The capillary gas chromatographic analysis of complex naturally occurring and food-product triglyceride mixtures is accomplished qualitatively and quantitatively on columns coated with methyl and methyl-phenyl (65%) silicones using programmed-temperature split/splitless and on-column injection. Faster analysis times are achieved using elevated initial column oven temperatures with cold initial injector temperatures. 相似文献
Oil-based polyurethanes were synthesized from triglyceride oil-based hydroxyl containing material and toluene diisocyanate or hexamethylene diisocyanate for wound dressing applications. The reactions were carried out with or without catalyst at 90 °C. The amount of free isocyanate during the reaction was determined by a FTIR-ATR method, and the results were compared with those from a back-titration method. The data obtained were used for determination of kinetic parameters. 相似文献
Nanocomposite film comprising of polyaniline (PANI) and single walled carbon nanotubes (SWCNT) has been fabricated onto indium‐tin‐oxide (ITO) coated glass plate using electrophoretic technique. Co‐immobilization of glycerol dehydrogenase (GDH) and lipase (LIP) has been done via N‐ethyl‐N′‐(3‐dimethylaminopropyl) carbodiimide and N‐hydroxysuccinimide chemistry to explore its application for triglyceride (tributyrin) sensing. Response studies have been done using linear sweep voltammetry revealing that LIP‐GDH/PANI‐SWCNT‐TB/ITO bioelectrode can detect tributyrin in the range of 50 to 400 mg dL?1 with low Michaelis–Menten constant of 1.138 mM, improved response time of 12 s, high sensitivity as 4.28×10?4 mA mg?1 dL and storage stability of about 13 weeks. 相似文献
The efficient production of nanoemulsions, with oil droplet sizes of less than 100 nm would facilitate the inclusion of oil soluble bio-active agents into a range of water based foods. Small droplet sizes lead to transparent emulsions so that product appearance is not altered by the addition of an oil phase. In this paper, we demonstrate that it is possible to create remarkably small transparent O/W nanoemulsions with average diameters as low as 40 nm from sunflower oil. This is achieved using ultrasound or high shear homogenization and a surfactant/co-surfactant/oil system that is well optimised. The minimum droplet size of 40 nm, was only obtained when both droplet deformability (surfactant design) and the applied shear (equipment geometry) were optimal. The time required to achieve the minimum droplet size was also clearly affected by the equipment configuration. Results at atmospheric pressure fitted an expected exponential relationship with the total energy density. However, we found that this relationship changes when an overpressure of up to 400 kPa is applied to the sonication vessel, leading to more efficient emulsion production. Oil stability is unaffected by the sonication process. 相似文献
Summary Normal-phase LC (NPLC) is a powerful method for the clean-up of fatty samples in the determination of organochlorine pesticides
(OCPs). The injected sample deactivates the stationary phase and the triglyceride matrix therefore serves as a polarity modifier
in the NPLC separation. Thus, the amount of sample injected is the key to both selectivity and sensitivity in matrixmodified
LC coupled to capillary GC.
In coupled LC-GC the NPLC separation becomes particularly critical because only a limited amount of the LC eluent can be transferred
to the GC and the triglyceride matrix must be prevented from entering the GC, because it degrades the performance of the injector
and the column. In previous applications method development was seriously hampered by these boundary conditions and tedious
and lengthy trial-and-error experiments were required to determine suitable experimental conditions. In this study an empirical
model was developed that describes the NPLC separation process in terms of column dimensions and fat loadability. The output
is given as the probability of achieving successful LC-GC analysis of a particular set of analytes, thus furnishing a useful
tool for the development of new applications in the field of exposure assessment and analysis of residues of apolar compounds
in fatty samples. The limitations of current procedures—maximum transfer volumes and minimal separation—are also discussed. 相似文献
Synthesized saturated phosphatidylcholine (PC) and egg yolk lecithin (EYL) were investigated to explore their influence on particle sizes in emulsions when dispersing various triglycerides (TG). One of four different kinds of synthesized saturated PC (DLPC, DMPC, DPPC and DSPC) or three different kinds of EYL (purified EYL (PEL) and hydrogenated purified EYL with two different iodine values (IV), R-20 and R-5), 2.5% (w/w) glycerol solution and one of four kinds of TG (tricaprylin, tricaprin, trilaurin and trimyristin) were sonicated five times for 1 min with intervals of 0.5 min. When using four kinds of synthesized saturated PCs as emulsifiers, the carbon numbers of each PC had a strong correlation with the mean diameters of the emulsion when analyzed with each of the four kinds of TG used in the study (regression function ranged from 0.811 to 0.915). The carbon numbers of the TG had less correlation with the mean diameters than the PC in simple regression analysis (regression function ranged from 0.236 to 0.875). Multiple regression analysis using the carbon numbers both of the PC and TG as independent variables was remarkably significant in the regression function (2.0 × 10−14) and all regression coefficients (2.7 × 10−13, 5.8 × 10−7 and 1.9 × 10−9 for PC, TG and intercept, respectively). Among the regression coefficients, the contribution of the carbon number of the PC was the most significant. These results indicated that a multiple regression function should be useful to estimate the mean diameters of emulsion droplets in any combinations of PC and TG used in this study.
In the experiments using three kinds of EYL, the mean diameters also tended to increase according to the order of PEL, R-20 and R-5, which corresponds to the order of degrees of saturation (IV = 75, 20 and 2, respectively). The experimental values for EYL were compared with the estimated values calculated by the multiple regression function derived from synthesized PC data using the arithmetic carbon number, based on the components of each EYL. The estimated mean diameters were at comparable levels to the corresponding experimental mean diameters in the most saturated hydrogenated lecithin (R-5), while those were larger than the experimental mean diameters in two less saturated kinds of lecithin (R-20 and purified EYL). These findings gave useful information on the mean diameters of emulsion droplets when designing an emulsion formulation using a particular combination of a phospholipid and triglyceride. 相似文献
Summary Three new methods of improving triglyceride separation by RP-HPLC using propionitrile as eluent and an RI detector are described. First the baseline was stabilized by indirect thermostating of the detector. Relatively high sensitivity adjustments (4×10–5 RI units full scale deflection) were possible allowing small fat samples to be injected (down to 200 g). Second the increase of selectivity with decreasing temperature and the increasing sharpness of peaks at higher temperatures are shown. A high temperature is indispensible for saturated long chain compounds which tend to crystallize on the column. To fulfill this requirement and avoid loss of selectivity temperature programming has been investigated. Third at higher temperatures an additional axial temperature gradient up to 0.05 K/cm was applied to enhance peak symmetry. All chromatograms achieved by those temperature gradients show higher resolution than those obtained at constant temperatures. Butterfat could be separated into more peaks than has previously been possible. The chromatogram of soybean oil, besides showing excellent selectivity for more polar components shows a series of ten long chain compounds following POP. 相似文献