF-1 inhibited protein tyrosine phosphorylation in IEC-6 cells. These results suggest there is a possible correlation between cell proliferation and IGF receptor tyrosine knase activity driven by AA.

• Preventive Nutrition and Food Science
• /
• v.5 no.2
• /
• pp.86-92
• /
• 2000

Conjugated linoleic acid(CLA) refers to a collective term of positional and geometric isomers of linoleic acid, which are different in their biological activities. The predominant isomer of CLA in animal tissues is cis-9, trans-11; smaller amounts of trans-10, cis-12 CLA isomers, CLA methyl ester (CLA-ME) was chemically syn-thesized from linoleic acid by the alkaline isomerization method. The synthetic CLA-ME, mainly composed of cis-9, trans-11 CLA and trans-10, cis-12 CLA, was dissolved in acetone, stored at 68$^{\circ}C$ for 1 day, and the supernatant(cis-9, trans-11 CLA-Me) was separated from the precipitate (trans-10, cis-12 CLA-Me). After the processes were repeated three times at -68$^{\circ}C$, the whole processes were repeated three times at -71$^{\circ}C$ in order to increase the purity of these two isomers. The cis-9, trans-11 CLA-Me and trans-10, cis-12 CLA isomers were further purified by the urea adduct. Purities of the cis-9, trans-11 CLA-Me and trans-10, cis-12 CLA-Me were 90.3 and 99.9%, respec-tively. This method could be employed for the preparation of a large quantity of highly purified cis-9, trans-11 CLA-Me or trans-10, cis-12 CLA-Me from synthetic CLA-Me.

• Preventive Nutrition and Food Science
• /
• v.8 no.3
• /
• pp.253-259
• /
• 2003

Conjugated linoleic acid (CLA) is a class of positional, geometric conjugated dienoic isomers of linoleic acid (LA). CLA activates the immune system, protects against tumorigenesis, and reduces the incidence of atherosclerosis. Trans-10, cis-12 CLA has specific effects on lipid metabolism, it has been shown to reduce body fat gain and regulates some adipocyte secreted proteins in vivo and in vitro. Here we report that a CLA mixture affects cytokine secretion from rat primary adipocytes. Rat primary adipocytes were treated with 1 mM, 100 $\mu$M, 1 $\mu$M or 100 nM CLA mixture doses; and leptin, tumor necrosis factor alpha (TNF a ), interleukin-6 (IL-6) and glycerol levels in the medium were measured. Leptin secretion was lower, TNF $\alpha$ secretion higher and IL-6 secretion did not change in response to the CLA mixture. Leptin and TNF $\alpha$ secretions did not change with CLA mixture treatment in a dose-dependent manner. In addition, the CLA mixture did not appear to enhance lipolysis in rat primary adipocytes. In conclusion, our study demonstrates that the decrease in leptin and increase in TNF $\alpha$ secretion in adipocytes treated with CLA mixture may be due to the apoptotic effect and to a reduction in peroxisome proliferator-activated receptor gamma (PPAR ${\gamma}$ ) ligands.

• Journal of Animal Science and Technology
• /
• v.46 no.6
• /
• pp.967-974
• /
• 2004

The current study was undertaken to determine the effect of various conjugated linoleic acid (CLA) isomers on differentiation of pig preadipocyte during culture. Preadipocyte(stroma-vascular cell) was isolated from the backfat of newborn pigs and cultured to differentiate into mature fat cell. Different doses of CLA isomers were treated to the culture media at different times. Cell differentiation was determined by measuring the glycerol3-phosphate dehydrogenase activity of the cultured preadipocytes. Twenty and fifty $\mu$M of trans110_cis 12 isomer of CLA inhibited differentiation of pig preadipocyte whereas cis9-cis II isomer stimulated the differentiation. Both cis9-transII and trans9-trans11 isomers showed no effect. Effect of CLA isomer was more evident at the early stage of culture(day 0-8), than the late stage(day 8-14). These results suggest that each CLA isomer has different effect on pig preadipocyte differentiation.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.32 no.8
• /
• pp.1200-1205
• /
• 2003

Structured lipids (SL) were synthesized by transesterification of corn oil and conjugated linoleic acid (CLA) in the continuous type reactor using sn-1,3 specific Rhizomucor miehei lipase. The parameters of reaction were observed in terms of flow rate, temperature, and substrate molar ratios. The highest incorporation of CLA was obtained with 1 mL/min flow rate, 55$^{\circ}C$ and 1 : 3 (corn oil/CLA) molar ratio, showing 10.26 ㏖%. When different reaction temperatures and substrate ratios were studied, the highest incorporation was obtained at $65^{\circ}C$ (17.33 ㏖%) and 1 : 5 (corn oil/CLA) ratio (17.50 ㏖%), respectively. After pancreatic lipase analysis, most of all CLA were found at sn-1,3 position. The iodine values of obtained SLs ranged from 110 to 120. From the neutral lipid analysis by normal-phase HPLC, produced SLs composed of 99.35 ∼ 99.89% triacylglycerols, 0.11 ∼ 0.51% 1,2- and 1,3-diacylglycerols, and 0.06 ∼ 0.22% monoacylglycerols.