We conducted a double-blind, controlled study to investigate the effects of prolonged ingestion of margarine containing medium-chain triglycerides (MCT-M) on serum lipids, apolipoprotein and vitamin A levels, and on postprandial thermogenesis, compared with those of margarine containing long-chain triglycerides (LCT-M). Healthy subjects (n = 26, Body Mass Index 22.6 ± 3.3 kg/m2, mean ± SD) were divided into two groups and ingested 1950-2400 kcal/day of energy, 59-69 g/day of total fat, and 42 g/day of test margarine (15 g/day of MCT or LCT) for 4 weeks. Intake of medium-chain fatty acids was significantly greater with the MCT-M diet (14.2 ± 0.4 g/day, mean ± SD) than with the LCT-M diet (0.2 ± 0.0 g/day) during the 4-week period. There were no significant differences in the blood concentrations of lipids, lipoproteins, apolipoproteins, retinol, glucose, insulin, ketone, hemocytes and electrolytes, or in measures of liver and renal function, between the diet groups. After prolonged ingestion of MCT-M, consumption of an MCT-M meal led to a significant increase in postprandial O2 consumption compared with an LCT-M meal (after 30 min: MCT-M 45 ± 7 ml/min vs. LCT-M 30 ± 7 ml/min; mean ± SE). In conclusion, we suggest that the influences of ingestion of MCT-M for 4 weeks on serum lipids, lipoproteins, apolipoproteins, retinol, ketones, plasma glucose and liver and renal function were similar to those of LCT-M. We also suggest that the prolonged ingestion of 15 g of MCT in healthy humans did not attenuate the postprandial thermogenesis caused by meals containing 5 g of MCT. From these suggestions, MCT-M have a possibility of being efficient foodstuff for preventing obesity in healthy humans.
A novel method for preserving labile lipid samples at ambient temperature was developed with a commercially available oxygen absorber. In order to optimize the preservation conditions, the changes in the fatty acid composition of a triacylglycerol mixture during storage were determined by thermally assisted hydrolysis and methylation gas chromatography in the presence of trimethylsulfonium hydroxide. The polyunsaturated fatty acid (PUFA) components of the sample proved to degrade during preservation at room temperature through autoxidation induced by the trace amount of residual oxygen in a plastic bag for storage even coexisting with the oxygen absorber. On the other hand, once the lipid sample in the plastic bag with the oxygen absorber was subjected to 7 days “pretreatment” in a refrigerator at about 2°C, the PUFA components of the lipid sample in the bag were kept almost completely unchanged during further preservation at room temperature for at least four weeks. The observed results indicated that the residual oxygen in the plastic bag was sufficiently eliminated by the oxygen absorber during the “pretreatment” at about 2°C. Therefore, the labile lipid samples can be preserved at room temperature for a long time without deterioration by using oxygen absorber combined with the appropriate “pretreatment” storage in chilled conditions for a certain period. Moreover, reliable transportation of various biomaterial samples to a distant laboratory is able to be carried out conveniently at ambient temperature by this novel storing method without utilizing any special freezing system.
An eight-Japanese laboratory collaborative study was undertaken to devise an improved safe rapid means for methyl-esterification (with potassium hydroxide-methanol as the reaction solution) for GC fatty acid determination in fats and oils. This group effort (Fatty Acid Derivative Subcommittee) was undertaken at the request of the Japan Oil Chemists’ Society. Optimal determination was initially made of parameters such as concentration and volume of the reaction solution and reaction period. By 0.2 mL 2 M potassium hydroxide-methanol as reaction solution, 98.6-102% recovery was confirmed in methyl-esterification for five kinds of triacylglycerol standards; tricaprylin, trilaurin, tripalmitin, tristearin, and triolein. Collaborative study with 8 laboratories on GC with coconut, lard, soybean, and palm oil by means of the fixed reaction conditions was carried out. Reproducibility coefficient of variation (CVR) ranged from 0.6 to 2.8% for major fatty acids with peak area ratio exceeding 10% and 1.6 to 9.6% for minor fatty acids with peak area ratio less than 10%. The present method was found to qualify tentatively as the official method of the Japan Oil Chemists’ Society.
Methyl, ethyl and butyl β-D-glucosaminide 6-O-fatty acid esters were prepared by the novel direct transglycosylation reaction of chitosan with methanol, ethanol and butanol using resting cells of the chitosan-assimilating strain, Penicillium sp. KS018 as the enzyme source of exo-β-D-GlcNase followed by the transesterification reaction with the fatty acid methyl ester using lipase. Transesterification by the lipase depended on enzyme origin, and reaction conditions, such as temperature and reaction pressure. Methyl, ethyl and butyl β-D-glucosaminide 6-O-fatty acid monoesters demonstrated excellent surface activity in aqueous solution. The antimicrobial properties of the 6-O-dodecanoyl-glucosaminides were stronger compared to dodecyl β-D-glucoside. The methyl, ethyl and butyl glucosaminide 6-O-fatty acid esters were all readily biodegradable by activated sludge.
In water-polyoxyethylene(n) alkyl(m) ether (CmEOn; C12EO25, C16EO25, C16EO30, C16EO40, C18EO20, C18;1EO50, C22EO30) systems and water-polyoxyethylene(n) cholesterol ether (ChEO30) system, the effect of chemical structures of surfactants and added perfume compounds on the stability of discontinuous cubic (I1) phase were investigated. When the hydrophobic chain length of surfactant is kept constant, the maximum temperature up to which the I1 phase can exist increases with increasing HLB value or the EO-chain length of surfactant. On the other hand, the maximum temperature of I1 phase increases with increasing the molecular size of surfactant at constant HLB value. Upon addition of hydrocarbon-type perfume, d -limonene (LN), the maximum temperature of I1 phase is almost unchanged, whereas it decreases largely upon addition of amphiphilic polar oil, such as α-hexyl cinnamic aldehyde (HCA), β-ionone (IN), benzyl acetate (BA), linalool (LL), geraniol (GL), eugenol (EL), and cis -3-hexenol (HL), and is in order LN>HCA>IN>BA>LL>GL>EL>HL, which is the same as the HLB temperature in the water/C12EO8/perfume systems. In general, the maximum temperature of ChEOn systems is higher than that of CmEOn systems, because even amphiphilic polar perfume compounds do not largely penetrate in the surfactant palisade layer in ChEOn systems. The interaction between cholesterol groups may be very strong, and therefore, may prevent the penetration of oil in the palisade layer.
The fatty acid composition of lipoprotein (a) is known for the cholesteryl ester, triglyceride and the total and major individual phospholipid fractions. Minor phospholipids’ fatty acids are unknown for lipoprotein (a). The minor phospholipids include phosphatidylinositol, phosphatidylserine and lysophosphatidylcholine. This study sought to elucidate the fatty acid composition of the minor individual phospholipids of lipoprotein (a). For validation and comparison, low density lipoprotein was from lipoprotein (a) donors’ blood. Palmitic acid was the major fatty acid in all minor phospholipids except phosphatidylinositol where stearic acid was the largest contributor for Lp(a).
Binding constants (Ka) of calixarene 1,3-alternate conformer 2 bearing two ester groups for alkali picrates have been determined in tetrahydrofuran. It has been established that (i) 2 forms the 1:1 complexes with alkali metal cations, (ii) the M+-2 complexes are not considerably solvent-separated because of the “weak encapsulation effect” for two ester groups of 2, however the Ka values for 2 are generally as large as those for 1 having four ester groups. Interestingly, the largest Ka was attained for K+ and 2 complexes. This is the first comparison for the recognition capacity between two ester groups and four ester groups in calixarene ester complexes.